Pennock's Fiero Forum
  Technical Discussion & Questions
  Surprised not many Ecotec 2.0 turbo swaps builds on here (Page 4)

Post New Topic  Post A Reply
Email This Page to Someone! | Printable Version

This topic is 5 pages long:  1   2   3   4   5 
Previous Page | Next Page
next newest topic | next oldest topic
Surprised not many Ecotec 2.0 turbo swaps builds on here by j bf1
Started on: 08-10-2013 11:26 PM
Replies: 185 (9703 views)
Last post by: Will on 08-03-2014 12:09 PM
dobey
Member
Posts: 11572
From:
Registered: Sep 2001


Feedback score: N/A
Leave feedback





Total ratings: 371
User Banned

Report this Post07-22-2014 10:58 AM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by army_greywolf:
I should remind you now, on stock turbo 425 ft lbs wheel torque is about what you get on 22.5 psi, I made that. That's pretty cheap go fast compared to other options, even a built ls4 gets expensive if you want to keep the DoD stuff and h/c/i swap...barring a turbo 3800. Turbo guys already know...it's easier to chew up parts in the trans and break axle shafts because of the torque. You don't think the LNF can break an F23...I'm telling you it'll break it in the first ten passes on a stock tune, especially on a rear wheel drive car...What's the torque rating for even an MILD LS4 at 2500 rpm, the LNF will beat that, drive an SS/TC first before you suggest an F23 will do the job. But then again, if a F23 can live behind a fiero on these boards, then let be what will be. I think it has lived behind LS4s because it's a MUCH smoother power delivery, like I already said, wheel hop and heavy footing has destroyed the vast majority of F35s. The F35 is built better with larger components and appearance suggests its a stronger transmission compared side by side. I believe this to actually be true, If you can get an LSD F23 I have never seen one, so far as I know the F35 and F40 are the only LSD optioned transmissions available on GM cars right now.


Actually, the transmissions, whether F23, F40, or others, tend to hold up to more power in the Fiero, than in the FWD cars. The physics are quite different, so don't assume just because people with tuned Cobalts are breaking transmissions left and right, that the same model of trans is going to explode in a Fiero. None of these GM transaxles are rated for as much torque as they are holding up to on a regular basis, even if the same transmissions in other cars are being blown to bits on a regular basis. I don't think anyone is using the F23 behind an LS4. Most all the LS4 swaps in Fieros are using the 4t65 auto, and only a few are using manual transmissions; a couple with the F40, and one with an NSX trans. And what is "mild" for an LS4, when you're comparing it to an LNF running almost 25 PSI, even if it is on the stock turbo? Unfortunately, the design of the LSx engines means to change the lifters, one must pull the heads off, so even mild upgrades can be a lot of work to do. The LNF is a turbo DOHC 4 cylinder, so changing cams and installing a big turbo are basically simple procedures, so yeah, it might be fairly cheap to make some big changes to it, but the limits of what it can handle and produce are much lower as well. With the LS4, deleting the DoD will allow you to make a lot more power, and simple bolt ons can get you a very broad and flat torque curve, over 400 lbs-ft between 2500-7000 RPM. But again, the cheapest route isn't an LS4 or an Ecotec. A turbo 3800 can be done cheaper and easier, than both.

 
quote
Originally posted by army_greywolf:
Second...maybe you should look at the lq4/lq9 and so forth in the trucks... they have a module for the throttle. I also used the wrong acronym, its a TAC module. The Cobalt doesn't have it, having been built right into the ECU, however...you do lose cruise control without a BCM, me personally, I enjoy cruise control, every vehicle I own has it. And yes to remove a BCM from the harness you lose something else...VATS. You can disable that in the tune but if you are trying to start the car without the actual ignition from the car...it still will not start. I had this problem personally. What I am trying to say here is this. Why would you pay extra money to remove something from a harness that can give you cruise control and other functionality such as using the cobalt column, steering wheel controls, radio...etc from the donor car. Even if you didn't have the donor car, you STILL can get cruise control off the vss and turn off the abs and body control fault codes as well as airbag codes via tune. Without the BCM you will not have cruise control, instruments (unless through the OBD II port).


If you're paying someone else to do it, it doesn't matter what you do with the BCM. No matter what you do, you're going to be paying for it. The BCM still isn't required though, unless you really just want a Cobalt with a Fiero body on top. There are several ways to get around all the various features you've mentioned. If you want to swap in the steering column, steering wheel, stereo, and everything else from the Cobalt, good for you, but it's not required, and not everyone wants it.

 
quote
Originally posted by army_greywolf:
Have a closer look at an LNF, where exactly are you going to put all these instrument sensors at? Tap the block? The aluminum extension behind the pump? There is one test port for oil pressure, but it requires you take part the engine to put the adapter on it...I know this because I installed a oil pressure/temperature sending unit on my Cobalt. The water temperature would require an in hose adapter, the sending unit on the engine is not calibrated for gauge use...it reads 40 degrees too cold and only varies slightly as it warms up, cold is 120, hot is 160 so go figure although this does not apply to all years LNFs. I wouldn't use fiero gauges on a high tech, high energy density engine like the LNF anyways...aftermarket would be the way to go. OBDII scan gauges like aeroforce interceptors, or the scangauge II cost money, one is 249.99 each last I checked the other is 179.99, youd need two aeroforce gauges for sure to get the necessary information from the engine.


I don't know where I'd mount the two sensors needed for running the Fiero gauges exactly, but I'd certainly find a place to put them, if I were doing an LNF swap and wanted to run the Fiero gauges. It's really not that hard a problem. CTS could go near the thermostat somewhere, and oil pressure I don't know where I'd put exactly. I don't know where the stock sensor is, and what obstructions would be an issue on that engine. But as an engineer, I can tell you I'd find a way to do it. As for tach and speed/odometer, they can almost certainly be driven off an ECM output, so don't need extra sensors in the trans or engine. The speedo should just need the Dakota Digital box to convert the PPM signal to what the Fiero gauge needs, and tach might need a simple circuit to fit the expected resistance.

Personally, I won't be using the stock Fiero gauges with my LS4 swap either. I'll be using the G8 GXP gauge cluster with the DIC display between the speedo/tach. I haven't made a final decision how I will go about making those gauges work exactly yet though.

 
quote
Originally posted by army_greywolf:
I guess I would do the prudent thing...spending extra money after ebay shopping an engine and trans seems more and more like you could simply buy the donor car and take everything. When all is said and done a tune, done remotely or in person is going to cost 400 or so bucks or you can buy HPTuners, do the tune yourself and have Trifecta send you a modified hpt file that deletes everything you don't actually have on the car anymore. The real reason I plan the swap is simple, it's a weight shedder, the engine is way ahead of it's time, nearly bullet proof since most of the porous blocks have been swapped at dealers by now...and unlike making more and more NA power, you have a massive power band that starts way low and carries to the top.


Good for you. I'm building a 4.8 LS4 with VVT and increased compression, because I want a V8 that gets good fuel economy, can make a nice broad torque curve, and can rev to 8000 RPM if I want it to. My plan is to build my own tuning software and not spend the $$$ for HPTuners or whatever, unless I can't figure out the Class 2/CAN bits necessary to do the tuning myself in the time it takes me to get the mechanical work done.

 
quote
Originally posted by army_greywolf:
Lastly semantics being what they are, yes it is controller area network..slang car area network...either for the purpose works. I don't want to start a war I want to clarify that there's more than meets the eye with an LNF. Most people think, ohh it's a turbo 4 it can't make v8 torque, it's all top end power, and that can't be more false. Your talking about 130 hp per liter guys-stock. A tuned wheel horsepower to to around 365hp...stock that equates to 200 engine hp per liter, if the zr1 made that kind of power your talking 1240 hp...theres alot to be done on an LS motor to make that kind of power. Even the LS4 has to push 690 engine hp to meet up with a stock LNF. I would expect to spend approx. $5500 on the swap, that includes the entire donor car probably with at least some go fast goodies already on it, materials, water air intercooler, exhaust work, tune, etc. You can save a negligible amount by custom harness, no bcm, no cradle, highly likely you wont get the timing cover side engine mount with the engine since its easier to simply unbolt the couple allen head bolts than it is to take the mount off the car...need to think about that when you dont get a donor car, it will be missing things you need.


There's more than meets the eye with any engine. But if you want to argue about numbers, displacement will always win. A stock LNF isn't making 200 HP/liter. You can blow your warranty and tune it to get close, but that isn't a stock LNF any longer. Cartuning sells a bolt-on turbo kit for the LS4 cars that puts it over 500 WHP. Hot Rod Magazine through a couple turbos on a stock 4.8 truck engine with intake, headers, and port/polished heads, and made 1200 HP. Yes, boost can make power, but same boost on a bigger engine will make more power. I'd hardly call that "a lot to be done" for an LS motor to make big power. Please don't try to turn this into a V8 vs 4 banger thread.

IP: Logged
army_greywolf
Member
Posts: 27
From: Madison, WI
Registered: Jul 2014


Feedback score: N/A
Leave feedback

Rate this member

Report this Post07-22-2014 03:46 PM Click Here to See the Profile for army_greywolfClick Here to Email army_greywolfSend a Private Message to army_greywolfEdit/Delete MessageReply w/QuoteDirect Link to This Post
I think you are trying to do just that. The bigger engines won't get the mileage the LNF will, which carries 30mpg+ no matter what you do to it. After sleeves, pistons, rings and rods my mileage went UP, retuning it...it went UP again. That translates to a car which will be 100 lbs lighter than stock with an LNF over a v6, at least, and fully 450 lbs lighter than the cobalt...the mileage will be higher, performance will be better...having max torque across 85% of the curve is a good thing. Sure it's an expensive swap but then...so's an LS4. And like I already stated...we already know the cheapest serious power is a turbo 3800 S2 L67. But that's weight for power, and I image the biggest reason for this swap is for track day cars, it reduces the weight bias significantly.

If it was easy to crack the E69 ecm more people would have done it besides Vince at trifecta and a handful of other specialty shops and tuning companies don't you think? Seeing as they are installed in better than 2 million cars now? I've tried hex editors, tried using rewritten OS...Vince will tell you the same thing, unless you've developed the OS for the ECM to begin with the learning curve is nearly insurmountable. Heck, let's call it like it is...if you can write your own editor efilive is offering a bounty on the LMM duramax ECM which is also the US cruze diesel ECM for anyone who can unlock a significant amount of tables. A hundred grand at least. I'm dead serious on that, if you have the know how...that's a damn HOUSE worth of money. I do not, therefore I stick to tuning. There was a GM engineer on the cobalt forums around 2009-2010 who had a vested interest in the porous block issue, he was contacting those of us with continued coolant loss directly. What he did tell us was that the E69 ECM is a torque managed ECM with more than 2800 tables. I can believe that...about 280 are unlocked now and none allow injector offset, injector calibrations...pre/main events much like the diesels...or VVT for that matter, just a cold/warm table for exhaust and intake cams. No decel... none of the fault tables for maf or o2 sensor failure...which would be nice for those who are running a 2.1 block or cams. So you see...it's just not "easy". If you work for Bosch then I'll just stick my foot in my mouth now and be done with it, after I beg you to help me find the injector flow rate tables so I can send a set of injectors out to industrial injection for extrude honing to run good ol E85 the right way.

The transmissions like I already stated break because of wheel hop and abuse. Fiero owners seem less likely to abuse and wheel hop is non existent right? I still stand by not using the F23 in either a LSJ or LNF combo, certainly cannot use the stock clutch for either. And yes I know, not everyone wants a cobalt with a fiero body but the FE5 suspension is a SERIOUS upgrade over stock or even modifed with konis and coil overs. That's very large vented rotors front and rear, brembos, a better master cylinder and the list continues to grow with much stronger hubs, stronger axle shafts, better sway bars, pretty much better everything from word go. Not only that but the front strut/spring combo is about the perfect rate for the rear of a fiero with an ecotec installed. To each their own, I intend to use as much of the car as I can, seats and dash included. My car has little to no rust, having been limited to surface rust and I feel I can daily it for the rest of it's days, with all likelyhood the LNF will outlive the car. I also know gas has doubled in price in ten years therefor I see no reason to think it ten more years it wont trend much further up...why would I go big now when it looks to be 7 to 8 dollar a gallon gas in the future. No thank you I'm smart enough to know when I've been beat, and I don't need that eventual wallet drain even if a bigger engine still get's 25+ that's incomparable to 35-40 or more from an LNF doing light duty work in an even lighter Fiero. Yea...your thinking, but that's a ways away from now, who cares? I do, and it's my car. When I get started I will create a build thread, in the meantime, any questions I can answer I will, or give the best unbiased opinion I can.

Also how do you plan to run hydraulic lifters to 8 grand? There's a flaw in that. Even if you do a valvetrain upgrade and go roller solids...then what? That's even MORE money which is yours to spend...but why? You'd lose any economy benefit you might have had to begin with.

------------------
1986 SE w/3.1 MPFI FWD and 4T60, 7730 ECM with flash prom, 1.6 rockers. Almost finished with the swap...LNF swap in the future, chassis stiffening and suspension updates first.

[This message has been edited by army_greywolf (edited 07-22-2014).]

IP: Logged
dobey
Member
Posts: 11572
From:
Registered: Sep 2001


Feedback score: N/A
Leave feedback





Total ratings: 371
User Banned

Report this Post07-22-2014 05:17 PM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by army_greywolf:
I think you are trying to do just that. The bigger engines won't get the mileage the LNF will, which carries 30mpg+ no matter what you do to it. After sleeves, pistons, rings and rods my mileage went UP, retuning it...it went UP again. That translates to a car which will be 100 lbs lighter than stock with an LNF over a v6, at least, and fully 450 lbs lighter than the cobalt...the mileage will be higher, performance will be better...having max torque across 85% of the curve is a good thing. Sure it's an expensive swap but then...so's an LS4. And like I already stated...we already know the cheapest serious power is a turbo 3800 S2 L67. But that's weight for power, and I image the biggest reason for this swap is for track day cars, it reduces the weight bias significantly.


Yeah, the weight difference isn't as much as you think it is. The stock Fiero 2.8 weighs about 350 lbs. The LNF with turbo weighs about 350 lbs. The 3800 weighs about 350 lbs. The LS V8s weigh about 450 lbs. Moving the battery will give you more of a weight bias change than swapping in a turbo Ecotec would.

 
quote
Originally posted by army_greywolf:
If it was easy to crack the E69 ecm more people would have done it besides Vince at trifecta and a handful of other specialty shops and tuning companies don't you think? Seeing as they are installed in better than 2 million cars now? I've tried hex editors, tried using rewritten OS...Vince will tell you the same thing, unless you've developed the OS for the ECM to begin with the learning curve is nearly insurmountable. Heck, let's call it like it is...if you can write your own editor efilive is offering a bounty on the LMM duramax ECM which is also the US cruze diesel ECM for anyone who can unlock a significant amount of tables. A hundred grand at least. I'm dead serious on that, if you have the know how...that's a damn HOUSE worth of money. I do not, therefore I stick to tuning. There was a GM engineer on the cobalt forums around 2009-2010 who had a vested interest in the porous block issue, he was contacting those of us with continued coolant loss directly. What he did tell us was that the E69 ECM is a torque managed ECM with more than 2800 tables. I can believe that...about 280 are unlocked now and none allow injector offset, injector calibrations...pre/main events much like the diesels...or VVT for that matter, just a cold/warm table for exhaust and intake cams. No decel... none of the fault tables for maf or o2 sensor failure...which would be nice for those who are running a 2.1 block or cams. So you see...it's just not "easy". If you work for Bosch then I'll just stick my foot in my mouth now and be done with it, after I beg you to help me find the injector flow rate tables so I can send a set of injectors out to industrial injection for extrude honing to run good ol E85 the right way.


I never said it was "easy." I said my plan was to write my own editor. I don't much care about unlocking the Ecotec ECUs at the moment. If I can write an editor and get it working well enough by the time I finish the mechanical build of my swap, to use it to tune my LS4, then I'll be happy with it. If it works well enough, I might even package it up, sell it, and add support for more systems. But I'm not going to waste a bunch of time and money to try and unlock programming for other ECUs, when I only have a vested interest in the swap I'm doing for myself; and I'm not letting my swap hinge on whether or not I do get an editor written.

 
quote
Originally posted by army_greywolf:
I also know gas has doubled in price in ten years therefor I see no reason to think it ten more years it wont trend much further up...why would I go big now when it looks to be 7 to 8 dollar a gallon gas in the future. No thank you I'm smart enough to know when I've been beat, and I don't need that eventual wallet drain even if a bigger engine still get's 25+ that's incomparable to 35-40 or more from an LNF doing light duty work in an even lighter Fiero.


If you say so. I'm pretty sure the Cobalt SS has a lower CD than the Fiero, so you will probably get roughly the same, or slightly less, highway MPG, and probably slightly more city MPG, with an LNF in a Fiero. What are you getting for city only MPG in an LNF Cobalt? It's definitely not 40. I'll definitely be getting over 30 MPG highway with my LS4 though.

 
quote
Originally posted by army_greywolf:
Also how do you plan to run hydraulic lifters to 8 grand? There's a flaw in that. Even if you do a valvetrain upgrade and go roller solids...then what? That's even MORE money which is yours to spend...but why? You'd lose any economy benefit you might have had to begin with.


http://www.lingenfelter.com...de=C158#.U87SsP614c0
That's how one runs the hydraulic rollers to 8000, along with a valve train that can do it. Why would I want to build an LSx V8 that can do that? Because I can, and it will sound incredible.

Please tell me how running an Ecotec to 8000 RPM with 30 PSI boost is any more economical than running a V8 to 8000 RPM. In either case you're burning a massive amount of fuel. At 30 PSI, you're burning roughly the same amount of fuel as an engine that is twice the displacement. Boost needs fuel too.
IP: Logged
army_greywolf
Member
Posts: 27
From: Madison, WI
Registered: Jul 2014


Feedback score: N/A
Leave feedback

Rate this member

Report this Post07-22-2014 10:08 PM Click Here to See the Profile for army_greywolfClick Here to Email army_greywolfSend a Private Message to army_greywolfEdit/Delete MessageReply w/QuoteDirect Link to This Post
Not suggesting it doesn't but 4 cylinders pounding away the same power will do so with less parasitic loss. The LNF doesn't go to 8 grand stock, in fact power peaks out around 5800 and starts tapering down by 6300, limitations of the stock turbo. The Drag c/e is probably less car for car on the fiero than it is in the Cobalt, mostly because the cobalt has a rather gigantic grill, several areas of turbulance such as the hood corners and mirrors then the trunk doesn't do the car any justice. It looks like it could be efficient but it's not. My car still got 25 mpg city reasonable driving, even a little hot rodding but not much. I've seen 37 mpg doing 80. Also you seem to have it mixed up, the idea is to stay within the highest efficiency area of the turbo charger and then upgrade when you start to go outside that window. I would never run 30 psi on a stock turbo and the upgraded turbo takes off 5-6 psi for the same power. The only difference is increased turbo lag which is still negligible.

I checked the link, what else has to be done to run those in an LS4 block, don't you have to delete DoD first? Does it affect VVT because I did some research (ten minutes worth admittedly) and I foresee VVT problems, namely leaking actuator from added drivetrain stress. Now take that with a grain of salt, correct components can handle the stress no problem and I'm sure someone has figured it out by now.

And why are we going back and forth, your going LS4 I'm going LNF, this is for those interested in an LNF.

I do however want to give you a bit of advice: If you want 8,000 RPM out of that engine you need to do a few things first> DoD delete, lifters with ceramic balls, girdled valvetrain, or paired mounts, either works. All aluminum roller tip rockers, probably a much lighter set of valves, beehived springs, titanium retainers...what your essentially looking at is an engine set up for full race. You would want an ATI superdamper harmonic balancer, take out the crank, rods, pistons and rings to have them all balanced because they will find their nearest exit if you make regular 8k appearances.

Now, 8k means pretty much nothing without the cam, heads and intake to support it which also makes your 4500 or so rpm window of drivability is tossed right there, the thing will be a bear to live with if you do weekend cruises or meets, it'll look and sound cool but that's about where that ends, and by that I mean the money you will have spent could as you say been replaced for more displacement aka an ls7. An aggressive cam that will run that high without choking the engine is going to be of little use actually driving it, if you just want to say it revs to 8 then all is well, but you wont make any power after six grand on an otherwise stock cam and head ls4.

Alternatives: For that kind of money you could TURBO an LS4...build and cryo treat the transmission then move on to things like driving the heck out of it. You may actually spend more money on a high rpm n/a motor than simply turbocharging the stock engine and building up the transmission this also increases efficiency. That's the difference between v twin motorcycles at the same horsepower as inline fours...the twins have two less cylinders and spin slower so they naturally always get better fuel mileage. As an example of course.

[This message has been edited by army_greywolf (edited 07-22-2014).]

IP: Logged
Sigler85GT
Member
Posts: 209
From: Elkhart, IN
Registered: Aug 2010


Feedback score: N/A
Leave feedback

Rate this member

Report this Post07-22-2014 10:30 PM Click Here to See the Profile for Sigler85GTClick Here to Email Sigler85GTSend a Private Message to Sigler85GTEdit/Delete MessageReply w/QuoteDirect Link to This Post
So you're saying i I put a v twin into my Fiero I will get better fuel mileage?
or does the weight of a car vs a motorcycle come into affect at some point
IP: Logged
dobey
Member
Posts: 11572
From:
Registered: Sep 2001


Feedback score: N/A
Leave feedback





Total ratings: 371
User Banned

Report this Post07-22-2014 10:44 PM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by army_greywolf:
Not suggesting it doesn't but 4 cylinders pounding away the same power will do so with less parasitic loss. The LNF doesn't go to 8 grand stock, in fact power peaks out around 5800 and starts tapering down by 6300, limitations of the stock turbo. The Drag c/e is probably less car for car on the fiero than it is in the Cobalt, mostly because the cobalt has a rather gigantic grill, several areas of turbulance such as the hood corners and mirrors then the trunk doesn't do the car any justice. It looks like it could be efficient but it's not. My car still got 25 mpg city reasonable driving, even a little hot rodding but not much. I've seen 37 mpg doing 80. Also you seem to have it mixed up, the idea is to stay within the highest efficiency area of the turbo charger and then upgrade when you start to go outside that window. I would never run 30 psi on a stock turbo and the upgraded turbo takes off 5-6 psi for the same power. The only difference is increased turbo lag which is still negligible.


Don't be confused because you think the Cobalt grille is large. The frontal area is still a little smaller than the Fiero. Cobalt SS CD is about 0.30, and Fiero GT is about 0.36. That 0.06 difference might seem small, but it does make a pretty big difference at highway speeds.

 
quote
Originally posted by army_greywolf:
I checked the link, what else has to be done to run those in an LS4 block, don't you have to delete DoD first? Does it affect VVT because I did some research (ten minutes worth admittedly) and I foresee VVT problems, namely leaking actuator from added drivetrain stress. Now take that with a grain of salt, correct components can handle the stress no problem and I'm sure someone has figured it out by now.


Yes, the race lifters do not do DoD, so that will no longer function. VVT shouldn't be a problem. The LS4 didn't come with VVT anyway, so it's a retrofit, but the LSx VVT is basically all handled at the cam sprocket at the timing cover. Running the race lifters won't have any effect on how well VVT works.

 
quote
Originally posted by army_greywolf:
And why are we going back and forth, your going LS4 I'm going LNF, this is for those interested in an LNF.


You keep comparing the LNF to the LS4. I'm actually building an LS4, so I'm merely pointing out where you're wrong, and that your comparison to the LS4 isn't helping this thread. We all know the reason why not many LNF swaps have been done, is because it's not an easy swap to do, and that there are cheaper and easier options that get you the same MPG, with the same weight advantages, and that make more power.

 
quote
Originally posted by army_greywolf:
I do however want to give you a bit of advice: If you want 8,000 RPM out of that engine you need to do a few things first> DoD delete, lifters with ceramic balls, girdled valvetrain, or paired mounts, either works. All aluminum roller tip rockers, probably a much lighter set of valves, beehived springs, titanium retainers...what your essentially looking at is an engine set up for full race. You would want an ATI superdamper harmonic balancer, take out the crank, rods, pistons and rings to have them all balanced because they will find their nearest exit if you make regular 8k appearances.


I know what to do for the build already. All of those things you mention aren't necessary.

 
quote
Originally posted by army_greywolf:
Now, 8k means pretty much nothing without the cam, heads and intake to support it which also makes your 4500 or so rpm window of drivability is tossed right there, the thing will be a bear to live with if you do weekend cruises or meets, it'll look and sound cool but that's about where that ends, and by that I mean the money you will have spent could as you say been replaced for more displacement aka an ls7. An aggressive cam that will run that high without choking the engine is going to be of little use actually driving it, if you just want to say it revs to 8 then all is well, but you wont make any power after six grand on an otherwise stock cam and head ls4.


I'm guessing you know little to nothing about the LS4, or the LS engines in general. Here's a dyno for an LS4, with a cam, LS7 exhaust manifolds, and LS2 intake:



It's hardly dropping off after 6000. And that's with the DoD hardware still installed on that engine. The cam is ground to work in a DoD engine. When he deletes the DoD, gets real lifters, and a cam not limited by the DoD, it'll be making more power and possibly in a broader range. There's absolutely nothing unbearable about that in terms of driveability. And I'm sorry, but you're not going to do an LS7 swap in a Fiero for anywhere near as cheap as an LS4. An LS7 swap is going to cost well over $10K.

 
quote
Originally posted by army_greywolf:
Alternatives: For that kind of money you could TURBO an LS4...build and cryo treat the transmission then move on to things like driving the heck out of it. You may actually spend more money on a high rpm n/a motor than simply turbocharging the stock engine and building up the transmission this also increases efficiency. That's the difference between v twin motorcycles at the same horsepower as inline fours...the twins have two less cylinders and spin slower so they naturally always get better fuel mileage. As an example of course.


I don't know what kind of money you're talking about, but the Cartuning turbo kit for the LS4 is $5500. LSD for the F40 is about $1000. Cryo for the F40 is about $1000 plus taking it apart, shipping all the pieces off to be treated, shipping them back, and putting it all back together. I highly doubt I'm going to spend that much on my build. I've got a very, very long way to go before I've spent that much.
IP: Logged
dobey
Member
Posts: 11572
From:
Registered: Sep 2001


Feedback score: N/A
Leave feedback





Total ratings: 371
User Banned

Report this Post07-22-2014 10:47 PM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post

dobey

11572 posts
Member since Sep 2001
 
quote
Originally posted by Sigler85GT:

So you're saying i I put a v twin into my Fiero I will get better fuel mileage?
or does the weight of a car vs a motorcycle come into affect at some point


Why bother with two cylinders when you can have just one? Just throw a Sachs single cylinder engine in there, and bolt a turbo that's 3x as large as the engine, onto it.
IP: Logged
army_greywolf
Member
Posts: 27
From: Madison, WI
Registered: Jul 2014


Feedback score: N/A
Leave feedback

Rate this member

Report this Post07-22-2014 11:27 PM Click Here to See the Profile for army_greywolfClick Here to Email army_greywolfSend a Private Message to army_greywolfEdit/Delete MessageReply w/QuoteDirect Link to This Post
Your playing to a comparison between types of motorcycle engines, comparison is between number of cylinders and efficiency, turbocharged or not. Factor in the obvious here, there is more metal to metal contact in a v8 than a 4 cylinder, or a 6, and the faster you spin it the less efficient it becomes even if it makes more power. Buying a kit for a turbo isn't really necessary, for around 2500 you can have a running 12 psi turbo LS4. Let's say you ignore transmission upgrades.

Where did you get your c/e measurements? Cobalt SS/TC Low Rise Stock Height 18" Wheels .324 High Rise Spoiler .329/ Pontiac Fiero 1986 Notchback, aero clip 14 inch wheels and the stock decklid spoiler .358.(Base .377) So a 1.5 inch lower, 18" wheels, proper tires and we're there. No problem. Still none of this applies for the purpose, I plan to at least belly pan what I can keep out of the air except for what needs alot of it.

Second, that's not a stock dyno graph so what exactly is that showing me? Oh wait that the power band is about 4500 rpms WIDE. Come on man, pay attention. Not only that but where is the torque, like I said before once the cam is swapped for something to take advantage of power at eight grand you lose torque in all the areas most cars are daily driven in. Now, it'll be a hell of a meets, shows and drag racing car, no doubt about it, but it won't be the greatest at daily driving.

Lastly, my knowledge is a mix of trial and error, personal ownership and talking to people who own, maintain, design and keep the cars with some of these engines. I am not sure how this became a diatribe about your 8k rpm LS4, it's not an LNF, it's not an ecotec and that's pretty much where this derailed conversation stops. If you want to continue you can email all you want.

[This message has been edited by army_greywolf (edited 07-22-2014).]

IP: Logged
dobey
Member
Posts: 11572
From:
Registered: Sep 2001


Feedback score: N/A
Leave feedback





Total ratings: 371
User Banned

Report this Post07-23-2014 09:08 AM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by army_greywolf:
Your playing to a comparison between types of motorcycle engines, comparison is between number of cylinders and efficiency, turbocharged or not. Factor in the obvious here, there is more metal to metal contact in a v8 than a 4 cylinder, or a 6, and the faster you spin it the less efficient it becomes even if it makes more power.


You're the one playing to that comparison, and the one who made it in the first place. Number of cylinders is only very loosely related to efficiency. Just because a V-twin spins slower, does not mean it is more efficient than a 4 cylinder. In fact, it has to spin slower for a few reasons. Just because there's more metal in an engine with more cylinders, doesn't mean it's going to be less efficient due to that. Frictional losses are mostly irrelevant, because more cylinders generally means you're making more power to overcome those losses, so they become very negligible. The lower fuel economy is more generally a result of more air means more fuel. Turbos have this same problem. More boost means more fuel required. If you're pushing 14.7 PSI at sea level, that means twice as much fuel will be needed as having no boost would require. I'm not sure what measurement of efficiency you're using, but average fuel economy doesn't tell you the whole story, especially in a boosted engine.

 
quote
Originally posted by army_greywolf:
Where did you get your c/e measurements? Cobalt SS/TC Low Rise Stock Height 18" Wheels .324 High Rise Spoiler .329/ Pontiac Fiero 1986 Notchback, aero clip 14 inch wheels and the stock decklid spoiler .358.(Base .377) So a 1.5 inch lower, 18" wheels, proper tires and we're there. No problem. Still none of this applies for the purpose, I plan to at least belly pan what I can keep out of the air except for what needs alot of it.


Where did you get those numbers? 18" wheels and tires aren't going to lower the CD. And 1.5" drop isn't going to lower the CD by 0.06. The 0.36 for the Fiero has been quoted on this forum many times, as documented by GM. The Cobalt number I've found quoted 0.30-0.32 by searching, depending on whether it's high or low spoiler. The 0.36 is for the fastback aero cars with wing. The notchback is more like 0.38-0.40 depending on aero nose and spoiler. If you really want to lower the CD, you'd need to start with a fastback car, maybe do a choptop, and convert it to a hatchback.

 
quote
Originally posted by army_greywolf:
Second, that's not a stock dyno graph so what exactly is that showing me? Oh wait that the power band is about 4500 rpms WIDE. Come on man, pay attention. Not only that but where is the torque, like I said before once the cam is swapped for something to take advantage of power at eight grand you lose torque in all the areas most cars are daily driven in. Now, it'll be a hell of a meets, shows and drag racing car, no doubt about it, but it won't be the greatest at daily driving.


I didn't say it was a stock dyno graph. I said exactly what it is showing. Do you not know how to read a dyno graph? It's making over 300 ft-lbs at the crank, at least between 2000-7000 RPM. That's 5000 wide, not 4500. It's a broad and relatively flat torque curve. And that engine and the cam in it, are currently very limited by what the DoD system can handle. Go read my post again. And second, building an engine that can run to 8000 RPM does not mean you can't make torque down low either, especially when VVT comes into play; and especially in an engine displacing 5 liters of air with > 10:1 compression ratio. Being able to rev that high sure isn't keeping the LS7 from making plenty of torque and being a daily driver. I don't know why you keep saying anything else can't also. My Honda does just fine going to 8500 too, though it's a tiny little 1.6 so isn't making anywhere near the amount of torque a 4.8 will, until I turbo it.

 
quote
Originally posted by army_greywolf:
Lastly, my knowledge is a mix of trial and error, personal ownership and talking to people who own, maintain, design and keep the cars with some of these engines. I am not sure how this became a diatribe about your 8k rpm LS4, it's not an LNF, it's not an ecotec and that's pretty much where this derailed conversation stops. If you want to continue you can email all you want.


Because you keep talking about LS4s and how they can't do all this magical stuff that an LNF supposedly can. All I mentioned was that I was building an LS4, not an Ecotec, and you started making a bunch of assumptions about my build, how it's not an Ecotec, and started trying to tell me how I should do my build. And you keep going on and on. If you want to talk about the LNF then talk about the LNF and not about what you think other engines can't do.

[This message has been edited by dobey (edited 07-23-2014).]

IP: Logged
zkhennings
Member
Posts: 1491
From: Massachusetts, USA
Registered: Oct 2010


Feedback score: (3)
Leave feedback

Rate this member

Report this Post07-23-2014 12:01 PM Click Here to See the Profile for zkhenningsSend a Private Message to zkhenningsEdit/Delete MessageReply w/QuoteDirect Link to This Post
But Turbo 4cyl is more efficient than a larger 8cyl (in general at same horsepower)

Turbo uses wasted horsepower from the pistons pushing out the exhaust to pull as much air into a 4cyl as would be used in he larger 8cyl. Because the compression is bumped up with the turbo, there is a more efficient burn of the gasoline.

Therefore in general there are mpg benefits at the same hp for a V8 and a much smaller 4cyl Turbo.
IP: Logged
BillS
Member
Posts: 604
From:
Registered: Apr 2000


Feedback score: N/A
Leave feedback

Rate this member

Report this Post07-23-2014 12:10 PM Click Here to See the Profile for BillSClick Here to Email BillSSend a Private Message to BillSEdit/Delete MessageReply w/QuoteDirect Link to This Post
Not to interrupt the bickering over V8 vs. I4, but I have always thought it a bit of a shame that GM never utilized the architecture of the Ecotec engines to create a V8, along the lines of the late and largely unlamented Northstar. Twin DOHC heads makes for a fairly wide engine, but the Fiero might be able to accommodate it.

Slapping a couple of LNF heads onto a V crankcase would net you around 6-800 bhp and you'd still get excellent mileage, something the NA V8 engines are not capable of doing. The crazy Cobalt guys are getting close on 500 bhp at the wheels on modded LNFs running race gas (the fuel system is insufficient to supply enough gas for that demand so they have to add extra injectors etc. - no larger capacity DI Injectors are available yet), but more realistically you can get 400 reliable BHP all day long without going inside the engines.

Not everyone is as crazy as this guy (570 BHP in a Cobalt) http://www.youtube.com/watch?v=erqFMigGLPk
IP: Logged
PFF
System Bot
dobey
Member
Posts: 11572
From:
Registered: Sep 2001


Feedback score: N/A
Leave feedback





Total ratings: 371
User Banned

Report this Post07-23-2014 12:19 PM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by zkhennings:
But Turbo 4cyl is more efficient than a larger 8cyl (in general at same horsepower)

Turbo uses wasted horsepower from the pistons pushing out the exhaust to pull as much air into a 4cyl as would be used in he larger 8cyl. Because the compression is bumped up with the turbo, there is a more efficient burn of the gasoline.


The fuel is not compressed by the turbo. Only air is. The only more efficient burn in an LNF over other engines, is due to the direct injection. With the SIDI, the fuel can be injected at a much better time, can be controlled better, and is injected at a much higher pressure than normal EFI systems. The stock compression ratio of the LNF is very conservative though, so it's also not as efficient as it could be.

Turbos also don't use wasted horsepower. There's no such thing as wasted horsepower. Having a turbo doesn't make the exhaust gas exit the engine more efficiently. Rather, it makes the exhaust gas exit the engine less efficiently, as it requires pressure building up between the cylinders and the turbo. The build-up of pressure in the manifold means the pistons have to work harder to expel the gases out of the engine, generally (as most turbo installs do not use perfectly designed manifolds and turbos). the turbo compressing the intake air, does help make up for the extra work the engine has to do, but it's not only a power increase that a turbo results in. A perfect system would be a lot more tuning than most people are willing to do. Just like any other engine modification, on any engine, regardless of cylinders, it is a balancing act.
IP: Logged
dobey
Member
Posts: 11572
From:
Registered: Sep 2001


Feedback score: N/A
Leave feedback





Total ratings: 371
User Banned

Report this Post07-23-2014 12:27 PM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by BillS:
Not to interrupt the bickering over V8 vs. I4, but I have always thought it a bit of a shame that GM never utilized the architecture of the Ecotec engines to create a V8, along the lines of the late and largely unlamented Northstar. Twin DOHC heads makes for a fairly wide engine, but the Fiero might be able to accommodate it.

Slapping a couple of LNF heads onto a V crankcase would net you around 6-800 bhp and you'd still get excellent mileage, something the NA V8 engines are not capable of doing. The crazy Cobalt guys are getting close on 500 bhp at the wheels on modded LNFs running race gas (the fuel system is insufficient to supply enough gas for that demand so they have to add extra injectors etc. - no larger capacity DI Injectors are available yet), but more realistically you can get 400 reliable BHP all day long without going inside the engines.


While it's not a DOHC engine, the new Gen V small block incorporates much of the technology from the Ecotec 4 cylinder, and High Feature V6 families. Ecotec also means a lot of different things around the world. It's just a brand name, and it's been used on several different engine families around the world, including the 3800.

As for larger injectors, the injectors off the Gen V LT1/LT4/Ecotec3 V8s might be usable. I don't know if they fit the 4 cylinder or V6 heads though. The HF V6 engines are also a really good choice if you want a "best of both worlds" type of engine, between the Ecotec I4 and the SBC. The LFX makes 325 HP already, and the new twin turbo engine in the ATS/CTS makes 420 HP. SIDI, VVT, DOHC V6, but it's not a cheap or terribly easy swap either, which is why there are so few of them.
IP: Logged
cvxjet
Member
Posts: 2347
From: ca, usa
Registered: May 2010


Feedback score: (1)
Leave feedback

Rate this member

Report this Post07-23-2014 06:36 PM Click Here to See the Profile for cvxjetClick Here to Email cvxjetSend a Private Message to cvxjetEdit/Delete MessageReply w/QuoteDirect Link to This Post
Ummmm....Yeah...No turbo lag; I remember when the second gen turbo porsche 911 came out and the road testers raved about "No turbo lag"!!!!!!....A few months later they were comparing a 911 turbo(2nd gen) to some other normally aspirated car, and there were "Bucket loads of lag".....There ain't any way to eliminate lag completely, short of an electric motor or a Nitrous system.

As for getting 35 mpg in your Solstice while the Vette gets "18/25".......My 99 Formula LS1 was rated at 17/24....I actually got 20/31. And your engine is stock too, right?

As for weight of the 2.8 vs LS ALL aluminum V8s, you need to compare engines that are ready to run- Starters and altenators or no, but you MUST include exhaust and intake manifolds- The L44 intake (all 3 pieces) weighs 27 lbs while the LS intakes weigh 9 lbs. There is no way that the LS V8 weighs 475 when an all iron 302 ford weighs 460....all tho a much stronger design(6 bolt mains etc) there is a huge difference in weight between aluminum vs iron blocks/heads. Don't weigh one with brackets/ancillaries and the other without.
IP: Logged
dobey
Member
Posts: 11572
From:
Registered: Sep 2001


Feedback score: N/A
Leave feedback





Total ratings: 371
User Banned

Report this Post07-23-2014 09:51 PM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by cvxjet:
As for weight of the 2.8 vs LS ALL aluminum V8s, you need to compare engines that are ready to run- Starters and altenators or no, but you MUST include exhaust and intake manifolds- The L44 intake (all 3 pieces) weighs 27 lbs while the LS intakes weigh 9 lbs. There is no way that the LS V8 weighs 475 when an all iron 302 ford weighs 460....all tho a much stronger design(6 bolt mains etc) there is a huge difference in weight between aluminum vs iron blocks/heads. Don't weigh one with brackets/ancillaries and the other without.


There is stll a LOT of steel in the all aluminum LS V8s. There's also a LOT of aluminum in there. There's a weight savings, but it's not as big as some people like to claim. I can tell you the shipping weight of my LS4 was around 525 lbs. That was without alternator, ac, wire harness, and a little bit of oil and coolant still left in it, and had the water pump and a few brackets, and the exhaust manifolds (don't recall if the crossover pipe was there or not). Those manifolds are ridiculously heavy though, being cast iron. The alternator bracket is also cast iron. The assembled heads are still like 50 lbs each. They are massive compared to the heads on the 2.8. The crank is also quite heavy. The 2.8 crank is much smaller of course. Smaller pistons, smaller rods, and smaller crank makes quite a difference. The oil pan is pretty hefty too. It's a thick cast aluminum piece that also provides better structural rigidity to the block. It's not like the thin steel pans of the old SBCs or the 2.8. It's a beefy pan with internal baffling and such.

The aluminum LSx engines are 100+ lbs lighter than the old iron SBC for sure, but the 2.8 is pretty heavy, and a much smaller engine than an LSx. So the LSx still weighs more, even if it is aluminum block and heads.

[This message has been edited by dobey (edited 07-23-2014).]

IP: Logged
zkhennings
Member
Posts: 1491
From: Massachusetts, USA
Registered: Oct 2010


Feedback score: (3)
Leave feedback

Rate this member

Report this Post07-23-2014 10:16 PM Click Here to See the Profile for zkhenningsSend a Private Message to zkhenningsEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by dobey:


The fuel is not compressed by the turbo. Only air is. The only more efficient burn in an LNF over other engines, is due to the direct injection. With the SIDI, the fuel can be injected at a much better time, can be controlled better, and is injected at a much higher pressure than normal EFI systems. The stock compression ratio of the LNF is very conservative though, so it's also not as efficient as it could be.

Turbos also don't use wasted horsepower. There's no such thing as wasted horsepower. Having a turbo doesn't make the exhaust gas exit the engine more efficiently. Rather, it makes the exhaust gas exit the engine less efficiently, as it requires pressure building up between the cylinders and the turbo. The build-up of pressure in the manifold means the pistons have to work harder to expel the gases out of the engine, generally (as most turbo installs do not use perfectly designed manifolds and turbos). the turbo compressing the intake air, does help make up for the extra work the engine has to do, but it's not only a power increase that a turbo results in. A perfect system would be a lot more tuning than most people are willing to do. Just like any other engine modification, on any engine, regardless of cylinders, it is a balancing act.


I disagree.

Why do companies make tiny turbo diesels or tiny gasoline powered turbo motors (fiat panda)? Efficiency, because turbos more than make up for the additional exhaust restriction, and the pressurized intake charge means that the air in the cylinders is starting at a higher pressure than an NA engine (0psi), which effectively bumps up the compression ratio. If 14.7psig is compressed at 10:1 vs 25psig compressed at 8:1, the resulting pressure will be higher in the turbo engine. And higher compression results in better atomization.

All I am saying is take a turbo 4 and a NA v8 with the same horsepower in the same car and the turbo engine will be more efficient. Maybe not by a huge margin but just from an engineering stand point it should be more efficient.

I think a turbo 4 is a way different experience than a big v8 and if you want a v8 you want a v8.

Ecotec swap are not more common because less people have done them and therefore there would require more pioneering. Also people usually don't want to put smaller engines in their cars.

I want a smaller engine because it will be much easier to work on (for example can pull the head easily), much easier to package, and the low weight in the rear will help with handling.

Also, an NA 3800 is 390lbs so add a turbo setup to that (IC, Turbo, additional exhaust weight, charge piping) and it is at least as heavy as an LS4. I think that a turbo ecotec is the lightest way to make as much power as it makes.

Another benefit of a turbo engine as far as fuel efficiency goes is that they can be driven below the rpm they make boost at, and the engine will then consume the fuel of a 2.0l where a 4.7l will always be consuming the fuel required to run a 4.7l engine. But yes I agree the conservative compression ratio of the turbo engine will come into play in lowering fuel efficiency.

I am ignoring DOHC vs Pushrod head design because I am talking in general terms, and not attempting to actually compare two real engines. I am just arguing the theory that a turbo engine is more efficient since you disagreed that a turbo can improve efficiency.
IP: Logged
dobey
Member
Posts: 11572
From:
Registered: Sep 2001


Feedback score: N/A
Leave feedback





Total ratings: 371
User Banned

Report this Post07-23-2014 10:50 PM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by zkhennings:
I disagree.

I am ignoring DOHC vs Pushrod head design because I am talking in general terms, and not attempting to actually compare two real engines. I am just arguing the theory that a turbo engine is more efficient since you disagreed that a turbo can improve efficiency.


Turbos do not improve efficiency. Bolting a turbo on an engine does not make it more efficient. It makes it possible for that engine to make more power in the RPM range where the turbo is compressing the intake charge.

It's not theory, it's fact. A lower displacement engine requiring less fuel than a much larger displacement engine is completely unrelated to the turbo. There's a lot more to fuel economy than just displacement as well, otherwise the stock 2.8 in the Fiero would be getting 40 MPG, just like the 2.5 does. The 2.5 doesn't have a turbo. And the 2.8 not getting 40 MPG has nothing to do with the displacement or the 2 extra cylinders it has over the 2.5. And it's not aerodynamics or gearing that give it a huge advantage. So why does the Duke in a coupe get 12-15 MPG more on the highway than the 2.8 in the GT body? 40 MPG can be had with the 2.8, but it requires several changes to the engine.

IP: Logged
wftb
Member
Posts: 3680
From: kincardine,ontario,canada
Registered: Jun 2005


Feedback score: (4)
Leave feedback

Rate this member

Report this Post07-23-2014 11:42 PM Click Here to See the Profile for wftbClick Here to Email wftbSend a Private Message to wftbEdit/Delete MessageReply w/QuoteDirect Link to This Post
turbos do improve efficiency in modern engines .the reason is has been stated multiple times in this thread : when you dont need the extra power of the turbo you are feeding less gas in to a smaller engine .I have not driven one of the newer electonically controlled waste gate/ blow off valve motors , but my setup only builds boost when i want it to .I run 10:1 CR so my engine without the turbo makes the same power as a stock 2.2 eco .on the highway at a steady 70 mph i see 40+mpg .local driving is 28-32 (I live 90 miles from an expressway ) turbos are the future of the gasoline engine , no matter how many cylinders you have .the current crop of ferrari's are going to be the last N/A motors .the next gen will be turbo .
IP: Logged
zkhennings
Member
Posts: 1491
From: Massachusetts, USA
Registered: Oct 2010


Feedback score: (3)
Leave feedback

Rate this member

Report this Post07-24-2014 02:53 AM Click Here to See the Profile for zkhenningsSend a Private Message to zkhenningsEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by dobey:


Turbos do not improve efficiency. Bolting a turbo on an engine does not make it more efficient. It makes it possible for that engine to make more power in the RPM range where the turbo is compressing the intake charge.

It's not theory, it's fact. A lower displacement engine requiring less fuel than a much larger displacement engine is completely unrelated to the turbo. There's a lot more to fuel economy than just displacement as well, otherwise the stock 2.8 in the Fiero would be getting 40 MPG, just like the 2.5 does. The 2.5 doesn't have a turbo. And the 2.8 not getting 40 MPG has nothing to do with the displacement or the 2 extra cylinders it has over the 2.5. And it's not aerodynamics or gearing that give it a huge advantage. So why does the Duke in a coupe get 12-15 MPG more on the highway than the 2.8 in the GT body? 40 MPG can be had with the 2.8, but it requires several changes to the engine.


OK. Take an iron duke. Scale down piston area to get a lower displacement (effectively sleeve the engine and use smaller pistons). No other changes. It makes less HP. Add a turbo to bump HP to stock levels. The smaller turbo duke will get better mpgs. Car manufacturers already use this concept, and are starting to use it more and more.

IP: Logged
thesameguy
Member
Posts: 1428
From: California
Registered: Dec 2012


Feedback score: N/A
Leave feedback

Rate this member

Report this Post07-24-2014 04:29 AM Click Here to See the Profile for thesameguyClick Here to Email thesameguySend a Private Message to thesameguyEdit/Delete MessageReply w/QuoteDirect Link to This Post
Not sure it's that simple. The reasons turbos are making such a big comeback is because they are part of a bigger equation. It takes a specific amount of fuel to produce a given amount of power. You still need to maintain a fairly narrow air:fuel ratio - it doesn't matter how many cylinders or how big the effective displacement of the engine is. Yeah, fewer cylinders (less moving parts) and smaller cylinders (better combustion control) help, but not to the degree you're suggesting. Direct injection and higher tolerable static compression ratios are really the key here - it just so happens that direct injection means that turbos make more sense than they used to, and they allow manufacturers to take advantage of those incremental improvements inherent to simpler engines.

Your example of the turbo'd iron duke will probably fall flat on its face - in the past, as was discussed elsewhere, adding boost to a port injected engine means lowering static compression ratio which will *largely* undo the potential fuel savings of turbocharging. A C5 Corvette, rated at 18/25 mpg by the EPA turns in numbers almost identical to a much lighter conventionally injected Saab 900 Turbo (19/26), or a similarly weighted Volvo turbo (17/24) or name-your-port-injected-turbo-car. The reason why turbos gained popularity initially is twofold - in Europe, they allowed bigger power out of smaller engines to skirt motor vehicle taxes, and in the US they allowed manufacturers which had otherwise non-competitive engines (like the Mitsu/Chrysler 2.6l or the Volvo B-series) to make US-friendly power levels. Of course manufacturers sold these cars as more fuel efficient, but if you really dig down, in real world conditions, you'll find mileage numbers very similar to naturally aspirated motors of similar power levels.

Yeah, you can simplify the current situation and say "car manufacturers get better mpgs from turbos," but the *truth* is that car manufacturers get better mpgs out of direct injected turbo motors with specific cylinder characteristics and variable valve timing and per-cylinder spark timing control. Turbos are just part of the equation. A significant improvement in economy can also be gained using those same techniques and no turbo. The naturally aspirated Ford Fiesta gets nearly 30% better fuel economy than the Mk I Ford Focus while making more power out of a smaller engine despite nearly identical curb weights (2535 vs 2485, base model to base model).

IP: Logged
Will
Member
Posts: 13584
From: Where you least expect me
Registered: Jun 2000


Feedback score: (1)
Leave feedback





Total ratings: 234
Rate this member

Report this Post07-24-2014 08:35 AM Click Here to See the Profile for WillClick Here to Email WillSend a Private Message to WillEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by army_greywolf:
mostly because distance tower to tower is not very different cobalt to fiero, therefore the use of the cobalt's lower control arms, struts and so forth means you get at least HALF of an fe5 suspension package, sway bar included. There are some things to consider...the knuckles need to be swapped side for side, but that's not a huge issue either, then you save on machine work, you get to use big brakes, the brembos would work...with an adjustable proportioning valve.


If the Cobalt front suspension and engine mounting scheme is so prone to wheel hop, why go to lengths to swap it?

The idea of bolting a front suspension from a FWD car into the back end of a mid-engine car is one of the things that gave the Fiero all the suspension problems it has.
The side-view control arm alignment that gives the front end of a FWD car anti-dive will give the rear end of a RWD car pro-squat. That's exactly what happened to the '84-'87 Fieros.
If you swap an '88 Fiero, you need to understand that the geometry of the Cobalt front end would be a downgrade.

 
quote
Originally posted by army_greywolf:

The F35 has been a victim of it's own success, namely living with a top performer engine in a car known for launch wheel hop, cab (control arm bushing) failures...and also with no lift shift.


Wheel hop will kill anything. It's like detonation... a lot of unlikely combos can survive without detonation or wheel hop, but no combo will survive with detonation/wheel hop. Rear ends in C5 Corvettes and Cadillac CTS-V's die from wheelhop. I broke a CV joint cup in my Northstar car (with Getrag 282 transmission) due to wheel hop.

Once wheel hop is controlled, the F23 does fine, as several swappers on this forum, including high horsepower turbo 3800 builds (If you think the LNF is a torque monster, you just don't know), have demonstrated.

 
quote
Originally posted by army_greywolf:
DISCLAIMER: Most of the kids/young guys I deal with in reference to these cars drive harder than I do.


IOW, they drive like idiots.

I've made a Getrag 282 live behind a 300+ WHP Northstar. I take off hard, I shift hard... I don't spare it. But I drive it smart and avoid wheel hop.

 
quote
Originally posted by army_greywolf:
Have a closer look at an LNF, where exactly are you going to put all these instrument sensors at? Tap the block? The aluminum extension behind the pump? There is one test port for oil pressure, but it requires you take part the engine to put the adapter on it...I know this because I installed a oil pressure/temperature sending unit on my Cobalt. The water temperature would require an in hose adapter, the sending unit on the engine is not calibrated for gauge use...


If there's an oil pressure switch, it can be swapped for a gauge sender.
There's a 3 wire coolant temp sensor which includes the signal and return wires for the ECM temp sensing as well as a single wire resistance to ground sensor for a guage. It drops in place of the single element CTS on the older cars. I'm running one on my Northstar.

 
quote
Originally posted by army_greywolf:
Lastly semantics being what they are, yes it is controller area network..slang car area network...either for the purpose works. I don't want to start a war I want to clarify that there's more than meets the eye with an LNF. Most people think, ohh it's a turbo 4 it can't make v8 torque, it's all top end power, and that can't be more false. Your talking about 130 hp per liter guys-stock. A tuned wheel horsepower to to around 365hp...stock that equates to 200 engine hp per liter, if the zr1 made that kind of power your talking 1240 hp...theres alot to be done on an LS motor to make that kind of power. Even the LS4 has to push 690 engine hp to meet up with a stock LNF. I would expect to spend approx. $5500 on the swap, that includes the entire donor car probably with at least some go fast goodies already on it, materials, water air intercooler, exhaust work, tune, etc. You can save a negligible amount by custom harness, no bcm, no cradle, highly likely you wont get the timing cover side engine mount with the engine since its easier to simply unbolt the couple allen head bolts than it is to take the mount off the car...need to think about that when you dont get a donor car, it will be missing things you need.


Don't be a ricer. Specific output is meaningless.
An LS4 would need about 380 at the wheels to "meet up with" a 365 WHP LNF, the power difference being due only to the weight difference.

Looking forward to seeing you do the swap. Post a build thread.

[This message has been edited by Will (edited 07-24-2014).]

IP: Logged
PFF
System Bot
Will
Member
Posts: 13584
From: Where you least expect me
Registered: Jun 2000


Feedback score: (1)
Leave feedback





Total ratings: 234
Rate this member

Report this Post07-24-2014 08:46 AM Click Here to See the Profile for WillClick Here to Email WillSend a Private Message to WillEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by army_greywolf:

Also it's not so much that pistons on the LNF fail but the ringlands melt, it's a weak spot and I believe a heat issue moreso than pressure.


That sounds like a detonation and/or blowby issue...

 
quote
Originally posted by army_greywolf:

I have to correct myself the engine has sleeves and they are wet sleeves but they are unsupported in the block, gen 1 sleeves are installed top down and secured on both ends by block and head, the LSJ is press fit as well, but it's only secured from one end, through the bottom into a cast unsupported, im not sure what you would call it but the idea at the time was to fit them all top and bottom with the head sitting on not the sleeves but an additional cast in portion of the block. Gen 2 ecotec, aka LNF are presfit into the engine with the sleeve itself as the sealing surface. When upgrading the LSJ, the cast support is machined out and the same sleeve type you find in an LNF gets pressed in. I have a hard time making this "visual" but I can find pictures.



I'm curious about pics of that, because every other aluminum engine GM makes has cast-in-place dry liners. I find it hard to believe they'd take a step backwards from technology, production and reliability standards to run pressed-in wet liners.
IP: Logged
dobey
Member
Posts: 11572
From:
Registered: Sep 2001


Feedback score: N/A
Leave feedback





Total ratings: 371
User Banned

Report this Post07-24-2014 08:53 AM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by wftb:
turbos do improve efficiency in modern engines .the reason is has been stated multiple times in this thread : when you dont need the extra power of the turbo you are feeding less gas in to a smaller engine


That does not improve the efficiency of the engine. That just means the smaller engine is using less fuel than the larger engine. What improved fuel economy was the smaller engine, not the turbo. Not using the turbo, the engine is equally efficient with it bolted on the exhaust, or with it not there at all. When the turbo is supplying full boost to the engine, you're burning more gas.

Please stop equating having a DOHC 4 cylinder that uses less gas than an OHV V8 that is 3 times the displacement, with "turbos make engines more efficient." They are not the same thing.
IP: Logged
Will
Member
Posts: 13584
From: Where you least expect me
Registered: Jun 2000


Feedback score: (1)
Leave feedback





Total ratings: 234
Rate this member

Report this Post07-24-2014 09:02 AM Click Here to See the Profile for WillClick Here to Email WillSend a Private Message to WillEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by dobey:

Don't be confused because you think the Cobalt grille is large. The frontal area is still a little smaller than the Fiero.


What? The Cobalt is INCHES taller than a Fiero. -> Much more frontal area...

[This message has been edited by Will (edited 07-24-2014).]

IP: Logged
Will
Member
Posts: 13584
From: Where you least expect me
Registered: Jun 2000


Feedback score: (1)
Leave feedback





Total ratings: 234
Rate this member

Report this Post07-24-2014 09:03 AM Click Here to See the Profile for WillClick Here to Email WillSend a Private Message to WillEdit/Delete MessageReply w/QuoteDirect Link to This Post

Will

13584 posts
Member since Jun 2000
 
quote
Originally posted by army_greywolf:

Factor in the obvious here, there is more metal to metal contact in a v8 than a 4 cylinder, or a 6,


Most of the friction in an engine is in the piston rings... that's how cylinder count bears on the issue.
IP: Logged
dobey
Member
Posts: 11572
From:
Registered: Sep 2001


Feedback score: N/A
Leave feedback





Total ratings: 371
User Banned

Report this Post07-24-2014 09:04 AM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by zkhennings:


OK. Take an iron duke. Scale down piston area to get a lower displacement (effectively sleeve the engine and use smaller pistons). No other changes. It makes less HP. Add a turbo to bump HP to stock levels. The smaller turbo duke will get better mpgs. Car manufacturers already use this concept, and are starting to use it more and more.


No, it won't get better MPGs. You're not improving any of the technology in the engine, simply by making the pistons smaller and throwing a turbo on it. And the turbo isn't doing anything to the efficiency of the engine. Fuel economy and engine efficiency are not the same thing. Nor are massively decreasing engine displacement, and a turbo. You keep saying one thing, and claiming the other thing is what is making the improvement to the fuel economy. It's not.
IP: Logged
dobey
Member
Posts: 11572
From:
Registered: Sep 2001


Feedback score: N/A
Leave feedback





Total ratings: 371
User Banned

Report this Post07-24-2014 09:05 AM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post

dobey

11572 posts
Member since Sep 2001
 
quote
Originally posted by Will:


What? The Cobalt is INCHES taller than a Fiero.


And a few inches narrower, no? Maybe they're closer than I recall, but the CD is still about 0.06 lower on the Cobalt than the Fiero.
IP: Logged
cvxjet
Member
Posts: 2347
From: ca, usa
Registered: May 2010


Feedback score: (1)
Leave feedback

Rate this member

Report this Post07-24-2014 12:39 PM Click Here to See the Profile for cvxjetClick Here to Email cvxjetSend a Private Message to cvxjetEdit/Delete MessageReply w/QuoteDirect Link to This Post
HP = Fuel Burned = MPG. Take a 6L V8 and turn it 3000 and a 3L turning 6000 and they are basically using the same fuel and will come very close in HP. A turbo pumps MORE air so it uses more fuel- The efficiency gain comes from not using the turbo during cruise....But the Turbo engine tends to have compromises that hurt efficiency, like a lower compression ratio. The new direct injection engines help this problem immensely, but it's all basically Air pumped = power and MPG.

Toyota tried to do a ski boat and it failed because the 4V V8 had to turn higher RPMs- boats have no gears(Basically) so your cruise rpm is a % of your max power rpm. Big engines turn slower. My CVX20 Jet has a 460/400HP that maxes out at 5000, so cruise is 3000 @ 30 mph. The Yamaha twin jet boat uses small engines that max out at 10,000....They cruise at 6000 @ 30...who the heck wants to be turning 6000 while just cruising? And I get 3.8 mpg @30, while those Yamahas get 2.8 @ 30.....Yes, my old Cast iron V8 is more efficient. Just as comparison, the "Prius" of boats is a small low-profile (tahiti style) with a 4 cyl merc I/O.....They get 8 mpg....Remember, your not commuting in the dang things!

[This message has been edited by cvxjet (edited 07-24-2014).]

IP: Logged
wftb
Member
Posts: 3680
From: kincardine,ontario,canada
Registered: Jun 2005


Feedback score: (4)
Leave feedback

Rate this member

Report this Post07-24-2014 12:52 PM Click Here to See the Profile for wftbClick Here to Email wftbSend a Private Message to wftbEdit/Delete MessageReply w/QuoteDirect Link to This Post
sounds like you have a 2 stroke yamaha there so really you cant compare that to your boat .i have an 18 ' grew bowrider that if i cruise at 35 mph i get 10 mpg .that is at about 3600 rpm .pin it and cruise at 5300 rpm and 50 mph and mileage drops to around 3 mpg .i have a suzuki 140 hp 4 stroke outboard .i would like to know how the merc's with the superchargers do for mileage .but this is getting way off topic .

[This message has been edited by wftb (edited 07-24-2014).]

IP: Logged
cvxjet
Member
Posts: 2347
From: ca, usa
Registered: May 2010


Feedback score: (1)
Leave feedback

Rate this member

Report this Post07-24-2014 09:54 PM Click Here to See the Profile for cvxjetClick Here to Email cvxjetSend a Private Message to cvxjetEdit/Delete MessageReply w/QuoteDirect Link to This Post
What kind of speed and acceleration are you getting out of your boat...just curious. As for off topic, well, maybe, but I look at the question of which engine is the best for the Fiero as a question of which engine gives the most performance/MPG/$$$. My 3.4 PR engine has 200 lb/ft @ 2800...To get that kind of torque out of a 4V @ 2800, you'd need a 4.6. I surprise the heck out of people by leaving it in a cruise gear(4 @ 40/ 5 @ 60) and squeezing the throttle...I could go with a "Modern" engine for more dough, and have 100 lb/ft @ 2800, but then I'd have to down shift any time I wanted accel....And I don't like Turbos....I guess I live in another world, which is governed by one acronym; K.I.S.S. As for the Big block jet boat vs any prop boat- you haven't felt throttle response until you open the throttle and have the tach needle on 460 ci engine move in lock-step with the throttle. I have full thrust at 0 mph, while a prop only rotates the water, and takes seconds to spin up to redline.

I have no problem with an ecotec in a Fiero- they were going with the Quad-4 for 1989, and the ecotec is a quantum leap beyond that. I really like Vee engines, and can't stand the sound of the ricer cars(Including Cobalts & Neons). In fact, the Fiero exhaust is the only six I like the sound of.
IP: Logged
dobey
Member
Posts: 11572
From:
Registered: Sep 2001


Feedback score: N/A
Leave feedback





Total ratings: 371
User Banned

Report this Post07-24-2014 10:11 PM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by cvxjet:
My 3.4 PR engine has 200 lb/ft @ 2800...To get that kind of torque out of a 4V @ 2800, you'd need a 4.6


Not really. The 3.6 LLT DOHC V6 has a very broad and relatively flat torque curve, and even the lower output versions of it are making around 200 lbs-ft at 2800. The LFX is making even more than that.

The 2.0 LNF (which this thread is about) makes even more than that, thanks to the turbo:


Peak torque is 248 lb-ft right around 2700. And it makes over 200 lb-ft between 2000-6200 RPM. Pretty sure your 3.4 doesn't have a power band like that.
IP: Logged
PFF
System Bot
army_greywolf
Member
Posts: 27
From: Madison, WI
Registered: Jul 2014


Feedback score: N/A
Leave feedback

Rate this member

Report this Post07-24-2014 11:33 PM Click Here to See the Profile for army_greywolfClick Here to Email army_greywolfSend a Private Message to army_greywolfEdit/Delete MessageReply w/QuoteDirect Link to This Post
To Will, the ring land issue has much more to do with tuned cars having a very high EGT, I had a gauge on my car and I noticed 1600 was breached anytime I pulled hard in 3rd. There's a reason for this, DI runs lean, it's designed that way. Second the stock LNF pistons have very little metal where the ring lands are...it wouldn't take much to melt them because they are the farthest point from the oil squirter, closest to the top compression ring and exposed to high pressure and temperature...nothing to do with knock.

Also...there are more than a few daily driver 550hp/600 tq combinations running around out there.

And lastly...I am not going to downgrade to an F23 for the sake of it, both the LSJ and LNF come with an F35 so that's reason enough to leave well enough alone, that and you can get a well made limited slip for it too...factory.

The reason the front suspension hops is because the car was designed for street performance...not drag racing. Yes it does great in that arena but come on...it's a cheap fwd sport compact. No...where I have the most fun was the road course. The car ate corvettes and bimmers for breakfast (and tires too..) It felt like starting out with a 50 grand track day car but you have air conditioning to boot, and that was my experience. The suspension will do it's job properly I can assure you of that, and if it doesn't well...it'tt get cut up as soon as I find a better solution.

There's a book for building ecotecs on amazon. If your dead curious on how they are built, that's the way to go. I am NOT up and up on LSJs like the LNF but the LNF is certainly a pressed in wet sleeve engine. The LSJ is also a sleeved engine, i do not think they are cast in...the other ecotecs I am unsure. The LSJ can be adapted for LNF sleeves with some machining and is generally an accepted upgrade going north of 450 hp. Same with the LNF, the sleeves are beefy but not strong enough for more than 450-500.

LNF is more drivable at high power levels than the LSJ for sure, having driven both cars with more than 450 hp. LSJ is cheaper but not much once you talk power adders. Stock for stock a track day setup should get the LNF over the LSJ, you will enjoy it more.

And as for turbocharging? It's generally accepted a turbocharger can be made in such a way that a smaller displacement engine producing the same max power as a larger displacement engine of the same overall configuration will be more efficient. This isn't an internet engineering thing...if it was false GM wouldn't be putting 1.4 turbo engines in cruze ecos or sonics...and having customers report 46 plus mpg when the larger n/a motor with near the same power gets worse mileage. Start combining less cylinders, better engine designs, injection strategies and turbocharging...it becomes a win win situation, mileage and power. No h/c/i swapped LS in the world will get better mileage at the same power than the stock LS turbocharged with a well matched turbo. I'd take the check to the bank on that one too.

I mean, if that wasn't true why would Fiat, GM, Nissan, VW, Audi, BMW, Mercedes, Smart, Porsche and McLaren all be using this strategy as bang for the buck...power and mileage. Don't try to tell me it's because of the following: "Cheaper...sounds better..." It may sound interesting but nothing will every replace a cammed hemi or LS motor...ever or a lambo v12. And cheaper it is not, else they'd just keep cranking out 2.2 ecotecs and 3500s...the tech is near peak and to increase mileage motors must get smaller and forced induction.
IP: Logged
Will
Member
Posts: 13584
From: Where you least expect me
Registered: Jun 2000


Feedback score: (1)
Leave feedback





Total ratings: 234
Rate this member

Report this Post07-25-2014 07:44 AM Click Here to See the Profile for WillClick Here to Email WillSend a Private Message to WillEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by cvxjet:

What kind of speed and acceleration are you getting out of your boat...just curious. As for off topic, well, maybe, but I look at the question of which engine is the best for the Fiero as a question of which engine gives the most performance/MPG/$$$. My 3.4 PR engine has 200 lb/ft @ 2800...To get that kind of torque out of a 4V @ 2800, you'd need a 4.6.


 
quote
Originally posted by dobey:

Peak torque is 248 lb-ft right around 2700. And it makes over 200 lb-ft between 2000-6200 RPM. Pretty sure your 3.4 doesn't have a power band like that.


My 4.6 Northstar makes over 250 ftlbs to the wheels from 1000 RPM. It accelerates up hill from 30 mph in 5th gear at 1100 RPM.

IP: Logged
Will
Member
Posts: 13584
From: Where you least expect me
Registered: Jun 2000


Feedback score: (1)
Leave feedback





Total ratings: 234
Rate this member

Report this Post07-25-2014 07:52 AM Click Here to See the Profile for WillClick Here to Email WillSend a Private Message to WillEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by army_greywolf:

To Will, the ring land issue has much more to do with tuned cars having a very high EGT, I had a gauge on my car and I noticed 1600 was breached anytime I pulled hard in 3rd. There's a reason for this, DI runs lean, it's designed that way. Second the stock LNF pistons have very little metal where the ring lands are...it wouldn't take much to melt them because they are the farthest point from the oil squirter, closest to the top compression ring and exposed to high pressure and temperature...nothing to do with knock.


Those are very risky EGT's... sounds like "tuned" means "mis-tuned" in this case.

High EGT's burn exhaust valves; they don't melt pistons.

Due to in-chamber mixture motion, there's a boundary layer of gas between the combustion gasses and the piston/chamber. The boundary layer insulates the piston and chamber from the a lot of the heat of combustion. Detonation breaks up this boundary layer and allows extremely rapid heat transfer to the chamber and/or piston. I've never heard of melted/cracked ring lands due to EGT's without detonation.

The high velocity flow around the exhaust valve reduces the boundary layer thickness and allows more heat transfer into the exhaust valve... that's why high EGT's burn exhaust valves.

DI isn't designed to run lean... it's designed for a good distribution of fuel due to in-chamber mixture motion. If it's a stratified charge burn, the mixture around the plug will be rich and easy to light while the mixture elsewhere in the chamber might be lean. However, that's only at part throttle.

[This message has been edited by Will (edited 07-25-2014).]

IP: Logged
Will
Member
Posts: 13584
From: Where you least expect me
Registered: Jun 2000


Feedback score: (1)
Leave feedback





Total ratings: 234
Rate this member

Report this Post07-25-2014 07:58 AM Click Here to See the Profile for WillClick Here to Email WillSend a Private Message to WillEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by army_greywolf:

I am NOT up and up on LSJs like the LNF but the LNF is certainly a pressed in wet sleeve engine.


Doesn't look like it to me.
Do you have a better photo?

http://i1137.photobucket.co...Zooome7/DSC00119.jpg



The cut block does look like it's wet liner, but it also looks cast-in.

Obviously, the big potential problem with wet liner is the potential for coolant to leak around the base of the liner into the crank case and contaminate the oil. GM tried wet liners on the Caddy 4.9, and went to cast-in dry liners for the Northstar, LS family, high feature V6 and the Ecotecs that I've seen.

[This message has been edited by Will (edited 07-25-2014).]

IP: Logged
dobey
Member
Posts: 11572
From:
Registered: Sep 2001


Feedback score: N/A
Leave feedback





Total ratings: 371
User Banned

Report this Post07-25-2014 08:52 AM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by army_greywolf:
The LSJ is also a sleeved engine, i do not think they are cast in...the other ecotecs I am unsure.


All aluminum blocks are sleeved engines. They have to be. Aluminum cylinders would expand and distort, under the heat.

 
quote
Originally posted by army_greywolf:
And as for turbocharging? It's generally accepted a turbocharger can be made in such a way that a smaller displacement engine producing the same max power as a larger displacement engine of the same overall configuration will be more efficient. This isn't an internet engineering thing...if it was false GM wouldn't be putting 1.4 turbo engines in cruze ecos or sonics...and having customers report 46 plus mpg when the larger n/a motor with near the same power gets worse mileage. Start combining less cylinders, better engine designs, injection strategies and turbocharging...it becomes a win win situation, mileage and power. No h/c/i swapped LS in the world will get better mileage at the same power than the stock LS turbocharged with a well matched turbo. I'd take the check to the bank on that one too.


Stop equating differences in displacement as simply being turbocharger making engines more efficient. The displacement change and technology are what make the engine more efficient, not the turbo. All the turbo does is make it so the tiny little 1.4L can actually be enjoyable to drive, as well as efficient. Of course the Cruze Eco gets much better MPG than the 1.8L cars. It has a lot of changes they don't. Weight reduction, lighter wheels, low rolling resistance tires, and better aero. Saying all of that MPG gained is because of the turbo is just ignorance.

 
quote
Originally posted by army_greywolf:
I mean, if that wasn't true why would Fiat, GM, Nissan, VW, Audi, BMW, Mercedes, Smart, Porsche and McLaren all be using this strategy as bang for the buck...power and mileage. Don't try to tell me it's because of the following: "Cheaper...sounds better..." It may sound interesting but nothing will every replace a cammed hemi or LS motor...ever or a lambo v12. And cheaper it is not, else they'd just keep cranking out 2.2 ecotecs and 3500s...the tech is near peak and to increase mileage motors must get smaller and forced induction.


They're all using small displacement engines with turbos for one reason. Government. In the US, Federal law has manadated that N% of every manufacturer's production fleet must attain XX MPG by YY date. Similar laws have been made all throughout Europe. How does GM meet those CAFE standards in the US? More compact cars with smaller engines, more hybrid engines, fewer big sedans and trucks, and fewer brands, and fewer engine families. If slapping a turbo on an engine made it more efficient, every vehicle GM sells would have a turbo on it, even the petrol powered trucks and the Corvette.

Turbos may be more efficient than superchargers at providing boost to an engine, but they do not automatically make an engine more efficient by bolting one one.
IP: Logged
Will
Member
Posts: 13584
From: Where you least expect me
Registered: Jun 2000


Feedback score: (1)
Leave feedback





Total ratings: 234
Rate this member

Report this Post07-25-2014 09:55 AM Click Here to See the Profile for WillClick Here to Email WillSend a Private Message to WillEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by dobey:
All aluminum blocks are sleeved engines. They have to be. Aluminum cylinders would expand and distort, under the heat.


I thought he meant inserted sleeves vice cast in place.
IP: Logged
Will
Member
Posts: 13584
From: Where you least expect me
Registered: Jun 2000


Feedback score: (1)
Leave feedback





Total ratings: 234
Rate this member

Report this Post07-25-2014 10:03 AM Click Here to See the Profile for WillClick Here to Email WillSend a Private Message to WillEdit/Delete MessageReply w/QuoteDirect Link to This Post
Thermal efficiency and fuel economy are two different things. Thermal efficiency is how well the engine converts fuel to power... how much fuel flow does it take to make 1 HP?

It takes a certain amount of power to push a car down the road at a certain speed.

The first way to get better mileage is to reduce the amount of power it takes to push the car.

The next way is to reduce the amount of fuel the engine requires to generate that power.

A gasoline engine at part throttle always has pumping losses. The closer an engine operates to WOT, the less pumping loss it incurs. Operating a small engine at large throttle opening to move the car down the road reduces pumping losses and improves fuel mileage.
HOWEVER, because the engine is so small, the driver needs to use WOT a LOT more often to accelerate. This incurs offsetting fuel mileage penalties due to running the engine under power enrichment (richening of the mixture at WOT).

A turbo is even worse, as it tends to like richer mixtures than a naturally aspirated engine.

The DI allows power enrichment to be less rich, as well as helping a small engine spool a turbo better than it could with port injection.

Actually, the engine's compression ratio isn't what determines thermal efficiency. The *EXPANSION* ratio is what does that. The expansion ratio from the cylinders to the atmosphere is lower at part throttle and lower at high boost. Long runner manifolding like the Mazda Skyactiv engines run can offset this, but not eliminate it. Reducing exhaust manifold pressure gets the system closer to operating in "crossover". In that operating regime, boost is higher and backpressure and phenomenal gains in efficiency and power are possible.

Of course the ideal fuel efficiency engine will be something like a DI/VVT 500cc inline twin running 120 psi of boost through a staged turbo system in "crossover".

[This message has been edited by Will (edited 07-25-2014).]

IP: Logged
zkhennings
Member
Posts: 1491
From: Massachusetts, USA
Registered: Oct 2010


Feedback score: (3)
Leave feedback

Rate this member

Report this Post07-25-2014 11:05 AM Click Here to See the Profile for zkhenningsSend a Private Message to zkhenningsEdit/Delete MessageReply w/QuoteDirect Link to This Post
My friend's 2007 Audi rs4 has an aluminum V8 that is unsleeved... Instead it has a very thin very hard coating on the cylinder surface.

And Will,
An engine running at part throttle creates a vacuum in the intake manifold and therefore within the cylinders themselves when the piston is just switching over from intake stroke to compression stroke resulting in... Well less fuel and air in the cylinder as the starting pressure within the cylinder is under 0 gage pressure correct? And at WOT and 100% VE the pressure in the cylinder should be 0 gage pressure when the intake valve closes. So in effect, cylinder pressures are reduced when driving at part throttle. What effect does this have on the ability of the engine to turn fuel into power?

I always assumed in the past that a higher compression puts more energy into the fuel and air mixture which allows the fuel to atomize better.

So I understand expansion ratio and how it lowers exhaust temps and therefore volume of exhaust gases, but I am not sure I understand why boost or part throttle would effect the expansion ratio.

[This message has been edited by zkhennings (edited 07-25-2014).]

IP: Logged
Will
Member
Posts: 13584
From: Where you least expect me
Registered: Jun 2000


Feedback score: (1)
Leave feedback





Total ratings: 234
Rate this member

Report this Post07-25-2014 11:54 AM Click Here to See the Profile for WillClick Here to Email WillSend a Private Message to WillEdit/Delete MessageReply w/QuoteDirect Link to This Post
If you started with air or mixture at 7.4 psi absolute (half of atmospheric) and compressed it adiabatically at a ratio of 12:1, then expand that air back to 14.7 psi atmospheric pressure, it'll only expand 6:1

This is what happens when a cylinder pulls from the intake manifold at part throttle, then exhausts to atmospheric pressure. The exhaust energy is similar to an engine at lower compression operating at WOT.

European manufacturers have been using high silicon aluminum linerless blocks for a while now.

Ferrari had pressed-in wet liners as late as the mid-2000's in the Dino engine family, though.

[This message has been edited by Will (edited 07-25-2014).]

IP: Logged
Previous Page | Next Page

This topic is 5 pages long:  1   2   3   4   5 
next newest topic | next oldest topic

All times are ET (US)

Post New Topic  Post A Reply
Hop to:

Contact Us | Back To Main Page

Advertizing on PFF | Fiero Parts Vendors
PFF Merchandise | Fiero Gallery | Ogre's Cave
Real-Time Chat | Fiero Related Auctions on eBay



Copyright (c) 1999, C. Pennock