quote Originally posted by Will: 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.

So then wouldn't a boosted application result in a higher expansion ratio?

lets clear up one thing : from the ecotec build book : Flanged thin wall iron cylinder sleeves are press fit into a semi floating aluminum support structure .so ecotecs are definitely not cast in sleeves .and all ecotecs are built the same way . as far as modern turbo engines being more efficient , i was at the local ford dealer to order a part today and i saw a brand new fusion that has a 1.5L 4 cyl DI turbo motor .that is the biggest car i have ever seen with a 1.5L motor . you can argue all day long over what should work better and how one versus the other should work better , but CAFE regs are making turbo motors # 1 choice of manufacturers everywhere . The other choice is a hybrid powertrain , and there are a lot of versions of those out there now too . ( edit : i did not notice any mention of this fusion being a hybrid )

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

I already said they were sleeved, but how I wasn't positive on, I wasn't sure if ALL LSJs were wet sleeve or not.

Couple things: DI as Will admitted runs a leaner PE, this is absolutely true...for the most part .87-.91 lambda is acceptable PE at WOT. The heat issue is literally from injection duration and not anything else...Vince sent me a tune that began the injection event 35 degrees sooner and that netted me a 200 degree WOT egt reduction with no other changes. I suspect that's alot more to do with where the piston is at during the injection. That's not a design flaw persay...probably an original tune (there is no table I can personally change for this) to inject fuel at the most turbulent moment. Also DI pistons are specially designed to create turbulence. The K04 turbocharger on the cobalt is similar to the "EFR" turbos BW makes...involving a precise balance and a set of wheels made for "the daily driver" this means it's incredibly efficient in the 0-15 psi range. No chinese ebay turbo can compare and yes turbo selection makes as much or more of a difference than a cam choice when setting up a FI build.

I went on the power tour in 2010 with a guy running a turbo LS2 powered GTO, seriously tall rear end and a six speed. He got near the same mileage I did and neither of us rolled on eco tire...anything, bfg kdw2s if it concerns.

Like most of you have said, the window for stoich mixture is pretty narrow. A turbo gives the engine a chance to expand that window at greater throttle angles, PE on the DI motor doesn't take til your into boost a bit.

Compression Ratio of the LNF is 9.2 to 1, the exhaust valves are inconel, sodium filled...i think, in either case it's a refractory metal, not real likely to melt or distort at any temperature an engine can come up with. The engine comes factory with low tension piston rings, which is why it is also wet sleeved. The turbo as I said is water cooled and twin scroll which allows it to be slightly larger than usual and still spool up quick. Manifold is stainless, again probably because the engineers knew the engine could get hot, they went to great lengths to ensure survivability while running the PE as lean as possible. Should look at a stage one tune, it's leaner than I am comfortable with and GM did it.

Ah well...LNF will be nice...but then...plot twist...

LUZ-2.0 CDI from the north american chevy cruze diesel

Not alot I know of it other than iron block, aluminum head, small but violently quick to boost turbo and that the transmission it's mated with is pretty tough. My aunt bought one last october, great daily driver, tons of torque, 47-50 mpg...unbelievable. How likely id be able to score one...I don't know. Tuning? Well youtube fleece performance cruze and you will see what I mean. Discuss, gentlemanly, y'all are decent people aren't you?

One of the questions was whether the sleeves were cast in or press fit .They are press fit .They are also dry sleeves , going by the picture I have in my build thread on page 13 .You can see block material surrounds the entire sleeve assembly .

From Wiki:

Efficiency generally describes the extent to which time, effort or cost is well used for the intended task or purpose. It is often used with the specific purpose of relaying the capability of a specific application of effort to produce a specific outcome effectively with a minimum amount or quantity of waste, expense, or unnecessary effort. "Efficiency" has widely varying meanings in different disciplines.

The term "efficient" is very much confused and misused with the term "effective". In general, efficiency is a measurable concept, quantitatively determined by the ratio of output to input. "Effectiveness", is a relatively vague, non-quantitative concept, mainly concerned with achieving objectives. In several of these cases, efficiency can be expressed as a result as percentage of what ideally could be expected, hence with 100% as ideal case. This does not always apply, not even in all cases where efficiency can be assigned a numerical value, e.g. not for specific impulse.



I think Will made the point...many often throw the word "efficiency" around we do not know what in particular is been said...thermodynamics? Economy? etc, etc... what...? Put a turbo on a car...step on the gas everywhere you go...consequences? Take ur NA car several hundred feet above sea level...get on the gas, also consequences? cruise a turbocharged car on the free way without getting into it...? so many variables and this is where Dobey point is true...what efficiency does a turbocharger actually make on its own? It brings with is its own relative atmosphere, but needs ancillary devices to make it "__________!!"

I think we are looking at a spectrum argument here...look at the 80's and see the technology of that era...mpg sucked on turbocharged vehicles or was not that different from their respective NA variants all else held equal...follow the continuum ...and then today the technology has made it possible to actually see a more manageable MPG in concert with a turbo but this is a small window I am referring to (fuel consumption)...

[This message has been edited by nocuttt (edited 07-26-2014).]

quote Originally posted by nocuttt: I think we are looking at a spectrum argument here...look at the 80's and see the technology of that era...mpg sucked on turbocharged vehicles or was not that different from their respective NA variants all else held equal...follow the continuum ...and then today the technology has made it possible to actually see a more manageable MPG in concert with a turbo but this is a small window I am referring to (fuel consumption)...

If we want to discuss efficiency of an internal combustion engine, then we need to discuss it in terms of Brake Specific Fuel Consumption.

Discussing MPG doesn't work, because many things have an affect on MPG, such as vehicle weight, tire size, transmission gearing, speed limits, flow of traffic, and so on. To compare a 2.0L turbo engine to a 6.0L engine, both of which make 400 HP, you need to measure the fuel consumption of the engine at the RPM where it is making that horsepower.

It takes a certain amount of power to push a vehicle that weighs a certain amount, through a mass of air at a certain pressure, based on the balance, gearing, tire size, and drag coefficient of the vehicle. Making more power than is needed to do that, at a given RPM, means you will burn more fuel than is needed, and you get a lower MPG. Making only the exact amount of power needed to move the vehicle at any given RPM, means only the fuel being needed is burned, and you will attain the maximum MPG possible in that vehicle, short of alternate drive motors such as in a hybrid car. That's why Honda Civics that weigh 2200 lbs with tiny tires, and 1.5L N/A engines with no low end torque can get 30+ MPG in the city. And why a 5500 lb pickup truck gets 13 MPG in the city. Take the engine out of the Honda and put it in the 500+ lb heavier Fiero, and it will get worse MPG. Take the engine out of the truck and put it in the Fiero, and it will get better MPG. But that doesn't mean the Fiero made the engine itself more efficient.

I hear of all kind of arguments- thermal-efficiency, brake-specific fuel consumption, EPA ratings.....I drove a Formula/LS1 for 6 years and averaged 24 mpg- highway I got 30-32. As for rating efficiency by HP/CI, that's only important when CI is limited artificially, such as racing engine limits or engine tax. I don't care if I have 1 CI or 500 CI- What's the power, how is it delivered, and what is the MPG. After that, physical size, weight, and cost.

There are a number of new engines on the horizon that will throw the CI measurements into a crocked hat- The orbital(If they ever get the bugs out of it), the Six stroke, and the floating piston......The only way to really compare any engines is to put them in the same basic vehicle and test them. You can have a hybrid/diesel setup that can get thru the 1/4 in 10" and gets 40 mpg average, yet the driving experience may suck.....I like simplicity, I like to shift(in a sportscar) and I like torque. All of this can basically come with a PR V6 or V8.

I wish to heck that GM had stayed with the PR-V6 for a few more years- to find a 3500 w/cam-in-cam, all-aluminum construction and DI would be dream come true. Maybe 250+ hp, 250+ torque, with 80% from 1500-6000, and 25/35mpg, plus 100 lbs lighter than the 2.8. And a lower center of gravity than OHC engines.

quote Originally posted by cvxjet: I wish to heck that GM had stayed with the PR-V6 for a few more years- to find a 3500 w/cam-in-cam, all-aluminum construction and DI would be dream come true. Maybe 250+ hp, 250+ torque, with 80% from 1500-6000, and 25/35mpg, plus 100 lbs lighter than the 2.8. And a lower center of gravity than OHC engines.

They still make one. The 4.3 Ecotec3 engine for the trucks. It's aluminum, SIDI, VVT, AFM, and makes plenty of torque. If you really want a new V6 with all the cool tech, anyway.

Drove one, freakin' dream Dobey...it's like 30 years after they started building these sawed off 350s they finally got it right. The 5.3 is another serious upgrade over the previous generation. SIDI makes a pretty big difference to things especially how smooth and seemless the engine feels.

quote Originally posted by army_greywolf: Drove one, freakin' dream Dobey...it's like 30 years after they started building these sawed off 350s they finally got it right. The 5.3 is another serious upgrade over the previous generation. SIDI makes a pretty big difference to things especially how smooth and seemless the engine feels.

Probably more the VVT that makes a difference in how smooth the engine feels. If you drove one of the new trucks, they've also got a lot more insulation, so you're just going to feel less anyway. But yeah, the modern high tech engines are way beyond what was being built 30 years ago.

Not the VVT, driven and repaired dozens of VVT cars (and a few trucks now) by far the DI makes the difference it's just that kind of smooth. I know the VVT is a life saver for dual cam engines when talking about torque but with the 4.3 cam in block I believe that allows a more aggressive cam and still pass emissions...same with the DI, its all about emissions and the federal mpg mandate thing theyve got going.

And good you brought up Brake Specific Fuel Consumption, that sort of defines what I am after. Another thing is parasitic driveline loss, which can be measured on a dyno. You can even get a reasonable idea of actual efficiency by comparing your injector duty cycle with your dyno graph, done correctly (knowing your actual fuel pressure to the half pound or so throughout the range you can about deadeye that number. Most dyno operators can hook up a pressure transducer to the shraeder valve and log your fuel pressure at the same time...then you simply graph it with your tuner log of injector duty cycle.

The LNF can grab this data without the use of a dyno to arrive at this number but with any mods its not expected to be accurate and I think the GM engineer told us it can be off up to 7% based on factors like oil condition, ambient temps, humidity and fuel quality. A dyno session will show an actual hard number based on some " maths"

[This message has been edited by army_greywolf (edited 07-28-2014).]

quote Originally posted by zkhennings: So then wouldn't a boosted application result in a higher expansion ratio?

The cylinder is exhausting to the turbine inlet, which has a higher pressure than atmospheric (probably a higher pressure than the intake manifold as well).

Tighter tolerances when the engine is hot. Larger wet steel sleeve expands less than smaller dry sleeve or for that matter high silicon aluminum. Low tension rings require everything to be machined just so to get the most of everything. The build book states quite clearly this is the primary benefit of a wet sleeve, tighter tolerance, less piston to wall clearance is necessary, less ring gap and tension, more power. That good enough?

Also, to clarifiy...nobody I know has ever burned a valve or seat on an LNF...not to say it hasn't or can't happen just that I haven't seen it. You would also be right they do everything they can to get the catalyst warmed up, and keep it hot. The piston does two things, one is to aid cold starting according to GM the other is to create chamber turbulence at high piston speeds, also according to GM.

[This message has been edited by army_greywolf (edited 07-28-2014).]

All stock ecotec blocks have dry sleeves .LSJ , LNF ,LE5 and L61 all use the same basic block .The sleeves are completely surrounded by the aluminum block .Coolant passages only surround the block material that holds the sleeve assembly in place .I have the build book , I have not found anything about wet sleeves . What page is that info on because I would like to be corrected if I am wrong .

You are most certainly wrong the LNF is wet sleeve. Is the last four of the book ISBN 8686? That's for LSJs. Amazon has the 3rd edition but don't buy it the 4th edition will be out in october. "Ecotec Build Book" current edition last four is 8728 but you will also (if thats not already what you have) want to have a look at the solstice performance handbook which covers the LNF specifically with build combinations for road racing, drifting and drag racing. Hope that helps. I think the 3rd edition can be downloaded in pdf too. The LNF service manual supplement for the cobalt can also be downloaded but i don't know where, I will look and get back to you.

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

That was already posted, the stock LNF sleeve is a wet sleeve, hell I've installed darton sleeves in an otherwise factory LNF.

I have the third edition and I just went through it .And looking at the picture on the link provided I dont see anything that resembles a wet sleeve .I have also been researching the outfits that put in the darton sleeves and they dont seem real clear about what they do .When I built my turbo 2.2 eco that is in my fiero now , I briefly considered getting it sleeved .I found that there was a high failure rate on sleeved Gen 1 blocks and decided it was not worth it .The stock gen 1 block will handle up to 500 hp and that is a lot more than I was ever shooting for . I am going to keep looking for a picture of a wet sleeve assembly but I dont think I will find one .The major improvement in the new LNF blocks are that they are sand cast and have more ribbing than the old bocks .This gains 5 lbs in weight and a stronger block .There is nothing in the third edition build book about the new LNF block that is in use now . A wet sleeve is flanged on the top and drops down in the engine block and is completely surrounded by the engine coolant .They are sealed by O rings top and bottom to prevent coolant leaks .That is the definition I have for wet sleeves .

This is true but the fact remains coolant passes around the outside of the sleeve and that means wet sleeve correct, the rest is semantics. And yes the new Darton sleeves are worlds better than the previous offerings circa 2009-2010. My point is simple, like the LS motors there is a pretty serious and growing following behind the ecotec and it won't be long before we have someone break a 1,000 hp, already had 898 and 791 between zzp and mongo(A guy that used to be on the css forums) respectively. ((LSJ and LNF respectively as well))

[This message has been edited by army_greywolf (edited 07-29-2014).]

quote Originally posted by army_greywolf: My point is simple, like the LS motors there is a pretty serious and growing following behind the ecotec and it won't be long before we have someone break a 1,000 hp,

GM already did it.

quote Originally posted by army_greywolf: Tighter tolerances when the engine is hot. Larger wet steel sleeve expands less than smaller dry sleeve or for that matter high silicon aluminum. Low tension rings require everything to be machined just so to get the most of everything. The build book states quite clearly this is the primary benefit of a wet sleeve, tighter tolerance, less piston to wall clearance is necessary, less ring gap and tension, more power. That good enough?

No, that's marketing crap.

A wet steel sleeve will expand like a wet steel sleeve... that is it will expand with the TCE of steel, which means that it expands more slowly than the piston. This requires the piston to be fit loose when cold, as the piston will expand more than the bore does.

A cast-in-place sleeve is pre-stressed (squeezed) by the cooling aluminum during the casting process such that it expands at the same rate as the aluminum. The piston is also aluminum. The bore and piston expanding at the same rate is what allows tight piston to bore clearance.

The feature primarily responsible for allowing tight hot clearances in modern engines is having the head bolt threads deep in the outer block wall outside the water jacket instead of in the deck surface as with traditional small block Chevies and similar old engines.
I think every engine designed in the last 20 years has this feature.

[This message has been edited by Will (edited 07-29-2014).]

quote Originally posted by army_greywolf: This is true but the fact remains coolant passes around the outside of the sleeve and that means wet sleeve correct, the rest is semantics. And yes the new Darton sleeves are worlds better than the previous offerings circa 2009-2010. My point is simple, like the LS motors there is a pretty serious and growing following behind the ecotec and it won't be long before we have someone break a 1,000 hp, already had 898 and 791 between zzp and mongo(A guy that used to be on the css forums) respectively. ((LSJ and LNF respectively as well))

If you go to the link you posted above and press the right hand arrow eventually you will get to a cutaway picture that shows the aluminum block material surrounding the entire LNF sleeve .Stock from the factory , they are cast in place dry sleeves .When the machine shop cuts the sleeves and machines the block to put in the MID dartons , the resulting exposed coolant jacket gives the impression that the LNF came with wet sleeves but it is not the case . The LNF engine is what it is : a high output lightweight engine that would work great in a fiero .Add the GM tune and bump it up to 300 /300 and it would be an awesome performer .But as far as high horsepower potential , it will never see the 1400+ HP that the L61 based motor acheived . I believe that there comes a point where all the sculpturing in the piston crown is going to prevent the kind of airflow needed to push beyond the 1000HP mark .If I had to do my build over again , I would use the LNF platform .But only because i am happy with the power level they come with stock and it would be cheaper than replicating what I have done to my 2.2 .

Agreed the LNF is not as max horsepower capable as say the LSJ. The DI system is still relatively infantile as far as aftermarket concerns. Now that said with the ecotec3 engines out that won't remain so for very long.

Not all aluminum expands faster than steel it has alot to do with composition and manufacturing processes. Forged over cast, high silicon, etc. You would not sleeve a lnf or lsj on stock pistons nor would you place cast pistons in a sleeved block. I would be inclined to use a piston made with a low thermal expansion alloy which allows me to tightly fit it to the sleeve AND use low tension rings which if you look at Wiseco documentation is exactly what they prescribe for a high horsepower ecotec build. I guess you need to do more research, not all aluminum alloys are created equal.

quote Originally posted by army_greywolf: Not all aluminum expands faster than steel

Yes, it does. Go look up the numbers.

http://ntrs.nasa.gov/archiv....gov/20030106070.pdf - A NASA 16% Si alloy specifically designed for pistons
18.50 x 10^-6 per K.
http://idpsun.engin.umd.umi...in/AluminumAlloy-390 - Standard A390 aluminum commonly used for engine blocks
18 x 10^-6 per C (a C = a K)

http://idpsun.engin.umd.umi...in/AluminumAlloy-390
Cast Grey Iron is 10.8 x 10^-6 / K
Carbon steel is ~13

quote Originally posted by army_greywolf: Agreed the LNF is not as max horsepower capable as say the LSJ. The DI system is still relatively infantile as far as aftermarket concerns. Now that said with the ecotec3 engines out that won't remain so for very long. Not all aluminum expands faster than steel it has alot to do with composition and manufacturing processes. Forged over cast, high silicon, etc. You would not sleeve a lnf or lsj on stock pistons nor would you place cast pistons in a sleeved block. I would be inclined to use a piston made with a low thermal expansion alloy which allows me to tightly fit it to the sleeve AND use low tension rings which if you look at Wiseco documentation is exactly what they prescribe for a high horsepower ecotec build. I guess you need to do more research, not all aluminum alloys are created equal.

I'm not trying to beat you down... just trying to get across "do the right thing for the right reason".

I'd like to see pics of an LNF block/sleeves. That would be informative.