You know, diesel engine manufacturers used to both supercharge and turbocharge their engines in the same way WCF is doing with this 3800. For a very important reason, they stopped doing so. More on that in a min.
I think the WCF SC'ed, TC'ed 3800 Fiero is all show with little go, personally. Getting back to the SC and TC, everyone is forgetting the heat factor. Yes you can compress the air twice and get even more volume in the engine but you are still trying to shove more heat in. All this heat is going to limit the amount of timing and boost the 3800 can handle, thus limiting its power potential. The only advantage of running both a turbo and an SC that I can see is an attempt to solve the turbo lag problem. However, compensating for less than a second of turbo lag by ultimately making the car slower in the long run really doesn't make any sense. You are better off just running EITHER an SC or a TC that best matches the engine you are putting it on.
Bottom line with the WCF car: I don't see an intercooler and I have not heard anyone say this car will have an intercooler so I am left with the conclusion that this engine would be lucky to run faster than most stock 3800 II SC engines.
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03:23 AM
West Coast Fiero Member
Posts: 2044 From: Los Angeles, CA, USA Registered: Jun 2001
Why does everyone have such a goddam hard-on for a damn intercooler? Simply put, the pure physics of an air over air intercooler have proved that this method would be the least efficient in lowering intake temps when compared to water or fuel injection. The beauty of using fuel to cool the intake charge is astronomical - not only does it have a better heat-transfer coefficient than the A over A, but this method can also be used in conjunction with Engine management, just like Chris West' car.....
LOOK, I am not gonna argue with you over the internet as arguing impedes on valuable masterbation time ( HAHAHA ) so whatever you say is right and dont let anyone tell you its wrong and continue to stay closed minded on your somewhat stable thoeries.
You can try asking Chris yourself on the theory and application of the assembly, however Chris has pretty much given up on trying to explain how to properly turbocharge an electronicly controlled internal combustion engine to those that call and ask as they refuse to listen to any new input and would rather hear that "it is ok to continue doing what your doing" from Chris.
To some it up one would have to ask if this setup simply works, or works well.... from driving the car, it works QUITE f**king well as the car loves to spin the wheels and lose traction in any gear at any speed.
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05:46 AM
mrfixit58 Member
Posts: 3330 From: Seffner, Fl, USA Registered: Jul 99
air at a given boost has the same oxygen... so if u run the turbo at 5..then the super at 10......how is that different thatn running jsut the super at 10. its not like magicly 10 psi can hold more oxygen...air is approx 20% O2....doesnt matter if its compressed or not....if its compressed u jsut get more VOLUME of air into the engine thus more O2. Nitrous actually ADDS O2.
...
Have you ever stacked two house fans one in front of the other? What happens to the second fan? It speeds up. That's right, it will run faster and pull less amps then running the fan in stagnate air.
So if you apply this theory to the turbo/supercharged combo... Using the turbocharger for the first stage of boost, the supercharger will work less to gain the "10" psi (as in your example). Therefor, you can get the same boost with less work. which means the engine is making power more efficiently.
Simply, it costs you vertually nothing to use the exhaust gases to gain the first 5 psi and your supercharger had to work less to go from 5 psi to 10 psi.
The only limitation to this set-up is that yor exahust system is criticle. It has to have the right exhaust velocity to spin the turbo correctly (get the right turbo rpm and the right engine rpm) but, at the same time, not be so restrictive that it chokes the motor.
Mr.Fixit58 just hit the nail square on the head...lol! I think everyone has an opinion especially on twincharging, but that is the beauty...If you don't believe it works then come down to Cali...It was a blast to see this thing move...REALLY! Sorry you CANNOT compare a 3800SC to this??? I have seen very powerful 3800 Fieros but I think this one takes the cake as the absolute sleepr...This thing hit 14psi almost at the blink of an eye...I was on the edge of believing...NOW I AM A strong believer!...you cannot absolutely believe the crap you read without application this is a good example...and yes aftermarket engine management makes a difference!!
Darth Inefficiency is a thin-line...subjective!! What makes an L67 inefficient is the inherent design of the blower we can all agree??? However when you are shoving another xpsi into the blower guess what happens???Yep now you skew your hard data...I don't disagree with you, but I also don't agree...remember a blower will make so much power till it hits "the point of no return" well so will this design but in no way has this hit that point either...so you see, your data is still flawed...well to a point! In theory, you also seal the blades in the blower by increasing its efficiency...so their are inherent benefits still...however you cannot compare a 3800 Sc nor can you compare a 3800 turbo as this is a very different animal... Timing? cannot be a problem because you input whatever you "DEEM" safe...you threw GMonopoly in the trash...(stock PCM)...
[This message has been edited by nocutt (edited 09-06-2003).]
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02:34 AM
Will Member
Posts: 14226 From: Where you least expect me Registered: Jun 2000
Blowers and turbochargers go about compressing air in quite different ways. A roots type blower makes boost based on airflow ratio across the blower. A centrifugal compressor sets up a pressure ratio across it. Assuming for the sake of the example approximately equal VE across all RPM, then a blower will make boost that is a function of the ratio of airflow of the supercharger vs the airflow of the engine. If the SC moves 62 ci of air per revolution, and the engine pulls 93 ci (~80% VE) per revolution, then the drive ratio would have to be 150% for the SC to break even. A 200% drive ratio would mean that the blower moves 124 ci for every 93 ci the engine takes in. With 100% adiabatic efficiency, this would be 124/93 = 1.33 bar MAP or about 5 psi. The actual boost is going to be significantly more than this as the adiabatic efficiency of the blower is significantly less than 100%. At a 200% drive ratio, the SC would pull air like a 3.8*1.33 = 5.0 litre engine, so any turbo pushing air into the blower would need to be sized for a 5 litre engine. This is all pretty basic.
The engine should act just like a turbo 5 litre. The presence of the SC shouldn't make any difference, as far as the turbo is concerned.
Now, the turbo compresses the air flowing through it at 1.5 pressure ratio, for example, and generates about 7 psi of boost, but at something less than a 1.5 density ratio due to its adiabatic efficiency, which is much better than the blower's, but not 100%. This 22 psi absolute pressure is feeding the blower, which grabs 124 ci per engine revolution and tries to push it into 93 ci of cylinder volume, increasing the pressure by 1.33+pressure increase to due additional heat from abysmal efficiency, or a minimum of 30 psi MAP, or about 15 psi of boost. Although the blower only made 5 psi of boost fed by atmospheric pressure, it made 8 psi when fed by higher pressure. The methods of forced induction are somewhat synergistic in their effects.
However, an engine fed by a turbo alone would make more power at 15 psi of boost than the twin charged engine because its intake temp would be cooler and the intake charge denser, and it wouldn't have the parasitic loss of the supercharger to deal with.
An engine fed by a turbo alone would pull like a 3.8 litre off the line, then get really fast when the turbo spooled. A twin-charged engine would pull like a 5 litre off the line, then get somewhat faster as the turbo spooled.
Basically, the heat and inefficiency of the blower compromise the efficacy of a twin charged setup. I would really love to try one with a much more efficient twin screw blower, however.
The Mk I MR2 guys do this with their 4A-GZE supercharged engines. They add a turbo to augment the boost of the supercharger, but those are 1.6 litre engines, so they need all the low RPM help they can get. I don't think a 3800 in a Fiero really needs much help at low RPM.
My personal preference on the 3800 would be for straight turbo, although I'd probably keep the SC manifold and use an SC air/water intercooler with a custom plenum on top and the throttle body of my choice.
As far as intercooling goes, water/alcohol injection is at least as good as a really good intercooler, and you can't built a really good intercooler into a Fiero. Fuel/Nitrous has the same properties. In fact supplemental injection at the throttle body is not uncommon for piggy back fuel strategies. At WOT, throttle body injection is as good as port injection. Port injection would be used at low RPM for driveability and economy, but once those injectors are maxed, a set of injectors at the throttle body kicks in to keep the fuel supply steady. The heat of vaporization of the fuel helps cool the intake charge before it reaches the cylinders. Also, a setup like this lends itself well to wet N2O use. A little squeeze on a twin charged engine would be a really cool triple-power-adder arrangement, as well as cooling the intake charge and spooling the turbo faster.
I still want an intercooler so I don't have to think about how much water/alcohol/nitrous I have left, but that's my opinion.
------------------ '87 Fiero GT: Northstar, Getrag, TGP wheels, rear sway bar, rod end links, bushings, etc.
'90 Pontiac 6000 SE AWD: Leaking ABS unit fixed, load levelling rear suspension fixed, still slow
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12:16 PM
Oct 17th, 2003
Neal Steffek Junior Member
Posts: 3 From: West Allis, WI,53214 Registered: Oct 2003
I don't want to be an ass since this is my first post here but to be honest, I don’t see how having a turbo AND a SC is going to help. There are a LOT of people on www.clubgp.com looking at this and wondering "why?"
With our GTP's we use the 3800 SC'd with a M90. The best thing is to get an IC for us.
If you want to get a IC for this try the IC from www.zzperformance.com You will have to work a little with it, but I think it would work best for what you are doing.
Keep this updated, as there are a lot of people with GTP's waiting to see what happens.
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11:40 PM
Oct 18th, 2003
spddy Member
Posts: 815 From: Concord ,ca usa Registered: Mar 2003
pics will be comming soon. but why you ask ? Why not...it is definatly different and so far on the dyno its putting just over 400 at the rear wheels and we've just started a massive intercooler instal which on paper will be good for another 50 to 80 more ponies This thing is a monster and aside from that it looks really cool too...
I don't want to be an ass since this is my first post here but to be honest, I don’t see how having a turbo AND a SC is going to help. There are a LOT of people on www.clubgp.com looking at this and wondering "why?"
With our GTP's we use the 3800 SC'd with a M90. The best thing is to get an IC for us.
If you want to get a IC for this try the IC from www.zzperformance.com You will have to work a little with it, but I think it would work best for what you are doing.
Keep this updated, as there are a lot of people with GTP's waiting to see what happens.
Why get a small pulley on an L67? why rev the engine higher than the stock red-line? why turbo a 3800? Why ask why? LOL! A lot of folks have speculated the pitfalls but still the car dynoed at 425hp at 12 or 14 psi NON intercooled on a stock S1! A stock L67 will not make 400hp @ 14 psi intercooled Sc or turbo... This shows the potential of both the engine and FI especially turbos...I remember when I was told I will 'blow the bottom-end out' an L36 if I decided to turbo it? yeah right...that was almost 7yrs ago... This simply put it isn't for everybody, but folks with the S1 engines...this is just another avenue...
[This message has been edited by nocutt (edited 10-18-2003).]
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12:16 AM
Neal Steffek Junior Member
Posts: 3 From: West Allis, WI,53214 Registered: Oct 2003
Why get a small pulley on an L67? why rev the engine higher than the stock red-line?
The thing is, you CAN'T do those things. At least now on a stock 3800. You CAN do a smaller pulley, higher RPM IF you have the supporting things to get the air out of the 3800 easier/faster. Think of your engine as a garden hose, there is no use pushing the water into the hose, if you can't get it out faster.
Also The PSI has NOTHING to do with power, the more PSI/boost you put into that engine the LESS HP it is going to make. Why you ask? Because the air/boost is going to be so damn hot that that all the timing is going to be pulled, thus a slow car. This car NEEDS an IC to even be considered serious.
The thing is, you CAN'T do those things. At least now on a stock 3800. You CAN do a smaller pulley, higher RPM IF you have the supporting things to get the air out of the 3800 easier/faster. Think of your engine as a garden hose, there is no use pushing the water into the hose, if you can't get it out faster.
Neal trust me...you aren't saying anything new to me...I wanted to use those lines as examples of ppl arguing over moot points... When I turbocharged my engine back in late '97/ early'98 there was virtually NOTHING for the L67 besides the BPU's. I decided to do what ALMOST EVERYONE...even thrasher said was impossible to do...that is almost the same analogy here...the S1 3800 have virtually no aftermarket either and I remember the owner of this twincharged fiero was stuck with this engine due to unscrupulous folks on the net...hence this particular project was put into fruition. It is different, it goes against the grain. Like I have said and will keep on saying, let someone produce empirical data...I will shut up
quote
Also The PSI has NOTHING to do with power, the more PSI/boost you put into that engine the LESS HP it is going to make. Why you ask? Because the air/boost is going to be so damn hot that that all the timing is going to be pulled, thus a slow car. This car NEEDS an IC to even be considered serious.
Hope this helps a bit.
Generally speaking...you are correct, however we aren't using this data as hard evidence but as a reference because you aren't starting at atmospheric pressure anymore + the GN turbo has not yet even stated heating till say 17psi (so we are still within its efficiency ring)...so the data has changed, also we aren't using GM's PCM...so again your data has changed, the blower isn't "ask" to spin more than how it came from the factory...(so technically it is still running within it rev range) do you understand where I am coming from... Yes I am with you with the IC, but let us not remove the fact...this engine has posted more than 400 hp to the wheels without an IC...no stock L67 will attain this without some other supporting mods @ the same boost level with a blower or the same turbo... NB: There is even more ways to make this unit more optimal...however it is beyond the scope of the thread...lol!!
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01:26 AM
PFF
System Bot
Darth Fiero Member
Posts: 5921 From: Waterloo, Indiana Registered: Oct 2002
Why does everyone have such a goddam hard-on for a damn intercooler? Simply put, the pure physics of an air over air intercooler have proved that this method would be the least efficient in lowering intake temps when compared to water or fuel injection.
Tell you what, I think you need to take that statement over to www.turbobuick.com and post it there and see how many people will disagree with you. GM made 2 versions of the GN, the hot air ones (84-85) that did not have an intercooler and the intercooled (86-87) ones. Pound for pound, I have NEVER seen a hot air GN hold a candle to an intercooled one.
Besides that some of you are comparing apples to oranges if you are talking about the L67 intercooler. It is a water-to-air unit that really isn't that great. I have seen some tests that show only a 20 degree intake temp drop which isn't much. Furthermore, I have heard from people running these IC's that they had to put on a smaller pulley after installing the IC just because it was such a restriction.
As far as injecting something to help cool the intake charge, I will have to say that the two best things you can use are alcohol and propane. I don't like the N2O idea because it is too dangerous especially under boost. I have seen enough nitrous explosions in my time to keep me from wanting it on any of my cars. Besides, the whole point of having an intercooler is to cool down the intake charge without having to worry about filling another tank just to do that job.
But getting back to the whole turbo on an SC deal, you only really need one. Turbos are more effecient than any SC could hope to be and when you try to use both of them at the same time, the SC usually ends up being more of a restriction than a help. Don't believe me? Prove me wrong.
------------------ 1987 Fiero Coupe 3800 Series II Intercooled Turbo (12.79et @ 106.6mph) 1987 Trans Am GTA 5.7L Superram 4L60-E (13.1et @ 109mph)http://dtcc.cz28.com GM EFI chip reprogramming & V6 Engine Conversions
[This message has been edited by Darth Fiero (edited 10-18-2003).]
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01:30 AM
spddy Member
Posts: 815 From: Concord ,ca usa Registered: Mar 2003
Yes it is true that the turbo can be more restrictive when matched up with the s/c but only if sized up wrong....we did a test by putting a larger turbo on this motor, #1 it became a lot less restrictive #2 it now has a hell of a lot more pull all the way through rpm range And to answer another ? YES the car is up and running
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02:20 AM
Dec 6th, 2003
boristheblade Member
Posts: 501 From: Rochester, MN Registered: Nov 2003
Here we can see the beginnings of the stainless steel exhaust header that will be replacing the factory 3800 Series 1 units. These will be perfect for the turbocharged application as the material is much more suited for this application versus mild steel.
wow...OMG ! the best of all 3 worlds ! 1. displacement 3.8 Litres 2. supercharging 3. TURBO
my only worry is the lack of expansion room in the flange, believe me under max exhaust temps that flange will grow approx .0625 to .125 (please don't ask me how I know!) right were ya don't want it to so hopefully those enlongated exhaust bolt holes will be enough
keep post'in
------------------ 84 Fiero Turbo Vortec 4300 Phantom GT L35 block, Syclone Intake and ECM T04B 50lb injectors, 3 bar map sens, T04B H3 Turbo www.cardomain.com/id/vortecfiero Murphy's Constant Matter will be damaged in direct proportion to its value Murphy's Law of Thermodynamics Things get worse under pressure. Arthur C. Clarke "Any significantly advanced technology is indistinguishable from magic"
