12.38 et @ 110 mph in a 3800 Turbo Fiero

[Darth Fiero]

Finally, low 12's. Last year, I went 12.79 @ 106mph but that was with a rediculously small intercooler and 2.5" exhaust. Earlier this year I upgraded to a modified stock GN intercooler, 3" mandrel bent exhaust tubing, and a Magnaflow wide-open muffler. First, let me start by saying that I cannot say enough good things about this muffler. This is the BEST muffler I have ever used, and it is quieter than a Flowmaster, Dynomax Super Turbo, or a Holley Terminator...speaking from personal experience. With it's straight-thru flow design, I don't see how it can't flow better than any chambered muffler. But enough with the advertisement...

Anyway, here are the mods to the car:

-approx 3000lbs without me in it
-3800 Series II L67 shortblock
-mildly ported L36 heads
-Camaro L36 intake
-36lb L67 injectors
-stock cam and rockers
-stock GN turbo with ported exhaust housing
-GN intercooler w/ modified inlet/outlet
-3" mandrel bent exhaust w/ 3" magnaflow muffler
-4T60-E trans w/ 3.33 final drive
-95 Bonneville PCM with custom tuning done by me

here is a link to the timeslip: http://dtcc.cz28.com/3800turbo1238.jpg

1.784 60' using BFG 225 55/16 Traction T/A H-rated
12.381 1/4 mile ET
110.03 MPH

93 octane pump gas w/ Klotz hitrate octane boost; 15lbs max boost launching at 2lbs. 20 deg timing at WOT with 0 KR. Shifting at approx 5600rpm.

The MPH looks slightly low to me which tells me the engine is making a lot more TQ than HP, but on a stock cam what do I expect? I have heard that Erson will regrind a stock cam to just about any spec for less than $100 so I might have to check them out.

 

[BuickPower3800]

Very nice! I bet that thing feels like a Saturn V rocket blasting to the moon!

 

[FastFieros]

Go Darth !

Ok, it was my first post so I had to make it Fiero related and productive.

Good luck on your racing to the 11's.

Loyde
http://www.fastfieros.com

 

[nocutt]

I thought you were going to upgrade to bigger comp/turb wheels?
You are reaching the ragged edge of the turbo, (I am sure you know)... Anywayz once you get that car into the 11's I will hate you
MUCH RESPECT MAN, you deserve it...especially with all the info you put out there...

 

[Nocooler]

That's pretty cool.....

Time for alky injection and 20psi......

What are you using for a computer - modifed L67?

Congrats

Jeremy

 

[Darth Fiero]

Originally posted by Nocooler
That's pretty cool.....

Time for alky injection and 20psi......

What are you using for a computer - modifed L67?

Congrats

Jeremy

I am using a 1995 Bonneville Series I SC PCM that I have done a custom chip for. This computer is hooked up to the popular 3.0" LT1 style MAF sensor (actually from a 3100 V6) that is mounted right before the throttle body (blow-thru).

 

[steveX]

Darth , I know the F-body cars come with a 3.5" MAF sensor. also don`t you think it will be better if you mount the maf on the inlet side of the turbo. I figure the ECM will respond better to the un-compress air. Compress air has heat and the MAF will send a false reading to the ECM since the MAF use a Heated wire element.

Also going with the 3.5 " maf might be better since the fuel table of a 5.7 liter and 3.8 with 8 psi (boost) are very close. But then again you are running 15 psi with 0KR which is pretty good.

12.38 is very good. you will smoke alot cars in my town. what you have there is a good street sleeper. I use to street race me BLT until i lost me lic, which i will receive in the next 3 months.

good luck with you project. i remember 5 yrs ago the member of TGP forum said a turbocharge 3800 motor can not me done. now everybody is jumping on the turbo band wagon. figure.

 

[Darth Fiero]

Originally posted by steveX
Darth , I know the F-body cars come with a 3.5" MAF sensor. also don`t you think it will be better if you mount the maf on the inlet side of the turbo. I figure the ECM will respond better to the un-compress air. Compress air has heat and the MAF will send a false reading to the ECM since the MAF use a Heated wire element.

Steve, I am glad you brought this up. I did start out with the MAF sensor mounted between the turbo and air filter. However, the results were the engine had a tendancy to stall at slower speeds if it was under boost and I suddenly let off the gas. It turns out the PCM was reading the air coming back thru the turbo which was registering air flow which caused the PCM to send the IAC counts to ZERO and make the fuel go rich for some reason which was killing the engine.

Once I moved the MAF to just before the throttle body, my throttle response and drivability improved by 200% and the PCM appears to be delivering the correct amount of fuel under all boost conditions.

Also going with the 3.5 " maf might be better since the fuel table of a 5.7 liter and 3.8 with 8 psi (boost) are very close. But then again you are running 15 psi with 0KR which is pretty good.

My induction piping from the turbo to the intercooler to the throttle body is only 2.5". I didn't see any point in running a 3.5" sensor since a 3" unit fit better. Again, no problems in tuning this PCM to the 3.0" sensor.

12.38 is very good. you will smoke alot cars in my town. what you have there is a good street sleeper. I use to street race me BLT until i lost me lic, which i will receive in the next 3 months.

good luck with you project. i remember 5 yrs ago the member of TGP forum said a turbocharge 3800 motor can not me done. now everybody is jumping on the turbo band wagon. figure.

Yea, I even remember there was a tuning company out there that told me I would never get the full potential out of a turbocharged 3800 using the 95 OBDI PCM. Funny, 12.38's using the stock cam in a 3000lb car sounds like I am getting pretty close to the full potential even using this "stone-age" 95 OBDI computer. The bonus is I can swap chips out at the track which is a lot easier than flashing a PCM or swapping the complete unit. In time I am sure I will probably upgrade to an OBDII unit once I gain the ability to tune them myself. But right now the only limitations I see wrong with the 95 OBDI computer is it won't control a 4T65-E transmission. Oh well, good thing my 4T60-E is holding up just fine.

 

[Beau]

Trying to figure out what I can do for manifolds on my 98 GTP, thats already got a turbo cam in it, and l36 L&UIM installled.

Intense SII turbo cam PS, makes 10 less horse NA all through the power band, cept like at 5600 rpm than the stock cam NA.

Yes I know turbo cams dont run NA :] But I would think it would have been better than -10 horse :}

 

[INTENSE-Racing]

Intense SII turbo cam PS, makes 10 less horse NA all through the power band, cept like at 5600 rpm than the stock cam NA.

We ran in the tens FWD with that same cam more than a year ago. Designed by Cam Motion, it's clearly an excellent turbo grind.

Scott

 

[Beau]

Im also wondering if my lifters went flat? Is it possible? I mean how should I test them? Im running stock lifters with 84k on them, with 132 lbs seat pressure. I've always heard lifter tick since Ive installed them, but the car always ran great even NA.

What do you all think?