I just bought an '89 GTA w/an L98 5.7 TPI motor. The engine already had Hooker Super Comp Shorty Headers, Flowmaster Exhaust, and a K&N Airfilter. I have just purchased some SLP runners, BBK AFPR, 1.6 Roller Tip Rockers, and a used JET Airfoil. All of which has not been installed yet. Stock 700R4 and 3.27? gears.

Two questions:
1) Assuming the engine is running correctly as it appears to be, what type of performance should I expect with this setup?

2) How the heck do I install this JET airfoil. I does not bolt on, its supposed to sit in the TB and then be held in place by the air intake tube. But in order to get it to fit properly, it sits fairly far inside the intake tube, and away from the TB. It appears to cause more of an air restriction than to help anything. Any hints would be greatly appreciated.

 

First off...Welcome Aboard!!!!! Now down to business. Your L98 (with those mods) should net you mid 14's if the engine is in good shape. You already have the exhaust side of it taken care of...now you have to go to the intake side of it. Your stock TPI intake is good, but only to about 4000 to 4500 RPM's. After you hit that range you can feel the motor start to die off. I opted for a much easier solution to the intake problem...Nitrous!!! For the amount of money you spend on the intake you can get a nitrous system...Good Luck

Later

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1989 Formula 350
K&N air filter, air foil, TB Bypass, AFPR (set at 45 psi), A.I.R. yanked out, Accel 8mm wires, Fireball external coil, Pulley (just the crank), gutted MAF, corvette servo, Hooker super comp. shorties, 3" exhaust all the way back, No cats, Flowmaster 40 series muffler (one in one out turned down)---Developed a bad habit....bottle related!!!!75 Shot of Nitrous
http://www.theformulasource.com/owne...php?siteid=144

So they made him get rid of it...For decency ya know....But it came back the next day...

My webpage:www.cardomain.com/id/1fastformula

 

I can't afford NO2. Hit the bottle a few times, go fill up. Do it again and again. Buy a supercharger or intakes and you have something to hold in years to come. 8 yrs later I still have my Accel Superram TB, Plenum Runners and Base Manifold. What will you have after 8 years? A bunch of receipts? IMO, NO2 should only be used as a power adder and not to compensate for a crummy intake.

 

For a real good mod go to Scoggin-Dickey and get yourself a set of Vortec heads and their intake to match, they say with a hot cam kit they pushed over 300 HP, the heads are $238 a peice and the intake is $399 (?) and then some to complete the heads.If I wasn't rebuilding my 94 Z28 I would do it and then put a miniram on it and you got one bad beast!

John

 

aklim....first I would like to say thanks for all the knowledge you have shared here. Now for the money you have paid for your intake setup, I highly doubt you can get the 75-150 HP out of them. Yes...Nitrous is a power adder, but for the money it is the best HP gain out there. A hell of a feeling when I hit that little button and feel the car shoot up to 100 in a rush of power. Like I said, You have helped everyone here (including me ) and you are respected. keep up the good work my man..

Later

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1989 Formula 350
K&N air filter, air foil, TB Bypass, AFPR (set at 45 psi), A.I.R. yanked out, Accel 8mm wires, Fireball external coil, Pulley (just the crank), gutted MAF, corvette servo, Hooker super comp. shorties, 3" exhaust all the way back, No cats, Flowmaster 40 series muffler (one in one out turned down)---Developed a bad habit....bottle related!!!!75 Shot of Nitrous
http://www.theformulasource.com/owne...php?siteid=144

So they made him get rid of it...For decency ya know....But it came back the next day...

My webpage:www.cardomain.com/id/1fastformula

 

I'd say low 14's with traction with those extra mods. Dont forget to save up some money to have the trans rebuilt, if it hasnt been already.

The SLP runners prefer cars with mods over stock setups, but they'll work for now until you decide to get heads/cam.


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1991 Camaro Z28
350 L98 w/ T56 (originally 305 LB9 w/ T5)
318 RWHP, 419 RWTQ
12.803 @ 108.50 MPH (1.932 60')
Member: SoCal F-Bodies
ThirdGen 4-Life!

 

Thanks for the input. I'm hoping for low 14's after everything is installed. I really don't want to go with NO2, mainly because I want power all the time, not simply on demand, and I don't want to have to worry about filling a bottle.

Any other thoughts on the SLP runners? Can I expect a negative impact to my off the line torque with these runners...if so, how bad?

 

you dont need the airfoil. the bbk tb already has it formed on the inside where it would normaly go on the stock tb. you'll see a nice gain with the afpr. set at about 42 psi shoul be real nice. a little on the lean side is never bad... you can squeeze a few more horses out that way. vortech heads do respond real well int the l98. power band is small but a hell of lot of torque in these motors. hope this helps.


doug

 

Wanna bet? If you make it lean and the air is hotter than you thought it would be, you will make more power when you put that NEW stroker motor in. The risk is detonation. The ECM is capable of retarding up to 6 degrees and then it is done whether you have detonation or not.

I wish people would just either learn how to program the EPROM themselves on a junk car or pay someone to do it. This fiddling with the AFPR is not good, IMO. You are trying to trick the ECM into doing something you want and that is bad. You should be changing the fuel maps in the ECM for the conditon. This way, the fuel curve is lean no matter what you are doing. If you wanted to do it that way, rip out the ECM and go with a carburator. The idea of an ECM is to change the characteristics based on Barometric Pressure, Air Temp, Engine Temp, etc. The ECM will go on to think that there is a certain amount of air therefore the pulse width should be so much. Outside of that window, it will not be able to compensate. Stock pressure of 45 down to 42 is a 6.67% difference already. MAS are better than Speed Density for adjustments but there is still a window. For WOT, I believe it goes off the settings in the EPROM and it could be bad if it detonates. Even if it does it enough that the KS can pull out timing to stop it (losing power in the process), the accumulated knocking will add up to a new engine.

If you must use the AFPR to change fuel pressure, you should raise the pressure by a few pounds AND drop the pulse width to compensate.

 

Where are you from Chief Poncho?

 

Only 6 degrees? I've seen up to 20 degrees in some chips.

Quote:

<font face="Verdana, Arial" size="2">MAS are better than Speed Density for adjustments but there is still a window.

BS! But lets not turn this into another MAF vs MAP debate...

 

I do believe it was still knocking on my old motor and I saw the diacom take out 6 degrees but if it had kept taking out timing, the knocking would have stopped which was why I said 6 degrees. I know it did not take out 20 degrees on my car or it would have stopped knocking. I also do know that the injectors were the wrong ones and were 26 pph when the chip was programmed for 3o pph. As soon as I realized that I changed injectors.

I am not trying to turn it into a MAF vs MAP debate but I have seen it where the motor runs better with MAF after modifications than those with a MAP. I believe that the MAF is better adapting to changes because it measures the actual amount of air coming in rather than assuming it based on MAP readings.

 

You won't see much of a gain from just the SLP runners. They are nice, but they really need to be matched with a new intake manifold and a ported plenum for the full effect.

I'm predicting real low 14s and possibly high 13s if you get some nice traction and the weather is nice