Hey guys. I picked up my 88 GTA about 3 weeks ago and I'm getting it up to street condition after it has been sitting with the PO for a few years. He tells me (and I have yet to verify) that the car has a 3000 stall, 3.73s, and a completely worked transmission. By worked i mean he somehow spent $3000 on it 6 years ago and can only tell me it has a shift-kit.

The car is the L98 auto and has 85,8XX miles and everything else is stock down to the paper air filter. He claims that he ran the car about 5 years ago and it ran 12.9Xs all day. I should also add that he wasn't the most knowledgeable guy with these cars, saying at one point that "this car was the first year for the WS-6 package" and "I also have a 2005 Trans Am at home."

I can attest to the gear whine and the shift-kit. If you make a turn from a stop in this car and it shifts into 2nd before you straighten the wheel, the tires will spin and the rear fishtails out. This is at 20mph too. I haven't had time or found a place to launch it yet, but the car is definitely a rocket. I can't brake stand above 1500rpm without the tires going up so I can't confirm the stall. I'd like to get underneath it and check everything out, but I don't have a lift or decent jack right now.

My question for you guys is if you think 12.9s is bs or not. When I was buying the car I just dismissed that it was possible with an 88 GTA being high 14s at best stock. After driving it I'm not so sure now, but I also have never driven a car that could run 12.9. I want to take it to the track and find out, but the car still needs a full tune-up and all the fluids changed. Thanks in advance for your help.

~Matt

 

Probably a low 14 maybe high 13 sec. car. Sounds like the guy was a tool.

 

3000 stall and a L98 TPI don't usually go together. The converter stall needs to match the camshaft. If the cam is still stock then the converter has way too much stall. Since the TPI usually runs out of steam in the 5500-5800 range, having a high stall converter means there's very little rpm range for the engine to work. Might work well at the dragstrip but would really suck on the street.

Doesn't matter what gear ratio is in the diff, there shouldn't be any gear whine.

 

The guy was a tool. I know that a 3000 stall and 3.73s are probably the worst two mods that anyone can do to a stock L98, but unfortunately that is what I have to work with. They would be farthest from what I would have done because I wouldn't want to immediately force the car into high rpms where it can't breathe. My next mods will be trying to match the gears and stall because it would be pointless to spend money putting stock parts back in. All new intake parts like a cold-air kit, 52mm TB, runners, intake manifold, plenum, and airfoil are my plan, plus a custom Comp cam, full exhaust, chip tune, 1.6 rr, aluminum/ported L98 vette heads and LS1 front brakes.

My only question was really what you guys thought it would run and/or if 12.9 is completely made up. My thought was mid to low 14s.

~Matt

 

This totally hits 2 of my pet peeves... idiots that are full of crap and misconceptions about the TPI...

The idiot that you bought the car from I can't do anything about, and if he has a 2005 TA.... well...

but the TPI... well the tpi setup is tuned for best power right around 3500rpm. Yes, they typically fall flat before 5000rpm (my 87 formula 350 ran fastest shifting at 4600rpm according to the datalogs), but a 2800-3200rpm stall converter is about perfect for the car, if it's something like a PI or Yank which is still relatively drivable on the street, good STR and with a proper lockup clutch.

3.73's would be right around the sweet spot for these cars running a 1/4 also, with a 26-28" tall sticky tire...

That said, _I doubt_ that someone clueless ran a 12.9 out of an otherwise stock L98 car. It's possible with what you're describing (I got a 13.5@100 out of my formula 350 with nothing but an SLP cold air and cat back and a lot of tuning, I suspect that the right gears, converter, shift kit and some sticky tires could get you another 1/2 second but only one or 2 mph, I didn't go any further because my second gear was slipping and finally let go), but most people only run 14-15s with these cars.

 

I have been driving it on the street and the only place that the car feels at all weak is at off-idle. With the slightest amount of gas it jumps and just wants to peel out. Even at the top of first it pulls all the way up to the shift point with no feeling of a drop off. I did a brake-stand in an empty parking lot the other day and got her to just under 3k rpms so the stall is probably correct. I want to take it to the track before they close for the winter so I'm hoping I can squeeze it in soon.

~Matt

 

I had full bolt ons (pulleys 1.6 rockers, HSR intake, full exhaust, mild tuning)with 2800 stall and 3.42's with full suspension and I hit 12.95 at 103.8 on a 1.71 60 foot I believe i was.

STock TPI with exhaust, 2800 stall and 3.42's I went 13.63 at 97 on a 1.75 or so 60 foot i cant recall. So I doubt he is running 12.9's but there has been a car here claim to hit 12.9's with stock TPI and bolt ons/stall/gear...

Your mods are good for a aftermarket TPI intake and some 1.6 rockers, or better yet a stealth ram or superram if you can find one. Heck even a miniram. ANy shorter runner intake will love those gears and stall.

 

Thanks for the input guys. I'm having a large problem with the car now involving traction and I'd like to try to fix it without slicks or expensive race tires. I'm talking about a full burnout at a roll with 1/2 throttle. Any decent amount of acceleration and the tires go up and I fishtail, and yes the tires are still good with plenty of tread and good psi.

What rear suspension mods could help me hook up? If I remember right, I think its the rear lower control arms that can be replaced or adjusted. I plan to replace any worn suspension components and all the bushings in the near future. My goal is autocross so I don't want to skimp on any suspension mods, especially when I can't even get the car to go forward.

~Matt

 

shocks/springs to fit the style of driving you do...adjustable shocks and be used to help traction on street tires as well as slicks.

LCA relocation brackets. Keep the rear of the LCA pointing downward/lower than the front where it attaches to the car frame. That will help plant the rear and eliminate wheel hop issues and poor traction issues.

adjustable torque arm with abit better pinion angle can help some as well.

At some point however, a car will just spin tire easily if it has enough power. But you shouldnt be torching the tires like that with half throttle from a roll unless its a slow roll on slippy pavement.

What size tires and what are the ratings on the tire that you are using? What speed roll?

 

I would guess 20mph and half throttle and I will just sit and spin. Definitely at 3/4 throttle. I don't get that heavy, G (as in gravity) feeling in my stomach when I get on it in this car, but it turns these tires into pencil erasers. The tires are definitely the stock size (245 60 16?) because I checked when I was buying the car.

I have the Eibach Pro-kit in my garage which will eventually go on, but I was waiting to save up and get Koni yellows and install them all at once.

I plan to hit the 1/4 mile next Friday but I feel like I'll have to wait to get to WOT and have like a 3+ second 60ft just to hook the way things are now. Theres no way I'll be able to buy anything and/or install it before then, so I'm just asking for the future. I should have times with the current set-up next Friday.

 

yeah i can see it spinning in first with 3000 stall and those gears at 20mph but it should eventually hook if the tires were decent treadwear rating and traction ratings. Just need to feather it out the hole until it hooks.

 

You could throw a sandbag in the back for some wieght. Or a dead body. Your choice. But anything that Orr listed will work for you too.

 

I've always run better times in my 4th gen with a full tank of gas, even if it is 100lbs heavier...

 

My 89 with a stock 150 K mile L98 went 13.87 at 101 with 4.10 gears and a manual trans, that was with a carb swap, so, if anything, you should be low 14s maybe.

 

The original spare tire is still in the back so there is a little weight. It's really annoying when turning though because it rolls around. I also took the car on the highway last night and I definitely need to change the speedo gear because it is way off.

~Matt

 

Bolt the spare down like you are supposed to.

 

Don't worry I took it out already. It was just sitting in that nook in the trunk when I bought it.

~Matt

 

Let's see some pictures of the engine. Sounds pretty quick.