I have an '89 ASC GTA Convertible, bone stock. 3.27 axle, auto.

What 1/4 times have you guys seen with stock or close to stock L98 engines?

 

Mine ran 14.40s at 96 with 150,000 miles.

I believe I weighed in at 3340 without me in it.

 

14.2 @ 97/96

 

In sig.


The 90-92 Z28 cars are going to be faster than your car.

 

What free mods do you have done? All I have is a MSD 6A, accel coil, K+N, and TB airfoil

 

I put in a conical K&N to get rid of the airbox, bumped the timing to 12.5-13 degrees, took the screens and fins out of the MAF, bypassed the coolant around the TB, which makes it really easy to clean the TB. 180 thermostat, ported plenum,AFPR set at 48psi(not really free, but cheap).

The things that made the most difference were the KN, timing and cleaning the TB.

nick

 

One of my friends has a 1988 GTA L98 and the other has a 1990 IROC L98.
The GTA stock with 73,000 miles ran a 14.8
The IROC ran a 14.6

 

Wow, you guys with the 14.2 1/4 mile times... are those times stock!!!??? At a drag track??? Cause my GTA only does 14.559 with a few mods like exhaust and intake and ignition. I don't see how you guys got such fast cars.

 

14.3 @98mph here... But there are a lot of reasons why you wont pull that kind of time stock out of an 89 GTA convertible. First and foremost you've got at least 500lbs extra to haul down the 1320. Second you're running MAF instead of speed density. Typically a maf 350 in a Firebird is somewhere between 14.5 and 15 flat depending on driver, track conditions, etc. Add to that the convertible top and reinforcements and I'd say you'd be lucky to hit below 15's with it in stock condition.

 

I still don't know how you guys are pulling low 14's stock... and I am pulling mid 14's with mods

 

Dude it was just explained, b/c of your weight and MAF......It looks like you've been here for a while you really should know these things by now. Sorry if i sound like an a$$ but these are basics, just look at the old post and trust me you'll understand and learn alot, i know i did

 

I have had my MAF car in the 14.4s, for several runs on a warm day. Hard call what you consider "stock". I have never pulled the valve covers or exhaust manifolds yet, so my block and heads are stock. Done many other basic first mods. Car had about 55,000 on it last summer when runs were made. Since then I had the tranny worked on, now I have the base intake off for porting work.

Can't wait to run it this year.
Also, 3.73s are coming, so I plan to get into the 13's!!!!

 

OK, so that explains my car... but an earlier post said that a GTA was only 2 tenths of a second behind an Camaro.

Also, I know someone with a 1988 Formula350 who is running an average of 13.9's with quite a few mods. Now when I am talking stock, I mean NOTHING done to your car at all.

 

Well, I ran my 14.40 @96 in bone stock conditions in a nice cold day. Perfect weather for running. This was actually at around 135-140,000 miles.

I then cut the air box, bumped up the timing and threw on a catback exhaust and ran a 14.20 @97.55 on a 90+ degree day. I actually think I might have had a slightly higher trap speed on one of them.

I was hoping to get back up there on a cold day and try again, but haven't got around to it. Headers will be next and I'll give it another try. Just mainly trying for 13's.

Then a 100 shot and a small cam, and I'll be aiming for high 12s.

 

Yeah, BM92Z ran a 14.1 with I think just K&N's. Some dude with a 87 Formula L98 on here ran 14.2 with the timing advanced. Also heard of various other stock 87-89 IROC's running 14.2's and the 90's Z28's running 14.1's myself and in tests.

 

most of it is in your 60' times. thats were my problems are too but, I have a few mods

 

My best time was all stock, normal tune up stuff, plugs, cap, rotor, fuel filter, K&N, 02 sensor, with bald tires and 113,000 miles, launching at idle. Temp was warm (JULY) and I had been sitting in staging lanes for 5 minutes... The only change to the car that really would bend the all stock status would be that I removed the airbox. I actually did this in the staging lanes, took thirty seconds with a flat blade screw driver and a 10mm wrench, I'd still say it was stock, but picky people might disagree.

 

The cars running at sea level will be faster also, my 90 ran 14.30s btw.

 

Any guesses at what I'd be running in 1/4? The car is in great shape.

Look at the sig for mods

 

wow... i'd say 13.7@ 99MPH... don't ask me how I know.. CAUSE I DON'T LOL... just a guess... but hey, let me know if I am close.. hehe

 

Before I did any mods, I ran her at the track in Salt Lake City (4500 ft above sea level) and pullled off an altitude corrected 14.70. Since then I have made a few mods but nothing serious as of yet, but I still manage traction limited 13.90s (alt. corr). There is alot ot be said for these motors once you get 'em to breath.

JD

 

id say low 14's all that stereo **** will slow you down

 

See sig. (ran on Nittos Drag radials)
The best I could get with street tires was 14.202

 

i went 14.0 on a blizzack snow tires. All i have is borla and a stock 90 vette motor

 

you used snow tires at a drag track?

 

Doing a base line before my mods i ran a 15.3 at 89mph with what turned out ot be 3 cracked pistions and 6 bad rings (she was in bad shape)

 

what the heck.... why is my car so slow then? Or, wait.. why are the cars they use to get factory performance specs so slow?

 

nblanchard I have to agree with you. ever book or mag that i have read i have never seen times in the 14's without mods

check out this to see for your self
http://www.gtasourcepage.com/RoadTestsMainPage.html

if they can not do better than that with a new car i have to question the results of others who beat it by a second or more with 60k+ on them

 

How much more can that top add to the car? Tech Data says the convertible is 3377+ options, so I figure 3550 for the curb weight, max.

I saw 2 braces under the car, and the top itself is one thin layer of canvas under a layer of vinyl, extremely thin overall. I can't see that as being much heavier if at all than the t-tops/glass hatch it replaces.
The brackets and all that are light as well.

Last week I ran dead even with a Mercedes CLK430.. 0-60 in 6.1, 14.5 in the 1/4.. So i'm assuming I should be able to see somewhere in the mid-high 14's. Also note that the GTA has MSD 6a, accel coil, K+N cone filter, and the TB airfoil. Next is ported plenum/AFPR. Before the plenum and AFPR, do you guys think 14.6-8 is realistic?

 

Steve, do you have exhaust done? Cause your times are about what I am running now

Trigger, thanx for your supports... I also got my test numbers from gtasourcepage

 

No, I haven't touched the exhaust - that's coming in a few months, im looking at an american thunder cat back, then some headers.

 

hmmm... well... I guess I'll have to wait and see what I get come april 20th.