Can anyone tell me the stock performance figures, esp. top speed, 0-60mph etc - for a stock 1989 TA GTA with L98 5.7l TPI with 3.23 gears please?

Thanks in advance.

Gordon

 

0-60 should be around 6.2s
1/4 mile should be about 14.5s
top speed probally about 150
JP

 

Stock top speed should be about (actually exactly) 116 mph, that's where the computer regulates.

Later, Garrett

 

For a L98 car? I beg to differ. I believe the L03s were limited but I don't know of any TPI motors that were. Top speed stock would be around 150mph.

 

Yup, i doubt its limitted to a pathetically low speed like that. My HO 4bbl can best 130mph, so a TPI 350 should be able to do at least that.

 

I know that my Bro's '88 IROC-Z 5.7 TPI with 3.27's would get to 116 really fast but that was it until he put a thrasher chip in it then it was around 145 - 150. He was close to hanging with the B4C but not quite (B4C was close to 160)

Later, Garrett

 

my 88 formula 350 all stock went well over 116
when i last looked down i saw 125 mph..

i went close to 130 mpg in my 88 iroc-z 5.7

1/4 miles are like around 14.6's

 

WOW 130 miles per gallon!!!!
Do tell how...

L98s were not stopped at 116mph. I have had mine at 140 according to the speedometer, almost totally stock. I don't know if it really was 140 but it was past 116.
Mark

 

Thanks guys.

I've only had it up to about 130mph so far. I wouldn't mind a bit of that 130mpg action - pity is was only a typo!

Gordon

 

With the kickdown from 4th at WOT do you end up obtaining your top speed in 3rd with the foot on the floor - or in 4th by gentle throttle pressure?

 

You will tach out before hitting top speed in 3rd, top speed is achieved in 4th, I hit 142 MPH in 4th but ran out of road before seeing if it would go any faster, but I believe that was probably all she had. I have the L98, auto, 3.23 setup and most people on this board will probably hit between 140-145 with that setup.

 

Thanks Benny.

How much extra top speed do you think the 2.7x gears are worth?

 

Hard to say since the spedos only go to 145 but I believe there is a RPM conversion, but you would need a very long flat road with no cops. I have heard of people pegging the 145 spedo but you would have to put spedometer error up their too, maybe +/- 10 MPH, I don't know. Going that fast was very scary especially with the road I was on and I will not do it again, basically because there is no point to it, most of people who race on this forum are quick bursts (1/4 mile, stoplight to stoplight) but there are some who like the top speed stuff. I just know for once I did 142 MPH and leave it at that. You really need to know the road to test the top speed, one wrong move and its history.

 

Back in the day Motor Trend did a Top Speed shootout with the GTA in its test, it was an L98 Auto, Im not sure of the gears though and they got it up to 141mph on a high speed oval track.

 

I have been wodering the same thing about my car. Anyone know what the estimated top speed is for my car?

It's a 88 305 TPI Auto with 2.73 gears. Correct me if i am wrong, but the TPI cars didn't come with limiters did they?

 

Through all the info I have read on these cars the past year I have not seen any proof there is a limiter on TPI cars.

Given yours is a LB9 Auto it most likey has the "peanut" cam as its called with the motor putting out 190hp in stock form. Id have to guess your top speed would be 130mph +/-.

 

This makes me think. My 87' with 3.27 gears got up to 135 no prob then all the sudden seemed to hit a wall. It made me think i have a 135 limiter, or it could be just TPI running out of breath. The car is stock besides k&ns and upgraded 700r4. However seems like other near stock 350's on this board have beaten 140. Makes me wonder what up. The runs VERY well so i doubt its a power loss problem.

 

Yeah I got that write up I think the drtivers window was sucked out In any case they weren't as fast as IROCs. Besides you'll never really know
unless you get a radar gun! Speedos are usally a few mph optimisitc at really high speeds.

 

when my car was stock l03 2.73's i went to 135 racing a rustang and still had pedal left but the stang was slower and i was trying to rearend him so i slowed down.

 

The 3rd gen firebird has always had better aerodynamics, but the camaro always had a better intake worth a few more hp. Its a toss up, and they'll probably top out around the same speeds.

I read a magazine where a b4c topped out at 150mph. It wouldn't suprise me if the 5.7's were able to run to 145mph or 150mph with enough road. The power and aerodynamics are definitely there.

 

actually, a number of tests i've seen (and done personally at lower speeds) would argue that at least the pontiac VSS driven speedometers are generally accurate ±1 MPH over their entire 140MPH range. if you look back over old road tests done by pros, they're usually right on with the radar gun even at speeds 130+

 

Well thats werid---my auto LO3 stops at 185--or 115mph

 

I've hit 141mph according to my digi speedo. BTW they are not kidding about the windows getting sucked out either...

 

Well the top speed depends if you got the Vehicle speed sensor delete or not.

 

ALL TPI cars top speeds are limited by physics only, no computer controled crap to stop them.

ALL TBI cars are set around 115MPH IROC's and RS's - these cars can get around it with the tech article for "modifying" the VSS.

 

Well I guess im the only crazy one so far that has pegged the speedo. The only mods on the car at the time were TES headers, gutted cat, flowmaster 2 chamber, TB airfoil, and a hypertech chip. Like the rest of you i wonder about the accuracy of our speedos but the needle was past the 145 mark on its way to the trip reset button. She might have had a little more left but im guessing I was around 155mph. I think 160mph might be about the best she could do at the time. The car also had the stock 3.23 or 2.77 gears at the time, i forget which it had when I got it. Probably the 3.23's. It was quite a rush especially at 2 in the morning on a wide open flat US route here in michigan. Nobody else on the road so I could concentrate on the driving. Around 130-135 the windows do start to suck out too I dont know what the top speed of my car is now seeing that I put a TH350 trans and a 3.45 gear in her. Shes quicker up to speed but she is at yellow line at 130mph. Id guess I could do 145mph maybe redlining it out all the way.

 

Far from it 88Blk

I purchased my IROC new in Germany. Saw top speed at least weekly for 5 yrs and 85k miles.

As far as speed limiters go...yes. If your TPI didn't come with speed-rated tires then it was limited by the chip. Due to the myriad of option packages at the time I don't know if there were any L98s that came out of the factory with anything less.

 

My windows have never sucked out from high speeds. Are you sure yours are aealing properly?

 

My windows have always felt fine at 130mph - no sensation of them being sucked out at all.

 

No problem with the windows here either but i dont like the way the steering feels at high speed.

 

obviously cause some windows get sucked does not mean all windows do

 

My seals around my windows are the originals and they have seen better days. Im sure when I replace all the seals they wont suck out as much if at all.

Lounge Lizard- good to know im not the only crazy one

 

well Motor Trend probably had HITHERE press car that was not too old and the window(s) were sucked out.

 

Yes I do remember them stating the windows sucked out.

Keep in mind though the IROCs went faster for a few reasons, the better intake designs and the fact that GTA's were "luxury" oriented which made them heavier.

I still wouldnt have a GTA any other way

 

I have the motor trend article you guys are talking about, it's from August 1987. The GTA topped out at 141.53 mph and the IROC topped out at 144.11mph. It stated that the window pulled away from the weatherstripping at approximately 100mph in the GTA. Both cars were 210hp, and the GTA was about 100 lbs heavier.

 

not quite--87 IROCs 5.7 were 220hp

 

I own a 1989 trans am gta convertible. Black on black on black...my top speed was 155 mph...

 

155mph

 

I've had several of these (never an 88) but 87 and 89's, 5.7, speed was never governed, able to run as fast as all the rest of the parts allowed. Been in the mid 160's with a "stock" 5.7 on a closed road course.... (stock means controlled by a factory computer)

 

16 year old thread bump... This might be a new record.

Dumb thread belongs in the theoretical racing forum anyway.