Topic no longer needed.

 

I'm sure someone will come along with some definitive numbers, but the 1/4 mile time has to be a little letter than that. The L03 (TBI) cars with 170 H.P. and 2.73 rear gears run around a 16 flat, give or take.

 

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I've got some experience with this, having owned 3 305 TPIs...one M5 and 2 A4s.

Your 0-60, believe it or not, is around 8.5 seconds with the A4, assuming 2.73 or 2.77 gears. Hot Rod tested an '86 and got that number. 1/4 mile will be around 16 flat.

M5 cars will be a lot quicker due to a cam change (215hp vs 190), better gearing, and the efficiency of the 5 speed. My 215hp M5 '88 Trans Am, with the standard 3.08 gears, was more fun to drive than my 230hp A4 '88 IROC 350.

If/when I get another third gen (FINALLY buying a house in the next 30 days, and will have a 3 car garage again!!!) in another 1-2 years, I will be searching high and low for a 305 TPI M5 car. That's the combo to have in my opinion....

 

Amen brother...
I have not done traps but have done several timed runs with a co-pilot timing me and I was around 6.5 - 6.7

 

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Slips from my 87 IROC 305 TPI/5spd G92

Best 60' was 2.052 seconds with the best 1/4 14.579@91.71

Car at the time was bone stock with 88k miles showing.

 

My 85 iroc 305 tpi auto ran a 14.70 on a cool fall day back in the early nineties .. all it had done to it was a flowmaster muffler and k & n filters .. that car ran better then alot of the 350 cars I've owned ..

 

85s have the L69 cam and are shockingly fast compared to other LB9 automatic cars.

 

Right. L69 cam, L69 exhaust - basically an L69 with TPI. And a standard 3.42 gear on the IROC-Zs.

My '85 feels quite a bit faster than most 5.7 2.77/2.73 geared cars I've driven. The only problem is, on a non-posi car like mine, it will convert rubber into blue smoke with astonishing ease. It's almost annoying - believe it or not.

 

It shocks me that GM would sell something like that. They had to have test mules in '85 with LB9s and open diffs that were absolutely useless. The LB9 should have mandated G80 in '85.... Well heck, G80 should have been STANDARD in any Z28 or IROC, period. The fact that it wasn't is shameful...

 

I can't give hard numbers but I think my car is in the high 14s at 91 or so. Based on feel and having raced my cousin in his 05 GTP.
5 speed vert.

I would think the a4 should muster low 15s at 88 on a good day.

 

TRUE!The 85s were fast when they came out. My 87 GTA Lb9 auto while stock turned 15.44

 

Bet this car would make some L98s sweat.

 

Made a few stock Grand Nationals and just about every 5.0 Mustang sweat back when it was new.

 

85 cars were WAY faster than 86 cars

 

Back in the fall of 1992 (Junior year of high school), I had an 86 IROC-Z. TPI 305, auto. A buddy had an 85 Z28, TPI, auto. We lined em up one day after school and he could walk right by me.

 

I ran an 88 GTA at our local 1/8th mile dragstrip 25 years ago. It was a 28k mile car, 305 TPI, auto. I had a 100hp NOS kit and some bolt ons. At the track it ran a 10.18@66 mph with no nitrous, and a 9.27@76 mph on the juice.

I had a bye run on one pass, so I didn't run the nitrous. It was hot and muggy that day, so the numbers could have probably been a little better with better conditions.

 

I've never run the 1/4 in anger or timed a 0-60, but if I had to guess based on reading, documents that came with the car, and feel versus the many other cars I've driven, my 91 B4C T5 LB9 is probably about 6.5 seconds 0-60 and somewhere in the mid to low 14s for the 1/4 mile, somewhere in the 90-100 MPH range.

The auto 305s are abysmally slow. If it's a 305, it better have the T5. If it's an auto, it better have the L98.

Correctly optioned thirdgens were actually quite quick for there time (in many cases quicker than the non-special edition 60's muscle cars). Now they'll lose to minivans.

These cars are most fun in "street speed" situations - rolling in the 20-60 MPH range on windy roads, where the TPI and T5 have lots of torque and response.

 

My 91Z28 auto LB9 car ran a best of 14.79 and consistently.under 15 sec@96mph. Stock other than cat-delete, 3in exhaust and a performance chip. Had the 2.73s also. Car ran strong for what it was. I'd bet a 91-92 T5 LB9 could turn in the lower 14s with the right driver.