OK, after alot of replacing sensors, tuning and basic maintainence work that was never done by the previous owner, I took my 87 IROC to the track and have run a best of 14.46 @ 93 MPH, with a 2.01 60 ft
1987 L98 stock mass air system, 700R4, 3.27 posi
Here's the "mods" done to my car.. and it has 160,000 miles on it.
SLP Torque convertor
B&M shift kit
air foil
TB coolant bypass
set TPS according to tech articles
set IAC also
removed lower portion of airbox
removed MAF screens
removed belt for air pump and A/C
Flowmaster 3" cat back with 3 chamber muffler, not crossflow design
160* thermostat

Nothing major as far as modifications. Suspension is all stock, the 1/4 was done from idle.. anything over that at launch and the 60ft times are terrible

I have noticed that the SD cars, run a little better 1/4 times with simmilar setups, but the MPH seems to be significantly higher
My friend who goes to the track with me has a 92 Z28, 305 5 speed, G92 car with dual cats.
He has run a BEST of 14.88 @ 97 MPH with a 2.1 60ft
I am going 4 tenths faster but 4 MPH slower

Is this because the dual cat setup flows better and allows the engine to breathe better.. or is the SD system making the difference? If I could get more out of the top end of my car it would pick up quite a few tenths it would seem.


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Member of The Connecticut F Body Association
1987 IROC 5.7 - 14.46 @ 93
1988 Formula
1986 Z28

[This message has been edited by Jay (edited July 15, 2001).]

 

If both your cars are in good tune, I am guessing that it has to with your 60 ft time and the fact that he has a 5 speed. Your .1 lower 60ft is worth almost .2 in the 1/4 mile. The fact that you have one less gear and 20% HP loss in your automatic than he does probably accounts for his higher trap speed, less RPM drop between gear changes and better power transfer to the ground. Your 350 also has more torque off the line than the 305 which can account for the better ET, but his 305 has the same amount of horsepower.

 

I have also noticed the higher MPH with L98 cars that are newer than mine, just looking at times from this board and other thirdgen boards.
My other friend that went with me to the track has a bone stock 40,000 mile L98 IROC that ran a 14.8 @ 92 MPH.. the 60ft was 2.1

 

Most likely his mph was higher because his car is a manual. They usually seem to get higher trap speeds than a similar auto.

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Jason 92Z28