gear change, went slower, what gives?

[Andy Lappin]

I just changed up from a 323 to a 373 in my 99 convertible a4 auto ws6 car.
Here is the strange part, I went 2-10ths slower. I had a best of 13.48 in February with 77 degree temps, dry air. Just went to the track and ran a 13.70 with a about a 85 dgeree and more humid day. My 60' times on both runs were 1.943 and 1.972. Anybody experience anything like this? I thought the gears would give me a couple tenths?
MODS, 99/t/a, 2800 vigilante stall, hooker cat back, ported throttle body, slp lid, computer tune. Stock exhaust manifolds and y-pipe.

One guy tells me since I don't have headers that the car is just choking out sooner with the steeper gears since it can't breath without headers. Anybody heard of this equation?

Thanks for any help,
Andylappin@aol.com

[ss~zoso~ss]

might want to change your shift points, and also does you car shift into OD while in the 1/4th because that will take more time

[mrr23]

some of it is in the hotter and more humid temps right now. i only saw a tenth when i went from 3.23 to 4.10. same when i went from a stock converter to the yank PY3400E. difference being winter to summer.

[nabdrill]

something is not right. I went from 3.23 to 3.73 w/ a 3K conv and picked up almost half a sec in the 1/8th.

How do your 1/8 mile compare

[silverTA2002]

More importantly than your 1/4 mile time...... what is the MPH change?

You could be spinning more than you think now.

[Andy Lappin]

Allright, in the 1/8 mile with the 323's and 15 degree temp change i had a 8.697/ 82.31 mph, 1/4 was 13.48 @ 102.38 mph. the temp was cooler.

1/8 mile with the 373's and 15 degree hotter temp, 8.799/80.28 mph, 1/4 was 13.65 @ 101.91 mph, this is what is boggling my mind, the 1/8 mph is slower with lower gears, makes no sense. the car is hooking well, i feel virtually no spin with the heated up drag radials. One guy mentioned the shift points, this could have a factor as they are set at 6000 rpm in all gears. I can't remember if the car went into 4th in the 1/4. it never did with the 323's but that is different. But even doing a burnout, the car just feels like it has lost power, i virtually did not notice one power change when I changed from 323's to 373's. only thing is it shifts sooner, nothing else. it is very dissapointing as i thought i would get something out of the swap.
thanks for any help.
andy

[silverTA2002]

Shift points SHOULDN'T be changed with a gear swap.

Proper shift points are determined by the transmission gearing in each gear and the Torque you're making at different rpms.

Rear end ratio and tire size, etc. do not affect shift rpm.

[98Z-28Camaro]

might want to change your shift points, and also does you car shift into OD while in the 1/4th because that will take more time


How can you speed up the od shift speed? Any tricks to doing this?

[silverz28camaro]

on a cool night my car ran a 13.1 , a week later it was about 15 degres warmer and my worst was 13.7 (WTF) i thought , but as the night cooled i did run a 13.3, temp plays a big part go back when the temp drops

OR, next time i go i am going to put a cool jel pack on my intake to see if that helps out with more dense air, also let the car cool don't do such a massive burnout, that will heat the engine compartment up, get a cooler thermo and programer to lower fan operations, this will help, my 13.7 was after a huge burnout, next run i didnt do the burnout and ran a 13.59

Play around with letting the car cool down between runs, also make sure the car is maintained well, oil plugs filter you know

[john99]

Like silver says I think the Florida heat is slowing you down.
I envy the guys in New Jersey with that low alltitude and great DA
they really run fast.

[98 Gold Formula]

If you did not change your gear ratio in your computer that is the problem.
You need to flash the new gears to have everything back to normal look at your speedo it is off also if you did not change these values in your computer.