Corvette Forum : DigitalCorvettes.com Corvette Forums banner

1 - 10 of 10 Posts

·
Official Forklift Driver
Joined
·
7,068 Posts
Discussion Starter #1
I am not sure exactly how my '87 will lanuch because the car is not done yet. I plan to get a convertor in the 2800 stall neighborhood. Right now when I try to feather it with the shifter in (D), it shifts 1-2 too fast for my liking. Any little tiny bit of let-up on the pedal and it shifts to 2nd. I'm sure I can set it for a slightly higher shift point than now when I'm done but I thought it shifted too fast with the 2.59's. All shifts are so smooth, I can barely feel them. Overall, can I assume that is a sign that the tranny is in good order?

If I manual shift I can get better traction at launch. I start in (1), let off the gas, manual shift to (2), get on the gas and all is fine up to that point. The transition from 2nd to 3rd (D) is FOREVER!:rolleyes: :(

If after the convertor goes in and it still shifts too fast, my plan is to launch w/ the shifter in (1) and once I get traction with (1) still WOT slide it into (D). I've tried it this way a few times already and it seems to work good but am I doing any damage this way?

TIA,

John
 

·
DC Crew
Joined
·
53,220 Posts
War machine said:
I am not sure exactly how my '87 will lanuch because the car is not done yet. I plan to get a convertor in the 2800 stall neighborhood. Right now when I try to feather it with the shifter in (D), it shifts 1-2 too fast for my liking. Any little tiny bit of let-up on the pedal and it shifts to 2nd. I'm sure I can set it for a slightly higher shift point than now when I'm done but I thought it shifted too fast with the 2.59's. All shifts are so smooth, I can barely feel them. Overall, can I assume that is a sign that the tranny is in good order?

If I manual shift I can get better traction at launch. I start in (1), let off the gas, manual shift to (2), get on the gas and all is fine up to that point. The transition from 2nd to 3rd (D) is FOREVER!:rolleyes: :(

If after the convertor goes in and it still shifts too fast, my plan is to launch w/ the shifter in (1) and once I get traction with (1) still WOT slide it into (D). I've tried it this way a few times already and it seems to work good but am I doing any damage this way?

TIA,

John
Hey John, I'm going to shoot this over to C4 topics where the mechanics hang out. I think you'll get a much faster response...
:thumbsup:
 

·
Registered
Joined
·
3,027 Posts
I wouldn't let up on the gas between shifts, no real need for it and it will end up hurting your times.

Otherwise, everything sounds hunky dorry. I usually manually shift when I'm drag racing. Now, it's been a long time since I had 2.59's so, I don't remember how fast I had to shift between 1-2.
 

·
Registered
Joined
·
336 Posts
I would definately manually shift the 700R4, when I had my 92 with 2.59's it would shift from 1-2 at about 5000rpm, the car moved much better holding the shift closer to the 6K rpm mark, do not let off on the shift, it will hurt your times for sure. On the newer cars (94+) with the 4L60 trans, you want to just leave it in drive since the ECM controls all the shifts
 

·
Official Forklift Driver
Joined
·
7,068 Posts
Discussion Starter #5
Thanks for the input guys!!

In 2001, there was a guy I talked to in the Rt.66 staging lanes and he told me about an early C4 A4 he used to drag. He started going through his method of manually shifting and he said it gave him some good ET's. Then I started to think that maybe this guy was pullin my chain and was waiting for my trans to go KAPLOOIE!!!


I'm going to be testing @ U.S. 41 as soon as the temps allow it. I can wait!! I haven't been on a track since Sept 2001! :( Knowing my luck it will stay sub 40 degrees til my car is back at Powerhouse for the rest of the mods and tuning. That means I will be rusty and crusty by the time the Challenge starts. I'm starting to envision 2.2 and 2.3 60ft. times. :stick: :laughing:
 

·
Obsessive Customizer
Joined
·
535 Posts
The 700R4 is designed to shift at the optimal gas mileage shift points. Mine shifts through all 4 gears before it hits 30 miles an hour if I leave it in automatic.
At the track I manually shift it. Now I have a 1969 400 SBC with 2x4 carbs on my 91 now but when the L98 was in it I shifted at the same points (4500 RPM) and my ET's we always much better. I launch at 2200 RPM's (but basically because that it the only RPM that the street tires won't break loose).
I also usually only go through 2 gears in the 1/8th mile and only 3 gears in the 1/4 mile. Never go into overdrive on the track, it'll kill your time.
One important point: if your engine is making 375hp or more - the 700R4 will not last very long on the track shifting manually. I have already lost 2 tranny's this way. I had to beef up the 700R4 with my engine set-up. I few mechanics will tell you that the 700R4 is not a goo street transmission. I tend to agree on the high HP but stock C4's are fine.
 

·
Registered
Joined
·
3,710 Posts
War machine said:

If I manual shift I can get better traction at launch. I start in (1), let off the gas, manual shift to (2), get on the gas and all is fine up to that point. The transition from 2nd to 3rd (D) is FOREVER!:rolleyes: :(

TIA,

John
No need to let off the gas, it will kill your times!
 

·
Official Forklift Driver
Joined
·
7,068 Posts
Discussion Starter #8
customvettes said:
I launch at 2200 RPM's (but basically because that it the only RPM that the street tires won't break loose).
I normally launch from idle b/c the stall was around 1800 and these '87 brakes SUCK!!

With the new convertor going in I will try again to launch at a higher RPM.

Thanks again for the responses!:buhbye:
 

·
Registered
Joined
·
3,710 Posts
When you're at the track next, try letting the car shift for itself and compare those times to when you manually shift. Whenever I ran my C5, I just put the trans in 3 and went.
Experiment!!
 

·
Official Forklift Driver
Joined
·
7,068 Posts
Discussion Starter #10
They way I've done it all along is leave it in 3rd. I tried a couple times launching from higher rpms and that didn't work too well but I never tried to shift it manually at the track.

I drive it around town manually when I want to rev it up a bit. I wasn't ever concerned about wheel spin then. Just since I got the car back with the 3.54 gear and cam is when I started to try launching manually w/ minimal wheel spin.

I don't think manually is going to cut it at the track. The time it takes from 2nd to 3rd is WAYYYYY tooo long. I counted yesterday and it's almost 2 seconds. If I have it in auto the shift is almost instantaneous. Will a higher stall TC shorten the manual shift time from 2nd to 3rd?
 
1 - 10 of 10 Posts
Top