Transmission decision dilemma

[ivanko]

Originally Posted by streetfytr68

That's false. Both shift timing and firmness are 100% fully programmable. Delaying the 1-2 shift or completing it sooner is just a few software keystrokes away. Likewise with firmness. So if you don't like the 1-2 shift, you will simply adjust it without breaking a sweat. An electronic transmission gives you complete digital control over calibration relative to throttle position (load) rpm, and vehicle speed. A pre-electronic transmission simply cannot compare.

Furthermore I would suggest that your transmission failures--given proper components and modification--might be a direct result of the limited calibration control available from a 700R4. The engine is hitting the transmission harder than allowable under some combination of circumstances. And since your 700R4 builder is a specialist, I can only assume that he has fine-tuned the calibration as well as possible. Without computer control, he just does not have the means to take it to the next level.

It's all about the computer.

I agree and I believe the repetitive hard shifts even at part throttle have a cumulative effect and have finally taken their toll. It must have been metal fatigue since I didn't do anything crazy when it broke.

I watched the video on your site and am curious if you had programmed your transmisison to shift softer during the filming? I know it's difficult to tell from the video clip, but the shifts seemed noticeably slower than what I've experienced with my transmission.

[Steve Chryssos]

Originally Posted by ivanko

I watched the video on your site and am curious if you had programmed your transmisison to shift softer during the filming? I know it's difficult to tell from the video clip, but the shifts seemed noticeably slower than what I've experienced with my transmission.

Your first instinct when tuning is to set everything on kill--y'know: Do your best Michael Schumacher impersonation. The you tend to go back and make the shifts only as hard as they need to be.

WOT 1-2 shift: Lightning quick
Part throttle 2-3 shift: Softer

Think in terms of having full control over throttle position, rpm and wheel speed as opposed to taking whatever your trans shop gives you with a pre-electronic "shift kit" Much like comparing jets in a carburetor to a digital fuel injection map.

[Turbo Deuce]

I had an aftermarket 700r4 with 2500 stall in my chevy ll @ 350rwhp and a 150 shot. The car was a street car that got some track time. Shifts were firm and the trans was pretty good except having to replace clutch packs once a year. I feel I was lucky. One thing I did not like was the gear spread from 1st to 2nd.

I have a 4l80e now in the car with a 383 and a T76 turbo. The set up will make 900fwhp. The 700r4 would have pucked its guts with this set up. The gear spread is better, as the 4l80e is like the turbo 400 spread. I am running the TCI controller and can set shift points by MPH in any gear. I can set WOT shift points and never have to shift manually.

I am concerned your trans man can even compare the 700r4 to a 4l80e. If you make over 500hp and want overdrive the 4L80E is the chioce.

[MickyT]

Im running a Gear Vendor with a Turbo 350 and although the power isnt in the same range yet as you mention when I researched overdrive transmissions it seemed like the logical solution for now and as we add power. We have only had the car on the road for a week however gotta say its a pretty cool setup.