Diablosport Forums

I got my U7198 a month ago and have loaded the performance tune and started to adjust the shifting speed and pressures. Here is what I have done: turned up shift speed, increased shift pressure and TP position and shifting. Basicly I turned all the shift settings up because with the stock tune the car shifts like Grandpa on a Sunday drive. I did not adjust any shift settings related to shift MPH or RPMs

The issue I'm having is on the 3rd to 4th shift I get a rev in the RPMs before the actual shift. What will happen is the RPMs will jump up ~200 then drop back down then it will shift and it only happens on the 3rd to 4th shift. In my attempts to resolve this I have gone back in and backed out each of the shift settings and found this related to TP position and shifting (the last option in the list) Unfortunately the stock 3rd to 4th shift is the worst out of them all.

This is on a 2000 corvette automatic. Unfortunately I dont have the predator with me to get the hardware/firmware specs from it. I'm pretty sure they are the latest and greatest but I will get them if needed.

Ok checked the tool and:
bios: 6.01
HW: 1.01
SWrev: 2.13
Mfg Date: 09/02

Do you have the stock gears and torque converter?

Thanks

Yup. 2.73 gears

I know its been awhile but any news/help on this? My original RPM jump I listed was a little high its more around the 200 range but still very noticeable.

c5y2k wrote:I know its been awhile but any news/help on this? My original RPM jump I listed was a little high its more around the 200 range but still very noticeable.

It's just the nature of the beast. Since you told the ECM to shift faster and ignore torque management the shifts don't "blend" in from third to fourth so it causes it to momentarily to not be in any gear and causes the jump in RPMs. (It should only be about 2 tenths of second.)