I need help please
Thread Starter
TECH Senior Member
Joined: Mar 2004
Posts: 14,620
Likes: 17
From: BFE
I need help please Could anyone lend me a hand with this?
https://ls1tech.com/forums/showthrea...46#post6776946
Thanks
Mark
https://ls1tech.com/forums/showthrea...46#post6776946
Thanks
Mark
Assuming you have something other than a factory 2.73 or 3.23 (safe assumption 
), did you adjust the tune for those gears in the upshift/downshift and TCC lock/unlock tables that are all MPH referenced? If not, you need to. Once you do that, for WOT you need to pick what you want to work with - MPH or RPM. The PCM won't command an upshift until both 'triggers' have been satisfied. So, you set one quite a bit lower than the other so the PCM only has to wait for one trigger. Most work with RPM.
Example - Desired shift @ 6600 RPM for the 2>3 shift. That's roughly 81mph on a car running 3.73's. So, set the RPM at 6400 and the MPH at something like 62. If it won't shift in time, drop the RPM 100 or so. If it shifts too soon, bump the RPM up 25~50 at a time until it shifts where you want. You kind of have to apply a fudge factor....
The rev limiter is usually ~200 RPM higher than the shift point to give a bit of a cushion. The other thing you could look to do is to increase the pressure or drop the desired shift times slightly. I emphasize slightly because I don't want you to come after me with a gun if the trans goes boom from the added line pressure.
), did you adjust the tune for those gears in the upshift/downshift and TCC lock/unlock tables that are all MPH referenced? If not, you need to. Once you do that, for WOT you need to pick what you want to work with - MPH or RPM. The PCM won't command an upshift until both 'triggers' have been satisfied. So, you set one quite a bit lower than the other so the PCM only has to wait for one trigger. Most work with RPM.Example - Desired shift @ 6600 RPM for the 2>3 shift. That's roughly 81mph on a car running 3.73's. So, set the RPM at 6400 and the MPH at something like 62. If it won't shift in time, drop the RPM 100 or so. If it shifts too soon, bump the RPM up 25~50 at a time until it shifts where you want. You kind of have to apply a fudge factor....
The rev limiter is usually ~200 RPM higher than the shift point to give a bit of a cushion. The other thing you could look to do is to increase the pressure or drop the desired shift times slightly. I emphasize slightly because I don't want you to come after me with a gun if the trans goes boom from the added line pressure.
Thread Starter
TECH Senior Member
Joined: Mar 2004
Posts: 14,620
Likes: 17
From: BFE
Hi SSpdDmon,
Thanks, I think I understand what the issue is. i need to adjust my MPH. Time for some test and tune.
I can't adjust pressure as my tranny is vaccuum mod.
Thanks again for the help and the good explanation, as much as I know in the mechanical aspect of the motor, tuning is a whole other spectrum for me.
Thanks, I think I understand what the issue is. i need to adjust my MPH. Time for some test and tune.
I can't adjust pressure as my tranny is vaccuum mod.
Thanks again for the help and the good explanation, as much as I know in the mechanical aspect of the motor, tuning is a whole other spectrum for me.
