transmission tuning

I just had a quick question but I figured I'd leave the title more broad so it might be more useful.

What is the stock transmission fluid pressure and what are you tuners running it at?

Not an easy question. I actually installed a pressure gauge once, to the port right next to the vent on top of the transmission. Pressure changes all the time, based on load, gear selector position, etc. In the tuning software we can generally only set the pressure in terms of percentage of pressure solenoid position, i.e. we can choose 0-100%, but in general we don't have access to the full transmission tables, so you can't change this everywhere.

I saw pressure anywhere from 60psi to 220 psi on my pressure gauge.

Limit is supposed to be 96 PSI. I've never seen the PCM report anything higher (from wherever it's measured). The pressure is regulated in steps, based on calculated torque, so it varies constantly as you pout more load on the transmission. Generally you want less pressure at less load, and more pressure under higher torque (WOT). Setting the table is a find balance that is based on your shift points, driving habits, and personal preference. It took me a full year to nail down a pressure curve that works with my normal driving as well as high-demand performance. If you do it right, you can have "performance shift" when you need it without pressing any buttons.

AA, I think that's a mistake in the PT. It says PSI, but I think it's supposed to say %.

Interesting, I never knew that. Now I want to know why my transmission can't give me 100%.

torque converter losses. don't sweat it...

Albertj

Stock looks to be 96psi, but HPT will accept 100%

The reason I really posted about this was I see something like "trans line pressure increased for yadda yadda performance gains" as a basic piece of the tune all the vendors sell and it's not fully apparent to me, what they are actually referring to but I know I noticed a difference at one point when I had an intense S1 pcm for a couple days.

Looking back, it's hard to tell the detail of that diffence enough to compare it to my tune I did now (shortened shift times and such) I do see that value showing "96" in my program. So thats all that is? I just know I recal people saying the first thing is to simply bump up line pressure (in general)

What year is your car again, Codith?

AA wrote:

What year is your car again, Codith?

1997 everything but trans which is from a 98

Which tuner are you using?

In the HPT trans shift pressures are found under the (from my feeble memory) transmission parameters. In there you should find shift times, shift pressures and shift speeds.