Thread: performance shift

Originally Posted by IndeedSS

Most people find performance shift settings great for daily driiving, and leave it on all of the time. I think having a switch though would be nice though.

Do the OSID's on GTPs without Performance Shift have the Performance Shift tables setup up? On the Impalas, Performance Shift and Normal have identical values in the tables.

Nevermind: I just looked at a stock 2002 GTP bin and they do have different values. The Performance Shift tables are not that aggressive, but they are different than Normal.

Well yeah GM is not gonna put massively different settings in the peformance shift. I think they mostly took off the speed limiter, and changed some shift points to hint at more spirited shifting, but nothing crazy.

Of course you are gonna seek out people in the community who have redone their tranny tunes and get their profiles to make a better performance shift tune. I have Chris O's tune he uses on his GTP, different shift points and such beyond what the stock performance shift has to offer

I like my more crisp shifts for normal driving. Less wear and tear on the clutches plus higher line pressure is a lower duty cycle (less wear) for the dreaded pressure control solenoid.

Originally Posted by Reptile

Partially right. The speed limiter is set up in the spark and fuel tables, not the transmission settings.

DOH! Spanks for pointing that out sir...........

Speaking of spark................plugs......................

Originally Posted by Preotic

They don't have the performance shift after 99.......

My '00 GTP has it right on the shifter like normal.

Originally Posted by Reptile

Partially right. The speed limiter is set up in the spark and fuel tables, not the transmission settings.

So forgive me, I'm new i guess only owned it for 2 months, when on performace shift there is no speed limiter? Or is it just raised up higher? Don't really need to go that fast but just curious.

Speed limiter is there based off your stock tire speed rating. Going to performance shift wouldn't magically swap tires on your car, so I highly doubt GM upped the overall speed limiter for performance shift. They may have extended some shift points, but I doubt your final limiter was lifted.

Originally Posted by Sabrewings

Speed limiter is there based off your stock tire speed rating. Going to performance shift wouldn't magically swap tires on your car, so I highly doubt GM upped the overall speed limiter for performance shift. They may have extended some shift points, but I doubt your final limiter was lifted.

Well I got that from the Article that had the wiring setup for the Performance switch. I will try and track it down and reread it. Maybe I mistook what they said *shrugs*

****EDIT****

I went to the Quebec Grand Prix Forum boards where I originally got the article, but the person who posted the pictures through his own personal web account no longer has them posted Figures!!

Originally Posted by Sabrewings

Speed limiter is there based off your stock tire speed rating. Going to performance shift wouldn't magically swap tires on your car, so I highly doubt GM upped the overall speed limiter for performance shift. They may have extended some shift points, but I doubt your final limiter was lifted.

Very true.....the speed limiter is there as a lawsuit prevention tool by the car manufacturer. If your car came with H rated tires on it from the factory, your speed limiter will be set to under 130MPH. If you change tires to a V rated tire, it will still be under 130MPH unless you have a some type of PCM editing program/tool. Be very careful when editing your speed limiter. If you choose to increase it to say 255MPH, and you are runing H rated tires, and make some long runs at 135MPH, you do run the risk of the tires coming apart. You should never drive faster than the speed rating of your tires for any length of time.

Performance shift only effects the line pressure (firmer shifts) and the time between shifts (how fast it will shift). Anything else, such as:

Higher or lower RPM's at the shift point

Speed limiter increase or decrease (my teenager learned about this one. Hers is limited to 75MPH and I told her if she gets a ticket in town, I will lower it to 35MPH and she wont be able to take the interstate anywhere)

Higher or lower MPH at the shift point

And a whole slew of other things like Torque Management.

If your going to adjust this stuff, ALWAYS us a 400RPM buffer, meaning if you want the car to shift at 6000RPM, set your tune to 5600RPM. By the time the car gets the signal to shift (@5600RPM) and everything switches over you will be at 6000RPM.

2000 was the last year for STOCK performance shift by the way.

webracin