Cool idea. Wish I had the know-how to attempt something like this.

Don't have much to contribute here unfortunately, just showing my support. Hope you can figure it out!

 

Thank you for your reply. I WILL find an answer. No reason for this not to work.

the NO2 idea is still bumping around in my head for the long run but i will likely put a button on the back of the steering wheel center.
<uuuhhh and="" the="" nitros="" idea="" is="" still="" in="" my="" head="" too="" but="" i'll="" do="" it="" differently,="" like="" a="" button="" on="" back="" of="" steering="" wheel.="" </uuuhhh>

 

Haven't read it yet but it sounds like it has potential.

Midwest 3800 &bull; How to add performance shift to you PCM in 01-02 GTP's [ Guest ]

 

Sounds neat. I like the idea and can see the reasoning. If there was a way that in low performance mode to lower boost on a turbo with softer trans and improve mpg that would be awesome. For my traction control Im going to install a toggle switch to look like a missle launch switch lol.

 

Looks like that is your answer - which also explains why I couldn't find anything on it on the diagram I looked at - I pulled up a 2002 Grand Prix w/ a 3.8.

So I pulled up a '99 and low and behold the performance shift switch is on it.

 

wth is a 40 mph downshift? Would this keep me from shifting to second mid burnout?

 

There may be an issue with the actual pressure sensors and switches on the transmission and the way it talks to the PCM

In a comparison between a 99 GP and an 03 MC Pin 21/C2 appears to be correct as far as activating the Performance Mode of the Transmission.

However, In looking at the pin outs that were sent to me to compare there are pressure switches that are not completely addressed on the Monte.

These switches will control the pressures in Performance mode.

So, What i need to find out for the harness that goes TO the PCM is where to locate the wiring FROM the transmission pressure switches on the HD Transmission and their routing.

What this means to me is that the pressure sensors on the HD trans need to be hooked in to really do this properly. The tables are there.

To me, it appears that depending on where the wiring harness from the Transmission actually connects to the main harness that I may need to check the compatibility for the harness sitting on the engine unless there is a separate attachment for those sensors and switches.

Pins 22 on C1 and pins 17, 57 on C2 are the issue with controlling the pressure in the transmission with reference to the torque via the sensor on pin 71 on C1 and pin 9 on C2 which are common to both.

Other than that it would appear that the pressure would be controlled directly as a function of the reading of table when the trans is put into Perf mode of course assuming that it would read from the correct table regardless of whether or not those sensors and switches are there and set the pressure simi-blindly or by some means that I have not arrived at.

I know that when i changed the pressure table for "normal" that the shift properties changed so there has to be something sensing that pressure request.

So to show my ignorance do you know anything about these pins and where they actually "hook up"?

It appears that the PCM is reading from 22, 71/C1 and 9/C2 processing and executing on pins 17, 57 /C2.

It would be great if somebody had a source for a wiring diagram concerning this and see if there is a definite correlation to year model of the HD transmission.

I'm thinking that the pin outs on an `O3 GP should be compared in order to determine the differences in the 3 Pin Outs. I was sent a pin out for a 99 GP and an 03 Monte.

GM is sorta quirky (read that as illogical) sometimes but i would think that they would keep same year model or year model group W bodies the same wouldn't they?

That's a really long winded way for me to try and reason out what else happens when Pin 21/C2 is activated for Perf mode.

Pins in question compared
99 GP to 03 MC Connector 1 (end view)
pin wire circuit description
22 PNK 1224 Transmission Fluid Pressure Switch A Input - 22 Not Used
71 is the same on both and is Requested Torque Signal

Connector 2 (end view)
pin wire circuit description
9 is the same on both Delivered Torque Signal
17 RED 1226 Transmission Fluid Pressure Switch C - 17 Not Used
21 DK BLU 1493 Normal / Performance Switch Input - 21 Not Used
57 DK BLU 1225 Transmission Fluid Pressure Switch B - 57 Not Used

I'm not sure the guy doing this harness extension for me wants me to share his info so for now I'll refrain, at least till he says it's OK. Not sure he wants to fool with another one.

What are your thoughts?

Thanks, And away We go......

 

Since your turbo boost is controlled by a waste gate, presumably you could hook up an electronic boost control and work the boost that way. I have had really bad luck with electronic boost controls and prefer to use a manual one.

As far as the mileage is concerned, if your VE table is set up correctly for your car simply not standing on it would help.

You will note that in our PCM's we really do not have a way to change the way the engine acts by reading MAP. There are tricks that will allow you to do some stuff but without a custom OS the tables that address positive manifold pressure are not there, They stop at ambient pressure unfortunately.

 

Im curious as to what kind of mods you have on the engine, turbo charged, supercharged?

 

Turbo. Mentioned in the SIG.
I will elaborate further when it's together. Trying to keep a semi-intelligent log of what's happening including part number and processes

I'm starting to get a little old I guess. This will likely be one of if not the last cars i build. Getting hard to get up and down from under it. I'd like to make it work really well and of course look OK to. Experience is great, but it wears you out.