Tom Robison

NSFW

I won't claim to really know this stuff but I've got a demo version of HP Tuners and a stock HPT file, and there are some clues in there about the PCM's role in traction control...

There's a table that HPTuners calls "Traction control spark retard vs. RPM" that appears to be used to retard ignition timing in response to a signal from a traction control module.

There's also a table that is used to selectively disable cylinders in response to a torque reduction signal from the TCM.

I'm sure it's not the whole story, but it's a start.

Why do you ask?

Tom Robison

tblu92

Both the traction control system and the ABS brake system uses data from all 4 wheel speed sensors---The TC system uses the data to prevent the wheels from spinning on a hard launch and the ABS system uses the data to prevent the wheels from skidding on a hard stop---You can delete almost all the traction control with tuning in your ECM But never all of it--As far as the ABS braking goes this involves the ECM the BCM and the ABS controllers---Why wou;d you ever mess with the ABS braking system ? It saves your *** !!

NSFW

Have you read about what people call "ice mode?" I'm sure that's not what GM called it when they created it, but it's a widely despised "feature" of C5 ABS.

Like so much else about the car, it works fine for most people most of the time, it just isn't tuned for track use. Which seems like a solvable problem, if we could just get access to the parameters.

Tom Robison

oneandgone

I apologize for hijacking, but can you please tell me more about this? What can be deleted, what are we stuck with, and how is it done?

tblu92

In the C5 ECM there are adjustable tables the set the max limit of TQ you can have when the TC button is ON The factory setting is 350 Ft lbs of TQ For a teenage driver you can lower this # to like 250 and they cannot spin the tires as long as the TC button is ON
On the opposite side you can rasie the MAxX TQ valve beyond 350 ft lbs---This table however maxes out at 640 ft lbs----
BUT even though if you set the value to the max 640--- on a hard launch you will still see the TC indicator light go on breifly meaning that the ECM is still remoeving some TQ that it does not allow to be tuned out entirely
PS you should also DELETE the "Abuse MGMT" table as well -----this will give you just a little more allowed TQ--

oneandgone

Great info, thank you. All of this can be done with HP Tuners?

RonSSNova

tblu92

YES thks Ron
Going even a step further There is a table that limits the throttle opening on a drive by wire car-- In EFILIVE it is called "ETC Pedal Torque Limit Reduction " This table does not allow the T Body to go to WOT basically until the engine reaches Max TQ---So it kills off most of your bottom end-----
Say if you ar at a stop light and floor the throttle to WOT---It actually will NOT go WOT until you reach apprx 3600 RPM----This is stock GM tuning---- Easy fix is to set this entire table to read "100%" Now your throttle will act like a cable throttle system without any limits

romandian

have you done that with no bad things happening?

"** CAUTION ** Setting this too high can cause the throttle to stay open when you lift off the pedal."