Anyone have experience implementing custom traction control? I'm in the process of writing a traction control routine for M4.4 and was wondering what the best method for implementation would be.

My current (untested) routine intercepts the ignition code and performs a check of the current gear before the routine outputs the ignition start signal (rising slope for dwell charging start). If the detected gear is equal to 0, meaning no gear sync/loss of traction, then ignition will be cut. From what I have read, for traction control to work it must be quick. This routine I designed is executed every ignition event, which I assume will be quick enough, but I think gear status is updated only once every main loop iteration, which varies from 30hz-13hz depending on RPM. I could possibly move the gear detection routine into the ignition timer overflow routine along with ignition logic, but I think the additional code overhead might cause timing issues with the rest of the code.

My question is, how many ignition events should I cut to restore traction (x of y events), or would it be better to retard timing instead of cutting ignition? I was thinking of starting a timer at the beginning of traction control and increasing ignition cut events while gear detection remains at 0.

Will 13hz be quick enough for effective traction control?

Gear detection is based on comparing VMESS to RPM, I know that aftermarket systems use wheel speed sensors, will this system of traction control even work?

Yes, you are right, testing on the car is the best course of action. I've just been waiting for my wheels to get back from paint for the past 2 weeks, and have been stuck with 'thought experiments'. They come back tomorrow though.

From what I can tell; the gear detection routine assumes a gear of 5, lookups the equivalent final gear ratio from a table, divides the gear ratio by the current speed and compares this to the current RPM. If they match within a given range (a 1x5 table based on gear) then the current gear is considered synced and placed into XRAM 0xFA94. If they do not match then the gear is decremented and the loop run again. I can't tell what the caller of the function due to some funky non-standard multi-bank code switching.

M4.4 is load based, which I guess is somewhat equivalent to torque, but it is so rudimentary that a torque based routine would be impossible.