C127 Brake Lock Warning Lights

[muzza47]

Hi I am looking for information to configure Brake Lock Warning Lights
I am using a C127 Dash Logger collection data through OBD2 port with Standard GM E38 Ecu I have all 4 Wheel sensors being logged
if any one could point me in the right direction to configure Brake Lock Warning Lights it would be greatly appreciated.
Cheers

[David Ferguson]

I typically use a conditions like:

Wheel Speed FL < 30 mph and G Force Long <= 0.75G to set a "LF Lockup" status channel (renamed from "Condition XX").

This works for our sports racers where the slowest corners are typically 40 mph, and braking is often in the 2G range. I'm not sure this will work as effectively with the slower update rates of ODB-2, but you asked for a directdion...

[muzza47]

Thanks David it gives me something to play around with I wouldn’t have thought to use G Force I was thinking Wheel Speed Vs Ground Speed or GPS Speed
Ill give it a go
cheers

[David Ferguson]

I suppose you could try to make a table to generate "lock up speed", that would be GPS Speed - 10-20 mph (ie, GPS=40, Lockup Speed=25, GPS=100, lockup=90), then your test could be "Wheel Speed FL < "lock up speed".

One issue is that GPS speed does lag by 50ms or more, so with aggressive braking, the wheel speed could be quite a bit less than the GPS speed, but still not be locked up.

[Stephen Dean]

As David said,

GPS has its uses, lockup detection and traction control are not one of them.

GPS versus Wheel Speed.PNG (34.82 KiB) Viewed 12268 times

[evolve]

What I did it was to set up a table for each wheel that is a predicted wheel speed ch. This is on a 7in dash so In a lock up event I light up the corresponding side lights so you know when and what wheel locked. I use the center lights on the sides to trigger a heavy brake event when the pressure goes above a set PSI. If I see green side lights I know I am in the right range but if I see blue side lights I got too aggressive in brake zones. This isn't a perfect but It helps me get up to speed on new tracks quicker.