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Old 08-19-2015, 05:24 PM   #30 (permalink)
BGTV8
A True Z Fanatic
 
Join Date: Dec 2009
Location: 03350 Australia
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Originally Posted by V1H View Post
Hi there. I was curious about this jaw sensor mod as I've only done the power brake mod for burnouts. I am not tracking and didn't know about trail-braking but read up on it now. It is clearly a desirable skill on the track (and road). But can you elaborate why and in what way the ECM interferes when trail-braking? Does the VCD apply additional unwanted brake during a fast corner? Why would switching off VCD not suffice. Thx for enlightening me
Just seen this comment ............

There are two inter-related electronic stability control functions, ESC and VDC. ESC is basically monitoring difference between wheel speeds at all 4 corners and if the rear wheels are turning faster than the fronts, the ECU will cut fuel/ignition to stop the wheel-spin and keep you straight.

VDC monitors "yaw" and it is trying to determine if the car is sliding and will trigger one or more brake calipers via the ABS controller. For instance, VDC figures that if you have a little left hand lock in the steering, and the yaw sensor shows lateral acceleration to the right (i.e. sliding to the right - what you get when cornering hard to the left with a slide), it will trigger the right rear brake to try and straighten the car up so you can then steer out of trouble.

All very good except if I am flat in 4th on the approach to T9 at Philip Island GP circuit - a part of the circuit where your are turning left, the car is sliding towards the right hand side of the track and you require a trail brake deep into the approach and the VDC gives your right rear brake caliper a tweak which pitches the car right towards the wall - THAT gets your attention. It is exactly the wrong thing for the electronics to be doing, and why I have a switch to disable it.

Road car safety algorithms are usually the precise opposite of what you require on a track.
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