tuning out the brake override

[drop360]

Oh hell yes! Nice find! Thank you.

 

[Andy Hollis]

Thank you for this.

I am a dyed-in-the-wool left-foot-braker for autocrossing and have gotten into the BOS a number of times during trailbraking situations. No more worries now.

 

[drop360]

I could be doing something wrong, but... I've tried this several times with my 2011 sport model, and it does not seem to work. :'(

 

[Andy Hollis]

I could be doing something wrong, but... I've tried this several times with my 2011 sport model, and it does not seem to work. :'(

It took me about an hour of trying to get it right.

What I do now for autocross runs...

1) Turn key to "on" (not start, not ACC), which is where the dash indicators all come on. Now pause for a couple of seconds for most of the lights to go off
2) push both gas and brake to the floor
3) Wait 15 seconds, just to make sure...and I have a timer running on my phone to get it right
4) release brake and gas, push clutch, start car
5) Turn TC off.

On the way to the start line, driving in first gear, I'll push on the brake pedal a couple of times for a couple of seconds to verify BOS is disabled. Mental note if it isn't.

I'm about 70% success rate on disable so far. I may mount a small, cheap stopwatch on the console somewhere.

 

[drop360]

I shall try some more, with renewed vigor!

 

[Sweetums]

Thank you for this.

I am a dyed-in-the-wool left-foot-braker for autocrossing and have gotten into the BOS a number of times during trailbraking situations. No more worries now.

No problem.


I'm going to go play in the dirt at IndySCCA's RallyCross in a few weeks, so I've been trying to figure this out. I just got started in autocrossing with the 2 and I'm having a blast - finally signed up for membership last weekend.

 

[drop360]

Despite some solid effort, I am still not able to get the Miata technique to work with my 2. However, I have done some more investigating, and found a way to disable the BOS.

Under the dash, near the top of the brake pedal, is what I will call a plunger switch. The plunger is depressed when the brake pedal is up, and the plunger releases as the brake pedal is pressed. This plunger has a plug with 4 wires going into it. The plunger switch controls the brake lights. I had an idea that perhaps it could also be linked to the BOS. I pulled the plug, and as expected - no brake lights. But it also killed the BOS!

So, my questions are 1) Can I assume two of the wires run to the brake lights, and the other two somehow report back to the ECU? 2) How do I determine which wires go to the brake lights? 3) Is it likely that any other system (aside from BOS) would be getting info from that plunger switch? 4) How can I safely determine if any other systems are affected by pulling the plug?

I would like to either permanently disable the BOS, or splice in a dash mounted switch to turn it off and on at will. Clearly I can't disable my brake lights permanently, and I don't want to disable anything else that might be really important.

Any thoughts?

-Matt

 

[zps2004]

Do you just autocross the car? There is no rule that I know of that says your brake light have to work. Just unplug it before you run.

 

[drop360]

I actually don't race at all. I took a one day rally lesson at Team O'Neil, and learned how to left foot brake. Everytime the roads get slippery in the winter I long for the under/oversteer control that left foot braking provides. It is just not possible with the BOS. Basically, I discovered an amazing way to control my car, and it frustrates the hell out of me that my car is prohibiting me from doing it.

 

[extremez31]

l woud not assume 2 wires go to the light and 2 go back to the ECU. More likely there is a ABS module like in the Fiesta controlling ABS, TCS and the BOS. If you can get a wiring diagram the best thing to do is hard wire a switch in the cabin to cut the signal to this mystery box and retain the brake light. If you do any HPDE trackdays youll need all lights working.