The "Pedal Dance" testing

[CSG Mike]

I don't remember the original post (and a quick search didn't find it...), but someone had posted up a sequence to turn off additional electronics in the car. The sequence is as follows:

- Turn on the car. The car must be FULLY warmed up. You must do the entire sequence within 30 seconds of starting the car.
- Pull the e-brake 3 times. Hold/lock the e-brake on the 3rd pull.
- Press the brake pedal 3 times. Hold it down the third time.
- Pull the hand brake 3 more times. Hold/lock the hand brake on the 3rd pull
- Press the brake pedal 2 more times.
- On the last press of the brake pedal, two yellow lights should have come on.

I purposely used staggered brake compounds to test whether the brake dance does anything; here are my conclusions.

- The pedal dance eliminates electronic brake force distribution.
- The pedal dance also eliminates the "panic brake" function.
- I tried trail braking mid-turn with the "normal" electronic aids off, but without the pedal dance. This resulted in a spin; the car literally locked up the rear brakes. My speculation is that the car recognized the fronts locking up, and put additional force on the rear brakes. The problem here, is that I had purposely put a much lower friction pad in the back, so it kept sending more and more brake pressure to the back, until it just locked. Once it locked, it stayed locked, even though I was not stepping on the brakes.
- I tried this again a few more times. Same result.
- I then tried again, but with a rear brake bias. This time, pressing on the brakes mid-turn or trail braking always resulted in the car straightening out and/or plowing.
- With the pedal dance, I can trail brake or brake in the middle of a turn for rotation just fine, regardless of pad setup.

Moral of the story: if you're driving on a track or at an autocross, do the pedal dance! (Remember, ALL aids will be off)

All testing was done on a closed course, at the "Balcony", courtesy of Willow Springs Raceway.



*edit*

From another post:

Originally Posted by CSG Mike

This past weekend at WSIR and the 2nd FT86CUP event, we did some additional Brake Dance testing.

Quick and dirty:
Without the brake dance, if you upset the car's computers enough, it will still re-engage traction and stability control. This specifically involves enough of a loss of traction that you're getting what the ECU believe to be uncontrolled wheelspin, the equivalent of lifting a rear wheel. The slip light will turn solid, and the traction/stability lights will turn off. After the "uncontrolled wheel spin" is eliminated, the slip light will turn off, and the traction/stability lights will turn back on (indicating that the systems are again "disabled")

This was most apparent through Turn 8 of WSIR, which is an ultra high speed, extremely bumpy sweeper. This was replicated lap after lap. The stability control engaging at 110+MPH was rather... scary. There were some 100+MPH slides induced BY THE COMPUTER.

Results were independently reproduced by @D1cker in his own car; Derek is the fastest non shop-sponsored FR-S/BRZ driver in SoCal.

You can also experience this by going through a driveway where you lift a rear wheel from lack of droop. Even with traction/stability off, the ECU will still engage traction/stability, and brake the wheel to allow the wheel in contact with the ground to put some power down.

Moral of the story: If you are doing performance driving and are comfortable turning the computer aids off, do the pedal dance!


Original pedal dance thread here: http://www.ft86club.com/forums/showthread.php?t=25494

Originally Posted by CSG Mike

Of note:

I was able to replicate the "slip light turning solid when going over big bumps or left foot braking" this weekend while canyoning when not using the pedal dance.

It's also typically accompanied with a CEL. The CEL is soft and goes away after a while.
@D1cker

[Aznsky]

Wow those are some very helpful results!

I'm assuming the electronics go back to normal after you restart the car?

I wonder how this was figured out and whether or not we can make it simpler.

[CSG Mike]

Yes, the electronics go back to normal after restarting the car. You'll need to do it every time you start the car when you want all aids to be off.

[Dave-ROR]

Originally Posted by Aznsky

Wow those are some very helpful results!

I'm assuming the electronics go back to normal after you restart the car?

I wonder how this was figured out and whether or not we can make it simpler.

They do. This is a diagnostic mode really.

[gmookher]

pic of the two yellow lights please?

[OrbitalEllipses]

Originally Posted by gmookher

pic of the two yellow lights please?

TRAC OFF and VSC slip light, I'm assuming.

[TOMIMOTO]

I don't know why, but the process reminds me of this.

[CSG David]

Originally Posted by TOMIMOTO

I don't know why, but the process reminds me of this.

Pretty close to that. :p

[Dave-ROR]

Originally Posted by OrbitalEllipses

TRAC OFF and VSC slip light, I'm assuming.

Close. Trac off and VSC off. Ie the same two lights that light up when you hold the traction/VSC off button for 5 seconds.

[mla163]

Does it affect ABS?

[coyote]

Having experienced the lock up to which you refer in other vehicles, I appreciate this post.

When I read the thread title, I was however expecting to see this old video:

[ame="http://www.youtube.com/watch?v=Ts29KKhKXds"]Walter Rohl - YouTube[/ame]

[SubieNate]

How is the brake bias with EBD off? I read somewhere that people were worried it would shift with ABS and/or EBD off.

Nathan

[CSG Mike]

Originally Posted by SubieNate

How is the brake bias with EBD off? I read somewhere that people were worried it would shift with ABS and/or EBD off.

Nathan

I had no trouble trail braking. You can always stagger pads with a higher friction pad in the front; modern cars generally have a rear bias.

Originally Posted by mla163

Does it affect ABS?

Nope.

[driver01]

worked for me, thanks