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-   -   The "Pedal Dance" testing (https://www.ft86club.com/forums/showthread.php?t=25494)

CSG Mike 01-02-2013 06:43 PM

The "Pedal Dance" testing
 
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:

Quote:

Originally Posted by CSG Mike (Post 882932)
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

Quote:

Originally Posted by CSG Mike (Post 899723)
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 01-02-2013 06:52 PM

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 01-02-2013 06:54 PM

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 01-02-2013 06:55 PM

Quote:

Originally Posted by Aznsky (Post 640410)
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 01-02-2013 06:56 PM

pic of the two yellow lights please?

OrbitalEllipses 01-02-2013 06:59 PM

Quote:

Originally Posted by gmookher (Post 640425)
pic of the two yellow lights please?

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

TOMIMOTO 01-02-2013 07:10 PM

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

http://play-this.org/wp-content/uplo...onamiucode.png

CSG David 01-02-2013 07:23 PM

Quote:

Originally Posted by TOMIMOTO (Post 640456)
I don't know why, but the process reminds me of this.

http://play-this.org/wp-content/uplo...onamiucode.png

Pretty close to that. :p

Dave-ROR 01-02-2013 07:28 PM

Quote:

Originally Posted by OrbitalEllipses (Post 640434)
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 01-02-2013 07:46 PM

Does it affect ABS?

coyote 01-02-2013 08:28 PM

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 01-02-2013 08:36 PM

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 01-02-2013 08:38 PM

Quote:

Originally Posted by SubieNate (Post 640631)
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.

Quote:

Originally Posted by mla163 (Post 640547)
Does it affect ABS?

Nope.

driver01 01-02-2013 09:17 PM

worked for me, thanks

CSG Mike 01-02-2013 09:52 PM

A clutch bypass should have no effect on it; I've done it both holding and not holding the clutch down, as well as in gear and in neutral...

SubaSteve 01-02-2013 09:57 PM

Quote:

Originally Posted by Aznsky (Post 640410)
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.

I know a tech who said there was a way to turn it all off but he wouldn't say how. I don't think they're supposed to divulge this info.

celica73 01-02-2013 10:37 PM

Well, I did the pedal dance right. Mike's procedure worked for me, though it took a while because I kept trying before the car warmed up. It might be easier to use my techstream cable. I worry about pulling things from the OBD port when the engine is running, and I won't want the laptop in the car all the time.

Asterisked Accolade 01-02-2013 11:39 PM

This should almost be a sticky thread.

bpracer 01-03-2013 12:39 AM

Ah, now I get it! This is the third thread mentioning "the pedal dance" but not the real effect.

BlaineWasHere 01-03-2013 12:39 AM

Good info!

Lee358 01-03-2013 12:48 AM

good info thanks!

RL_BRZ 01-03-2013 01:05 AM

Thanks for sharing... I vote to Sticky this Thread.... :-)

cobrabyte 01-03-2013 01:10 AM

So, now someone with Arduino smarts should create a little board that performs the 'dance' with the push of a button. I dread having to do this before every track session interval.

Thanks for the info, OP!

FrX 01-03-2013 02:44 AM

Quote:

Originally Posted by CSG Mike (Post 640389)
- 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.


This reminds me greatly of a scenario I experienced in my last Autocross (:sigh:). Thanks for testing this out for us. I'll have to check it out myself the next time I go out.

Moto-P 01-05-2013 11:16 PM

Ok the secret is out I guess... :)
Just be very careful as the FRS is a rapid responding car and if the driver isn't quick and accurate and very versed with dynamic car control, things can get hazardous pretty fast at high momentum inputs. We learned on analog cars like this in the past with older cars, but threashold was a lot more forgiving back then with moderate tires and compliant frames, chassis and suspension.

This car is like driving a Lancia Stratos or a Lotus Elise when it's fully analog, and if you ask anyone of age who know them, you'll understand what I am getting at here.

Go for it! But stay safe!!

nix 01-05-2013 11:30 PM

This was posted in September by @086A who found it in the repair manual. This ft86 system is called auto lsd it's like a supplement to the diff where the electronics apply abs pulse to the loaded wheel when the lsd is struggling.

http://www.ft86club.com/forums/showt...186#post464598

Quote:

Originally Posted by cobrabyte (Post 641139)
So, now someone with Arduino smarts should create a little board that performs the 'dance' with the push of a button. I dread having to do this before every track session interval.

Thanks for the info, OP!

It's already done. Search for 'VSC cut'. Autofactory was one of the earliest. http://www.autofactory.jp/product/to...?mode=s&seq=14

Moto-P 01-05-2013 11:38 PM

Quote:

Originally Posted by Moto-P (Post 646981)
Ok the secret is out I guess... :)
Just be very careful as the FRS is a rapid responding car and if the driver isn't quick and accurate and very versed with dynamic car control, things can get hazardous pretty fast at high momentum inputs. We learned on analog cars like this in the past with older cars, but threshold was a lot more forgiving back then with moderate tires and compliant frames, chassis and suspension.

This car is like driving a Lancia Stratos or a Lotus Elise when it's fully analog, and if you ask anyone of age who know them, you'll understand what I am getting at here.

Go for it! But stay safe!!

Just wanted to add, Yes the normally available TRC/VSC full off will function almost the same.
The VSC intervention in the all off mode from 3 sec press of TRC switch, normally available will allow almost all but the largest of slip angles, and allows you to be sideways pretty much in most all situations...

What you get with this additional step is the ABS function to turn off, leaving you with fully analog car. But in most cases the ABS is a completely beneficial thing and unless you're training to be a better all-around driver, the ABS should be left on so you're not flat spotting tires or losing precious seconds off the lap by having it being off. :)

It's not a performance enhancing mode really, it is more a diagnostic mode for benching the car's performance without electronic intervention.

nix 01-06-2013 12:02 AM

Quote:

Originally Posted by Moto-P (Post 647015)
What you get with this additional step is the ABS function to turn off, leaving you with fully analog car. But in most cases the ABS is a completely beneficial thing and unless you're training to be a better all-around driver, the ABS should be left on so you're not flat spotting tires or losing precious seconds off the lap by having it being off. :)

ABS is still active in this mode. What it does is disable VSC, TC, Auto LSD. I agree with you though people should be careful!!

Moto-P 01-06-2013 12:14 AM

Quote:

Originally Posted by nix (Post 647047)
ABS is still active in this mode. What it does is disable VSC, TC, Auto LSD. I agree with you though people should be careful!!

Wow really? I wonder how Mike got his FRS to lock up the tires on the track this way... More mysteries.. ack!

nix 01-06-2013 12:33 AM

Yeah I am a grip driver but still had problems with it kicking in. Most people here wouldn't need this mode but for those who really push their cars it's great.

I have thought about installing the auto factory cut switch since I have the matching interior panel space but because I have a push start button I think I have to break the starter barrel open to splice into it. Bit of a job for a rainy day ..

ayau 01-06-2013 12:34 AM

I'm getting two sides of this debate.

1) The pedal dance will disable ABS.

2) The pedal dance will disable auto LSD.

Which one is it?

Can someone clearly explain how this pedal dance is different than holding down the traction button down for 5 seconds?

CSG Mike 01-06-2013 01:00 AM

Quote:

Originally Posted by Moto-P (Post 647072)
Wow really? I wonder how Mike got his FRS to lock up the tires on the track this way... More mysteries.. ack!

Brake bias; electronic brake distribution freaked out and put all the braking force to the rear. I was running a large differential between the front and rear in terms of both compound and piston surface area.

CSG Mike 01-06-2013 01:01 AM

Quote:

Originally Posted by ayau (Post 647106)
I'm getting two sides of this debate.

1) The pedal dance will disable ABS.

2) The pedal dance will disable auto LSD.

Which one is it?

Can someone clearly explain how this pedal dance is different than holding down the traction button down for 5 seconds?

My conclusion is that it disables electronic brake distribution and the "panic stop" mode. You can stab at the pedal, and it won't "add pressure".

Take it for what you will; that's just what I discovered in my testing, and as always, YMMV.

ayau 01-06-2013 01:05 AM

Quote:

Originally Posted by CSG Mike (Post 647144)
My conclusion is that it disables electronic brake distribution and the "panic stop" mode. You can stab at the pedal, and it won't "add pressure".

Take it for what you will; that's just what I discovered in my testing, and as always, YMMV.

So does it disable every single electronic aid for this car? It seems like we need to get the real answer from Toyota/Subaru.

CSG Mike 01-06-2013 01:07 AM

Quote:

Originally Posted by ayau (Post 647147)
So does it disable every single electronic aid for this car? It seems like we need to get the real answer from Toyota/Subaru.

Given that it's officially a "diagnostic mode", I think so. The does exactly what I ask it to do in this mode, whether its trail braking, sliding, drifting, or gripping.

gmookher 01-06-2013 03:24 AM

Quote:

Originally Posted by CSG Mike (Post 647142)
Brake bias; electronic brake distribution freaked out and put all the braking force to the rear. I was running a large differential between the front and rear in terms of both compound and piston surface area.

curious, what pad combo?
must go play with the pedal dance tomorrow!
gem

Acree 01-06-2013 03:52 AM

Is anyone interested in a module to do this for them?

-Acree

CSG David 01-06-2013 04:04 AM

Quote:

Originally Posted by gmookher (Post 647297)
curious, what pad combo?
must go play with the pedal dance tomorrow!
gem

XP10/XP8 on the 225 RS3 fronts and 215 Z1SS rear tires.

The CSG BRZ currently runs XP12 all around and 225 RS3s all around.

CSG Mike 01-06-2013 04:10 AM

Quote:

Originally Posted by CSG David (Post 647329)
XP10/XP8 on the 225 RS3 fronts and 215 Z1SS rear tires.

The CSG BRZ currently runs XP12 all around and 225 RS3s all around.

I may have tried some other combos... :D

DarkSunrise 01-06-2013 09:46 AM

CSG Crew, really appreciate the time and effort you guys are putting into the development of this car (and your willingness to share your results).


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