The "Pedal Dance" testing

[sw20kosh]

Originally Posted by CSG Mike

Let it idle for a bit before your session.

You should be warming up the entire car before driving hard, as previously mentioned...

Yes I always let it idle before sessions start.

I just didn't know if that was sufficient. You mentioned the temp has to be perfect or else it won't work. Got it

[CSG Mike]

Originally Posted by sw20kosh

Yes I always let it idle before sessions start.

I just didn't know if that was sufficient. You mentioned the temp has to be perfect or else it won't work. Got it

Well, not literally perfect, but stabilized at normal operating temperature

[sw20kosh]

Originally Posted by R2

If you don't mind my asking, what is this "Ice Mode" you speak of?

x2

[Evil86]

Originally Posted by sw20kosh

x2

I copied this from the scca forum. http://www.sccaforums.com/forums/for...90/scope/posts

"In 'ice mode,' no brakes are applied, so you should be able to steer still. The causes of it are different from car to car, but usually it can be summarized as the ABS system'getting confused' and thinking there is not enough grip to apply any braking at all. It's more common on cars that lift tires while cornering, but can be caused by an imbalance in braking capability between the front and rear axle or abrupt braking application. Most 'ice mode' situations can be avoided by squeezing the brakes on rather then stabbing them, so if you regularly encounter this situation your braking style should be the first thing investigated. From there you could look at brake pad compounds and/or chassis setup changes. I find brake pad compound has the biggest impact for me though."

Insofar as the braking style goes, autox normally involves "abrupt braking," so no more Pedal Dance in Autox for me.

[Porsche]

Originally Posted by Evil86

it can be summarized as the ABS system'getting confused' ... Insofar as the braking style goes, autox normally involves "abrupt braking," so no more Pedal Dance in Autox for me.

It may be that the “diagnostic mode” is not very safe. It’s not clear to me what this is intended for. Why is the ABS still active after the pedal dance?

Since the ABS is the source of the trouble, particularly paired with the EBD, why not try finishing the job of turning off the nannies? I believe if the ABS were to be disabled, then the subsystem EBD and the TRC and VSC would all be disabled as well.

Would you consider disabling your ABS for autocross? That might work well, especially in autocross. Now, NOTHING would be enabled.

I would be interested in the results, regardless of any issue of compliance with the class rules. I’m interested in how to make this car more responsive and reliably consistent. And safer.

This “ice mode” problem is serious, and even potentially lethal outside of an autocross course. A number of people have severely damaged some expensive machinery when struck with this “ice mode” problem, this ABS confusion. It may not be random, but it is certainly dangerous. The Bosch Motorsport ABS M solution is expensive at $8000 and up, installed, and even that may not be foolproof although said to be in a different class altogether.

My concern with disabling the ABS on most modern cars is that they were designed with ABS in mind, and the old-style brake proportioning valve was eliminated in favor of the more sophisticated electronic brake force distribution (EBD). So, what “native brake balance” would we be left with were we to disable the ABS+EBD?

Logic tells me the brakes would be heavily front-biased, but I don’t know. This might severely degrade overall performance. I don’t know.

I’m hoping you, or someone, can tell us.

P.S. Don’t forget to practice finding your threshold point off the track before taking a run; you don’t want to square off your tires at every turn now that there’s no ABS to prevent lock-up.

[DriftEightSix]

Originally Posted by 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.

anyone know if this can be tuned to be a simple button press instead of this fancy foot work stuff?

[rice_classic]

Originally Posted by Porsche

My concern with disabling the ABS on most modern cars is that they were designed with ABS in mind, and the old-style brake proportioning valve was eliminated in favor of the more sophisticated electronic brake force distribution (EBD). So, what “native brake balance” would we be left with were we to disable the ABS+EBD?

I would also like to know how to completely disable it all. As for the conundrum of what happens with brake balance with it all shut off, that's fine with me as that's a super easy solution as opposed to trying to drive "around" a possible ice mode situation or worse, running into the car in front of you because the nannie's are confused.

Brake balancing is easy with just choosing compounds or one can go full boar and get a brake biasing system installed in the car. After all... it's just money.

[7thgear]

so i'm confused after reading this

when you disable everything but the ABS via peddle dance then you get a hidden "ice mode" problem or the other way around?

Should i do peddle dance + abs fuse pull for autocross days?

[Kido1986]

I got the Ice Mode issue many times as well. Stopping using it for autocross as it ruined a few runs.

Not sure what would happen if you did dance + abs pull... hmmm

[tintumz22]

Quick question. Do you recommend this to a newb in HPDE? or turning off any of the traction controls of the car?

[Porsche]

Originally Posted by tintumz22

Quick question. Do you recommend this to a newb in HPDE?

NO!

or turning off any of the traction controls of the car?

Well now, that depends, doesn't it?

After a time, you might want to try Sport Mode, but I would advise having an instructor assess your performance first before trying that, just to be on the safe side.

In the end reducing/removing the "aids" is the only way you're going to learn, I'd think.

High speed driving is a harsh "mistress." There are no do-overs, and sometimes the consequences of an error can be severe, fatal even.

Find a slow section of track, one accompanied by a large, safe run-off area where an errant driver is unlikely to damage the car or himself. Confine your initial work with Sport Mode to that corner until you "master" it.

This is NOT "school" where you get falsely praised for doing crap work.

Remember, Mother Nature and The Laws of Physics will literally KILL you, ruthlessly, mercilessly, and without a second thought.

But then, that's what makes it interesting, isn't it?

Be careful out there and take chances only with YOUR life, not someone else's.

Right?!

[Porsche]

Originally Posted by Kido1986

I got the Ice Mode issue many times as well. Stopping using it for autocross as it ruined a few runs.

Not sure what would happen if you did dance + abs pull... hmmm

What'll it cost you?

I expect you already know this, but remember that you're right foot is now the "pulsing device" to keep from locking your front wheels more than a fraction of a second. It will take a while to master threshold braking without the (dangerous) crutch of ABS.

If you do square off your tires, flat spot them, they can be shaved to concentric trueness again.

I'd be obliged if you would attempt an autocross weekend with the ABS turned OFF. Once having pulled the fuse, I'm not sure anything else would need to be done, since, if I'm not mistaken, all the Nannies depend on the ABS system to function.

I'd love to hear a detailed account of your experience.

[Porsche]

Originally Posted by Kido1986

I got the Ice Mode issue many times as well. Stopping using it for autocross as it ruined a few runs.

Could you clarify this, please?

Are you suggesting that you believe you experienced Ice Mode AFTER defeating most of the Nannies, i.e. all but ABS, with the pedal dance?

How could that be?

I'm not challenging you, I'm trying to understand...

I wish cars were simple again.

[Porsche]

Originally Posted by 7thgear

so i'm confused after reading this

when you disable everything but the ABS via peddle dance then you get a hidden "ice mode" problem or the other way around?

My imperfect understanding is that Ice Mode is a consequence of the ABS system functioning "normally," i.e. FUBAR.

I thought the pedal dance eliminated this problem, but it remains unclear to me.

Should i do peddle dance + abs fuse pull for autocross days?

Yes, please.

And don't forget the rest of us awaiting your report.