Stability control is not fully defeatable?
 

It appears that traction control is not actually fully defeatable in the BRZ. I switched from Toyo R888 to Toyo RR's (grippier tires) yesterday at Vir and on high speed/ high g corners, it was intervening. It especially cut in going up the esses, taking away throttle and applying the brake.

I have a dozen track days on the R888's and have played with the car enough to know that typically, with traction/ stability all off, you can do donuts all day long.
It seems that the added grip of Vir's new surface with these grippier tires are exceeding the g's that the ecu will allow.

Has anyone that's racing or who's running stickier tires like Hoosiers run into this? Anyone who can offer a solution or knows of a source that might be able to problem solve this?

Thanks and btw, the RR's are a nice step up from the R888's! Lots of grip :-)

Long story short: if you can turn on traction control by the buttons, you still have some type of traction control (even if the lights are turned on on the dash)

-alex

Even pedal dance won't completely eliminate all aids, you have to remove the abs fuse.

I was able to drift without any issues (plenty of manji/tankslappers on purpose) with the pedal dance only.

Never had to pull any fuses.

-alex

Jon Miller has a video from Roebling posted on here that features helmet cam view. The TC off lights are illuminated but the yellow stability light still blinks away in high G turns. He was running A6's at the time.

I blieve the pedal dance torns everything off except the ABS.

WIth the 5 second button push, EBD is still active.

I found that out at one of my recent track days.
The rear brake rotors were over 100 degrees centigrade cooler.

I essentially had to throw away a day and a half worth of data and start over.

D

Pedal dance :thumbsup:

With the 5-second press, your e-diff (and the other braking aids) is still on. Pretty sure that's what the source of the blinking traction light is. I run into this on A6's. Basically, so much grip (like the RRs) that I'm running out of travel and lifting the inside rear, so the e-diff kicks in. It only happened when I was on both factory sway bars, and only on throttle exit application. It actually introduces some exit oversteer for me until the roll relief from the slide sets the inside tire back down. Never had it with the stock front/disconnected rear or with stock rear/stiffer front. Rear end stays on the ground, problem (and big throttle exit oversteer) goes away.

For me, this is beneficial, without the e-diff, when one drive wheel is in the air, a Torsen becomes an open diff, which means no power reaching the tire that actually is in contact with the ground.

I've gotten the car into a couple of extended tank-slappers (and spun it) on the factory tires with the 5-second press. No intervention there. So, that's why I think it's something else happening - at least in mine and the OP's case.

E diff???

What is that?

Emergency

System applies brake to wheel off the ground to force the Torsen LSD to transfer power to wheel on the ground; Electronic Differential.

Nope, it's the electronic helper that applies brakes to a rear wheel if you get it in the air or totally unload it so that the mechanical diff doesn't behave like an open diff.

Pedal dance is the only way to go. The only aid still active is ABS.

FT86 content included:

http://www.cnet.com/videos/car-tech-...als-explained/

And our "E-diff" works by applying brakes to the wheel that is slipping.

Thanks for the link to the pedal dance solution. Great advice...I found a bunch more material on the topic. Thanks to all of you who have responded!

Unfortunately, I'm feeling a sense of deja vu all over again! My friend and I bought Cayman S's in 2007 and ran into the "ice" hard brake pedal and traction control issues. Being a newer car, like the BRZ, there wasn't a lot of data to confirm our problem but it eventually surfaced. My buddy spent tremendous time and money and eventually solved the issue with a BMW Bosch Racing Brake controller..... the same solution that most grand am race teams were using. I sold the cayman and built a spec miata and had a blast for 5 years with that.

Anyway, The BRZ is certainly a great platform but as is the case with other modern cars.... street car safety technology is not track friendly. I've modified the BRZ with better brakes (AP Racing Sprint Kit), coilovers, more aggressive tires and sintered race pads which together, are awesome but are apparently bringing on stability/ brake issues by confusing the ecu?

So what is the best solution? Backing off the brake pads and tires may help reduce the problem but of course, I hate to go backwards. Pedal dance may help the stability control intervention but it sounds like the hard "ice" pedal will still be there. Is there a documented solution that is less complicated than replacing the brake controller with a Bosch system?

Eric

I can reproduce ice mode at will. It is, quite frankly, 100% driver error. If you are inducing ice mode, you're stabbing at the brake, HARD, and are probably deep into ABS engagement.

A lot of drivers use ABS as a crutch instead of a learning tool, and get accustomed to being able to just stomp on the brake pedal in any car, any time, and expect to be able to stop.

Slow down your brake input, learn to properly modulate the brake pedal, and you will never, ever encounter it.

If this continues to be an issue, I will grab some datalogs demonstrating ice mode, and give empirical evidence substantiating the above statements.

CGS Mike is gonna go all Takumi on our asses.

Disagree that it is 100% - say you hit a bump and a front wheel jumps in the air, that could trigger ice mode. That said, changing your braking technique will eliminate nearly all of the problems. Fully agree that too many people use ABS as a crutch to try to brake later and cram the car into the turn.

Slip Angle is coming from a non-ABS platform and I'm sure that's part of the problem (as I did, the transition wasn't easy for me). It's pretty crappy to drive and think "I need to avoid pissing off my electronics" rather than using the brake pedal as the tool God and physics intended it to be.

You mean Ryosuke...


I wish there was a no ABS option for this car, I would have gone with it...my last 2 vehicles did not have ABS. With the FRS I can feel the EBD system working things out and trying to correct... then I have to correct to the corrections...aaaaahhhhhh! STOP it already and just turn yourself OFF!

Will ice mode occur on a smooth, flat section of track when stabbing the brake pedal like a wild man?

Its not an electronic diff.
The diff has no electronics in it.

An electronic diff is a diff that actually adjusts the lockup.

Yes... I've actually gone off while trying to reproduce it cuz I actually induced it and just... didn't slow down :lol:

So what do you propose we call the Twin's version?
It uses: Electronics, an open Diff, and the ABS system to approximate a limited slip diff.

We could call it the: Almost, but not quite, entirely UN-like electronic diff.

Or ABNQEUED :thumbup:

In fact this system could be better than a LSD if the software was smart enough.

we have a torsen, not an open diff



ehh..


when the goal is achieving maximum power delivery, using BRAKES is highly counter-productive

I have heard this comment before, and when it applies to braking the wheel that is lifted it absolutely does NOT slow the car down.

Or are you saying that a true limited slip diff slows the car down?

By braking the wheel that is lifting you are applying MORE power to the wheel that is not lifting.
How can that possibly slow the car down?

I suppose letting the lifted wheel spin like crazy (then chirp when it sets back down) is the fastest way around the track??

And I guess using the brakes to stop wheel slip during acceleration (you know "traction control") is also slower than just spinning the wheels.
I guess we need to tell the drag guys they are doing it wrong.

I'm saying that the system where you have an open diff and slip is controlled by individual brakes won't be all that effective when your actual goal is to have the car rotate by slipping


yes you can have a very nice VSC system designed that will actuate all the brakes for you and keep the car rock steady, but how is it going to know that you actually want to drift the dang thing?


I suppose you can have knobs, and you flip a switch to let the car know "okay right now I want to have some fun"?

maybe in 10 years they'll have brain wave sensors and the car will just KNOW


:bonk:

Hope it was fun! :D

Will ice mode in this car stop if after inducing it the driver releases a slight amount of brake pressure, or maybe a bit more? If not, what do you do to get the braking back?

From what I was told by @Scoobysouth that the aids kick back in at 1.3gs with the normal button press. After that you need to use the pedal dance.

Personally I used it once when the info came out. May give it a shot this weekend.

It definitely slows you down.
First it turns our car into 1wd
And 2
The system is too slow. By the time it steals away the precious power, the traction event is long gone.

A TRUE lsd would not slow the car down.

I just put a Kaaz into mine (review coming) and its definitely better.

A true LSD works by preventing the traction loss, and promoting the car's ability to put down power under cornering.

The ECU's emulated LSD function works by reducing torque to the spinning wheel, and giving it resistance, to give the Torsen a chance to work. It works by reducing your ability to accelerate in a situation where you are not accelerating at all.

http://www.ft86club.com/forums/showthread.php?t=68310

SO you are arguing that if the cars does NOTHING to the wheel that is lifted, the car would go faster around the corner......UM OK.... NOT

If the car allows one rear wheel to lift, and does nothing to stop the spin, we have ZERO wheel drive.

I suppose none of you naysayers have ever heard of applying the E-brake with a torsen to apply power to the wheel that is still on the ground?


Sounds like you are agreeing with me.
The electronic LSD is better than no electronic intervention at all.
So by applying the brake at the proper time, to the proper wheel makes you go faster around the corner.

well for one thing the real problem is that you're lifting your inside wheel


having your car finger pinch the brakes just so that the torsen can work is collectively known as a "hack"


:bonk:

This is exactly why I do NOT run a rear sway bar on my 914.
Without a LSD, the car is faster without the sway bar, becasue the inside rear is less likely to lift

ohh you're one of THOSE people

Darn, beat me to it.

It's so abrupt that it upsets the car. The places where it kicks in around here, I'm going 120+, so I'll pass on it.

It'll activate all the time angling out of driveways with a low-droop car though.

:sigh:

Threads like this are why I don't come here looking for input on setup anymore.