Is There an ABS Ice Mode?

[Reaper]

At a rallyX last weekend I came up to a wet hairpin at full throttle and last second nailed the brakes -- as with prior runs. This time the pedal was brick hard, didn't depress at all, and the car shot off the course with no brakes. In many years of rallyX I've never had that happen with this car although I did have it on a past Evo 10 where it was said to be ABS Ice Mode. Anyone had any experience with this on the FiST? The traction control was long-pressed off...as always. Didn't recur on subsequent runs. But once was enough.

 

[tri-pedaler]

At a rallyX last weekend I came up to a wet hairpin at full throttle and last second nailed the brakes -- as with prior runs. This time the pedal was brick hard, didn't depress at all, and the car shot off the course with no brakes. In many years of rallyX I've never had that happen with this car although I did have it on a past Evo 10 where it was said to be ABS Ice Mode. Anyone had any experience with this on the FiST? The traction control was long-pressed off...as always. Didn't recur on subsequent runs. But once was enough.

Yikes. Seems like an issue with brakes rather than electronics. Maybe do a flush and bleed with Forscan?

 

[Dialcaliper]

I haven’t seen any mention or evidence of “ice mode” in our ABS programming.

What pads are you running on and how old are they? Sounds like a lot of braking during RallyX, especially with multiple runs.

In a RallyX or Autocross situation where you run the brakes hard and then basically stop the car, there’s not much airflow to cool the brakes between runs, and if you did 3-4 runs in the span of a couple hours, your brake pads may well have cooked and what you described in the other thread may be just straight up brake pad overheating/fade, especially if your pads aren’t that new.

Longer cooldown or being more cautious could easily explain it not happening on later runs. Modern brake pads, especially high friction/performance pads tend to maintain good friction through operating temperature and then fall off a cliff pretty quickly once they start overheating, so pad fade can come on a lot more suddenly than you might expect for run-of-the-mill NPC car organic brake pads that start fading more gradually as they get hot.

Most temperature charts for brake pads don’t show it, but found this one from Hawk that actually shows the ramp and fade, and you can see just how rapidly pads fall of when you exceed the operating range. Also keep in mind the generic “OEM” pad in the plot is a pretty boring pad and they’re not all the same. Stock summer pads are probably something closer to an HPS pad

 

[Intuit]

Linking threads...
https://www.fiestastforum.com/threads/has-anyone-ditched-the-antilock.32997/post-517238

 

[Reaper]

Stock brakes. Not really that heat abusive because we're on dirt so traction limited. But TVC might give the fronts a work-out. I've got an IR temp gun, I'll have to check them out. But I'm thinking excess heat boils fluid and results in low pedal -- opposite to what I experienced. I believe this was not lack of friction...the pedal didn't move at all and that's typically due to ALB push-back. I would have had to have brake pedal motion to clamp the brakes. So I think the pedal was unable to activate the brakes to any significant extent. Typical approach for Ice Mode. I also shot off the course the first time my EvoX did it but I learned to anticipate when it would happen and double stroked the brakes...quick gentle spike and then cram down. Worked on that car, maybe will on this one.

 

[Intuit]

Might feel some pulsing and hear some noise when when ABS intervenes to keep the wheel rolling but I don't think the pedal goes hard.

The lack of friction with brake-fade can provide the tactile-illusion of a lack of pedal travel.