[ICTsccaCamaro]

Both of my 5th gens would ICE mode BAD at autocross's, so far the ZL1 1LE has yet to ICE mode once with a full season of autocross and a trackday under it's belt.

[apexit53]

Originally Posted by TrackClub

Good discussion. I think an average autox pavement has a lot to do with it vs say: tire choices. So it sure seems that either bumps and/or very quick transitions between rear wheel spin and hard brake applications are the major cause. Why technically speaking i have no idea, except that is surely looks that such instances make ABS engage to prevent lock up, yet be unable to engage just yet, perhaps due to the car being unsettled.

Interestingly, even pros point out to bumps and street circuits in general (due to bumps) as having to be treated very carefully and GENTLY under braking. I know i have said it before, but the initial (softer) application (even if only for a nano second) to settle the rear before standing on the brakes is crucial. It is also much harder to accomplish (well) vs just say it.

Here's some general thoughts on late braking from the pros. Note - specifically - what is being said in the first 1.5 mins of this quick vid. This is not at all unlike the problems that pros in race cars can experience in similar situations.

http://safeisfast.com/video/late-braking/

I will say that i was able to mitigate the icemode at my locals. but once i got to nationals(also why i sold it) i wasn't used to the grip levels and i had to back off to hot hit icemode. leaving me feeling like i left time out there every year.

[HawkeyeMike]

Originally Posted by TrackClub

Good discussion. I think an average autox pavement has a lot to do with it vs say: tire choices. So it sure seems that either bumps and/or very quick transitions between rear wheel spin and hard brake applications are the major cause. Why technically speaking i have no idea, except that is surely looks that such instances make ABS engage to prevent lock up, yet be unable to engage just yet, perhaps due to the car being unsettled.

Interestingly, even pros point out to bumps and street circuits in general (due to bumps) as having to be treated very carefully and GENTLY under braking. I know i have said it before, but the initial (softer) application (even if only for a nano second) to settle the rear before standing on the brakes is crucial. It is also much harder to accomplish (well) vs just say it.

Here's some general thoughts on late braking from the pros. Note - specifically - what is being said in the first 1.5 mins of this quick vid. This is not at all unlike the problems that pros in race cars can experience in similar situations.

http://safeisfast.com/video/late-braking/

Ya, this is good advice, I will experiment some and see what I can do to minimize the issue. As I play this back in my mind, more and more I'm thinking I've been focusing on the wrong thing (braking). I'm starting to think that this has more to do with rear-wheel spin. It is happening right at the end of high 2nd gear straights, where I'm going directly and quickly from full 2nd gear high RPM slightly spinning rear tires to the brake. So maybe the car is thinking "hey this dudes on the gas and his rears are spinning, wait brakes now? We must be on ice." I'm going to try and specifically ease off the throttle ever so slightly before the hard braking zone, just to ensure the rears aren't spinning at all...and see if that helps.
Which of course brings up a whole different set of driving style questions. My philosophy with these high-HP RWD cars is that in general, wheelspin = slower, but being right on the edge during acceleration...always being between solid traction and just a bit of spin is the fastest way to accelerate these cars. Feel the wheels spin a bit, back off a little, smoothly apply the throttle until they spin again, repeat...Thoughts on this?
Thanks again,
Mike

[bpang1234]

I never had this happen all of last year (3 days or 13 20-minute sessions) and I made my front brakes shoot flames because I was diving into the brake zone too late LOL.

[TrackClub]

Originally Posted by HawkeyeMike

Ya, this is good advice, I will experiment some and see what I can do to minimize the issue. As I play this back in my mind, more and more I'm thinking I've been focusing on the wrong thing (braking). I'm starting to think that this has more to do with rear-wheel spin. It is happening right at the end of high 2nd gear straights, where I'm going directly and quickly from full 2nd gear high RPM slightly spinning rear tires to the brake. So maybe the car is thinking "hey this dudes on the gas and his rears are spinning, wait brakes now? We must be on ice." I'm going to try and specifically ease off the throttle ever so slightly before the hard braking zone, just to ensure the rears aren't spinning at all...and see if that helps.
Which of course brings up a whole different set of driving style questions. My philosophy with these high-HP RWD cars is that in general, wheelspin = slower, but being right on the edge during acceleration...always being between solid traction and just a bit of spin is the fastest way to accelerate these cars. Feel the wheels spin a bit, back off a little, smoothly apply the throttle until they spin again, repeat...Thoughts on this?
Thanks again,
Mike

Well, Tadge says there is no such mode as "ice mode" programmed in ABS. But he makes remarks about rear wheel spin. Id read it again as he explains it pretty well.
I do think it might be something regarding front wheels about to be locked up but the rears still spinning.
As far as wheel spin, it will feel faster but wont be. Having said that, i dont do autox and you dont have PTM to engage PTM Race which albeit generous regarding tire slip under acceleration, will prevent too much slip and hence maximize forward movement instead. So perhaps be a wee bit more progressive with the throttle and then try just a momentary soft touch on a brake pedal before standing on it. I used to practice it in my daily vehicles until it became a habit after i went off in my Vette at the Glen. The same thing will happen in a sim btw like iRacing: if one stomps on a brake the fronts will lock up, or ABS will engage and brake zones will become much longer. Neither is good as neither accomplishes the type of deceleration one is expecting. As i had mentioned, i dont get even a hint of ice mode in my 1le on a road circuit no matter if i overshoot the braking zone and really have to stand on it. There is one particular short course where i need to throw the car into corners to be fast and brake very late and hard. Trust me this is not very smooth and puts the car on its nose Then again, road courses proly offer much fewer bumps in braking zones vs autox venues. Sorry i cant be of further assistance here. Zero experience on autox. Wish ya best of luck!

[Norm Peterson]

Originally Posted by TrackClub

... if one stomps on a brake the fronts will lock up, or ABS will engage and brake zones will become much longer.

Makes sense. You'd be beating the forward load transfer, which can't be fully developed before the front suspension has reached or at least almost reached max nose dive. Which momentarily puts the front in an "overbraked" condition assuming that the proportioning was set to work with full forward load transfer being completed.

Even with a 2.0 Hz front suspension, it could take up to 500 milliseconds for the fraction of the load transfer carried through the springs to be fully developed. Dynamic load transfer through the shocks could effectively shorten that up a bit.


Norm

[BlueinTN]

Tadge explanation of ABS short comings is nice and all but really if your not getting the data you need from "four wheel sensors" then you add extra sensors in IE driveshaft speeds, G forces etc to get what you want. its 2019 not 1989.



If this is a safety issue then the bottom dollar shouldnt be an issue.


Im just following along on this thread I have been lucky I never had problems so far but I have countless more miles on vehicles without ABS than with and I have alot to learn.

[apexit53]

Originally Posted by BlueinTN

Tadge explanation of ABS short comings is nice and all but really if your not getting the data you need from "four wheel sensors" then you add extra sensors in IE driveshaft speeds, G forces etc to get what you want. its 2019 not 1989.



If this is a safety issue then the bottom dollar shouldnt be an issue.


Im just following along on this thread I have been lucky I never had problems so far but I have countless more miles on vehicles without ABS than with and I have alot to learn.

Here is the problem. its a safety issue for a select few people. 80% of camaro owners will never get this issue cause they will never put sticky tires on the car. It is now fixed but does require you to get a 2019 or newer.

[Norm Peterson]

Originally Posted by BlueinTN

Tadge explanation of ABS short comings is nice and all but really if your not getting the data you need from "four wheel sensors" then you add extra sensors in IE driveshaft speeds, G forces etc to get what you want. its 2019 not 1989.

If this is a safety issue then the bottom dollar shouldnt be an issue.

My understanding - and this comes from reading more than just Tadge's explanation - is that certifying ABS to any specified set of requirements is not a simple process. The principle of "first, do no harm" probably applies to building additional capability in some situations, where you might not be able to tolerate a decrease under different conditions. Split-mu conditions, where the tires on one side have far better grip than the tires on the other side comes to mind. Think bare pavement vs slush, snow, or even ice.

Im just following along on this thread I have been lucky I never had problems so far but I have countless more miles on vehicles without ABS than with and I have alot to learn.

I think I'd credit all that experience without ABS over "luck" here. I'm guessing that at least 70% of the miles I've ever driven in my life were without ABS as well. The ABS-oriented technique of "stomp hard and fast and hold it there" would not be as ingrained (if it has become ingrained at all) because that would have been exactly the wrong thing for us to be doing back in the non-ABS days.


Norm

[TheRealJA105]

Originally Posted by ICTsccaCamaro

Both of my 5th gens would ICE mode BAD at autocross's, so far the ZL1 1LE has yet to ICE mode once with a full season of autocross and a trackday under it's belt.

This must have been the problem I was having at my last autocross. Coming out of a long slalom into a hairpin i was definitely going from wheelspin to immediate brake. I felt like i had almost no brakes and the car was pushing crazy wide every run. 6th gen SS w/ supercharger and I'm sure it was affected greatly by my failed tire experiment I was running drag radials on the back that were smaller diameter than the fronts.

I was experimenting for a few reasons:
1) Hoping the DRs would give me better traction - fail as they are old and have some dry rot cracks
2) Because they are old and have dry rot cracks i want to burn them off at low speeds and not on a 120mph pass.
3) I'm a HPDE guy so i didn't really care how I did at autocross and didn't want to be burning my rear G3s off for no great reason.
4) Bring on the flaming for running DRs, but I will try it again with new taller ones and I think it still may work. The supercharger needs more tire than the G3s at autocross speeds and the sidewalls can also handle autocross cornering just fine.

[Norm Peterson]

Originally Posted by TheRealJA105

4) Bring on the flaming for running DRs, but I will try it again with new taller ones and I think it still may work. The supercharger needs more tire than the G3s at autocross speeds and the sidewalls can also handle autocross cornering just fine.

No flame from me. I've heard of people running DRs at autocross going back at least 15 years.

They might work better with wheels as wide as you can find that you can still fit to the car.


Norm

[TrackClub]

Originally Posted by BlueinTN

Tadge explanation of ABS short comings is nice and all but really if your not getting the data you need from "four wheel sensors" then you add extra sensors in IE driveshaft speeds, G forces etc to get what you want. its 2019 not 1989.



If this is a safety issue then the bottom dollar shouldnt be an issue.


Im just following along on this thread I have been lucky I never had problems so far but I have countless more miles on vehicles without ABS than with and I have alot to learn.

I dont believe Tadge has stated they have insufficient data. What he has stated is that ABS calibration is sensitive to algo input assumptions (based on stock parms plus some variants outside of it) but making the latter "endless" is simply impossible. Not even race ABS is capable of it and that's why most of those come with driver adjustability re: intervention levels.

From what i have read here:

- the issue seems to manifest itself at autox courses only, specifically when rears are still spinning while brakes are hammered, perhaps also with bumps involved

- 1LE cars seem less (if at all) prone to this issue

- by and large only heavily modded cars are prone to this issue

- changing driver inputs (even slightly - per Tadge) prevents the issue (and agrees with my own experience with my previous car)

- no reported issues at road circuits even with modified cars incl slicks and/or race brake pads.

Regardless of the above, if one hammers the brakes and engages ABS the brake zone will elongate (by design) to prevent lock up and the car will NOT slow down at an expected rate. Thats a sign of driver braking error unless the pavent is slick with ice, snow, water, etc. So dont hammer the brakes! Get some pro coaching if you cant figure it out. Or disconnect the ABS (and you will figure it out very fast: guaranteed!). Or buy a racing ABS (and then learn how to adjust it properly based on conditions et al: see link below)

https://www.worldtimeattack.com/inde...y-you-need-it/

Bottom line: asking ABS to act as an aid for poor braking skill is a short sighted solution at best. Asking stock ABS to perform unnatural acts on a heavily modded car, while over driving it at the same time is not realistic either.

[Nick S]

Have you tried pulling the ABS fuse out for Autocross and see how the car responds in the same situations?

I have seen numerous threads about "Ice Mode" on both Camaro forums and Corvette forums.

I have also experienced this condition myself at Autocross but never at a road course track.

But I have found that in Autocross when trying to set a faster time the tendency is to accelerate full throttle until the very last possible minute (and oftentimes later than where braking should begin because we all get greedy with this) and then jump off the gas and stomp the brake pedal to full pressure. There is no time for weight to transfer to the front tires in this situation so you are going to easily overpower the front tires and lock them up otherwise.

At the track I get on the brakes differently. I press the brake pedal about 50% to get the brakes activated, get the weight transferred to the front tires and let the car settle into it's "braking stance" and then I give the brake pedal full pressure. This all happens quickly but it's not a stomp of the brake pedal.

In any performance driving, smoother transitions of weight will make the car/suspension happier. So I have tried to retrain myself in Autocross to try and not go until the very last minute (because normally I would get greedy on this anyhow and go too far). So I back my braking start point up a little so I can be smoother with the brake apply. I think this helps be smoother through the corner as well.

I guess one way you can test to see if the "Ice Mode" was activating on you even if you feel the physics of the situation indicate it should not have happened is to find the fuse for your ABS module and pull it out for Autocross. This would disable your ABS system so you can drive without any ABS intervention. Then go and try to repeat the situations that caused your "Ice Mode" to activate and see what the response of the car is. I'm betting that most of the time "Ice Mode" activated that if ABS did not intervene you would lock up the front tires and you still would not slow down very well but you would also flat spot the tires.

It's an easy thing to do to try and test the car's response in similar situations without having to really spend a bunch of money on any mods.

[Chris V]

I've gotten ice mode twice in my car - same turn, same course, same day. Grissom AFB during Optima's DriveAutoX. One wheel in the air, turning and braking at the same time.

If you keep all four wheels on the ground, you won't have ice mode.

If you brake in a straight line, you won't have ice mode.

It doesn't happen on tracks.

There are different calibrations *by tire* and by model. A base SS on all-seasons would have a lesser ABS calibration than one on Summer tires. The ZL1 1LE comes on SC3Rs, so it gets the most aggressive calibration.

If you want to add the 19+ calibration to your 2017-2018 (but not 2016) car, you can, but it's not easy. You need the brake controller off of a 19+ car with the same brake configuration. It's plug and play, but that requires pry bars and pulling the cowl, in addition to getting a computer with the calibration on it.

I lean pretty hard on my brakes on track, and have never had an issue. For autocross, just brake an instant sooner and get back to power. You're not going to beat cars with cornering speed on this platform anyway, just get back to power.