Originally Posted by BostonDMD

Front and rear were mounted at same time, first used on the 911 when doing DEs 2.5 years ago, then sat in garage, last month mounted on the Cayman.
....

Originally Posted by Dave DE

Are you using stock tires sizes on the Cayman? They aren't the same as a 911, and non-stock size/stagger can increase the chances of ice mode.

Originally Posted by Matt Romanowski

Turn 3 at NHMS (where DMD had his problem) is really a bumpy braking zone. Also, it can be done to brake in a different section of the track - it's the basic rain line. You start out about 2 car widths off of the left edge of the track and drive into the normal turn in point while braking. It is the basic rain line and still pretty quick.

Originally Posted by BostonDMD

Well, I am going back the beginning of May, hopefully I will have a camera installed by then so we can see if turn 3 is smooth as glass or not.....

and if it happens again....

Till then wish me luck.......

Originally Posted by jrgordonsenior

What's weird to me is that I've never experienced it in any of my race cars and I brake late and hard initially, coming off into the corner. I've certainly gone into the ABS mode when hitting bumps while braking hard, but I've never experienced the "ice mode". In my avatar I'm braking down from 150+ to a second gear turn in and I never, ever have had an issue there at Cal Speedway. Oh and I run Patron Yokes, 640 fronts, 680 rears.

I don't know if any of this is relevant but....My 1999, 996 is light 2600 w/driver, on all stock calipers & rotors. I use RS29f, RS14r Pagids running on Endless fluid. I run my Clubsports (JRZ's previously) with lots of rebound and very little bump so I can run over gators, corner workers, etc.

Originally Posted by onefastviking

Do you drive any bumpy tracks ? Or do you stay off the bumps ? Not curbs and such, but lots of little higher frequency bumps.

It's really not a condition that happens often, it must be in just the right combination of conditions. When it does happen it's an eye opener for a second or two.

Originally Posted by onefastviking

I've done more than my share of research into this and have quite a bit of experience with driving and wrenching to solve the dreaded "black ice" mode.

A number of things can cause the condition and usually it's obvious to each driver once it is discussed in detail which they suffer from.

First off it's not a "Porsche" only condition, nor a model specific condition. Yes, some do more than others, in part to certain characteristics of the car,model,year, tires, and suspension. I have now seen, and/or, experienced it in Porsche, BMW, Mercedes, Audi, Mazda, and even a Mitsubishi.
Basically, the street car ABS systems are designed specifically as "street car" systems operating under street car conditions. As race tires are added, stickier tires, mismatched tires (either in brands,or even build dates which cause a harder/softer rubber compound), different sized tires, different suspension, cars driven on bumpy tracks, and I am sure a few other conditions I have yet to discover. The stock ABS systems are not programmed for these parameters and in some cases are not even designed to - think a 3 channel system vs a 4 channel system. I will say some of the ABS systems are designed better than others, the old 1990 911 ABS system is not as good as the 2011 GT3 system, although it still can happen in both given the right, or I guess wrong, parameters.

The ABS systems that were allowed in Grand Am to correct this condition have been the Bosch Motorsports unit and also a BMW system that the software had been highly modified for operating under "race" conditions. Both of these systems are not inexpensive, nor really for a do-it-yourself installer. Attempting to use the street car BMW ABS system,once you figured out which one it is, will not be any better than what you have without the reprogrammed software for the ABS ECU.

The most common things I see causing it on modified (race) cars are suspensions set improperly on bumpy tracks, or different diameter tire size.
The most common thing I see on more stock street cars are a different set of dates on the front tires vs the rear tires, kinda common when the rear tires wear out faster on a 911 or fronts if unable to get the needed camber. Or also a bumpy track with a harsh pedal application.

So my first question for the OP would be have you recently replaced JUST the front or rear tires ? Check what the manufacture dates on both front and rear are.

Second question, are you jumping on the brakes and is it a bumpy section of track where you experience it ?

Also, for anyone that does experience this condition of "black ice" = hard pedal and zero stopping power. - If you release the pressure on the brake pedal and reapply brakes, you will usually have brakes again, you will probably have blown the corner at that point but it beats going into the corner with no brakes at all.

Keep in mind this condition is different than foot going to the floor with air in the lines, in which you would want to pump the brake pedal and also different than a fading brake in which you would want to cool the brakes more.

Standard disclaimer applies, should you feel your car suffers from any braking condition, you should take the car to your automobile service specialist to determine what is the cause and get it corrected.

Originally Posted by kurt M

Thanks for the good info. I have heard about ice mode with Porsche for a while but don't tend to deal with other brands and did not know if it was pervasive. I have had some guys tell me that pumping or lift off and try again did not clear the issue. There is also a add on kill switch type of setup for some of the cars. Can this be adapted to the newer ones that can also go ice mode? Say a guy wants to race a car on bumpy tracks and use R comps and race pads. (This combination is not unheard of from what I have seen) Is there a good ABS kill that can be rigged up or is it just better to lift off the brake pedal and try again?