as some of us know when tracking or for me autocrossing as you go quickly from WOT to jumping on brakes they dont work !!! the pedal is rock hard and wont depress downward . please if this never has happened to you or you never heard of it please dont comment ! this is a real thing and scary as hell as you blow through a stop box or slowing down for a for a tight turn after a straightaway< as we know who has experienced this its not every time its only when you least expect it !!!! fyi im on my 4th C7 and its the same on everyone of them > 2014 base, 2015 z51 mag and nonmag car and now 2016 zo6 .yes i do know its called iceing and i dont believe it has much to do with what tires or pads we are running but its in the T/C tune or ABS tune !!! im just trying not to crash my car in a parking lot when autocrossing < anyone have anything to add or a fix for this ? thank you

 

There was a thread last year (I believe it was Village Idiot) that got into a fair bit of detail on this. If you don't get a good response here, you should search for that.

 

 

Does your car do it when using any of the stock tires? I haven't had it happen on my C7Z but I had a couple of scary situations that happened with my C6Z that took me off the end VIR's T1 at some seriously high speeds. I became very tentative approaching that turn after that braking way too soon and at much lower speeds.

I don't think there will be a solution other than the driver solution. Some of it has to do with how we hit the brake pedal but there are probably 20 or 30 other things that may be factors as well. The problem ABS designers have is the number of different scenarios they have to account for. I imagine it makes power train tuning look like child's play. The ABS guys have to account for all sorts of grip surfaces from asphalt pavement, to concrete, to gravel, to dirt, to slushy, to icy, to snowy, to wet, to lubricated by something dropped on the pavement from another car and then have to calibrate the system for different grip surfaces from one side of the car to the other. Worrying about rare cases of off road ICE Mode that occur probably doesn't get very high on their radar. One wheel could be in ABS mode while the others have grip or it could be three are in ABS mode while one has grip. I have used ABS on many of an icy road and have never found any action like the so called ICE Mode. Touching the brake pedal on a slick icy surface will cause one or more wheels to stop turning and then the ABS works to keep them turning to some degree so the driver can maintain control. The pedal will vibrate, sink a little and the occupant/s can feel the individual wheels ABSing even on very slick surfaces. In the rare instance when the touching the brake pedal locks up all 4 wheels at exactly the same time the car will slide without ABS activating since the EBCM interprets that action the same as if you came to a normal stop on a perfectly good road.

When the ABS is doing what we have experienced it is truly far from any mode that it would work in when on real ice. ABS always gets some pedal vibration and a sinking of the pedal to some degree. A hard non sinking pedal and lack of brake force is something else.

Bill

 

 

 

FE7 or FE6 car? Got any PDR data of the issue? Just interested in taking a look at the data.

 

 

 

 

If he can’t fix it it’s not broken!! Lol

 

I know about the ice mode, where the system runs pretty inefficient if you stab the brakes too hard, and the only way out is to lift and re-engage the brakes (pumping it).

However, what you're saying seems to be low vacuum issue. When on boost, I think the system doesn't charge up the brake system, and keeps whatever boost it has by the help of a check-valve. Theoretically, the system should get charged up again when you shift, etc. This would only be a problem on a forced induction engine, though; not on an LT1.

I remember adding a much stronger check valve to my brake's booster line for my FI Miata, to make sure the boost doesn't bleed when on full throttle for too long. Perhaps you should check into that? I also wonder if a split second lift before braking could help, but I know you would not want that..

 

thanks everyone who responded especially bill dearborn , poor-sha and x25 who i respect all of their opinions. with that being said this is a real problem that its hard to believe its not more of a concern to the corvette world ! i wonder how many times a C7 crashed because someone hit the brakes to quickly or to hard ?? omg really !! thanks again my forum friends and i will be sure to slow down before i slow down because the life i save might be my own !!

 

If you transmit your raw PDR video file to Sean he can use the included performance data to evaluate what was going on with the car. It is far more than green lights and red lights in the video. One thing I learned a long time ago is when slamming on the brakes don't do that. First engage the brake and then apply full pressure. A slight couple of millisecond variation of slamming on the brakes but avoids the initial shock until the brake pads and rotors are fully engaged.

As for Ice Mode on my C6Z I was pretty sure it was activated by tire slippage on the wheels that I was having happen every time I hit the brakes hard. Tires would rotate at a rate higher than the the wheels were rotating for an instant after the brakes were engaged.

Bill

 

 

Savage, like Bill said if you can put the raw unedited file up in dropbox/onedrive/google drive and send me a link I can pull it down and take a look at the data. I'll also need to know about when it happened. Unfortunately your car as a 2016 doesn't have the yaw and individual wheel speed channels in the stream but there is still lots of other data.

 

 

 

In my experience, high bite race pads make it easier to lock up brakes as suggested, and Hoosiers actually help prevent it since they're harder to lock up.

In any case, the solution will involve using the brake pedal at the threshold, not over, and also the steel nerves to be able to lift and reapply at threshold, if it's exceeded for some reason, and car is slowing sub-optimally.

I should also point out here: this happens with any car; it just looks like your combination (setup, way you use the car, etc.) makes it happen all the time for you. I'd definitely work on finding your setup's brake threshold. At that level, you'll be commanding one of the quickest slowing cars in the world, and be also confident about repeating it : ) Seriously, I love modern Corvette brakes!

 

I am wondering if a brake pad with softer bite would help. I know things like ride height and sway bars can be a factor as well as tires and surface being driven on as well as driving style. I have had several cars of different models and manufacturers in ice mode. It has always been autocross never on a road course.