Ice mode solution?

AutoX Z

I'm getting pretty sick of the ice mode on my car and have tried to try and fix it. Because of the SCCA rules Im pretty much limited to changing pads and fluid. Has anyone figured out a way to at least improve the braking performance with these restrictions?

Also FYI this is a daily street driven car and will only be used for autox. Please keep this in mind and don't bother recommending track-oriented solutions.

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cossie1600

The grippier pads only make it worse.

spearfish25

I swear that ice mode actually kicked in while I was on ice this past winter and caused my fender bender. Hate it. I want a class action lawsuit.

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Jordo!

I'm not familiar with this...?

Is this another VDC thing -- associated with the "icy" warning that comes on?

We don't get much ice in Floriduh, so...

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cossie1600

If you get on the brakes HARD on bumpy pavement, or just pull any sudden decel, the brakes will actually release slightly. Imagine you hit the brakes and expect 100% braking power, the brakes actually let go and only give you 10-20%. It's a scary feeling, but it seems to be a common thing on newer cars now. The problem is mostly with people that races, shouldn't be a problem when you drive on the street. It's called ice mode because the car can do the same thing when you hit an ice patch (brakes release upon hitting ice quickly)

This is my theory, some people might disagree.

AutoX Z

No it's a problem with the ABS computer. In heavy braking situations (tracking and autox) the abs wll engage early and limit the overall braking to maybe 30%. It seems to get worse with heat and "stabbing" the brakes.

It would make sense that pads with better bite would make it harder to be gentle on initial application and make ice mode happen more frequently. Maybe the solution is to use a less aggressive pad and give up some overall braking performance. I've also considered playing with dramatically different pads front and rear to change the brake balance.

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Jordo!

Oh, okay -- can't you just disable the ABS?

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AutoX Z

Not allowed in the class I compete in.

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Jordo!

Ergh... yeah, you'll probably have to play with pads then.

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cossie1600

Well I don't think the computer is faulty, it is doing its job by throwing the car in ice mode under sudden decel on just one side. You are right, less aggressive pads seem to lessen the problem. Autozone pads might do the job for you. I had a tough time staying out of ice mode with my RE11 with my XP10 at the track

It's a common problem with the 350 and Corvette too.

flashburn

So is there basically no fix for this (other than disabling ABS)?

I haven't yet faced "Ice Mode", but what exactly do you do when it happens? It sounds like it would cause a potential off-road/wall incident if you are braking at maximum threshold.

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cossie1600

you can back off the brakes slightly and reapply or just pray that it will grip eventually. on the track you will notice it hit at roughly around the same spots, i sometimes go out of line just to avoid the bumps. at autox you just have to train yourself not to freak out and fight throgh it

flashburn

Oh, so when you reapply the brakes, do you just apply less pressure than before?

It's good that it is somewhat predictable, since it would suck to be doing threshold braking on the same turn, and then all of a sudden the next time you take it and apply the same amount of braking you don't get what you expect. That could have some very bad end results.

Is it mostly bumps that cause this? Not that it matters for me, since the main track I do is Sebring, and that's probably the bumpiest track around.

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Current Ride: 2012 Chevrolet Corvette Grand Sport Centennial Edition Carbon Flash 6M
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ChrisSlicks

The problem is the ABS controller. They added a two new features to the 370Z which don't really work properly, Dynamic Brake Proportioning and Brake Assistance.

The biggest problem is the Brake Assistance, this feature actively boost the brake pressure you apply when you hit the pedal suddenly but not hard enough to engage ABS. It boosts the pressure such that you immediately go into ABS. Auto-X drivers are always hitting the brakes suddenly because we always leave braking to the last possible second. The problem lessens if you get onto the brakes progressively but if you go into ABS manually you still have the issue.

The second problem is related to the Dynamic Brake Proportioning and the ABS programming, and to a certain extent, heat. It is very easy to overheat the front brakes on this car at Auto-X especially if co-driving, there is simply no airflow at all. The ABS controller loses it's mind when the front brakes start to lose effectiveness compared to the rear brakes, this is a severe programming problem. The solution I have found is to run a low bite, high temperature front pad, and a lesser rear pad. This combats the bias issue and the temperature issue.

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cossie1600

thats what i do. lets say i am on the brake pedal hard at 95% at threshold braking, i just let off slightly to let say 90% to get rid of it and reapply hard again. the problem is worse with grippier pads, i dont know if slicks make the problem worse. i have re11, not sure if less grippy tires will do it easier or not.

one thing i know that is helpful is to hit the brakes slightly less hard. so instead of let say put 30 ft lb at the pedal, i would hit it with 20 ft lb of force. you still go all the way down on the brakes, you just have to hit it less hard initially to not flip the abs out. its the same reason why race pads hate the stock abs since they bite so hard and fast

i am with chris on the first point, but i am not sure if heat has anything to do with it ( i am not saying it doesnt, just saying i am not sure). you abuse the brakes way more at the track, you cant even compare a 135mph to 43mph turn to two 60 sec run to an autox.

this problem is not unqiue to the 370, 350 and corvettes have it too.