Ice mode braking

[Mn23]

Sorry guys I have been searching and reading a lot of the older posts but still can’t find the best way to cure ice mode on the track. Investng in a race abs controller is not an affordable option for me unfortunately. I do have a brake vacuum canister coming but not sure if this is the real fix...

I’m running Hawk DTC70/60 with Stillen cooling ducts, motul RBF660 and braided lines but car just won’t stop probably after a few hot laps (ice mode i guess)

Any help?

Thanks

[Rusty]

Sounds like you have brake fade. You have brakes, then they fade away after a few laps. Cool them off and they come back.

Ice mode is when you hit the brake pedal. And nothing happens. Usually in a bumpy corner. The brake pedal doesn't go to the floor either.

[BGTV8]

DTC-70 is an aggressive race pad ......... and seeing them fade is a surprise ...........

You need to look to improved cooling as HTC-70 should not fade in a few laps (their operating temps are 400-1600 DegF) so something in awry - question is how to figure out what it is

When the car won;t stop - do you have a long pedal ?? Could be you are boiling the fluid .... try and rule that out if possible

If not a long pedal, does pedal stiffness vary .... OR does the car simply not stop regardless of the pedal pressure (that is the classic definition of fade). if this, then maybe the pads were not bedded properly (or you have deposits on the rotor that come in to play when the rotor gets hot).

A rock-hard pedal, no ABS pulse and zero retardation can be ice-mode but it takes bumps/track ripples to trigger it - is not usual these days

Do you have any ideas on rotor temps when you get fade ?? Infra-red temp gauges are not overly accurate by that will tell you PDQ about whether you have fade or not.

Do you still have backing shims in place ... try some titanium shims to keep heat away from the pistons and fluid

Try a full brake fluid flush

Maybe try other pads .........

Are these pads in the car all the time or only when you are on track ....

What is the state of rotor deposits .... consider emery cloth to scuff up the rotors and re-bed the pads .............

I have used Ferodo DS2500 and DS3000, Endless MX-72 and ME-20, Project Mu HC+ and never experienced fade in ~5 laps ... so there is a problem there and like Rusty says, it does sound like fade rather than ice mode as ice mode is a solid pedal and zero retardation over bumps - I've only had ice-mode once and it scared the living daylights out of me .... occurred over bumps and with ABS triggered - then no retardation at all - is that your experience ??

Needs a methodical approach to establish what the problem is

[Mn23]

Thanks guys, my pedal never went to floor or soft that’s why I thought it wasn’t fading. The pedal did go stiff (but not solid hard i guess) and ABS pulsing for sure when I brake harder before the turns. I have checked no boiling fluids (RBF660), sometimes a bit smokes from the front brakes.
Maybe like you said improper bed in? I don’t have any brake noise thus I thought it was properly bedded in lol.
Brakes did come back fine after cooling down for a lap or two but happens again during harder braking after 3-4 laps.
It is a smaller 1.5km track with heavier braking and a bit bumpy.

Btw weather wasn’t hot and my friends Nismo had no problems even with his OE pads. Definitely something wrong with my setup. Did bleed the brakes when I install the cooling ducts and they are for track only also driving back and forth track. Will double check on the metal shims part.

Thanks

[2011 Nismo#91]

Originally Posted by Mn23

Thanks guys, my pedal never went to floor or soft that’s why I thought it wasn’t fading. The pedal did go stiff (but not solid hard i guess) and ABS pulsing for sure when I brake harder before the turns. I have checked no boiling fluids (RBF660), sometimes a bit smokes from the front brakes.

If abs was pulsing then you were at the point where your brakes were locking up your wheels, so they were working fine. I think this is a tire overheating issue rather then a brake issue. Tires become "greasy" if they get above their operating temps.

[cv129]

Curious what tires is OP running?

[Mn23]

I’m actually running RE71R before and now Pirelli slicks with a lot of grip. Weather was pretty cool so I didn’t have anything heating issues. Just didn’t get why the ABS is acting up, car is brand new 2017. I was pushing the car hard and was one of the faster cars there (before the brakes acting up lol), but still don’t see why the brakes give up so fast. Even tried bleeding the brakes again but not much better.

[Rusty]

Your brakes are overheating. You need to get more cooling on the rotors. The Stillen kit only uses 2" hose. You will need to go to at least a 3" hose or bigger. The slicks are giving you alot more grip. Hence the brake issue.

[cv129]

Sounds like the combination of high grip and high driver skill exceeds the heat dissipation capability of our stock brakes.

What cars have you previously run?

[Mn23]

Originally Posted by cv129

Sounds like the combination of high grip and high driver skill exceeds the heat dissipation capability of our stock brakes.

What cars have you previously run?

No I am not at all a skilled driver, just the setup on the Z is quite nice to drive. I had a 350Z as track car before with similar setup but didn’t have these brake issues.

Thanks Rusty, I even ran into the same problem with the RE71R, maybe the tracknis a bit bumpy? I am going to get Z1 2 piece rotors and a new set of pads to see. Don’t know how to deal with the Stillen brackets and the 3” hoses though lol

[Rusty]

Originally Posted by Mn23

No I am not at all a skilled driver, just the setup on the Z is quite nice to drive. I had a 350Z as track car before with similar setup but didn’t have these brake issues.

Thanks Rusty, I even ran into the same problem with the RE71R, maybe the tracknis a bit bumpy? I am going to get Z1 2 piece rotors and a new set of pads to see. Don’t know how to deal with the Stillen brackets and the 3” hoses though lol

I been using Carbtech XP10 front and XP8 on the rear with Racing Brake 2 piece rotors. Hard Braking Ti heat shields on the front pads. I have the Nismo RC brake ducts in the front bumper. I believe these bring in more air then the Non-Nismo front bumper inlets from Stillen.

To mod the Stillen kit for a 3" hose. Parts are out there.

[MinionZ]

I am in the process of developing a 3" ducting system at the rotor that should be a lot better than the stiller kit. Will shoot air into the top hat to force air out of the vanes and will have its own backing plate that's smaller. Backing plate pictured is the first version. Already on second that's being cut now lol

[Mn23]

Thanks Rusty and all.
I took the pads out to inspect and they look fine, bleed the brakes again. I’m also fabricating some cooling deflectors that ties on the rods to direct more air to the front brakes. Let see how that goes...

I’m still confused whether it’s actually an ABS ice mode or brake cooling issue. Again in ice mode, I should be experiencing stiff pedal and ABS pulse? Please correct me of I’m wrong.

[Eagle]

I'm thinking it could be the pad compound you're using. I've never run Hawks before but I do know they are pretty harsh on rotors so their bite must be pretty substantial.

That said I run Endless MX72+ and don't think I've ever encountered ice mode. I've had a couple lock up scenarios, but nothing abnormal for a track day.

Not sure what your braking technique is like but an agressive pad + an agressive driver may be the culprit. It's possible you may not need a pad with as much bite as your Hawks. Braking late isn't always the fastest way around the track

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