Ice mode solution?

ChrisSlicks · 04-04-2011, 10:51 AM

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.

boardkat · 05-03-2011, 07:31 PM

Quote:

Originally Posted by ChrisSlicks

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.

carbotech AX6 in the front, stock pad in the rear? would something like that work for autox? or is there enough heat building up in the pad that an XP8 front and AX6 rear might do the trick? in my solstice, i run AX6 front, XP8 rear, since the bias is slightly forward (and there is no funky brake assist/abs computer programming), but my understanding is that it's the opposite in the 370. i love the moderate initial bite (compared to RS4 and HP+ pads) and linear braking characteristics of the CT's, and the amount of heat they can handle!

flashburn · 04-04-2011, 10:43 AM

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.

cossie1600 · 04-04-2011, 10:59 AM

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.

ChrisSlicks · 04-04-2011, 11:23 AM

Quote:

Originally Posted by cossie1600

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.

The heat issue is only really an issue on the hotter days and if you are co-driving. I've had my brakes hot enough to cause fluid fade in auto-x but that only happened once and that was after doing 3 back to back runs after several other runs (co-driving and then a re-run). The issue with heat is that it shifts the brake bias even more rearward which the ABS controller doesn't deal with very well.

RCZ · 04-05-2011, 04:31 PM

So essentially still no fix guys?

cossie1600 · 04-05-2011, 06:23 PM

I can throw my XP10 on in the front and leave the stock in the rears and try that

flashburn · 04-17-2011, 02:16 PM

Quote:

Originally Posted by cossie1600

I can throw my XP10 on in the front and leave the stock in the rears and try that

Just wondering if you've been able to test out this setup yet?

cossie1600 · 04-05-2011, 08:01 PM

Heat was never an issue with me relating to ice mode. Ice mode occurs the harder/quicker I stab the brakes. I have done a few track events at the Z, the car will do it hot or cold or warm.

Red__Zed · 04-05-2011, 10:40 PM

I'm curious if the issue has been experienced by anyone with the base brakes. I've obviously run into heat issues, but haven't yet experienced the reduced brake force the way you guys are describing. Might help narrow down the issue if it isn't being experienced on the base brakes.

christian370z · 04-06-2011, 01:48 AM

Quote:

Originally Posted by Red__Zed

I'm curious if the issue has been experienced by anyone with the base brakes. I've obviously run into heat issues, but haven't yet experienced the reduced brake force the way you guys are describing. Might help narrow down the issue if it isn't being experienced on the base brakes.

Good point, but after pushing my base brakes to the point that Triple's could smell my brakes burning half a mile behind me with smoke billowing off them, I would not think they could last long enough or have enough bite to equal the conditions that trigger ice mode with the Akebonos.

Red__Zed · 04-06-2011, 09:04 PM

Quote:

Originally Posted by christian370z

Good point, but after pushing my base brakes to the point that Triple's could smell my brakes burning half a mile behind me with smoke billowing off them, I would not think they could last long enough or have enough bite to equal the conditions that trigger ice mode with the Akebonos.

I understood it is not heat related, besides that, if you got to that point, you should have been hot enough to trigger the condition if it was.

From what I can tell, it's due to issues with the ABS controller. It may be worth looking into why it doesn't seem to occur on base setups.

RCZ · 04-06-2011, 09:40 AM

Considering it happens to other cars too...I would imagine it has more to do with the programing of the ABS system. The worst part is that it's really only a matter of time before someone crashes on the track because of this. I've been really hesitant to get back out there and this is partly why. Even when the car was completely stock, I almost went off twice at a hairpin, if there had been anyone in front of me, it would not have been pretty. Maybe AM Racing has some kind of an answer for us considering they are building that gran-am 370z.

cossie1600 · 04-06-2011, 10:06 AM

yup,corvettes, even 350 had it. my rx8 never had it, probably because it never went fast enough to have huge nose dives.

i just learn to modulate my pedals better.

now i wonder if the problem will get better or worse if i were to put a set of slicks on my car

ChipsWithDips · 04-06-2011, 07:17 PM

I just got my Z and haven't experienced "ice mode" yet, but then again i've been going easy on it for the first 1200 miles. I plan to take it to the track in the future, so I'm curious what exactly you guys are talking about.

It sounds to me like people are simply describing brake fade. Or is there something different about "ice mode" that differentiates this from brake fade?

04-04-2011, 10:51 AM	#1 (permalink)
ChrisSlicks A True Z Fanatic Join Date: Mar 2009 Location: North East Posts: 6,203 Drives: 09 370Z Sport M6 Rep Power: 654	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. KapitalZ likes this. __________________ Hotchkis ARB \| Stillen CAI \| Art Pipes \| Berk CBE \| Stillen AP Racing Brakes \| AE Performance Oil Cooler \| BC Racing ER Coilovers \| Doran Control Arms

04-04-2011, 10:43 AM	#3 (permalink)
flashburn A True Z Fanatic Join Date: May 2009 Location: Central Florida Posts: 1,884 Drives: '12 Corvette GS 6M Rep Power: 20	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. __________________ Current Ride: 2012 Chevrolet Corvette Grand Sport Centennial Edition Carbon Flash 6M Previous Ride: 2009 Nissan 370Z Sport Platinum Graphite 7AT

04-04-2011, 10:59 AM	#4 (permalink)
cossie1600 A True Z Fanatic Join Date: Jun 2009 Location: californee way Posts: 5,380 Drives: 370, Leaf Rep Power: 31	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. KapitalZ likes this. Last edited by cossie1600; 04-04-2011 at 11:07 AM.

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04-05-2011, 04:31 PM	#6 (permalink)
RCZ A True Z Fanatic Join Date: Nov 2008 Location: Miami Posts: 6,403 Drives: '09 370Z Rep Power: 1119	So essentially still no fix guys?

04-05-2011, 06:23 PM	#7 (permalink)
cossie1600 A True Z Fanatic Join Date: Jun 2009 Location: californee way Posts: 5,380 Drives: 370, Leaf Rep Power: 31	I can throw my XP10 on in the front and leave the stock in the rears and try that

04-05-2011, 08:01 PM	#9 (permalink)
cossie1600 A True Z Fanatic Join Date: Jun 2009 Location: californee way Posts: 5,380 Drives: 370, Leaf Rep Power: 31	Heat was never an issue with me relating to ice mode. Ice mode occurs the harder/quicker I stab the brakes. I have done a few track events at the Z, the car will do it hot or cold or warm.

04-05-2011, 10:40 PM	#10 (permalink)
Red__Zed A True Z Fanatic Join Date: Jul 2010 Location: window seat Posts: 28,940 Drives: Mostly on two wheels Rep Power: 121	I'm curious if the issue has been experienced by anyone with the base brakes. I've obviously run into heat issues, but haven't yet experienced the reduced brake force the way you guys are describing. Might help narrow down the issue if it isn't being experienced on the base brakes.

04-06-2011, 09:40 AM	#13 (permalink)
RCZ A True Z Fanatic Join Date: Nov 2008 Location: Miami Posts: 6,403 Drives: '09 370Z Rep Power: 1119	Considering it happens to other cars too...I would imagine it has more to do with the programing of the ABS system. The worst part is that it's really only a matter of time before someone crashes on the track because of this. I've been really hesitant to get back out there and this is partly why. Even when the car was completely stock, I almost went off twice at a hairpin, if there had been anyone in front of me, it would not have been pretty. Maybe AM Racing has some kind of an answer for us considering they are building that gran-am 370z.

04-06-2011, 10:06 AM	#14 (permalink)
cossie1600 A True Z Fanatic Join Date: Jun 2009 Location: californee way Posts: 5,380 Drives: 370, Leaf Rep Power: 31	yup,corvettes, even 350 had it. my rx8 never had it, probably because it never went fast enough to have huge nose dives. i just learn to modulate my pedals better. now i wonder if the problem will get better or worse if i were to put a set of slicks on my car

04-06-2011, 07:17 PM	#15 (permalink)
ChipsWithDips Enthusiast Member Join Date: Mar 2011 Location: Austin, TX Posts: 279 Drives: '11 Gunmetal 370Z MT Rep Power: 15	I just got my Z and haven't experienced "ice mode" yet, but then again i've been going easy on it for the first 1200 miles. I plan to take it to the track in the future, so I'm curious what exactly you guys are talking about. It sounds to me like people are simply describing brake fade. Or is there something different about "ice mode" that differentiates this from brake fade?