In-Car at Willow Springs + Off-track dirt action...Thanks Ice Mode...

ryan0

you broke and it pulled one way? that sucks.. maybe just one side's pads over heated since there was so little compound left?

did it boost the braking pressure to that one side?

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M.Bonanni

From what I understand about the 370Z ABS/EBD system "ice mode" is a safety feature that monitors the yaw sensor, wheel speed sensors, vehicle speed, brake pressure, steering angle, etc. to determine if the car is in a "safe" situation to apply the brakes. If it thinks it is not in a "safe" situation to apply the brakes, the moment you try to the ABS/EBD takes over and sends brake pressure to whatever corners needed to keep the car under control. With track driving, particularly at that spot on WSIR in a modified 370Z I am guessing that the combination of the mph, g-forces, wheel speed, steering angle, etc. exceeded what the ABS/EBD considered "safe" to apply the brakes which would probably be true if I were in a bone stock 370Z with stock tires. So as soon as the brakes were activated the ABS/EBD took over and sent brake pressure to where it saw fit. Threshold braking is the most common scenario when people experience it for sure but I don't think it HAS to be threshold braking in a straight line, I think its just simply any scenario where the data coming in from all of the sensors exceeds what the ABS computer thinks is a safe situation to apply brakes. Because the car has EBD and can distribute the brake pressure differently to each corner how it reacts depends on the situation its in.

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cossie1600

You can try racerender for merging two videos together, I believe the basic version is free.

Shamu

I think most of us who have pushed these cars hard on track have experienced this issue. It's scary as hell. Especially those of us who threshold brake and trail brake.

Honestly I haven't experienced ice mode since putting large vacuum reservoir on stock braking system. I do think part of issue is vacuum related.

As far as bias when you disconnect abs. While yes bias goes to rear you can tune suspensions and brakes to work without car spinning. And it does take some modification of braking style.

I will be interested in what you do. I know race car up in Nor cal switched to expensive motorsports abs system. What are you thinking? I have heard that there might be ability to tune this out of stock system but no one is willing to take liability of doing this on stock system.

I think it's absolutely criminal that Nissan doesn't warn people about likelihood of this ice mode occurring in motorsports and prohibit track driving of these cars as part of warning to less experienced drivers. You and I and other experienced drivers have managed not to wad up car when this ice mode happens but how about less experienced driver who target fixates and doesn't know how to slow car down without brakes? I'm still convinced the car that magazine testers put into the wall when car was released experienced ice mode and not brake fade.

I'm also curious have you checked rear calipers and are they ok? No leaks etc. I had a stock caliper go bad which I think was contributing to ice mode issue as well.

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Grant

Dwnshift

What you guys experience is absolute nothing new...even the Porsche 997 street cars experienced this in Conti series...as well as mustangs...camaros and even the BMWs so it isn't just a Nissan thing.
Almost all the cars is ST run the Tevus system (allowed to or not) and
every car in GS is now allowed a Bosch Motorsports or Tevis abs system.
When ran the ST 128 BMW after 2 events on the OEM stock pump ...it was toast and only got worse.
Basically I think ice mode burns up the pump and once you start having "ice mode" it will just keep getting worse or more often.
The man to talk to is Kurt Jung..is an electronic guru espc. on ABS systems.
He is also the main dealer Motorsports for the Tevus system.
The Bosch system is pretty advanced 10 preprogrammed maps and 2 specific maps based on inputs for specific car measurements....front and rear track, vehicle weight, wheelbase, and front and rear tire circ.
Both systems are expensive ...but so is crash damage.

Shamu

They don't quite experience ice mode like we do in 370z. I have been long time Porsche guy and ice mode in Porsches , Mazdas and BMWs isn't nearly as scary as 370z ice mode. Hell my Boxster was raced over and over and never had this issue. My track going MX5 didn't have this issue either? So it's downright inaccurate to say many other street cars have this issue and that the issue is the same. The ice mode in 370 let's off brake pressure far too much at all corners at once and doesnt regain pressure quickly enough. While some other systems may experience minor ice mode issues they aren't the same as what we experience.

And no it's not new it's been issue since our car was released without much done to fix issue other than to put $10k race abs system on car or turn off abs.

Most of cars running grand am run expensive systems due to tuning available. If you are in series to win using stock abs isn't going to cut it typically.

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M.Bonanni

Honestly for me, this is my daily driver right now so I will likely just keep it off the track all together. Down the road if I am able to turn it into a dedicated track car then I would probably go with an aftermarket dual clutch setup with bias adjustment and bypass the ABS all together unless someone comes out with a programming fix.

I had my calipers re-built completely and have checked them periodically and still have the issue so I don't think that's the problem. I think what Downshift said about the pump burning up might be the key to why mine just keeps getting worse.

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Shamu

So wonder why mine was getting worse and worse and then when I put vacuum reservoir on circuit it stopped all together? Haven't had a single instance of ice mode since making that mod? That's only change I made to car as well. Same tracks, same tires, same pads. No ice. We use similar fix in Porsche world with fairly good success, but again ice mode in Porsche world isn't like ice mode we experience. At least with Porsches ice mode doesn't occur until you truly are at threshold and tires would be locked up and their system recovers more quickly than the system on370z. My experience with ice in 370 z prior to vaccum upgrade has been from initial application with car headed straight and I have had enough room to reapply and still nothing at all. Literally forces me to pitch car sideways to slow myself down.

I'm sure a burned out pump in some cars contributes to malfunctioning abs but I'm not sure that's our issue.

Also it's tough to compare a time trial car that takes limited stints on track to professionally driven endurance race cars on race slicks as well. That's a whole different world of stress on braking systems. Hell even racing systems fry in those environments.

Just wonder if spec 350z guys are running off tracks all the time like few stock abs system 370z track cars are. I know 350z had mild ice brake issue so does GTr but nothing like 370z.

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Grant

Dwnshift

Didn't say that was THE issue...I was saying that I belive..continued "ice mode" will burn up the pump...for sure a burnt up pump or failing pump will lead to ice mode more frequently
Which is exactly what I think is the main issue /cause stated waaaaaaay back when. The loss of vacuum or loss of proper built up supply to properly operate modern ABS systems....especially with complex intake / camshaft timing systems.
Again...not saying this is it...just my two cents.

Sh0velMan

What 'pump' are you guys talking about?

Shamu, can you post photos/info about your vacuum reservoir?

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Reaper42

I second this ^ would like more info ok Shamus fix

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Dwnshift

ABS block/pump
Vacuum assist brakes need vacuum operate the ABS... If there is not an ample amount of vacuum to supply the system to operate... You will not be able to compress the pistons of the brake calipers.. Giving the driver a super hard pedal.
To me... That's why I don't recommend super double throw down brake pads for tracking. Hugher clamping force will trigger ABS to cycle /use more vacuum...big slow hard hits in the pedal. Then there isn't enough time to build up the supply for the next corner... and it starts all over again.
The OEM ABS computer is not programmed for high sampling rates and cannot keep up with the short supply. A Motorsport ABS pump and computer has much faster sampling and cyles...and the pules felt in the pedal are much softer shorter and faster.... More efficient use of the vacuum supply.
The use of a vacuum accumulator or reservoir can help because it allows vacuum to build up giving the ABS a larger supply to feed from.
That's my version.

bigpat728

what size wheels and tires are you using on your z? i'm new to the z world and wanna start doing some track days and also wanna get some nice looking wheel that i can use both on street and track.

M.Bonanni

18 x 9.5" front with 275/35/18
18 x 10" rear with 285/35/18

There are a lot of great double duty street/track tires out there right now, most are around the 140-220 UTQG (treadwear) rating. The Hankook R-S3 is my personal favorite as its the grippiest on the track and also quite affordable in comparison to other tires in its class.

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bigpat728

awesome, i may just put some real good tires on my stock wheels. and just use them for track days then. thank you. btw i love the video.