Thanks, Josh. Appreciate Stillen getting involved with the diagnosis and hopefully someday a solution. You guys are uniquely positioned to address this one, given your brakes expertise, knowledge of the ECU, relationship with Nissan, and the fact that you have skin in the game with your own car!

Great to have you guys on board with this as well. Just keeps reinforcing why I like Stillen so much.

Travis, you say you lost steering input as well. Do you attest that to the slow cycle time of the ABS in "ice mode" or is there a remote possibility that you could have run over something slippery given that you were braking off-line?

Can't stress enough that it was an ABS issue... def not a track condition... the loss of steering has something to do with the fact that my power steering is only partially working right now so it takes a lot of force to begin with, i'm running 275 series r-comps on the front which don't turn in easily, and abs tends to strtn car out when stopping... all factors together made it harder to muscle the steering wheel

Gotcha. Was trying to figure out if you were saying that you were turning the wheel and nothing was happening or it was just really hard to turn the wheel. Now I see it was the latter.

Well this one has me really bummed. I thought we had solved this problem with brake upgrades. So its an ABS problem after all..

It hasn't happened to me in a while, but quick comment: I remember the first time it happened, it happened fairly quickly. Seemed like there was no warning, however the second time it happened, I felt the brakes gradually get worst and worst and then decided to really get on them when I thought they were about to fail and they did.

What I'm trying to get at is that it gradually built up to the point of failure, rather than being an on/off issue.

Considering that Travis switched his Calipers, rotors, pads, lines and fluid and its still happening AND in my experience it was a gradual failure (please others chime in, gradual or not?).... my first guess would be that it has something to do with heat buildup affecting a sensor in the ABS system.

Thoughts on that theory?

I don't think it is a heat issue, but will know more after this coming weekend when I test with temp paint / strips... when it happened this last weekend, i was 2 laps in... i have a trusted source as well that confirmed it is a variable wheel spin instigated problem - will PM you on this

Sure, if that's the case then we need to figure out how to fix the issue. Problem is that its very difficult to get anything done by Nissan. I mean...over a year in and we still don't have a real fix for the overheating....they aren't going to do anything for us here. I think aftermarket is going to have to take care of this one...hopefully Stillen can figure something out. I hope it is a simple issue rather than a combination of issues which will make it much harder to pinpoint the problem.

travis, do you have anyone with access to a Consult that could see if there's any codes in the ABS system?

Can anyone confirm that immediately releasing and then reapplying the brakes resolves the issue? I think this was briefly suggested a few pages back. Could be a life saver if it's true and the knowledge disseminated.

I believe I tried pumping but may not have fully lifted my foot off the pedal... so can't confirm 100%... we need to try and 'create' the condition in a parking lot so we can isolate the circumstances more precisely

As it turns out, I have my car at a local nissan dealer today for an unrelated BCM/ECM issue, and I may be able to get them to do this

Don't know if this will help. It appears that Porsche/Lotus also have this problem.

well, ABS Ice Mode finally got me... - Rennlist Discussion Forums

EDIT: Add Corvettes, Camaros, Mazda, Audi....

I pumped immediately since I'm used to it from karts, but it didnt change anything.

EDIT: More info

Raul, brilliant! I was just about to cross-post the exact same quote... #8 on the other board... the only problem with the theory is I remember pushing pretty hard on the pedal and not getting more braking response... I'm not certain this is spot on but... Stillen, this is prob the first thing you guys should look in to

Yup, I saw this posted on several sites...mainly because its the only explanation they have found coming from a credible source.... Lotus to be specific. I saw the explanation of the problem, but nowhere did I find a fix.

Best solution I've seen so far is disconnecting the abs sensor and threshold brake....not a bad suggestion on a dry circuit. Not for newbies.

Could this be related to what is discussed in this thread? ie: ABLS?

http://www.the370z.com/nissan-370z-g...etely-off.html

no, different issue

I have seen ABS "ice mode" on the Elise/Exige, working with quite a few drivers who did not like it one bit! Lotus eventually offered the "fix" in a Motorsports ABS module upgrade (something like $10k, IIRC). I don't know if the module is available for the street cars or just the Cup track (not road-legal) cars.

In the short term, it is best to get to the track and practice initiating the braking event. The key is to not stomp on the brake pedal. It can be firmly applied, but the ABS module looks at how fast the system pressure rises. If it senses a huge spike, the algorithms determine that you must be in big trouble and are about to have "a moment". The brake gods then take over and you are pretty much a passenger until you let off the brakes and try again. Of course, now you are in full panic and hit the pedal even harder, spawning another ice mode experience!

The best (at least the most colorful!) description I ever heard from a pro driver about proper braking technique came from Roberto Moreno when he was in the Swift chassis at Long Beach years ago. We were working on aero mods that would lessen the forward center of pressure shift under braking. On the road courses, the suspension would need to be run higher and softer for the bumps, so the car wanted to dive under braking and lift the rear. This lift "unsealed" the underwing tunnels, losing rear downforce. Working day and night in the wind tunnel to come up with solutions, we ended up with a car that had a big advantage going into the heavy braking zones. Roberto was so excited when getting out of the car after the first practice, proudly stating that no one could outbrake him. When I asked him how the car was reacting, he said it was "Perfect, like I am making love to the brake pedal." Uh, use your own judgment when interpreting that last statement.

For the long term, it would be best to continue to go to Nissan with the issue in hopes they offer a way to change it if enough people complain. There is nothing Stillen can do to modify the ABS that doesn't require more lawyers than currently out of work (sorry, under-employed) in southern California. One bad incident on the street in cold weather with a modified module and we'd all be looking for jobs!

Aftermarket brake companies should carry a serious product liability insurance policy (your does, right?), but modifying ABS modules would be a great way to get dropped quicker than the next guy to marry Pamela Anderson.

Chris

P.S. Roberto passed a lot of cars on that race day -- until one Mr. Tracy thought better of giving him enough room to get by. Two cars cannot occupy the same space at the same time!

^ Nor can a car and a wall and thats our big issue right now... luckily my local track has nice braking zone run-off's so the worst I have to worry about is getting dirty or clag on my tires.

Thanks for the input Chris, very helpful! So long story short we are SOL until Nissan decides to (yeah right) help us out with a less safe ABS system.

Let's call Nissan North America. I'm sure they'll have an upgrade for us right around the time the oil cooler TSB is issued :)

Excellent find on the article. So in theory, releasing the brakes and then applying more gently should fix the perceived loss of braking problem. In retrospect, do you think you guys were hammering the brakes harder/more abruptly during those times?

Guess we just need to make love to the pedal. Unfortunately auto-x turned me into a stomper, so I'm going to have to unlearn that habit. I believe Nissan's term for stomping on the pedal suddenly is called "Active Brake Assist". The problem with this "feature" is that it boosts brake pressure beyond what the driver input, causing a full ABS lock-up regardless of what the driver was actually trying to do.

As my wife always tells me:

"More technology, more problems"

...of course that line is usually used by her in reference to our computer, home theater remote control, or programmable air-conditioning controller.

The Lotus issue was perceived brake loss because of the change in pedal feel. In our case the pedal feel doesn't change except that you can feel the ABS modulating.

I think hammering the brakes definitely has something to do with it in my case.

:icon18:

Sounds so familiar...

on a more serious note, this thread offered some seriously interesting reading. Unfortunately I still have to do my fist track day with the Z (only 3 weeks away) so I can't offer a lot of interesting input on this ice mode issue. But it sure is a "good to know" before hitting the track. I was getting a bit worried that in addition to the oil overheating, this was another 370Z only track related issue, and I should have bought a used Elise or 911 as track toy instead, but it looks like this issue is not 370Z exclusive. Not much of a comforting thought, but still.

Anyway, I wouldn't mind being able to switch off just the ABS on the track. I have done track days with a lot less technologically sophisticated vehicles and I liked not having ABS:

http://www.the370z.com/attachment.ph...0&d=1268704408
Not so sophisticated Opel Kadett GSI (but lots of FWD fun, lift of over steer...)

http://www.the370z.com/attachment.ph...1&d=1268704408

Who needs ABS?? and no, I didn't hit the unfortunate Mazda 323 (protege) in front of me and yes I did have a flat spot on my tires after wards... :-)

I hope to have some more useful input to this tread after April 4th

If you have and oil cooler make sure you have high-temp pads.

Good discussion, all.

Chris_B, appreciate you stopping by to comment. I suspect you are right and we are going to have to learn to live with this for a while. Need to get to a parking lot and test/get used to it.

Re what happened... As best I can remember, I was trail braking when the mode initiated... then I think I stomped and when that didn't respond, I tried modulating pressure. Regardless of my inputs, I had the same rate of deceleration. But I'm going to have to get to a parking lot and try to recreate to be sure. So how can we set up bumps in a parking lot?? lol

No oil cooler yet: oil cooler, pads, brake fluid and stainless lines are all on the schedule for this this year. This fist track day will be stock and at 7/10's. I did get the 370 intending to take it to the track every now and then, just didn't get to it last year. (working for a supplier in the car industry did not allow for a lot of free time to spend at the track last year...)

A lot of the parking lots around here have speed bumps, but I don't think you want to drive out all this way to test your brakes...

I think a speed bump would tear off his whole front end, LOL.

To create a small raised bump you can use carpet wire protector rolls. Just need to find a way to attach it to the pavement that won't make the parking lot owner mad. For a crack in the pavement you're just going to have to find a natural one.

i think all you need to do is brake hard while turning and it will trigger it.

Wow - disappear for a bit and this is what happens.

This is actually great news to me. It means the issue is knowable and solvable. All it takes is pulling one fuse. I don't know about you all, but I would much rather ditch ABS than have the car fail to brake when I least expect it. At least then I can blame myself if I go off.

Absolutely awesome thread guys. Thanks to all who dredged this up.

^ I think pulling the ABS fuse will make your speedo not work. There is an ABS sensor that you can unplug that wont cause the speedo to stop working, but will still disable ABS.

Care to ellaborate on the ABS sensor? where is it?

Also, from previous posts, someone had stated that the ABS fuse a a 3 in 1, which also included VVEL, so you would need to cut just the ABS piece so the other two stayed intact....but I'm not sure.

If there is another device (fuse/sensor) that can effectively do the same thing, that would be useful!

I only autox my Z twice last year and did not encounter this issue...but the car will be HEAVILY autoxed this season on R compounds so this is of particular interest.

Additionally, as a left foot brake fan for autox, I am trying to solve the cut off of power when dragging the brake....hoping the ABS disable would solve both

That is correct. Ordering a spare might be a good idea.

Removing a wheel speed sensor should do the trick.

It depends on the smoothness of the track. On a really smooth surface you usually don't run into it, but the old airport we run on has big cracks, off camber surfaces, dips and crests. If you co-drive the car you might encounter pad-fade with the stock pads if the course is brake heavy, higher temp pads such as the Carbotech ones would be a requirement.

That's a good question. I don't think it will as it doesn't have anything to do with ABS. You will most likely have to disconnect the brake pedal switch (which will take out your brake lights as well).

So witch fuse I have to pull to disable the ABS?

If you want to pull the fuse, you will need to get a spare 3-in-one fuse with the correct values, and then cut out the center fuse of the 3. As I recall the other 2 items on the fuse were power windows and VVEL. I'll go make a note of the number.

Wait a minute....before contacting the dealer I think consideration has to first be given to the fact that he was doing x-events and that more precise details need to be given as to what exactly he was doing at the exact moment he noticed the ABS abberation.

It is entirely possible that the forces being created as a result of his driving reaction to the course could have created a wheel "reaction" that falsely simulated a condition that would normally trigger the ABS system as if the true condition that would trip the sensor trigger had actually happened (though it didn't).

In that case the ABS action would be entirely normal and is not something the dealer or Nissan should even get involved in since the car was being driven outside the normal driving parameters the car was primarly made to be driving under. That is the assumption of the risk on the owners part since the owner is driving the car in conditions beyond the intended use.

What we don't need is some stupid and pre-mature knee-jerk reaction by these drivers who want to push the envelope with their car that starts some kind of media bandwagon witch hunt like is happening to Toyota and Honda.

More chassis stiffening might help too.