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I just got home from my teams first endurance race at NJMP in Millville,NJ run by AER in a double 9hr format.
Drivers said the car drove great Saturday and by days end the brake pedal felt a little soft. Bled the brakes and sent them out on Sunday. First driver said the pedal felt odd after her stint the the 2nd driver got in and about 45 min in it flat-spotted the right front tire when the brakes went into ice mode.
Replace both calipers and new pads but ice mode was still engaged. Going to pull the car off the trailer and see what I find.
I just got home from my teams first endurance race at NJMP in Millville,NJ run by AER in a double 9hr format.
Drivers said the car drove great Saturday and by days end the brake pedal felt a little soft. Bled the brakes and sent them out on Sunday. First driver said the pedal felt odd after her stint the the 2nd driver got in and about 45 min in it flat-spotted the right front tire when the brakes went into ice mode.
Replace both calipers and new pads but ice mode was still engaged. Going to pull the car off the trailer and see what I find.
You sure it was ice mode? With non functional ABS the brake bias is such that the fronts lock REALLY easy and when they do it feels like you aren’t slowing down and you end up with less than round tires IME.
You sure it was ice mode? With non functional ABS the brake bias is such that the fronts lock REALLY easy and when they do it feels like you aren’t slowing down and you end up with less than round tires IME.
I'm very sure, cause the pedal was rock hard and the car wasn't the same as it was on Friday when I drove it in qualifying. Even my drivers were like the brakes failed and at first I was like you are crazy, but nope they're right something definitely was wrong.
What your drivers experienced is not ice mode. I guarantee it.
Think about it, man. What's the car do on a slippery surface? It keeps the tires rolling. When 'ice mode' is triggered, it does so very aggressively. Stopping distance increases because the car thinks there's less grip than there is.
What you have is a massive flat spot from an enormous lockup. That's a failed wheel speed sensor. Ice mode keeps the wheels turning. It doesn't lock them up.
When a sensor goes bad, it seems to just go to full pressure on that wheel. It's a failure mode that's designed to stop you in an emergency on the street, which is fine because you're rarely threshold braking on the street. Like, never. In racing conditions, however, it's super dangerous.
I highly recommend, with you doing endurance racing, that you replace the hubs before each race, and have a couple spares on hand at the track. They don't take that long to replace and they're not terribly expensive. There are no better aftermarket options; just get them from Mazdaspeed.
Even doing 'just' time trial, with its short sessions, I had a hub fail on me last season. I ended up with a flat spot, too. The harder you are on the hubs, the faster they fail.
Originally Posted by acbauza
I'm very sure, cause the pedal was rock hard and the car wasn't the same as it was on Friday when I drove it in qualifying. Even my drivers were like the brakes failed and at first I was like you are crazy, but nope they're right something definitely was wrong.
Starting to think that ABS has unleashed an entire generation who have no idea what locked up brakes are
”huh, wut ... something’s just not right, loud sqawling noise, car won’t steer, big cloud of smoke, smells like burnt rubber ... what’s going on?”, lol
my car hit ice mode a few times this weekend at VIR, braking deep into T14 at the end of the back straight. it's an uphill left sweeper if you brake really late. my left rear tire was probably in the air during braking which trigger ice mode. only time i've ever trigger ice mode (in most cars) is when braking while wheels in the air or car is light from going over a crest. sometimes even hitting a huge bump while braking. the pedal gets really stiff but the car doesnt slow down much, like the abs is super sensitive. just have to give the pedal a quick pump to reset the sensors and it's back to normal. my buddy in an s2000 said it happened to him at the same spot on the track.
Just curious if your car has DSC and if that possibly has any correlation even though it may be in off mode?
mine is non-DSC and I can’t recall ever having that happen.
It’s not necessarily a hub issue either; damaged sensor or electrical cable can be a problem too. In the past I had been lazy and left the the sensor electrical in place while disassembling the suspension, which at times would put tension on the cable. Never had a problem per se, but don’t do that anymore after Eric posted up the issue regarding the sensor and wiring back in the day.
edit: a bad ABS module could also be a potential source of the problem, but that’s more likely a failed mode only rather than intermittent.
Thought I'd add another data point to the failed sensor condition. Some background first:
New hubs installed in March
Hubs were direct from Mazda
First event in April they were fine (my driving was another story entirely)
Next event in May the car's threshold braking was horrible, locking up fronts intermittently
Next event in June was a bit better, but still intermittent lock up
I originally thought that I had done a poor job of bedding the new pads and rotors that went on the car for the May event. The brakes seemed better on Sunday after Saturday's mess. However, I was able to "drive around it" by easing into the brakes a bit more and generally avoiding full threshold braking. This is quite different than most reports of failed wheel sensors, since folks often report trouble even under modest braking. In June the brakes seemed to need to warm up a bit more than usual, then I could again "drive around it" ... besides, the Kink at Road America doesn't require braking. =)
Ok, so I'm generally an idiot about such things and tend to drive around maladies. I'm also super busy at events and don't have much time to trouble shoot (pit crew needed: pay is horrible, but the dad-jokes are great). In between events you would think I'd do better - and eventually I do. So I took a look at my data logs (originally just trying to see if the wheel lock up situation correlated to any other thing). Funny things found:
Individual wheel speed sensors in April were normal
In May the fronts both read 203.6 mph...at all times...even loading it on and off the trailer
In June the fronts just dropped off the map - literally no reading at all, not "0 mph", just blank
So obviously the trouble I had wasn't related to bad brake bedding. I still have last years hubs that I can swap back in. They were removed in working order, so those will go back in the car. I'll also inspect the cables carefully to see if there's any sort of damage there, but given that it's both fronts I'm doubtful that both lines would be equally damaged. Seems to me either (a) an ABS module error or (b) a bad batch of Mazda hubs floating around out there (I believe Nick's prematurely failed hubs were also OEM replacements from Mazda).
Thought I'd add another data point to the failed sensor condition. Some background first:
New hubs installed in March
Hubs were direct from Mazda
First event in April they were fine (my driving was another story entirely)
Next event in May the car's threshold braking was horrible, locking up fronts intermittently
Next event in June was a bit better, but still intermittent lock up
I originally thought that I had done a poor job of bedding the new pads and rotors that went on the car for the May event. The brakes seemed better on Sunday after Saturday's mess. However, I was able to "drive around it" by easing into the brakes a bit more and generally avoiding full threshold braking. This is quite different than most reports of failed wheel sensors, since folks often report trouble even under modest braking. In June the brakes seemed to need to warm up a bit more than usual, then I could again "drive around it" ... besides, the Kink at Road America doesn't require braking. =)
Ok, so I'm generally an idiot about such things and tend to drive around maladies. I'm also super busy at events and don't have much time to trouble shoot (pit crew needed: pay is horrible, but the dad-jokes are great). In between events you would think I'd do better - and eventually I do. So I took a look at my data logs (originally just trying to see if the wheel lock up situation correlated to any other thing). Funny things found:
Individual wheel speed sensors in April were normal
In May the fronts both read 203.6 mph...at all times...even loading it on and off the trailer
In June the fronts just dropped off the map - literally no reading at all, not "0 mph", just blank
So obviously the trouble I had wasn't related to bad brake bedding. I still have last years hubs that I can swap back in. They were removed in working order, so those will go back in the car. I'll also inspect the cables carefully to see if there's any sort of damage there, but given that it's both fronts I'm doubtful that both lines would be equally damaged. Seems to me either (a) an ABS module error or (b) a bad batch of Mazda hubs floating around out there (I believe Nick's prematurely failed hubs were also OEM replacements from Mazda).
Best,
-j
You can check them with a ohm meter. Check the hub itself then upstream of the harness. Stationary it’s at a fixed ohm I can’t recall what - all four are the same so can just check a good one to see what it’s suppose to be. Then when you spin it you will see it pip so can tell it’s working.
Just throwing this out for consideration since people sometimes think S2 parts are superior/upgraded and assume everything is swappable, which is not always true:
S1 hubs are a different part no. than S2 hubs; not sure if they are cross compatible. Seems like I heard or read before that they’re not, but can’t recall this with any confidence.
I have asked Mazdaspeed, because I wondered the same thing. They are not compatible with the S1’s ABS system, so they’d require changing that whole system to an S2. I was also told they’re really no different, anyway.
Now, they’ve been wrong before. But the connectors are different, so it would require making an adaptor or splicing to try it. That’s a lot of risk (given the way the car drives when a hub goes bad) for a part they said is no better.
Originally Posted by TeamRX8
Just throwing this out for consideration since people sometimes think S2 parts are superior/upgraded and assume everything is swappable, which is not always true:
S1 hubs are a different part no. than S2 hubs; not sure if they are cross compatible. Seems like I heard or read before that they’re not, but can’t recall this with any confidence.
Just to clarify; I wasn’t suggesting using them, just posting that it could be an issue if someone did that. If the connectors are different then it seems like it might be obvious.
01-18-2019, 09:51 AM
What's the car do on a slippery surface? It keeps the tires rolling. When 'ice mode' is triggered, it does so very aggressively. Stopping distance increases because the car thinks there's less grip than there is.
