Originally Posted by ResIpsa ...The ice mode always happened at the very end of large braking events (turn one and turn five) just before turn in. Before going into ice
|
|
LinkBack | Thread Tools | Display Modes |
05-04-2010, 11:07 AM | #121 (permalink) | |
A True Z Fanatic
Join Date: Jan 2009
Location: GSO
Posts: 2,803
Drives: VIR
Rep Power: 188 |
Quote:
|
|
05-04-2010, 01:39 PM | #122 (permalink) |
Premium Member
Join Date: Jan 2009
Location: North GA
Posts: 6,831
Drives: Twin Turbo Z34
Rep Power: 3682 |
I believe this to be a plausable cause. Mine only kicked in at the end of the braking distances. The car would be able to stop from 60-0 in approximately 50ft and then it would just ice mode to a 75-90ft stopping distance. That would also go to explain why on some surfaces the car would be fine but others it would ice mode hmmm... I think you on to something Travis!
__________________
Shop Cars: 2013 318whp Nismo VspecII 370z *SOLD*, 2009 1000hp+ 93oct 4.0L TT 370z Fast Intentions STAGE 4 #054 |
05-04-2010, 03:12 PM | #123 (permalink) |
Track Member
Join Date: Apr 2009
Location: Virginia
Posts: 564
Drives: 09 RACING HEN
Rep Power: 338 |
Another observation that I forgot to mention. My instructor did not seem all that concerned with the problem. The first time I experienced "ice mode" I was scared that he was going to direct me to pit and end my day. But he didn’t.
The second time it happened he told me to pit and had a marshal eyeball the brakes. The marshal took a look and said that the brakes were definitely hot but otherwise fine. After that session he solo’d me. So whatever he perceived in the passenger seat must have felt like simple driver error and not a mechanical issue. I imagine he thought it was simple brake lock up even though there was no tire squeal. Take this for what it’s worth, I am not sure if it adds anything to the story...
__________________
The Reed Law Firm; Michael Fasano VA Attorney and Counselor at Law: A Virginia Traffic, Criminal, and Family Lawyer.https://reedlawva.com/ |
05-04-2010, 04:06 PM | #124 (permalink) | |
A True Z Fanatic
Join Date: Mar 2009
Location: North East
Posts: 6,203
Drives: 09 370Z Sport M6
Rep Power: 653 |
Quote:
All of my testing has been done on hot and heavy auto-x conditions. It typically takes 20-30 minutes of build up under those conditions to reach a point that ice-mode kicks in for the braking zones. There are other conditions that activate the ice-mode as well such as sudden bumps, sand, marbles etc, but the heat related one has me beat. What's interesting is that during one of these ice-mode events, at the very end of braking once the car gets below about 15-20mph you suddenly get full braking back again. Totally bizarre.
__________________
Hotchkis ARB | Stillen CAI | Art Pipes | Berk CBE | Stillen AP Racing Brakes | AE Performance Oil Cooler | BC Racing ER Coilovers | Doran Control Arms Last edited by ChrisSlicks; 05-04-2010 at 04:08 PM. |
|
05-04-2010, 04:28 PM | #125 (permalink) | |
A True Z Fanatic
Join Date: Jan 2009
Location: GSO
Posts: 2,803
Drives: VIR
Rep Power: 188 |
trying to connect the theories... possible that as your brakes overheat, you're getting fade on inside front wheel and that wheel is therefore braking at a slower rate than the rest?
Quote:
|
|
05-04-2010, 04:44 PM | #126 (permalink) | |
A True Z Fanatic
Join Date: Mar 2009
Location: North East
Posts: 6,203
Drives: 09 370Z Sport M6
Rep Power: 653 |
Quote:
One thing that doesn't add up with that theory is that the brakes fully return after the car slows down to a slow speed the ABS computer apparently "exits" its ice-mode. There is also no pull or anything else that would indicate more braking for on one side or the other. There is however a large temperature differential front to rear, so it is possible that the ratio of front braking force vs rear braking force exceeds the ABS computer parameters causing the event.
__________________
Hotchkis ARB | Stillen CAI | Art Pipes | Berk CBE | Stillen AP Racing Brakes | AE Performance Oil Cooler | BC Racing ER Coilovers | Doran Control Arms Last edited by ChrisSlicks; 05-04-2010 at 04:51 PM. |
|
05-04-2010, 07:36 PM | #127 (permalink) |
Track Member
Join Date: Apr 2009
Location: Virginia
Posts: 564
Drives: 09 RACING HEN
Rep Power: 338 |
I will also confirm that after an ice mode event the brakes come back at 100% efficiency. If it was purely heat related I would expect some residual loss of braking following an ice mode event.
Also, I can confirm that during ice mode I never felt like the rear end was going to come around on me. Rather, the car just tracked straight ahead. This leads me to believe that whatever our ABS is doing is to create a heavily front biased brake condition. This of course would create a easily controlled straight slide (for anyone who does not know, too much rear brake bias creates a dangerous situation under braking whereby the rear of the car slides out much like a power slide under heavy acceleration). Also, this "ice mode" problem is not limited to the 370Z. Google the term ice mode and brakes and you will be amazed at how many cars have the exact same problem. My theory is that this is a result of ABS technology advancing faster than real world practicality. I imagine there is some algorithmic equation in our cars brain that decides it is better to allow the car to track in a straight line at a controllable 25% braking than to lock one wheel up or flip the car around.
__________________
The Reed Law Firm; Michael Fasano VA Attorney and Counselor at Law: A Virginia Traffic, Criminal, and Family Lawyer.https://reedlawva.com/ |
05-05-2010, 01:04 AM | #130 (permalink) |
A True Z Fanatic
Join Date: Jun 2009
Location: californee way
Posts: 5,380
Drives: 370, Leaf
Rep Power: 30 |
I only have two autox on the car so far, but ice mode was only apparent during complete panic stop when I have to do a complete stop at the finish line. It was never a real issue when I was running. I have a stock car with 265 and 285 tires
I have experienced ice mode in my 350, C6, RX-8, you just get used to it. |
05-05-2010, 01:05 AM | #131 (permalink) |
A True Z Fanatic
Join Date: Jun 2009
Location: californee way
Posts: 5,380
Drives: 370, Leaf
Rep Power: 30 |
I only have two autox on the car so far, but ice mode was only apparent during complete panic stop when I have to do a complete stop at the finish line. It was never a real issue when I was running. I have a stock car with 265 and 285 tires
I have experienced ice mode in my 350, C6, RX-8, you just get used to it. |
05-05-2010, 12:04 PM | #132 (permalink) | |
A True Z Fanatic
Join Date: Mar 2009
Location: North East
Posts: 6,203
Drives: 09 370Z Sport M6
Rep Power: 653 |
Quote:
I can brake as hard as I want for about 3 runs. After that I get ice-mode under firm straight line braking every time. It doesn't matter how gently I roll on to the brake either. The brakes are hot but not cooked, and the pads have twice the operating temperature range of stock (Mintex Extreme) but are not an aggressive compound at all. The brakes have a 15-minute cool down between runs. The front ABS actuators pulse away like crazy as if there is lock up yet there is none. I have tried altering the brake bias to the front and to the rear by using a more aggressive pad on one axle at a time. This had no benefit. Yes, stiffer suspension all around will prevent the weight transfer, and this is on the cards anyway, but the fact that it only happens to me when the brakes are warm makes me think there is something else at play here. Either the ABS computer is getting bad input from one of the wheel speed sensors due to heat expansion or something else in the ABS is acting up when the brake fluid temperatures rise.
__________________
Hotchkis ARB | Stillen CAI | Art Pipes | Berk CBE | Stillen AP Racing Brakes | AE Performance Oil Cooler | BC Racing ER Coilovers | Doran Control Arms |
|
05-05-2010, 12:42 PM | #133 (permalink) |
A True Z Fanatic
Join Date: Jan 2009
Location: GSO
Posts: 2,803
Drives: VIR
Rep Power: 188 |
chris, we need to construct tests for these theories... to rule out (or in) the heat theory, we need to measure temperature on the calipers and rotors and conduct trials... not sure how to test temp of the fluid though
|
05-05-2010, 01:10 PM | #134 (permalink) | |
A True Z Fanatic
Join Date: Mar 2009
Location: North East
Posts: 6,203
Drives: 09 370Z Sport M6
Rep Power: 653 |
Quote:
Okay for caliper temps I can use the temperature stickers and probably a portable laser thermometer (should read high enough). I will get some paint for the rotors and will see if 1400F is enough for the pyrometer, the 1800F unit is more expensive.
__________________
Hotchkis ARB | Stillen CAI | Art Pipes | Berk CBE | Stillen AP Racing Brakes | AE Performance Oil Cooler | BC Racing ER Coilovers | Doran Control Arms |
|
05-06-2010, 01:06 PM | #135 (permalink) |
A True Z Fanatic
Join Date: Mar 2009
Location: North East
Posts: 6,203
Drives: 09 370Z Sport M6
Rep Power: 653 |
Ok picked up an Infrared thermometer from Grainger, it's good up to 1832F. If anything on my car gets that hot I expect spontaneous combustion!
Extech 42512: Dual Laser InfraRed Thermometer
__________________
Hotchkis ARB | Stillen CAI | Art Pipes | Berk CBE | Stillen AP Racing Brakes | AE Performance Oil Cooler | BC Racing ER Coilovers | Doran Control Arms |
Bookmarks |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
does everyone have this problem? | mattkim85 | Nissan 370Z General Discussions | 43 | 11-14-2009 09:37 PM |
Problem after some Audio Upgrades | 209Z | Audio & Video | 1 | 06-13-2009 02:16 PM |
Is there or is there not a problem with the oil cooler? | sluggoZ | Nissan 370Z General Discussions | 26 | 03-18-2009 01:28 PM |
First Drive = One Problem | dedede | Nissan 370Z General Discussions | 14 | 12-31-2008 09:13 PM |
First potential problem? | xDIEGOx | Nissan 370Z General Discussions | 26 | 12-15-2008 12:30 PM |