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Discussion Starter #1
Ok, I've lived with this problem long enough and need to find a solution.

During Auto-Xing I experience "ICE MODE" at almost every event. Today I totally had no brakes at the end of a very fast part of the course. My heart is still pounding.

For those that don't know what "ICE MODE" is, it is when you loose 50-99% of the cars braking ability due to the braking system thinking you are ice.

  1. Does anyone know for sure what causes the braking system to do this?
  2. Does anyone know how the brake system works when it goes into ice mode?
  3. Does anybody have a remedy?
  4. Could people reply to this post with their experiences with ICE MODE. It would be interesting to see if everyone experiences it or just a few.
  5. Can you feel when the ABS kicks in on these cars? I never feel ABS on my runs, just the "ICE MODE" effect.
 

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It sounds like you might be talking about 'brake fade'. You could have some air in the lines. You could also be boiling the fluid which would cause air bubbles to get in the lines. You might want to try bleeding the breaks.

You might also want to upgrade to some different compound pads, high temp fluid, and stainless steel lines. :thumbsup:

-
 

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I've had ice-mode quite a bit in autocross, too. I think it happens when one of the rear tires is really unloaded or even up in the air. What has worked for me is to change my entry into a section of course that causes the ice-mode. A simple quick turn of the wheel to the outside of the turn (IOW, settling the car flat and straight) just before hitting the brakes has stopped the effect.

Where you have ice-mode and it is affecting your time, you have to change your line to be able to hit the brakes with the car settled better. I don't know what else to do.
 

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ice mode has pwnt me on a number of autocross runs. I haven't been able to narrow down a fix, other than the loose nut behind the steering wheel. Like Steve said, changing the line into a corner was the only thing I could do at my last event.
 

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Steve Wynne said it best - you must change your driving style. It took me half the season last year to fix my driving style. To help reduce it, I run Hawk HP+ pads up front, stock rears. The idea there being allow the front to do more braking, and bite quicker, so the car slows more before the rear inside tire becomes unloaded. That helps maybe 10%. The rest is going to be changing your driving style to brake in a straight line.

I used to get into ice mode all the time. Now that I've learned to adjust my driving, I very rarely encounter it. Sure, the revised driving style is probably not as optimum as if I could brake and turn a little at the same time, but with this brake system, it's best we can do.

As for what's happening...when one wheel locks, I think the ABS reduces brake pressure to all of the brakes until the locked wheel starts spinning again. Thus the sudden loss of braking capability. So basically, what ever you can do to keep load on the rear tires while braking will help. There's nothing better for doing this than driving straight while braking.

Unfortunately, there is no legal way to disable the ABS for stock class.
 

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I agree with what the Steves said. Just brake in a straight line, or change your line. It took a lot of de-programing for me to be able to do this. Especially with my "throw the vehicle around" bad habits. I also run Hawk hp+ in the front and stocks in the rear. This change made a difference, but not a huge one. Another thing that I have noticed is that when I run the rear koni's at full stiff, "ice mode" happens a lot more often. Which makes sense, since I have effectively stiffened the chassis, making the inside rear wheel more prone to lifting. So I have settled on going a 1/4 turn from full stiff in the rear, as my stiffest setting.
 

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Discussion Starter #8
Today I was trying the 225/50-16 Front and 215/40-16 Rear setup.

Do you think it was messing up the ABS by the difference in tire diameter?

I had a great setup today, and am currently in second place, even without brakes.
 

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No, I don't think the diameter would really hurt, unless the smaller tires were more prone to locking.
 

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pdqsrt4 said:
Can you feel when the ABS kicks in on these cars? I never feel ABS on my runs, just the "ICE MODE" effect.
To answer that part of your post, YES you can feel the ABS! It's a violent pulsing in the pedal and a grinding-type noise. If the ABS isn't kicking in, you could be breaking harder. Or your ABS isn't working.

It's said to be impossible to boil the fluid in the Neon brake system due to the phenolic brake pistons. Dodge engineers have run Pikes Peak with water for brake fluid just to prove it. I have experienced brake fade, though, due to some poor pads overheating. At Mopars at the Track I used EBC Yellow Stuff pads, and they were much better.
 

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It sound like the ABS is getting confused if you can't disconect by pulling the fuse or unplugging 1 of the sensors then you have to change your driving style as has been susgested no more TRAIL braking
 

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csx321 said:
pdqsrt4 said:
Can you feel when the ABS kicks in on these cars? I never feel ABS on my runs, just the "ICE MODE" effect.
To answer that part of your post, YES you can feel the ABS! It's a violent pulsing in the pedal and a grinding-type noise. If the ABS isn't kicking in, you could be breaking harder. Or your ABS isn't working.

It's said to be impossible to boil the fluid in the Neon brake system due to the phenolic brake pistons. Dodge engineers have run Pikes Peak with water for brake fluid just to prove it. I have experienced brake fade, though, due to some poor pads overheating. At Mopars at the Track I used EBC Yellow Stuff pads, and they were much better.

Just because someone tells you you will not die if you jump off a 25 story building doesnt mean you wont die. I have boiled my brake fluid ( motul ) at mid-ohio with yellowstuff pads on the front.

I have also experienced the ice mode. I am not that good of an autocrosser, but i have been autocrossing for about 12 years on and off.

Maybe a fix for the ice mode should be less brake's. you cant go fast with your foot on the brakes. HA HA.
 

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OK damnit quit guessing:
Ice mode is when the brake booster is not preloaded with vaccuum to assist the braking .. its similar to not having the car running and ending up with manual brakes. This is due to going from WOT or at least +psi boost to brakes too quickly. The engine hasn't had time to develop vacuum by the time you are asking the braking system to use the vacuum.. that hasnt yet built to a value that actually assists the brakes.

There is 2 drving style ways to fix this and one mechanical solution
1) wait a brief 1/4 pause between Tip Out and Brake In.
2) pump once then go hard to brakes (engine braking will develop the vacuum needed by the time the second application of the brakes happens)
OR mechanical solution: develop and build a vacuum 'resevoir' something that does an accusump type reserve but instead of oil for vacuum.

well ok one more driving style fix ... press really freaking hard on the brake pedal the brakes are still there and will work as if the car isnt started they will still work you just have to really press em.

David Jackson
 

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SteveW said:
I've had ice-mode quite a bit in autocross, too. I think it happens when one of the rear tires is really unloaded or even up in the air. What has worked for me is to change my entry into a section of course that causes the ice-mode. A simple quick turn of the wheel to the outside of the turn (IOW, settling the car flat and straight) just before hitting the brakes has stopped the effect.

Where you have ice-mode and it is affecting your time, you have to change your line to be able to hit the brakes with the car settled better. I don't know what else to do.
Steve,
I bet when you point the car straight for that breif second you are automaticly going to a maintenance throttle. This will bring the car back from +boost to vacuum long enough to preload the brake booster =] check it out

David
 

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DrmCtchr said:
OK damnit quit guessing:
Ice mode is when the brake booster is not preloaded with vaccuum to assist the braking .. its similar to not having the car running and ending up with manual brakes. This is due to going from WOT or at least +psi boost to brakes too quickly. The engine hasn't had time to develop vacuum by the time you are asking the braking system to use the vacuum.. that hasnt yet built to a value that actually assists the brakes.

There is 2 drving style ways to fix this and one mechanical solution
1) wait a brief 1/4 pause between Tip Out and Brake In.
2) pump once then go hard to brakes (engine braking will develop the vacuum needed by the time the second application of the brakes happens)
OR mechanical solution: develop and build a vacuum 'resevoir' something that does an accusump type reserve but instead of oil for vacuum.

well ok one more driving style fix ... press really freaking hard on the brake pedal the brakes are still there and will work as if the car isnt started they will still work you just have to really press em.

David Jackson
This isn't (at least what I've had) only rock hard brakes. What I've had is the ABS kicking in VERY prematurely and not settling down until I get the car straight and all 4 tires planted and spinning again. Basically the abs kicking in with very light pedal pressure, just like driving on ice.
 

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stowaway said:
Basically the abs kicking in with very light pedal pressure, just like driving on ice.
I don't think that's what the original poster is experiencing, though. He said he doesn't feel ABS, and I think there's no way you could not feel ABS kick in on this car.

hvacmike said:
Just because someone tells you you will not die if you jump off a 25 story building doesnt mean you wont die. I have boiled my brake fluid ( motul ) at mid-ohio with yellowstuff pads on the front.

I have also experienced the ice mode. I am not that good of an autocrosser
No, but I'm just more inclined to believe a Dodge suspension engineer and national champion autocrosser talking about brakes than I would be someone telling me to jump off a building.
 

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Why don't you pull one of the rear brake sensor wires, which disables the the ABS? That way even if you have one of the rear wheels up in the air, it won't go into ice mode.
 

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DrmCtchr said:
SteveW said:
I've had ice-mode quite a bit in autocross, too. I think it happens when one of the rear tires is really unloaded or even up in the air. What has worked for me is to change my entry into a section of course that causes the ice-mode. A simple quick turn of the wheel to the outside of the turn (IOW, settling the car flat and straight) just before hitting the brakes has stopped the effect.

Where you have ice-mode and it is affecting your time, you have to change your line to be able to hit the brakes with the car settled better. I don't know what else to do.
Steve,
I bet when you point the car straight for that breif second you are automaticly going to a maintenance throttle. This will bring the car back from +boost to vacuum long enough to preload the brake booster =] check it out

David
That could be the case and most of the time I have noticed that pressing really fricken hard on the brakes does give me something. I swear though, there have been times where I feel ABS pulsing and get no braking action or what we think of as ice-mode. 90% of what I get is just like what you describe though, thanks for the post!

Isn't there a check valve in the booster to hold vacuum? I do left foot brake and probably use up all that reserve by the time I really need the brakes, though.
 

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Im aware of the tendency of the ACR to get into ABS too easily. This is definitely not what's happening to the original poster (IMHO). The original poster said he was autocrossing and at the end of the fast area, he went to brakes and there wasnt anything there. this is due to not having vac avail to assist the booster. =]

David
 

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SteveW said:
DrmCtchr said:
SteveW said:
I've had ice-mode quite a bit in autocross, too. I think it happens when one of the rear tires is really unloaded or even up in the air. What has worked for me is to change my entry into a section of course that causes the ice-mode. A simple quick turn of the wheel to the outside of the turn (IOW, settling the car flat and straight) just before hitting the brakes has stopped the effect.

Where you have ice-mode and it is affecting your time, you have to change your line to be able to hit the brakes with the car settled better. I don't know what else to do.
Steve,
I bet when you point the car straight for that breif second you are automaticly going to a maintenance throttle. This will bring the car back from +boost to vacuum long enough to preload the brake booster =] check it out

David
That could be the case and most of the time I have noticed that pressing really fricken hard on the brakes does give me something. I swear though, there have been times where I feel ABS pulsing and get no braking action or what we think of as ice-mode. 90% of what I get is just like what you describe though, thanks for the post!

Isn't there a check valve in the booster to hold vacuum? I do left foot brake and probably use up all that reserve by the time I really need the brakes, though.
Steve yes there is a check valve but it doesnt always work properly (gravity and inertia are sometimes not your friends). And there is really only one application worth of vac stored in there on a good day =] I get to ABS often way before its needed I have some theories on that .. I should probably head to the test track and see if i can reproduce and dev a quick fix. Maybe if I have more time oneday soon .. I have like 5 track events Im teaching at in the next couple weeks and a Double Regional to prep for in my gen1 (must fix coolant retainment issues) =]. So I dont have much time.

D
 
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