I didnt see a dedicated brake forum so I figured Id post this here.

As the subject line implies... I don't see the usefullness of this feature beyond marketing glitz. I've never experienced brake fade on the street. I have experienced it on the track, but I can't imagine why you'd want your car to hide a really important warning signal that your brakes are going. Am I missing something?

For street use, it'll prevent you from plowing your car into the back of someone else's car coming down a long hill.

For track it's worthless.

I guess it could also allow a manufacturer to use slightly undersized or undercooled brakes to save a couple of pennies.

Hmm. I had never heard of it, so I googled it. After reading about what BMW claims, it sounds like they could have also named it "automatic rotor warping mode".

Hmm. I had never heard of it, so I googled it. After reading about what BMW claims, it sounds like they could have also named it "automatic rotor warping mode".
I was actually thinking "Automatic Brake Failure Warning Suppressor."

What drives me batshit in my Mom's 335i is that if you come off the gas relatively quickly and transition to the brake pedal fast enough, it'll decide that it's an emergency and you want full brakes at the first touch. I like ABS. Why can't we have brakes with simple ABS again? :(

I was actually thinking "Automatic Brake Failure Warning Suppressor."

E30s have had this feature since like 1985 when everyone pulls the bulb.

-Charlie

E30s have had this feature since like 1985 when everyone pulls the bulb.

-Charlie
No, this function applies the brakes harder and harder as they fade. Thus, you get the same braking for a given pedal effort until the brakes go away. (I do hope that BMW set some limits on it, mind you.)

No, this function applies the brakes harder and harder as they fade. Thus, you get the same braking for a given pedal effort until the brakes go away. (I do hope that BMW set some limits on it, mind you.)
this is the first time I'm hearing of this feature and it's scaring me...

so this means you actually can't feel/won't know that your brakes are actually fading until it's all over?? Is there a warning light or something? I think I saw in some of the extreme road test videos of the AMG Merc there's a huge red warning that flashes "brakes overheated" or something..

Worthless feature IMO.. if you're driving that hard on public roads you need to slow the f*ck down.

Worthless feature IMO.. if you're driving that hard on public roads you need to slow the f*ck down.

agreed.

Worthless feature IMO.. if you're driving that hard on public roads you need to slow the f*ck down.

oh walter.. what about those people we see every time we come back from tahoe, just riding their brakes the whole way down, this might be a useful tool.

but youre right any other time..useless. im sure you can take a sensor out, or fuse and it'll disable it

ok, good to know Im not the only one who thinks it's pointless. I saw in a features list for the 6 series. I just hope they don't plague the 335/135 with it. And if they do then I really hope you can disable it somehow.

I guess another issue is what happens when you install track pads that can take higher temps before fading. If the system is calibrated for lower temp pads wouldnt it think that fade is happening when it's not. arghh.

What drives me batshit in my Mom's 335i is that if you come off the gas relatively quickly and transition to the brake pedal fast enough, it'll decide that it's an emergency and you want full brakes at the first touch. I like ABS. Why can't we have brakes with simple ABS again? :(

I think I had a student once whose Benz (I think it was an AMG but I could be wrong) seemed to do this very thing. We'd feel like she was way over braking and too quickly.... but if she'd slow down and smoothly roll off the gas and roll on the brake, it didn't do it. It was a weird feeling for sure.

what about those people we see every time we come back from tahoe, just riding their brakes the whole way down, this might be a useful tool.

I think perhaps this is the kind of person this was designed for. When I go to and from the track I see people riding their brakes going down hills all the time. Once I was on a downhill stretch of the highway and someone was doing it and killed their brakes... I smelled the pads and saw the smoke as I was driving and a few secs later I see the culprit slowly trying to pull over and stop... with no brakes.... heh scary.

I think perhaps this is the kind of person this was designed for.

Just another electronic nanny saddling ALL of us for those who can't use their brains.

If one can't figure out that one is over using one's brakes and causing them to fail perhaps elimination from the gene pool via a trip over the side on the way down from Tahoe is not such a bad idea.

Just another electronic nanny saddling ALL of us for those who can't use their brains.

If one can't figure out that one is over using one's brakes and causing them to fail perhaps elimination from the gene pool via a trip over the side on the way down from Tahoe is not such a bad idea.

Or going downhill on either direction of the I-5 through the grapevine or the Valencia/Newhall areas.... I just would rather not be on the road near any of them when/if it happens....

Interestingly enough, I did have an occasion where my brakes "faded" at the track on the MZ4 Coupe, and it isn't as bad as you all describe it to be. You'll still feel either a spongy-ness to let you know something is wrong, but it still gives you the ability to slow down the car for the next corner.

The best I can describe it, is that the pedal goes softer than you expected, but the car slows down. And no, the fluid wasn't boiled because you let the brakes cool off, it comes right back. This was on street pads at a private Buttonwillow event in the summer where we got to drive on the track for as long as you can possibly want, and I think I was on the track for nearly 45+ minute by that time. It took me by surprise but I figured it was the "fade" prevention stuff. Did a cool-down lap and I was good to go again.

Compensation for the fact that new BMWs are overweight pigs with sh!tty brakes. This just completes the poseurfaction of the brand that began when the E46 M3 ZCP was introduced.

Keep in mind that the modern brake systems are very feature packed and optimized for street use.

Old school: force on the pedal * transfer function = braking force at contact patch

New school: pedal displacement = deceleration request. The brake ECU takes care of the rest (some systems aren't quite to that point).

Two natural extensions are fade compensation and emergency brake assist. Fade compensation makes the brake response consistent for your average driver. This is a good thing for the street: Imagine your "average" driver encounters fade and doesn't know what to do, so they wreck.

The emergency brake assist was implemented because in an emergency, your average driver brakes fast but not hard. Harder braking would prevent a collision in some cases, so the ECU looks at the rate of change of the decel demand and (to simplify greatly), extrapolates and increases the system pressure beyond what's required for the driver's decel demand.

Both systems are great for the street but out of their element on the track in the hands of an experienced driver.

BMW also has a brake drying feature. So when its raining, it has intervals that slightly apply the brakes to keep the rotors dry for emergency stopping. Crazy....

Compensation for the fact that new BMWs are overweight pigs with sh!tty brakes.

If that's the case then the 135 shouldn't need this feature because it will have massive brakes. But maybe BMW will put it in anyway <sigh>.

This just completes the poseurfaction of the brand that began when the E46 M3 ZCP was introduced.

Until recently I havent followed BMW too much, outside of the seemingly-default 1st place any BMW seems to earn in C&D, but when I read about stuff like this and other dumb stuff like [hate to open this can of worms again] the omission of the oil dipstick, it makes we wonder. Has BMW become a wannabe-Mercedes? (Ive always considered MB at the top of the poseur totem pole).

Interestingly enough, I did have an occasion where my brakes "faded" at the track on the MZ4 Coupe, and it isn't as bad as you all describe it to be. You'll still feel either a spongy-ness to let you know something is wrong, but it still gives you the ability to slow down the car for the next corner.

That's interesting, but even without the fade compensation feature you would still have been able to slow down, you just would have had to push the brake pedal harder instead of having the system do it for you.

Im still not convinced - whereever youre driving, be it track or descending a long mountain road, brake fade is a warning sign of impending bigger problems and a brake system should never mask that. (IMO of course!).

And I still want to know how the system knows that you don't have high-temp track pads installed.

Apoligies if Im preaching to the choir! :-)

That's interesting, but even without the fade compensation feature you would still have been able to slow down, you just would have had to push the brake pedal harder instead of having the system do it for you.

Yes. I would actually prefer that the "fade compensation" feature isn't there. However, I do believe that the fade compensation feature is tied into the DSC system, and that when you turn DSC off completely it also turns off stuff like "brake-prewipe" and fade compensation. The one time where the brake faded (and it could have been due to the DSC being left on by accident) I drove the entire session with DSC on. I've driven longer sessions with DSC off and never had the same "sensation" so I can't tell you if my suspicion is correct.

I think I had a student once whose Benz (I think it was an AMG but I could be wrong) seemed to do this very thing. We'd feel like she was way over braking and too quickly.... but if she'd slow down and smoothly roll off the gas and roll on the brake, it didn't do it. It was a weird feeling for sure.
MB does have this "feature," but it's MUCH less invasive. (I have a few thousand miles of AMG experience. Including the gloriously buggy brake-by-wire setup they foisted on my parents.)

With the 335i automatic, I engage this "feature" in normal driving every single time I come off the gas pedal. If I pause for half a second before touching the brakes, I can push much harder without the auto-park-on-highway feature kicking in.

With the 335i automatic, I engage this "feature" in normal driving every single time I come off the gas pedal. If I pause for half a second before touching the brakes, I can push much harder without the auto-park-on-highway feature kicking in.

Does turning off DTC stop it from doing this or is it still there?

Yes. I would actually prefer that the "fade compensation" feature isn't there. However, I do believe that the fade compensation feature is tied into the DSC system, and that when you turn DSC off completely it also turns off stuff like "brake-prewipe" and fade compensation. The one time where the brake faded (and it could have been due to the DSC being left on by accident) I drove the entire session with DSC on. I've driven longer sessions with DSC off and never had the same "sensation" so I can't tell you if my suspicion is correct.

I didn't think the MZ4s (or any of the current M line) had this fade compensation feature. ???

I didn't think the MZ4s (or any of the current M line) had this fade compensation feature. ???

It was outlined in the brochure and the owner's manual. If I find it after the move I'll scan it and post.

It was outlined in the brochure and the owner's manual. If I find it after the move I'll scan it and post.

It doesn't have it. I was bored so decided to look into what the deal was with this. From what I've been able to decipher here....

Fade compensation is a function of DTC which the Z4s DO have... however the MZ4s do NOT.... because they don't have DTC... only DSC. The thing you described as being part of DSC is DBC which most e46s have as well.

Anyone cross-eyed from all the acronyms yet? :help

If that's the case then the 135 shouldn't need this feature because it will have massive brakes. But maybe BMW will put it in anyway <sigh>.

Yeah, the 1er has proper brakes, but it's still massively overweight for what it is, the oil will still bake on the track just like the 335 and BMW didn't see fit to even make a performance differential optional.

So disappointing.