Brake woes

[dsdubs]

Hi everyone,

It's been a while since my first post, but I'm a frequent lurker!

A while back I boiled my brake fluid out on the track. I replaced it with better fluid, but after a couple sessions it became obvious there was still air in my lines (super squishy pedal). I have brand new pads and rotors.

Finally, I did a full flush, ran the pumps, and had my guy at BMW verify their feel. All was well. However, my last day at the track I could have sworn I had pretty bad fade after just 20 laps or so. Has anyone else had brake troubles like this? I always read the brakes on the 135s are amazing, but I've lost a lot of confidence in them. It could be I just suck at driving (I do), but my times are decent and I don't ride the brakes.

Thoughts?

[Focusedintntions]

Search button.....there are countless threads on this. OEM pads are fine for the street but don't do well with track abuse..

[Kgolf31]

Regardless of bigger calipers or not, OEM pads will fade.

People need to get out of their head that and BBK type/style brakes will eliminate fade, you still need dedicated pads for the track

[dsdubs]

Originally Posted by Focusedintntions

Search button.....there are countless threads on this. OEM pads are fine for the street but don't do well with track abuse..

I *just* replaced the pads. Does that not matter?

[Kgolf31]

Originally Posted by dsdubs

I *just* replaced the pads. Does that not matter?

Nope.

The compound cannot physically handle the extra heat.

[dsdubs]

Originally Posted by Kgolf31

Nope.

The compound cannot physically handle the extra heat.

Awesome, thanks for the feedback. I'll search around the forums for the best pads.

[MLSavage]

Best pad is different for each intended use. You have your street pad, a street + light performance (light track days) pad and your performance (full track day) pads.

In theory the middle pad is the best compromise, but it's just that on track duty, a compromise. It won't hold up to race conditions like the full track day pad. i.e. The pad you have to install and uninstall at the track, you can't drive to and from with them already installed.

Just an FYI of what to look out for given your use conditions.

[Kgolf31]

Originally Posted by MLSavage

Best pad is different for each intended use. You have your street pad, a street + light performance (light track days) pad and your performance (full track day) pads.

In theory the middle pad is the best compromise, but it's just that on track duty, a compromise. It won't hold up to race conditions like the full track day pad. i.e. The pad you have to install and uninstall at the track, you can't drive to and from with them already installed.

Just an FYI of what to look out for given your use conditions.

As easy as it sounds, It usually doesn't happen.

I run HP+ for autocross, and swap to OEM for DD. The pads are too loud for DDing and sounds like a bus stop. You need to drive like an ass to get them up to temp

[HP Autosport]

Originally Posted by dsdubs

Hi everyone,

It's been a while since my first post, but I'm a frequent lurker!

A while back I boiled my brake fluid out on the track. I replaced it with better fluid, but after a couple sessions it became obvious there was still air in my lines (super squishy pedal). I have brand new pads and rotors.

Finally, I did a full flush, ran the pumps, and had my guy at BMW verify their feel. All was well. However, my last day at the track I could have sworn I had pretty bad fade after just 20 laps or so. Has anyone else had brake troubles like this? I always read the brakes on the 135s are amazing, but I've lost a lot of confidence in them. It could be I just suck at driving (I do), but my times are decent and I don't ride the brakes.

Thoughts?

Which pad and fluid are you running? You should be on Hawk DTC-70, PCF01 or similar for the best track performance.

If you have a firm pedal, but the car does not slow down, you have faded the pads. If you have a soft pedal, you just boiled your brake fluid.

Even with full race pads, the 135i brakes still lacks thermal capacity, it needs larger rotors! However, with proper cooling ducts, race pads, very high temp fluid and good brake management by the driver, you may be able to go 20 laps without issues.

[Pyrat 2]

Originally Posted by HP Autowerks

Which pad and fluid are you running? You should be on Hawk DTC-70, PCF01 or similar for the best track performance.

If you have a firm pedal, but the car does not slow down, you have faded the pads. If you have a soft pedal, you just boiled your brake fluid.

Even with full race pads, the 135i brakes still lacks thermal capacity, it needs larger rotors! However, with proper cooling ducts, race pads, very high temp fluid and good brake management by the driver, you may be able to go 20 laps without issues.

You mention proper cooling ducts. I didn't see any on your site. Can you direct me in the right direction please. Thanks!

[Qbrozen]

It would be great if such a thing as better ducting were possible and existed.

I've got brand new ATE high performance fluid and brand new HP Plus pads and my pedal is still turning to mush by about lap 5. The heat buildup is just severe. I didn't even realize how bad until I tried checking/changing my tire pressures about 10 mins after getting off track. They were so hot that it took just 3 seconds of me pushing the pressure gauge on the valve stem before the gauge became too hot to hold! So to transfer that much heat through the wheel, through the valve stem, and through the gauge tells me that the heat at the rotor would probably take my skin right off instantly.

Anyway, I'm on the quest for cooler brakes. Any suggestions welcome. Which of the HP autowerks rotors dissipate heat the best? Would stainless lines help at all with the pedal feel? Does all that heat make the rubber lines that much worse?

[MLSavage]

Originally Posted by Qbrozen

It would be great if such a thing as better ducting were possible and existed.

I've got brand new ATE high performance fluid and brand new HP Plus pads and my pedal is still turning to mush by about lap 5. The heat buildup is just severe. I didn't even realize how bad until I tried checking/changing my tire pressures about 10 mins after getting off track. They were so hot that it took just 3 seconds of me pushing the pressure gauge on the valve stem before the gauge became too hot to hold! So to transfer that much heat through the wheel, through the valve stem, and through the gauge tells me that the heat at the rotor would probably take my skin right off instantly.

Anyway, I'm on the quest for cooler brakes. Any suggestions welcome. Which of the HP autowerks rotors dissipate heat the best? Would stainless lines help at all with the pedal feel? Does all that heat make the rubber lines that much worse?

The only downside to stainless lines is cost and time (of install.)

Turner has brake ducting sets. It looks as though we would need some minor work to fit them on our cars. Of course this simply looks like a hose you could buy at your local home improvement store.

[Focusedintntions]

Originally Posted by Qbrozen

It would be great if such a thing as better ducting were possible and existed.

I've got brand new ATE high performance fluid and brand new HP Plus pads and my pedal is still turning to mush by about lap 5. The heat buildup is just severe. I didn't even realize how bad until I tried checking/changing my tire pressures about 10 mins after getting off track. They were so hot that it took just 3 seconds of me pushing the pressure gauge on the valve stem before the gauge became too hot to hold! So to transfer that much heat through the wheel, through the valve stem, and through the gauge tells me that the heat at the rotor would probably take my skin right off instantly.

Anyway, I'm on the quest for cooler brakes. Any suggestions welcome. Which of the HP autowerks rotors dissipate heat the best? Would stainless lines help at all with the pedal feel? Does all that heat make the rubber lines that much worse?

The heats your wheels/tires build up isn't from the brakes but from the works they're doing as well. Sliding them around will build it up fast.

The ducting kits turner sells isn't a ducting kit...that just ducting hose and some clamps. Nobody makes a decent splash shield with a hose cut out for us, which we need. Then there's the issue of routing the hoses which is also a challenge with the tight space we have in the front end, especially when running larger wheels/tires

[MLSavage]

Cutting out a piece of the splash shield shouldn't be that difficult. I think I might come up with a solution and group sell it or at the very least an in-depth DIY that is pay-per-view muahahaha

The first problem is clearly the vent for {what I assume are} the brakes dumps directly onto the tire. You would have to turn that vent 180 to make it usable. That also requires cutting some of the plastic shrouding in the wheel-well. Lot's of DIY cutting/dremel'ing is needed.

[Focusedintntions]

Originally Posted by MLSavage

Cutting out a piece of the splash shield shouldn't be that difficult. I think I might come up with a solution and group sell it or at the very least an in-depth DIY that is pay-per-view muahahaha

The first problem is clearly the vent for {what I assume are} the brakes dumps directly onto the tire. You would have to turn that vent 180 to make it usable. That also requires cutting some of the plastic shrouding in the wheel-well. Lot's of DIY cutting/dremel'ing is needed.

You wouldn't be the first to try. I wish you good luck haha.

[Qbrozen]

The heat from the tires is not adding much, if anything, to the heat in the brakes. I can easily hold my hand to the tire after a run, but not so of the wheels.

yeah, after this past event, I'm thinking I'll have to come up with a DIY fix.

BUT, I also wanted to add something. This may have been obvious to some here, but I know it wasn't to me at first. After Monday's track session, after I posted here and I was falling asleep thinking about the next day, it occurred to me that I have been running with DTC on, which of course can utilize the brakes. So yesterday, I turned the system off completely. Sure enough, I experienced FAR less of a mushy pedal. I can only assume, then, that the DTC was working much harder than I knew. Yes, this resulted in being a bit harder on the tires, but no alarming lack of car control.

[Focusedintntions]

Anytime you're on track you should be turning all the nannies off. The car acts very unpredictable with it on....