[cburn]

Good morning!

I had my first track day yesterday and it was a blast! I noticed a few things about my 2011 BMW 335xi (Stock suspension and stock brakes).

1. The first few times I brake hard are ok. After that there is a pretty sever shaking on the front end that really wasn't right. Between session it would cool down and repeat. It doesn't seem to do this under normal (street driving) braking at all.

2. I hit the dreaded limp mode (Temp warning popped up and I lost power).
I know I need to add oil coolers to the car so I'll have to source the part with hose ports.

The track day was at Blackhawk farms and my best lap was 1:28 on the stock runflats. I really hope to get some new shoes for next season.

Thanks for any input guys, have a great day!

[Fundguy1]

Sounds like if you're going to track it you're gonna need a big brake kit and oil cooler.

[cburn]

Fundguy1. The oil cooler seems obvious but the brakes just were not working properly.

My guess is I have some loose bushings. Replace the rotors with drilled or slotted and some aggressive brake pads should do the trick.

Anyone else track on stock brakes?

[cburn]

Ahh well. I guess no none tracks their 335

[Cloud9blue]

Plenty of 335 being tracked. What you are experiencing is brake pad deposit on your rotor from your melting stock pads. Get some more aggressive track pads and some brake flush should solve your problem if you haven't damaged your rotor yet.

Stock oil cooler is adequate for the car if it is a chilly day and you have your heater blasting, which helps keep the engine cooler. But you should probably upgrade them anyway.

[cburn]

I have no Oil Cooler at all.

[Volasko]

Your front tension strut could be shot. This gives you a steering wheel shimmy under braking. Do a quick search for this issue and you find many threads that discuss this.

[cburn]

Thanks all!


Now I need to remove my mods and take it in to get all this shit resolved. The support department around here is shit. They never seem to figure anything out.

[GoRomeo]

Warped rotors

[CALWATERBOY]

Originally Posted by cburn

Thanks all!


Now I need to remove my mods and take it in to get all this shit resolved. The support department around here is shit. They never seem to figure anything out.

Teensy tiny little thing: Did you retorque your wheels before floggin' it?

With a torque wrench, not a stick or other....

[cburn]

Originally Posted by CALWATERBOY

Teensy tiny little thing: Did you retorque your wheels before floggin' it?

With a torque wrench, not a stick or other....

Not sure what you mean. I haven't ever taken the wheels off. It's under warranty so I haven't removed anything yet. (All the mods I've done did not require removing the wheels)

[Cacicgt7]

Originally Posted by GoRomeo

Warped rotors

Bingo.

You warped your rotors during the track day. Repeated high temp breaking heats the crap out of your rotors and can warp them pretty quickly. Probably need new ones now, and therfore you get to change the pads too.

[SGe92is]

Originally Posted by Cacicgt7

Bingo.

You warped your rotors during the track day. Repeated high temp breaking heats the crap out of your rotors and can warp them pretty quickly. Probably need new ones now, and therfore you get to change the pads too.

Not warped, but pad material that has built up unevenly on the rotor.

See Cloud9blue's post. That is what people call "warped rotors".

The easiest fix for this is to get a more aggressive pad and bed-in your new pads. This will remove the pad deposits from the rotor. The other fix is to get your rotors turned at a shop.

[techwhiz]

Originally Posted by GoRomeo

Warped rotors

Noooo............................................. ..........
See this: http://www.stoptech.com/technical-su...nd-other-myths

Rotors rarely warp. It's usually deposits.
Under hard breaking I suspect suspension components worn, especially at track speeds and braking demands.

[Cloud9blue]

Well if he was been heavily tracking the car with rotor that suffers severe uneven brake deposit, he could actually create localized hot spots on the rotors, which will become hot enough to actually change the metallurgy of the iron rotor.

This will actually lead to physically wrapped discs. This doesn't happen very often, but definitely possible if someone ignore the brakes long enough and keep on abusing it.

[GoRomeo]

Originally Posted by techwhiz

Noooo............................................. ..........
See this: http://www.stoptech.com/technical-su...nd-other-myths.

Rotors rarely warp. It's usually deposits.
Under hard breaking I suspect suspension components worn, especially at track speeds and braking demands.

Even so, warped rotors will happen way before worn out supension. This a 2011 model so its only 3 year old.

Deposits mostly cause squinking more than anything. Cheers!

[cburn]

I'm going to go with the brake deposits. The car doesn't shake unless I brake hard several times.

I was planing on getting new rotors and pads anyways. I'll check into the bushings as well.

Thanks again everyone for your help.

[Cloud9blue]

Judging from the age of your car and your post history, you got the car used, so it could be a possibility that the bushings are damaged from potholes or any road hazards that previous owner encountered in our lovely midwestern roads. I have seen 1 year old F10 with a split bushings, FYI...

Get the car on a lift and visually inspect all the bushings if you want to be sure. A damaged bushing is pretty easy to spot.

[cburn]

Originally Posted by Cloud9blue

Judging from the age of your car and your post history, you got the car used, so it could be a possibility that the bushings are damaged from potholes or any road hazards that previous owner encountered in our lovely midwestern roads. I have seen 1 year old F10 with a split bushings, FYI...

Get the car on a lift and visually inspect all the bushings if you want to be sure. A damaged bushing is pretty easy to spot.

Roger that. I have hit a few potholes myself. Cheers man, I really appreciate the advice.

[Nexic]

I had the exact same issue before changing my front pads and rotors. After some spirited driving and hard stops on the stock setup, I would get a shake from 40-20mph. It gradually got worse but would not be present when stopping lightly or dragging the pads. eventually stopping from 60-30 it would shake very severely. Upon looking at the rotors, I found that it was wearing unevenly and a lip formed. I replaced the front rotors and pads, when I took off the stock pads they ALL had cracks down the middle of them. These cracks seemed to have elevated the areas around the cracks almost as if the heat from braking made them expand. The expanded areas were making contact with the rotor first which is why it would not shake under light braking, only when you decide you want to stop did it shake, as the pads made full contact. This shaking was the uneven pads being mashed onto the rotors causing the shake. I have not had it since and I have upgraded to much better pads and rotors. The stock pads are not made for intense heat generated from 30+ minute sessions of spirited driving and braking or tracking. My guess is, they out gassed from the heat and since they did not have anywhere to vent to, the pad cracked.