Spectre23

I did a bit of searching and did not find my answer. But not really sure what to search for. I thought about posting this in the autocross area, but since it is Cayman specific I figured I would start here. If a moderator disagrees, please move it.

I recently purchased a 2007 Cobalt Blue Cayman S. It had all the right options I was looking for. PASM, Sport Chrono, PSE, Sport shifter. It is completely stock with 49K miles. I bought it a few weeks ago. Had the windows tinted the first weekend. And since it came with snow tires (one of which was damaged) I got some cheap Federal 595 RS-RR for daily driving and track days. I ordered some better wheels and tires for autocross, but they are not here yet. So the wife and I had to do the first autocross on the RS-RR’s.

On aggressive transition from turning right to turning left it made a noise in the front left corner of the car. Like a muffled rub/thud. At first I thought it sounded sort of like tire rub, but it was too short and a bit too abrupt to be that. After the autocross, I drove home without any noise. I put it up on the scissor lift and pulled the front wheels off as well as the front bumper so I could check things out. I did see a crack in each rotor that seems somewhat superficial right now, but I will keep a close eye on. Especially since the brakes were smoking after each run. And I don’t left foot brake, so it isn’t from dragging the brakes. There was one missing screw on the front apron. And the black plastic in the center grill opening was off of a couple of its clips. The bump stops are deteriorated to essentially non-existent status. All bolts are tight. All bushings appear to be fine, but they all have seals on them. But the seals are all in great shape. I pulled the condensers away from the radiators and cleaned those out good.

Worth noting is the noise is coming from the same corner that had the damaged tire.

Is there anything specific I should be looking for? Or any testing I should perform? I was unable to replicate the noise outside of an autocross environment. Sorry if this is a common issue everyone knows about. This is my first Porsche. BTW, FWIW, I ended up 13th out of 82 on stock size inferior tires with I believe 6 national champs in attendance. So I didn’t feel too bad about performance. Can’t wait for the new tires and wheels to get here. Hopefully they fit OK since they are a few mm larger diameter.

Also, is it common for these brakes to be smoking after an autocross run?

Here is a couple pictures from the event (not by me for obvious reasons). Sorry for the ugly painters tape. Being the first event, I wasn't sure how well the paint reacts to cone marks. Even with tape I got to see how easy they come off though

Bill Lehman

The car does not typically make a wheel rub sound at the LF. Your wheels look like after market, are they OEM offset? I'm surprised by smoking brakes during an AX but I don't do them. Was the heat from the front or rear? If rear brake, did you run with PSM on or off? If you're experienced, you never run a 987.1 with PSM on.

Spectre23

They are the factory Sport Design wheels. So they are narrower than the ideal factory wheels which is why I have others on order. The smokey brake was the right front. After the drive home, I took temps of brake rotors and wheel hubs and The fronts were pretty similar. One rear hub was about 10 degrees hotter than the other, but rotors were the same. Again, I will keep an eye on it. Could be a bearing or could have just been in the sun longer on the drive. I don't normally measure those temps, just wanted to check what I could since the car is new to me. I did run with PSM on. I only felt it hold me back twice so I just left it on.

daylorb

The rotor temp will fall pretty quickly - if you took it after drive home it would likely be quite a bit lower than just after the run...

Spectre23

Yeah, the reason I checked after the drive home was just to be sure the humming noise on the way home was road noise, not a bearing noise. These street tires I got are notoriously loud. They just seemed louder after the race.

Spectre23

BTW, I ordered new Pagid rotors to replace the stock ones since both fronts have cracks I don't like. Had to stick with OE style since slotted would boot me out of the class.

daylorb

Interesting - there are a number of threads about how the small cracks around the drill holes are not a big deal... you would definitely assume Pagid to be decent quality.

Spectre23

I'm not too worried about the crack, but it's a bit more than just small cracks around the holes

daylorb

Yes, that does not look like the cracks I've seen reference before. That is a bit more concerning. This is more similar to what I have seen posted in other threads:

mjdavis

I don't like that crack at all...

sholzer

Your brakes should not be smoking after an autocross run

Spectre23

Figured that. I'll see how it does after new rotors are on. Maybe there was some sort of degreaser the seller used on them that was burning off or something. Luckily they worked great.

Spectre23

Just an update.

1. The noise I think ended up being dried up bushings. Sprayed oil on all the bushings and the noise is gone.
2. Smoking of brakes is gone since changing out my rotors. I think the old rotors were so rusty, there was flakes of rust smoldering in the vents.
3. I am a bit disappointed in the Porsche engineers for putting zinc plated steel bolts in aluminum housings. I had to helicoil a hole for the brake caliper mount thanks to that stupidity. Worth noting is they did change the bolt material on the part number that supersedes the original.
4. After this weekend's autocross, I REALLY need a bigger front anti-roll bar. And the wait for my better wheels and tires is killing me.