My friend has a lightly modded WRX maybe pushing 250 to the wheels. He bought a stoptect brake kit. He has gone to 3 events in the last 3 months (one each month) TRACK EVENTS. Sebring Twice and Homestead once. After this last sebring event he just cracked his 3rd set of rotors! So far Stoptech has been replacing them but I think these are his last set they will cover. Thus an sugggestions on how to stop this? I suggested he Cryo the rotors, for 50$ a pair its worth it even if it doesnt work no? Finally will the FD rotors hold up to Track conditions?

 

What's his cooldown procedure? Is he sitting the ebrake? is he moving the car around after he returns to his paddock area?

Is he running any kind of brake ducting?

PaulC

 

I know this is probably a dumb question, but he's not running "cross-drilled" rotors, is he? On second thought, probably not, because Stoptech wouldn't be constantly replacing them if he was...

 

He is running slotted rotors.

His cool down procedure is one lap uber slow not hitting the brake once. He has all the stock ducting.

 

you will need to do some more research. what temps are the rotors reaching? what brake pads? what type of brake cooling(stock or additional cooling ducts)? type and size of brake rotors and calipers? I would start with some heat paint. this will give you an idea of the temps reached on the calipers and rotors. then adding some cooling ducts and maybe a switch in pad material. as you can see running a car on a race track can cause all types of problems even with a " big brake kit".

 

Well I mean he did his research and from my knowledge Stoptech doesnt mess around. He has the stock ducts plus w/e pads come with the stoptechs. He may swtich soon, . Think ducting is the problem?

 

Well, the first mistake is slotted rotors. Have him switch to a non slotted, non drilled rotor and see if the issue continues.

 

Their plain slotted not even drilled, he knows drilled suck but I didnt think slotted were bad or at least THAT bad =/

 

The StopTech may not be crap but that doesn't mean you can't still exceed the thermal capacity of the system.

You can fade the brakes through overheating the fluid, overheating the pads or overheating the rotors. Since the rotors are falling into pieces they are obviously too hot. That car with those brakes is still under-braked for that given track.

"StopTech" or any other named stamped on a component does not make it a silver bullet that solves all problems. Racers wish it were always that easy

 

Damon is on to what is likely the problem. just because companies are involved in racing doesn't mean everything they sell is made for the severe duty of race tracks. Stoptech is a very well respected company. I have not used them before, but they have many supporters. "bolt on" kits are not the end of the line when it comes to research and developement. it may be a switch in brake pads is all that is needed, maybe better cooling, but more info is needed to make an educated change. maybe a slightly thicker/heavier rotor would be more durable. maybe the racing life of these rotors is 8-10 hours of race time(not out of the realm of possibility). racers and race car owners know that parts on race cars last only a matter of hours at times. do some more testing and check with the Stoptech guys to give them some feedback. it sounds like they are willing to help, so take advantage of their knowledge.

 

Fatman0203: Why doesn't your buddy post here directly?

 

Doesnt see how the "RX7" club will benefit his "WRX" I told him were all the same, racers on the inside


Good points on everyones part. I guess we'll try ducting and hope for the best. BTW just because they crack doesnt mean they fade. THEY NEVER FADE, even after getting cracked they dont fade what so ever. He is running Motul DOT 4 fluid with very good pads (not sure what type)

 

post some pics. This is an interesting problem. I know that everyone gets the little stress cracks on the drilled stoptech rotors but having them crack is an entirely different matter. Everyone i know who has the kit loves it and hasn't had any real problems.

 

Pics would be interesting. Can you get & post some pics of the cracked rotors?

 

Sure I'll pass by his place tommorow.

 

My $0.02 would be the ducting as well. I currently destroy 2 sets of stock 1st gen rotors a year. With adequate ducting the wear to the rotors diminished greatly. Previous to pumping more air through the pads would wear much faster as would the rotors. In the end, Brake parts wear quickly under extreme use and the cooler you can keep the setup the better.

-Trent

 

Its very important to break in the rotors just like the pad. Do some quick stops from say 50 or so maybe 3 or 4. Let the rotor cool then do some from 60 maybe 3 or 4 then let them cool, finally some from 70 and let them cool fully each time. I crack rotors usually after 2 or 3 events then use the cracked ones for another couple events until a crack bleeds to the edge. If you use a some discipline and control your straight away speeds the entire braking system will really benefit from a few easy passes down the straight.

 

Ducting will help with longevity, but I still say the slotted rotors are exacerbating the issue. I don't know how to explain the metallurgical issues with cutting slots into rotor faces and how that will lead to cracking, but I do know that you are

- removing the amount of metal available for absorbtion of heat energy
- essentially planing off very small brake pad surface area due to the edge of the slot passing over the pad area.
- You've got uneven heating over the surface of the rotor

All IMHO of course, I'm not a brake expert.

PaulC

 

He did the whole bedding procedure and first lap warms them up. I will pass by his house today and take some pics for you guys.

 

Well, there's nothing magic about most anyone's big brake rotors. They are just iron rotors of a given size. They'll ALL crack. If your friend cracked Stop-Techs, then he would likely have cracked most anyone elses of the same size/mass. It isn't necessarily Stop Tech's fault, its a simple function of too much heat. He likely needs to get some real, dedicated brake ducting, or use a different pad, or some combination.

 

how do the stock brake ducts for a wrx look like? did you happen to have any pics?

 

Ok I forgot to take pics, since I forgot my camera
*slaps self on head* yet I can tell you more information. He does have ducting or to be more precise he has nothing infront of the rotors their getting direct air from the front. 2nd he says its because he trail brakes? Braking during the turn causing some bearings to move sideways and causing the rotor to flex? Is this true? Finally one rotor has stress cracks the other has CRACKS from where the bolts (inside allen wrench ones) were and spread out from there.

 

im confused, do you mean he does not have any brake sheilds at all/he took them off?

 

Im not sure what you mean by shields? The whole fenderwell inside thing ya he took that out. He just got his 4rth set of rotors (no stoptech did not replace these) yet their giving him a nice discount and he is sending in his cracked set so they can check them out. He is going to try ducting the brakes. The pads he is using are tough but not the hardest ones.

 

ahhh so he has no fender well liners. i though you ment he had some kinda stock brake ducts like this