Overheated pads?

[jcaspar1]

I spent a day at the Thunderhill Viperdays and am getting more aggressive with my braking. The day after I noticed that I was getting a lot of vibration with braking. I have previously overheated a set of the Axxis Ultimate pads at Thunderhill and had switched to their Club Race pads which are supposed to be have the same pad material as Brakeman #3's. I have a Stoptech front setup with Porsche deflectors and Motul RBC fluid. I figured I had just caused uneven brake pad material on the front rotors (happened with the Ultimates). When I finally got around to pulling the pads they looked like this:

The pads were quite crumbly and the edges were flared out and crumbled. I scuffed the rotors and went back to the Ultimates for the street.

My question is, what happened? Are these pads just overheated? Would real BM #3 pads do this? Would switching to BM #3's be better or should I go to real race pads for the track?

Thanks

 

[Tom F&L GoR]

I've seen that on the lifetime warranty cheapo pads I put on my Dakota. After a week chunks were falling out.

BTW, you might want to consult with ChuckB about "redistributing" your braking balance.

 

[Eric H]

the vibration you feel is the pad material getting SMEARED on your rotors, when the pads heat up quickly the material has a tendancy to melt slightly and leave residue on your rotors, after a couple hundred miles of driving with normal pads it should wear off...... or you can sand or resurface your rotors

And YES, those pads were WAY overheated.....

Tom........your calipers are on their way!! sorry! im a slacker!

 

[JGarrett]

I participate in or instruct about 26 track weekends a year. I know... I have no real life. I see Vipers at a host of venues and I see that the stock system just doesn't work well on the track and on good upgraded systems a street pad really just doesn't work well. On the street we brake hard only occasionally. Pads, rotors, fluid, lines all can cool back down. On the track you get the system hot, then hotter, then "cool" back down to just hot. We have a real rocket of a car that is somewhat heavy. IMHO the stock brakes are okay for the street but the track is tremendously more demanding and seriously compromises it's ability. I've gone through the standard progression as well. Stock brakes, Aerorotors, Porsche deflectors, BM3, Stainless steel lines, all the fluids. I would get fade and or lose brakes with all. On the track the failure happens at whatever you have as the weakest link first. Street fluid... you boil, regular lines the heat expands them ...loss of pressure, street pads.. cook em, wear them off, chunk them off etc. The solution I found to work best so far (I have yet to get fade or lose brakes) a Stoptech Big brake kit, 18 inch wheels, SS lines, Motul 600, Race pads, Archer ducting and checking the system after every run. There are other good solutions and products out there; this does work for me.

On my car I found the Porsche deflectors to provide only a marginal (worthless) effect on the rotor temps. You might want to consider a real cooling setup with duct work like Archer or Cone. BM 3s worked well but I was replacing the fronts after every weekend and sometimes during the weekend 2-3 days. The rears would go after 3-5 days. My car is now just a track car so I went with a full race pad and am actually getting 3-4 weekends of life. If you are running on the street the Stoptech system couldn't be much easier to switch pads back and forth...

Pardon my rant but I spent (Wasted) a lot of money getting to where I am now and I wish that someone told me early on "If you are going to use your car on the track get a real setup that others have already tried at the track and works there are no shortcuts."

All the best ,
Jim

 

[GTS Dean]

Brakeman pads get half the life of PFC (or less). Street pads should stay paired with street rotors. Race rotors and pads on the track only. Mixing compounds on the same rotor is just asking for funky deposits on the discs and equally funky performance.

Figure out where your braking points are, use them hard, then GET YOUR FOOT OFF THE BRAKE PEDAL and LET THEM COOL OFF.

IMO, Motul is junk fluid.

 

[jcaspar1]

I take it these pads are not the same as BM#3's. I think most of the overheating is me braking not hard enough for too long. With the price of Stoptech 2 piece rotors, swaping rotors is not an option for me so I guess I am stuck with the same pads for steet and track. I don't mind dust or squeeking. Are there any more race ready pads than the BM #3's for the track that could be run on the street. My current setup is:
17" Stoptech calipers on front with Club Race pads, SSlinesx4, Motul RBC, Porsche ducts and EBC reds on the rear with slotted rear rotors.

Am thinking about: BM #3 x 4, bored out rear caliper for use with stoptech fronts, and Cone ducts. Thanks for all the advice.

 

[Tom F&L GoR]

Timing issue: if you are interested in 38mm rears, please let me know ASAP. I have a batch at the machine shop now all being turned into 40mm's.

Also, going to 38mm rears (with StopTech fronts) will change the braking balance so that you'll have to re-think and re-visit the unequal characteristics front to rear (i.e. tire compounds, pad compounds) later.

If front brake temperatures are an issue, consider a brake fluid recirculation valve. For a DIY cost of about $250, it pushes brake fluid to the caliper via one set of brake lines, pulls it back through another. Therefore the fluid doesn't sit in the caliper and overheat.

or installed at Woodhouse.

 

[Chuck 98 RT/10]

Jeff, I have Stoptech fronts also. Tom set me up with a stock rear caliper upgrade that I'm getting good feedback from. I'm still testing but am growing to like it. I'll be doing more testing at Homestead next weekend.

 

[ViperRay]

I have a brake fluid recirculating valve in my GTS.
No more loss of pedal from fluid boil since then.

Prior to that had Cone ducts, air deflectors, Motul, etc.

I suspect I spent too much time on the brake pedal like someone said above... getting better at that though.

 

[jrkermode]

If you have the StopTech front only kit then you should not need Tom's modified rear calipers (your brake system should already be balanced).

Start with running BM3's. They're kind of noisy and dusty on the street, but they do OK as a street/track pad.

 

[Tom F&L GoR]

jrkermode, the upsize of the OEM rear calipers from 36mm to 38mm (using the OEM front calipers) roughly provides the same front to rear braking balance as the StopTech front kit (with the OEM rear calipers). StopTech front calipers have smaller than OEM pistons which mathematically can be duplicated by making the rear calipers larger. In either case, the result is still front-biased.

The 40mm rear caliper (with the OEM fronts) shifts even more braking performance to the rear for, what lots of folks have found, really nice front-to-rear balance.

So if you have StopTech fronts already, what to do? Chuck B is evaluating 38mm rear calipers in combination with his StopTech fronts, which again, mathematically, provides equivalent brake clamping balance front to rear as does the OEM front + 40mm rear combination.

This table shows the various combinations using piston areas. The actual brake clamping force would be a little different, as it includes rotor diameters, etc, but same conclusion and this way you can check my math!