I just got back from Summit Point, and after five 25-minute sessions I wore down a brand new (bedded in, yes) set of Carbotech XP-12s so badly that I don't think I can use them again. This is in my Turbo II, which tips the scales at 2950ish with me driving and a half tank of gas and supposedly has 213RWHP according to the dyno sheet from when the motor was built, which my buddy says is bullshit, he thinks it's more. I'm inclined to agree with him, as I overhauled Armitage's FD on the straightaway despite a not-so-good exit out of T10.

Bottom line is I'm consuming brake pads faster than I think I should be given the power and weight of the car. I don't think they overheated, they didn't fade at all. Thoughts?

 

Hawk Blues. Good for at least 5+ weekends and I change them out early. By far one of the most popular RX-7 ITS and EP pads.

I know an RX8 Koni Challenge car that used to run Blues now runs DTC-60 in the front and HT-10 in the rear. They suggested I try the same but haven't yet.

 

The pads are not the problem. Your car is generating more heat than the rotors can reject. You need to duct the brakes. If you already have the brakes ducted then you need a big brake kit. I'm lighter, but more powerful and in the same boat.

-Trent

 

Wow. You must be pretty quick.

Does Pagid make pads for you? I think John Magnuson mentioned that he switched to Pagid pads and has been getting great life out of them. He is also a very fast driver but has an FD. there are also a couple of fast prepared FC Turbo driver's out here in Cali. I think one is Flyin Brian (or something like that) and I forget the other.

 

Dunno how quick I am, I managed to run a 1:32 but most of my laps were in the 1:35 range. I know places on the track where I can pick up a lot of time but they are the places where going fast can have consequences if you screw up, and I didn't want to smash up my car at the last event of the season.

FC and FD use the same pads, so anything that's an option of the FD is an option for me as well.

Ducts for the brakes will be happening over the winter, among other things. A big brake kit for my car is expensive because all my wheels are 16" so I would need to buy two sets of 17" wheels and tires in addition to the brake kit. I think this one http://store.revolutionbrake.com/marx7genii5l.html will fit under 16" wheels, but I'm not sure the upsize in the rotors is enough to be worth it.

 

You will be amazed at the difference good ducting will make.
During the Edmonton Indy support race I had a duct fold up and get completely blocked off. A few laps later the brake fluid (fesh willwood 570) boiled and the pedal hit the floor. I fixed the ducts and finished the weekend. My best lap was 3 seconds behind a verhag ex-trans am corvette. (he's about 780 hp and 2800 lbs with huge slicks)

-Trent

 

I didn't boil the fluid or fade the pads though, the pedal stayed rock hard and the car stopped like I had thrown out an anchor. My front tires went away before the brakes did. I just used up an incredible amount of the pad material, the taper is pretty severe and the narrow part is down to less than half thickness.

 

Have you talked to the guys at Carbotech? That does not mesh at all with my experience with XP10s, which last me about 6 weekends before requiring replacement. I'd give them a call and talk about it, even if you do decide to make the switch to another pad.

PaulC

 

Just got off the phone with Mike Jr. at Carbotech. He thinks there is no way I should have burned through the XP12 that fast and that I should fully check out the braking system for problems. One side did wear much more than the other, but it was the right side, while you would normally expect the left pads to go away faster from trailbraking on a mostly right-hand course like Summit. The taper wear on the right side was also far more pronounced.

The calipers are all new and I didn't have any trouble pushing the pistons back in when I changed back to street pads for the winter. However, one of the pad separation springs (or whatever those springs that go between the pads and wrap around the retaining pins are called) had been previously damaged from contacting the rotor and is no longer very springy. Also, I don't have the metal shims that go in the hole in the caliper at the top and bottom to keep the edge of the backing plate off the caliper and keep them from digging into the aluminum, so it's possible they are hanging up on there.

The paint on the backing plates also turned white, which he says means the temps probably got so high that the rotors were glowing.

 

Actually I've been using Raybestos (ST-4 I think) pads with great results. They last many weekends, perform very well and are reasonably priced. They're a bit more expensive than Hawk pads but a lot easier on the rotors. I have not tried Pagid yet due to their high price.

My brakes are also larger than stock and ducted. As "TrentO" pointed out if you're badly overloading your brakes (very possible with aggressive track driving with stock FD or FC brakes) you're going to melt away any kind of pad quickly. Since you said you lost the pads in just one session this is probably the case. As "TrentO" said - try ducting first and then if necessary larger brakes.

- John

 

Yes, it is important to have well lubricated shims in place so that the pads slide freely or you'll get uneven wear as you experienced.

 

Hey Gene,
IMO if you're going over 135 mph (which I'm sure you are making that power) you will need some upgraded brakes like 12 or 13" in size and some fat HB 101 style pads.

When I run an FD with stock brakes I'll burn through hawke blues in a day just like you mentioned 4 or 5 sessions going 140 to 145. I'll put new pads on the second day and the rotors will basically need to get tossed after the weekend because of cracks.

You can add ducting etc.... but at those speeds with a thin pad and little surface area you'll chew through anything so I'd advise buying a BBK which will save you both money and headache in the long run.

 

Damnit, I haven't been lubing my shims!!!


Seriously, if you want the best get PFC's... but you'll need upgraded brakes, because they don't make them in stock sizes anymore.

 

I was over revving 4th gear and not going to 5th as my trans is really beat up and the 5-3 shift going into T1 is difficult to execute smoothly, which works out to about 125 mph. After 6k RPM the boost falls off to 5lbs, so it's not accelerating much up there. I also kept chickening out on my speed out of T10, I think I've got another 10-15 mph available there.

What are my options on the BBK? There's the not too expensive Wilwood one I posted that I think will fit under my wheels, or there's the big bucks KVR kit but then I'd need to spend $Texas on 17" wheels and tires.

 

I've been getting double the life from my pads since switching to the 99 brakes from stock. The larger rotor seems to help, also the staggered front pistons let the pads wear evenly. Pads are ntech lap day, the car makes over 400 whp and is on unshaved ra-1's.

 

Once you have the car sorted and get some more seat time you'll be glad you bought the best possible brake and wheel combo it's truly the meat and potatoes of your car. Wheels and tires with the proper brakes and suspension are like great speakers for a stereo and it appears your amp is already making some good power hehe.

 

That's the thing, the suspension and wheels and tires are working great so I hate to spend a shitload of money to get all new wheels. Especially since my track wheels are a beautiful set of old-school Volk GR-C that I got on the cheap. The tires are a set of BFG R-1s that I think I can get another season out of if I turn them inside out. Getting new wheels as good as those is gonna be super expensive.

 

It's always give and take so if you can't find a good caliper to work with the system I'd just go w/ good ducting and spend your money on Hawke blues (no better pad for the money) and rotors. I've also heard good things about the HD (might be HT) 10 hawkes but they cost a bit more than the blues.

 

If they cost more and last longer it might be a wash. Corksport actually has a 12.4" rotor KVR kit with AP calipers that may fit under the wheels, I emailed them, so we'll see what they say. It's megabucks at $2800, but it's two piece rotors and AP calipers instead of the cheapie wilwoods (not that wilwoods are bad per se, but they're wilwood's cheap ones) and one piece rotors that the other kit has.

 

Nascar cars use a 15" rim and have enough brakes to haul down a 2800 lbs car from some pretty high speeds on the roadcourses. A potential "big brake" option is to find a slightly larger caliper that is much thicker and a caliper to fit. I'm in the middle of fabricating my kit right now, but I went to a larger diameter as I already run 17" rims.

cheers,
-Trent