for cobalt's whats the split between xr3 and xr2? i'm ok on xr3 but i've heard some folks fade them pretty bad. if yer a refugee from carbotech may want to skip xr3.

 

I wouldn't use XR3's on the front of any car, at least any real race car with r-comps. I liked the XR2 much better on our ITA Integra (130hp, 2700lbs) than the XR3s. I would think any turbo miata would want at least XR2s.

 

lol @ blood, sometimes I get a little carried away. I ran on those same pads again on Saturday, inspected them, replaced the cracked rotor and I'll get at least another day on them, maybe 2. The pad is still thicker than the backing plate and I've run 7 days on them and you know I'm not *****-footing. I've also run 6-days on a set of rotors, finally pulling them due to the crack. I ran the last session of the day HARD on NAPA house brand and noticed zero difference in feel and no real measurable change in caliper temp. John, Jeff, and I all ran similar lap times with the DTC-60 and love them because we all like the higher-friction coefficient and the longevity.

My XP12's lasted 2 days at Hallett and tapered really bad in the Sport brakes, the Hawk blues did not taper in the caliper.

 

I run the xr2's in the front and like the way they feel, they seem to wear well too, Im running the xr4 in the rear, I may try the xr3 next time, not that I have any problems with the 4s in back but I could use less bias with the 3s and have more adjustment, Ill let everyone know how that set up works soon.

 

I'll be going back to the 60's after the current Carbotechs wear away. My carbos are wearing fine, but I perfer the feel of the 60's. Higher intital bite suits my style.

Plus Hawk offers NASA contigency..

 

Now I can justify $1500 in aero to get a shot at brake pad contingency. lol

 

Yeah LOL don't throw money at the car trying to get contingency. That is a losing battle, like gambling for casino comps. It is icing if you are going to do it anyway.

I'm going for a quick short-term fix with an XP12 upgrade, new corrado rotors, and adding ducting. I had a good talk yesterday with Emilio and he thinks this will work well enough for now with the ducting being the key change; I have no ducting now but it has been bumped up to the top of the to-do list.

This is just to get me through the next few months. Eventually I really should get a proper BBK.

 

Did they just wear out or did you have other issues? I just bought a set of these for my Dynalites. How many track miles roughly?

Cheers

 

I think it was a combination of track miles and getting very, very hot with no ducting. According to Emilio, and what I have read/heard, the operating temperature has a big impact on the pad longevity. I cannot tell you for sure what the track hours are but I would guess less than three. And I was not braking at threshold limit.

 

ZXTX overheated the rotors/pads. Again I have 6+ days on my Corrado rotors and DTC-60's and the rotors and pads usually look great. Overheat a pad and it will look like ZXTX stuff.

 

Well I did it again. I grooved another set of rotors at Harris Hill yesterday.

I added brake ducting over the weekend to keep things cooler. I replaced the front brakes with new XP12 pads and new Corrado rotors. I kept the same rotors and XP8s in the rear. I bedded the pads carefully at the track per Carbotech's procedure and visually verified the bluish looking transfer layer on the disks after bedding. I let them cool down for about an hour in cool, windy weather. Then I went back out for two separate sessions. After about 20-25 laps the rotors are heavily grooved again like the first set. The front pads are about a third to half gone. The rears still look good.

I adjusted the brake bias while out on the track (cockpit adjuster ****) until I had instability and rear lockup entering a corner, then I backed off a bit. So I think I have about as much load on the rear as it can stand.

I think I need more substantial brakes. They will pay for themselves since $200 in rotors and brake pads for every other track day will add up very quickly. I really only think I need them for the front. The rears are wearing just fine.

 

Try pad like Hawk DTC-60 or Hawk Blue. The Cali boys like Carbotech, I am sold on Hawk pads because my Carbotech's did the same thing yours are doing. I don't like the price of Carbotech, I don't like the feel, the life, and they tapered bad on my sport brakes. The Hawk Blues did not taper.

 

I need to try something different since this setup is not going to get me there. It may be relatively cheap to have the rotors turned and try a set of Hawk pads. That or just go with the inevitable TSE or 949 front BBK.

The good news is the car is otherwise solid.

 

I have run XR2's in the front XR4's in the rear. I’m liking XR2 on all 4 corners best.

Again these are pads you can slap on the same rotors you use for your street pads when you get to the track don't worry about bedding them in and they work great out of the box never had an issue with Judder inconsistent feel or anything. When you switch back to your street pads the rotors have been cleaned and smoothed and the street pad performance is improved as well having a smooth surface to bed in a new transfer layer with just a bit of normal driving.

Bob

 

Bob, how is longevity? What else have you used/how long did it last? I am using DTC-70s (even though I don't like how they modulate) because I can make them last at least 3 full days.

 

Is it just me or does it seem the faster you get the less pad problems you have?

 

My brake problems get worse and worse the faster I go. I think it has something to do with 40+mph more trap speed at the end of straightaways than a Spec Miata

 

He compared the same compound in an Enduro on stock brakes and on their BBK. With their BBK with better heat dissipation abilities, the pads lasted longer than on the stock brake system. I think it was around 6 vs 3 hrs. Correct me if I'm wrong, but I'm sure you can get the gist of what better heat dissipation will do for you.

I notice a lot of people run lesser pads in the rear (XP12/10, XP10/8, etc). Is there a specific reason for this? I see NA chassis lock up the fronts all the time, so it seems counter-intuitive to do so. I have an issue w/ mine under braking so I am trying to figure it out.

 

That will do it. Energy goes up with the square of the velocity. E=1/2mv^2.

 

I’m almost certain you will get more life out of the cobalt’s and I have never felt a pad that modulates better. They modulate pretty even whether they are hot or cold but seem to wear less if they stay at operating temp on the track. Street driving them cold will wear out rotors quickly and the pads seem to wear a bit faster when cold. I don’t have experience with the DTC-70s but for me the cobalt’s last significantly better than Carbotechs, Wilwood B's or anything else I have tried on the track, like twice the life at least.

Bob