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Discussion Starter #1

the car is a stock 2011 gt base with brembos and 3.73's as the only options.
i ran on the stock pirelli's with carbotech xp16 pads up front and xp8 on the rear (on the advice from carbotech).

i was able to knock off some very consistant 1:29's with open road, which i find to be very good for box stock. my previous american iron legal 95 GT, ran a best of 1:24, so i think its a very capable car...however, after the weekend, the front pads are toast (first event on them) and my rotors are showing signs of heat cracks AND my brembo dust boots are all fried! these things just cooked! i know that my AI car weighed 500lbs less, but they were lowly 2-pot, 13" cobra brakes WITHOUT brake ducts and they didn't have nearly the wear these did after the same amount of track time and similar MPH (around 140 at the end of the front straight for both).

i have 2 thoughts on this. 1) 500 lbs more means i need to cool them better even though they are bigger. 2) front nose dive is putting too much of the load on the front brakes.

what are your opinions on possible other culprits or what i can do to combat this issue? i was planning to make r-comps my first purchase for the 2012 season, but i think i need to hold off until i can get my braking situation worked out.
 

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Brake ducts are your friend. Install them if you plan to track the car frequently... Might even consider blowers on the lines, I run blowers on my AI car on the front, just ducts on the rear...
Not familiar with those pads, I use hawks (DTC60 front, DTC70 rear)... Are they track only pads, or trackable street pads?? To much heat will destroy any pad... but I'm sure you knew this already if you raced...
What did the rear look like? If they don't have near the wear as the fronts, you may have too much front bias, overworking the front of the car. Which is why I run a higher torque pad on the rear of my car, to improve the rear braking ability, which improves overall braking ability. Might consider a higher COF rear pad next time.
I ran the Brembo 13" setup on my AI car with the 1.10" rotors. Melted the dust boots quickly, but not a problem on a track car. Now I have the 13" stoptech set, if the calipers have dust boots they're probably gone now too. Not a concern to me....
Didn't watch the video yet, are you happy with how the car stopped/handled under braking?
 

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I loved your video and I can see why the brakes got so hot. Good driving!

You listed three issues and they are all obviously due to heat. You can't expect dust boots to last as they were never designed to last in this kind of environment especially in a fast car. I had a Z06 and burned them off in no time. That is why race cars don't have them. The heat cracks are from extreme heating and cooling. That doesn't necessarily mean the rotors are done though. I have used carbotechs but never the Xp16, but it is known that the higher the number the faster they wear. Heat has a hand in that too.

Since your ABS system will assist with adjusting rear bias, I wouldn't add overly aggressive pads to the rear as it might cause the fronts to work harder if the rear brakes can't get up to optimum temperature. But it can have the same effects if you do the opposite as well. Pick a rear brake pad that will work in the intended heat range you want. I'd try a minimum of an XP10. It might be worth running a lower pad up front as the XP16 is considered an extreme race pad. Since you are on street tires, I don't see why you couldn't run an Xp10 or Xp12 up front. They will definitely last longer and still offer good performance that won't fade.

You mentioned reaching 140mph in both cars, but the 2011 has to accelerate harder and also slow down more all while carrying an extra 500lbs. While you would think street tires are better than race tires in keeping brakes cooler, it will actually work in the opposite manner. Being able to take a corner 10+ mph faster means you don't have to slow down as much and the brakes don't have to work as hard. And even though you are exiting faster, the top speed vs corner entry speed difference should be less. This is assuming you don't add any power.

I haven't looked at the new fords, but I know gm does a good job of putting brake ducts on their vehicles. It is definitely worth copying their design at a minimum as an attempt to cool the brakes down as well. These are all simple steps to take and then you can adjust your plan after some more reevaluation.
 

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Discussion Starter #4
thanks for the input guys! the brakes performed well. they never faded and the car never pulled to the side. there was, however, a fair amount of steering wheel shudder in the biggest brake zone. i took a look at the boss brake duct kit. it would be an easy bolt in once i got a boss chin spoiler (which i wanted anyhow), but the duct goes directly to the back rotor surface, not the hub. i will likely have to build my own. good winter project:) i see both points on rear pad choice. i don't know the answer. maybe i will contact carbotech again and ask them for advice. i suspect the excessive nose dive is going to make any rear pad choice null, since there is virually no weight on the rear tires under heavy braking. oh, and i calculated my weight differential wrong. AI car was 3100 with driver. advertised weight of my car is 3650, which is without a driver. probably closer to an 800lb difference! holy crap!
 

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My buddy ran his 2011 w/Brembos at Road America a few months ago and they were pretty flawless. I say "pretty" due to the fact that he didn't bed the pads in before the event and likely had green fade at one point. During the next session, they were much better. The car is completely stock(besides the oil) and he was hitting between 135 and 140 3x per lap with no fade issues(other than the green fade). I'm sure if 'R' tires were used, stock pads wouldn't last, but they worked just fine on stock rubber. Carbotechs are known to be easy on rotors and have relatively short life(if you didn't know already). I don't think my buddy has looked at his brakes since he bought the car so I can't comment on their status.

Great video btw.
 

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XP16 with XP8 rear!?!?!

I know Carbotech thinks they are helping people when recommending less pad out back, but I feel, along with a few racer buddies that with these modern cars, running the same pad out back, or just SLIGHTLY less, is best. These cars use a lot more rear brake than you think! I assure you, no matter how little weight you think the rear still had, it was doing a lot more braking than the old days. Your nose dive is from way too soft springs and underdamped shocks, typical FORD OEM trait.

I'd recommend running the SAME pad if you add front ducts. The brakes will likely be operating at a similar temperature if the fronts are cooled and the rears are not, despite the fact the the fronts are doing most the work. Getting the rears involved more will not only increase pad life, but also braking performance.

I'm really digging these Raybestos ST43 pads... Lasting MUCH longer than the previous Carbotech XP10's. Thank you Mr. Kirby! ;)
 

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XP16 with XP8 rear!?!?!

I know Carbotech thinks they are helping people when recommending less pad out back, but I feel, along with a few racer buddies that with these modern cars, running the same pad out back, or just SLIGHTLY less, is best. These cars use a lot more rear brake than you think! I assure you, no matter how little weight you think the rear still had, it was doing a lot more braking than the old days. Your nose dive is from way too soft springs and underdamped shocks, typical FORD OEM trait.

I'd recommend running the SAME pad if you add front ducts. The brakes will likely be operating at a similar temperature if the fronts are cooled and the rears are not, despite the fact the the fronts are doing most the work. Getting the rears involved more will not only increase pad life, but also braking performance.

I'm really digging these Raybestos ST43 pads... Lasting MUCH longer than the previous Carbotech XP10's. Thank you Mr. Kirby! ;)
You're welcome. I've settled in on ST41s front and rear. Are you getting them from Randall Race Products in Mooresville?
 

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Discussion Starter #8
i was suprised they would have recommended less pad on the rear. i would think that the best way to get the fronts to last longer is to get the rears to pitch in more, not less! short of trying different brands and compounds until something works, i don't think there's a clear answer out there for me. the variables are too vast. even though we are all driving mustangs, they are all different years with all different performance parts, being driven by different people on different tracks. i can't even use the experience i have with my previous vehicles! this is frustrating!
 

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You're welcome. I've settled in on ST41s front and rear. Are you getting them from Randall Race Products in Mooresville?

Heck ya! What a wonderful operation and what a deal! I was getting them when they were moving locations, and it was a bit complicated (custom order from factory) but Jake took great care of me.

I decided against the more aggressive ST41s because I'm currently running the extreme summer Hankook RS3... might have overpowered my tires... When I get slicks, I'll likely do the ST41s.

Best-
 

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i was suprised they would have recommended less pad on the rear. i would think that the best way to get the fronts to last longer is to get the rears to pitch in more, not less! short of trying different brands and compounds until something works, i don't think there's a clear answer out there for me. the variables are too vast. even though we are all driving mustangs, they are all different years with all different performance parts, being driven by different people on different tracks. i can't even use the experience i have with my previous vehicles! this is frustrating!

You just need some cooling up front and more pad out back. Have you atleast removed the dust shields???
 
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