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#21
Mach 1 Member
Thread Starter
Hey SGWick, good question. I opted for the simplest solution, and I just swap my street pads (OE pads made by Ferrodo). It would be ideal to swap rotor and pad sets, but I'm too lazy, lol. I've been going back and forth between XP10s and Ferrodo pads with no issues for the last 7 track days. Never had issues with vibration or uneven wear or too deep grooving of the rotors. Going from XP10 to street pads is no big deal. The street pads scrub off the deposits in a few days usually. Going from street pads to XP10s I re-perform the bed in procedure, which basically means a 5 or 6 0.4g stops (near stops to be exact) followed by 5-7 threshold braking stops from 60 to 5mph in rapid succession. You know you did it right when you hear hissing noises and see smoke coming from the brakes. Then I let it sit for 30min and that's it! And as always remember to NOT set the parking brake.
Last edited by SGwick; 2/15/16 at 12:23 PM.
#22
Mach 1 Member
Thread Starter
What do you think about dtc60s upfront and xp8s in rear?
#23
Bullitt Member
I run xp10/xp8 with dedicated rotors for track days. For street driving I change out only my front pads and rotors to Hawk hps, leaving the Carbotech xp8 in the rear. And they have been squeaking just a little bit as of lately during Street driving.
#24
Mach 1 Member
Thread Starter
Thx redonblackpony :-) ordered DTC-60 (f) & XP8 (r). Both operating temps are great just hope XP8 friction doesn't mess with brake bias (causing oversteer) oh well
#25
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Yup, same here as redonblack. I leave the XP8s permanently. They squeak a little, but its really no big deal, and like they say: "brakes squeal because race car"
So what made you go with the DTC60s? From what I hear they are a pretty serious high grip pad. The reason I ask is because of brake bias like you mentioned. XP8s are grippier than stock, but isn't the DTC60 very grippy? Or is it a medium grip compound? I'm afraid you may experience what I did. But it wasn't oversteer, and it was controllable, just annoying.
My car would brake dance in high speed brake zones. The tail would swing left and right a few inches. I ended up putting a few degrees of steering to compensate. That's not supposed to happen though. But that was because I was running XP10 with stock rear pads for the first 2 seasons. The brake bias was too far forward, and I ended up under braking the rear. So the rear of the car would "run into" the front, and cause this wobble.
After I returned the bias to normal by properly matching the front to rear bias it went away. Give it a shot, but if you run into similar issues you know what to do.
So what made you go with the DTC60s? From what I hear they are a pretty serious high grip pad. The reason I ask is because of brake bias like you mentioned. XP8s are grippier than stock, but isn't the DTC60 very grippy? Or is it a medium grip compound? I'm afraid you may experience what I did. But it wasn't oversteer, and it was controllable, just annoying.
My car would brake dance in high speed brake zones. The tail would swing left and right a few inches. I ended up putting a few degrees of steering to compensate. That's not supposed to happen though. But that was because I was running XP10 with stock rear pads for the first 2 seasons. The brake bias was too far forward, and I ended up under braking the rear. So the rear of the car would "run into" the front, and cause this wobble.
After I returned the bias to normal by properly matching the front to rear bias it went away. Give it a shot, but if you run into similar issues you know what to do.
Last edited by 5.M0NSTER; 2/15/16 at 06:33 PM.
#26
Mach 1 Member
Thread Starter
I bought permatex extreme brake parts lubricant to help with the squeal putting on backing plate.
I was looking at dtc-50/60 and xp10 for the fronts. Really I based most of my decision on operational range of pads (matching them) = XP10 close to DTC60 (actually DTC50 was closer in temp but friction was closer to DTC70s, weird), considered mustangs 3.6k weight, and I already have hps in front I went with DTC60.
For the rear I looked at XP8, temps, HPS, HP+, HP 5.0 but the only rear hawk pad to match XP8 was hawk street/race pad (mostly reviews for noise/dust) and that was considered mostly a dedicated race pad for track only. So with no suitable substitute I went with XP8s (easier on rotors and a softer initial bite)
I was looking at dtc-50/60 and xp10 for the fronts. Really I based most of my decision on operational range of pads (matching them) = XP10 close to DTC60 (actually DTC50 was closer in temp but friction was closer to DTC70s, weird), considered mustangs 3.6k weight, and I already have hps in front I went with DTC60.
For the rear I looked at XP8, temps, HPS, HP+, HP 5.0 but the only rear hawk pad to match XP8 was hawk street/race pad (mostly reviews for noise/dust) and that was considered mostly a dedicated race pad for track only. So with no suitable substitute I went with XP8s (easier on rotors and a softer initial bite)
#28
Mach 1 Member
Thread Starter
I was thinking I wanted to maintain front brake bias so I didn't have oversteer (rear brake lock) under full braking. I figured that would be easier to control verses the rear dancing. Never considered "too much front bias", would lead to front lock/slide. We'll see, man so many variables to think about :-)
Was also considering tracking with TC off but not sure. Last time with sport mode, abs was kicking in (shaking felt through steering wheel) :-)
Was also considering tracking with TC off but not sure. Last time with sport mode, abs was kicking in (shaking felt through steering wheel) :-)
#29
Mach 1 Member
Thread Starter
Running dtc60s up front and possible more front brake bias I think I'll have to stiffen front struts to slow harder brake dive
#30
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ABS and EBD (electronic brake force distribution) are enough to prevent wheel lock. Locking was not the issue for me, but the tail wag was uncomfortable. More friction in the rear fixed it though, so if you run into issues you can either increase rear friction or reduce front.
I wouldn't worry about over steer with higher negative brake bias unless you're in a habit of trail braking
I wouldn't worry about over steer with higher negative brake bias unless you're in a habit of trail braking
#31
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I always wondered about that with respect to bigger rotors on the rear. The rear brakes on these cars do work pretty hard and I have had more issues with the rear getting hot than the front. Some guys put the bigger GT500 rotors on the rear; wouldn't that cause the same issue?
#32
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I always wondered about that with respect to bigger rotors on the rear. The rear brakes on these cars do work pretty hard and I have had more issues with the rear getting hot than the front. Some guys put the bigger GT500 rotors on the rear; wouldn't that cause the same issue?
When you change to a larger diameter rotor the arm of force chages, and multiplies your brake torque vs. brake pressure chart by a constant factor. That means that the gradient of brake torque change stays the same (delta tq vs, delta pressure), though the values are elevated compared to stock.
But if you switch to an aggressive pad, that changes the rate at which brake torque ramps in. So there is lot steeper gradient in how fast torque is changing compared to haw fast pressure is changing. The sudden change in gradient causes the issues with early locking/abs entry.
Hope the makes some sense!
#33
Mach 1 Member
Thread Starter
I always wondered about that with respect to bigger rotors on the rear. The rear brakes on these cars do work pretty hard and I have had more issues with the rear getting hot than the front. Some guys put the bigger GT500 rotors on the rear; wouldn't that cause the same issue?
#34
Mach 1 Member
Thread Starter
If you're worried about over-braking/locking the rears, main issue is actually with the compound.
When you change to a larger diameter rotor the arm of force chages, and multiplies your brake torque vs. brake pressure chart by a constant factor. That means that the gradient of brake torque change stays the same (delta tq vs, delta pressure), though the values are elevated compared to stock.
But if you switch to an aggressive pad, that changes the rate at which brake torque ramps in. So there is lot steeper gradient in how fast torque is changing compared to haw fast pressure is changing. The sudden change in gradient causes the issues with early locking/abs entry.
Hope the makes some sense!
When you change to a larger diameter rotor the arm of force chages, and multiplies your brake torque vs. brake pressure chart by a constant factor. That means that the gradient of brake torque change stays the same (delta tq vs, delta pressure), though the values are elevated compared to stock.
But if you switch to an aggressive pad, that changes the rate at which brake torque ramps in. So there is lot steeper gradient in how fast torque is changing compared to haw fast pressure is changing. The sudden change in gradient causes the issues with early locking/abs entry.
Hope the makes some sense!
Go with above Bert, it's factual verses mine, opinion :-) We can always count on you 5.Monster :-)
#35
Bullitt Member
What causes the rear brakes to overheat on the track is running with traction control on or running sport mode. The only thing that works for me is to disable traction control and stability track altogether.
#36
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Ah, that's a good point redonblack.
I have no rear over temp issues with my setup, but I run in Advancetrack Off, or Sport mode. If you do keep sport mode TC is still on, and so is vdc. I've gotten rear pad deposits from that before. You have to be really smooth in Sport Mode to avoid excessive TC/VDC hits.
I have no rear over temp issues with my setup, but I run in Advancetrack Off, or Sport mode. If you do keep sport mode TC is still on, and so is vdc. I've gotten rear pad deposits from that before. You have to be really smooth in Sport Mode to avoid excessive TC/VDC hits.
#37
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But I know others have had rear brake overheating issues, for example dmichaels went to both bigger rotors and a rear brake cooling set-up.
#38
Mach 1 Member
Thread Starter
Well I finally got my DTC60 and Carbotechs XP8, I'll find out if this combo works when I run Gateway and get it my brakes sorted before running Road America
#39
Shelby GT350 Member
Yes I do believe that is what caused it for me in the past -- using sport mode. Lately I have been turning it off completely. Sometimes the TCS fights me, sometimes it has saved me . . . with it turned off, I'm on my own.
But I know others have had rear brake overheating issues, for example dmichaels went to both bigger rotors and a rear brake cooling set-up.
But I know others have had rear brake overheating issues, for example dmichaels went to both bigger rotors and a rear brake cooling set-up.
First you'll likely enjoy the DTC60's. Aggressive pad that brakes HARD. Hope you're running R comps cause that pad is far too much for street tires. I think it'll work fine with xp8's in the back
I discovered very late last season that one of my rear caliper banjo bolts was ever so slightly too long and was rubbing on the piston inside the caliper. This was causing it to not retract enough and thereby rub the pad and create excessive heat. It's fixed now and at my last event, I had no brake issues to speak of. That said, my rear brakes still get super hot and I'm glad I did the gt500 rotors and read cooling. The other aspect of the gt500 rear rotors I e noticed is they seem to resist surface cracking much more than the GT rear rotors. Likely cause they are staying cooler, but I see almost no wear and zero indications of cracking after probably 10 track days on them.
For pads, I've been impressed with my Raybestos setup front and rear. The pricing I found could not be beat either
#40
Mach 1 Member
Thread Starter
Thx dmicheals for chimming in, now I'm looking at Toyo/Nitto r compound tires :-( the list never ends...