Hey Guys, Planing for the next set of rear pads, as most of my experience is from r50 land I thought I would see what is norm in R53 land. In the r50 I found axxis ULT or carbotech ax6 to work fine the rear. However, moving to the r53 quickly resulted in a need for better heat sinks up front. So I have poly B on 11.75x1 on the front. All stock in the rear for now, but I am wondering if something like a ULT or OEM pad would result is some funny bias issues when I get up to temp as I am going much faster now. I know the rear's basically do nothing but don't want to end up with faded rears or dramatically different friction profiles and freak out the abs So wanted to check if an OEM/autox pad like a ULT would still be fine or the rear, or if you track r53 folks found it necessary to also increase the pad level on the back as well as the front. And if you recommend all out track pads on the rear what would match my poly b pads reasonably well?
Also if anyone has rear temps or delta between front and rear temps that could be useful too i know my fronts get over 1100f but no idea on the rears. If they stay below 900 i think a mid range pad could be a decent call and extend rotor life...
..... I had some ideas, but I think you're already on to them. You might check with some of the race teams and see what works for them.
Thanks, I have been bugging some folks via email I am starting to think something with a wide temp range could carry me through getting some temperature data. Like a DTC-30, HT-10 or XP8. What I am thinking about is that the rears shouldn't get as hot, so I might not get a 'real' track pad up to temp. But as I have vented rotors on the front and the rears are solid do them end up the same temp-wise...? The other side of the argument being getting a 900F pad and ending up with 1200F temps on the rear would be less than ideal. In the 900F range on the r50 I liked the ULT so would probably get those if 900F level pads is the right way to go. Don't really know about the high temp rear pads, I do like the polys on the cars I have tried them on but nothing to fit oem rears... Anyone have thoughts between XP8, HT-10, DTC-30, etc for the rear? Don't how I missed this in my search: http://www.motoringalliance.com/forums/track-days-hpde-s/1385-rear-brake-pad-advice.html#axzz1wH7aXav6 But looks like nothing concrete was decided, though I can added RS-4 to the list to think about... lol
I run XP8's on the rear with good results and no issues. Have been limited to south course at VIR, where speeds aren't as high as some places but it's still hell on brakes with lots of braking per lap and little cool down time. I don't think I ever recorded rear brake temps, unfortunately, as the 8's were doing it for me, I didn't study it any further.
If you run with the DCS on the rear brakes will be used a lot more and will be hotter, so that's a factor.
Hey Blimey, thanks for the info, I see (stalker-ed your garage) you have some different pads for street and autoX do you change the rears as well or do you leave the XP8s on and just change the front? I don't mind swapping the fronts as they are easy but would like to avoid swapping rears if I can. Any trouble using them at low speed like at an autoX or to/from events? How different is the XP8 in feel compared to the AX6? i recall preferring the ULT characteristics to the AX6, but assume the XP8 would feel quite different as it is for different use. Good point on the DSC (it varies depending on how well i know the track, conditions etc) Thanks for the input!
Back when I ran Carbotechs, I used to run XP-12s in front and XP-8's in the rear. I didn't like how the car would squirm at the end of a long braking zone if you got on the brakes too hard. Now I run Performance Friction 01 pads, front and rear, and I can get on the brakes hard without the rear end getting loose. But the heat range split is more a function of braking style. If you get on the brakes smooth and slow, the rears will do more work because the weight transfer to the front is slower, so you want a bigger split to keep the bias forward. I'm not sure if my theories are 100% correct, but I know with my style of driving I've benefited from running the same pads front and rear.
As Ben suggests, a lot of this varies based on driving / braking style, track, conditions, etc. What works for one person may suck for another. That said - the AX6 and XP8 are very different pads. AX6- huge amount of bite, hot or cold, like throwing out a boat anchor. Which is great for autocross (when they're more likely to be cold than hot) and for mountain twisties (ditto). But they do have good heat tolerance - I've done crazy sub-16 minute runs on the Dragon and boiled fresh fluid... but not overheated the AX6 pads. Downsides of these pads - they are CRAZY noisy (like a subway train braking) and they wear much quicker than the bobcats. Fine for how I use them, but would be too loud and too short lived for daily driver pads. And super dusty. XP8- need to warm up to really bite. They're not "slick" when cold, but you definitely have noticeably less bite when cold than when hot. Probably more total heat tolerance than the AX6. Mine are probably a little less noisy than the AX6, but still noisy. Balance well with my XP12's on the front (with R56 front calipers). I run Bobcats daily, put on the AX6's when I'm headed to the mountains for a weekend or a crazy day run, and put on the XP8/12's when headed to the track. The rears are more of a pain than the fronts... but I've gotten used to it, and have learned to swap the rears pretty quickly.
FYI: Some rear oem caliper data I am chewing over... (effective temp range according to manufacturer): Carbotech XP8 (~$160) 200-1350°F Hawk HT-10 (~$170) 300-1300°F Porterfield R4 (~$130) 450-1200°F Performance Friction 97 (~$170) 250-anyone know???°F Raybestos ST-43 (~$220) ???-1200°F Hawk DTC-30 (~$140) 100-1200°F Carbotech AX6 (~$150) 50-1100°F Axxis ULT (~$100) 50-932°F I guess my preference would be something that doesn't have massive torque throwing off bias, could take whatever my temps are, and wouldn't destroy my rotors driving to/from events, autoX, etc when I have the BP-20s instead of the Poly Bs on the front. Luckily, I don't use the mini for DD duties. So many things to consider :crazy:
Run XP8s all the time on the rear and change out the fronts for track... How you brake, when you brake, how long you brake and when and how you come off the brakes are things to be considered....and one set up might not be best at all tracks...same with corners and straights. Guess what I'm trying to say is that brake choice is a compromise. Try some different combos and see what compromise fits your driving abilities and your cars performance envelope... Good luck and enjoy the ride!!
Didn't see everyone replies before I posted the temp data! Those Performance Frictions sound very inviting as the rear end squirms I get with the BP-20/AX6 combo along with a couple other things make me hesitant on the Poly B/XP8, although their temp range looks about right and are unrelated pads... To be honest I wasn't even considering the pad choice as a potential cause of the squirm…. I didn’t see the 01s listed for the rear oem caliper but I haven't looked hard yet. I don't expect trouble finding them in the wilwood pad shape for the front. Would you call them safe to drive to and from the track or are they very slick cold and should be swapped in the paddock? Next time around I will likely get matching front and rear, I just ending up out of whack a bit going through desynchronized car and caliper changes. Thanks for the input on the AX6 verusus XP8, I have also boiled fluid using the AX6 :cornut: their good heat tolerance is one of the reasons I thought to consider mid-level pads on the rear, but if the XP8 are just as streetable… Ouchie my brain, love eveyone's thoughts! Like minimark said this is a really tough subject without data on my car… Guess I just found a excuse to sign up for even more track days :ihih:
Safe to drive to and from the track, yes. Just leave a little extra stopping room. Good luck finding the rear pads. They exist, but I'm not sure they made any new ones this year. Another pad compound to check out is the Hawk DTC 60, part number HB445G.610 for the rears.
Yeah, I have only found one somewhat dodgy looking place for the PF01. My usual places have the PF97 in stock and I sent over the part number for the PF01, will see what they say. I have heard the new Hawk pads aren't as on/off as the old ones which is good..... looks like lots of people have the DTC 30/60/70 in stock for the rear and the wilwood shape i use on the front.
Looks like the poll is basically dead even, so I will just need to measure temps. I maybe looking for the impossible but is there a way of measuring brake temps that isn't a $75 jar of paint? I found a jar for $50 a while ago, do the caliper strips work just as well or have a different purpose?
Caliper strips basically measure fluid temps, while rotor paint measures rotor temps. The fluid in the caliper is going to be as hot as the caliper.
Racers Wholesale is about the least expensive I could find... Brake Temperature Paint - Genesis Technologies Brake Temp Paint I want to see that picture Blimey or we can't call you a real man.