I was going to mention the Porterfield R4 as I've been using them for both track and street and am rather happy with the performance. But, since they are not yet available in you application...
It's not that I hated it. I have been having some brake overheating issues and think at least some of it might be attributed to the rear pads. The ST-43's are a pretty aggressive front pad, and my thought is that the XP-8 is not as aggressive. If I am thinking about this correctly, when you apply the brakes the ST-43's have a larger coefficient of friction causing them to do a disproportionally larger amount of braking than the XP-8's.
Some of this is pure conjecture and some is based off the wear that I am seeing on my rear pads. I know rear pads don't really wear that much, but I have run more than 8 DE's, plus all my street driving on the rear pads, and they still look brand new.
In a shotgun approach to alleviate the boiling of brake fluid, this is one of the steps I am trying to eliminate as a possible issue. Dr. Mike and many others are running the TSW BDM ST-43/R4 combo and seem very happy with it.
On a side note, I just called PorterField and they indicated that they do make the R4 for the R56. They just don't have it listed on their site. I will post back once I actually have them in hand and verify they fit.
I had been running EBC Yellows, but had bad inner pad wear with the last set. I think they screwed up when boxing up the set of pads. This never happened before and I've been through at least a half dozen sets. I was getting about 8 DE weekends.
I have a set of Porterfield R4 on the rears now, and a set of HP+ in the track box to try after that.
Remember the brakes should work 70% on the front 30% on the back. I split my pads one heat range front to rear. XP12s in the front XP10 in the back. On the E30s we split 2 ranges because the rear rotors dont get hot enough. Track pads dont "work" untill they are up to temp. If your not smearing your pads on the rear you may want to try going down a heat range to an AX6. This will put the rotor/pad more in the correct temp range for your driving and give more bite on the rear.
Also brake temps change with air temp too. You may need to change heat ranges for winter track days because the rotors dont stay as hot as long in the cold weather.
i agree that the front brakes are doing most of the work. i have also discovered, however, that my rear brakes get hotter than my fronts. i run a TCE/willwood 13" front rotor w/ poly h pads, TCE rear rotors w/ R4 pads. solid vs. vented rotors are the culprit, i believe. i might go to a vented rear rotor on the racecar.
