Quote:
Originally Posted by WC-BRZ
Are you able to share some more details regarding the noise from the AP Sprint kit? I thought noise was mostly a function of race compound brake pads more than anything else.
The only other complaint I've heard about the AP Sprint kit is that not having any dust boots makes it an issue for year-round driving and likely requires frequent servicing. When you took off your kit, what did the pistons look like?
Anyway, not familiar with the noise so please share your experience  |
Well, personally, I was only sort of bothered by it. It definitely has a bit of a cringe factor especially when folks make a comment at a stop light or a parking lot meet. But, let me be perfectly straight, they are fucking loud. Like, really loud. Like loud enough that if you were straight piped it wouldn't matter because you'd hear your brakes over your exhaust loud. I upgraded because I needed more thermal mass which needed a larger rotor, but as a part of the process I wanted to go quieter (especially since my girlfriend hates my car and my neighbors hate me because of my brakes).
While it is true that generally its the pad compound selected and the quality of bedding process that determines noise, that's not true for J-hooked rotors. AP Racing does offer some BBKs which use modified slots rather than J-hooks, but J-hooks are the only option for kits sold in the US from Essex. J-hooks themselves are the primary factory in the vast majority of the brake noise originating from the AP Racing Sprint BBK. There's a few other things which factor into it, but it's not worth delving into. Main thing to understand is that it doesn't matter which pad compound you choose, the AP Racing Sprint BBK is loud... even on Carbotech 1521s and Ferodo DS2500 as a few "street" compounds I tried. I got used to the noise personally, but I'm not going to sugar-coat how bad it is. The folks at the garage I rent a lift from (you can see it in some photos) would know I was coming from 3 blocks away due to the stop light I always had to stop at and then from me braking to make the entry drive. I was always "pre-announced" anywhere I went.
Regarding the absence of a dust boot and serviceability, it's not really a problem to be honest. I live in South Texas, there's no salt on the roads, and I wash my car almost weekly. Basically it's a non-issue for me. While they are dirty coming off, after cleaning them off with brake clean it's clear the pistons are in good operational condition after pretty hard use and there is not even a need to rebuild the calipers yet. Consider that race calipers are usually built with the expectation of being rebuilt every season (roughly every year), so I'm actually pretty impressed with how well the AP Racing calipers held up. The two-piece rotor design also significantly assists in reducing unsprung mass, and the J-hooks make it have massive initial bite, so there's some advantages. But all-in-all, for my purposes it wasn't quite cutting the mustard. For someone doing significant amounts of AutoX in a class which allows a BBK this would be a great BBK to pair with some Carbotech AX6 or similar, but for serious road track use the Sprint BBK doesn't have enough thermal mass.
That's my 2 cents, after nearly 30 events on a Sprint BBK.