Quote:
Originally Posted by roastbeef
those 9668 kits are beautiful... if i ever have to look at brakes again, these are my next step. i love the thick pads. i take it they clear the 18x10.5 arc8's without a spacer?
i'm also curious to see how much of a difference in braking you notice... seems like a small upgrade, but i'd be interested in hearing your initial thoughts on it.
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They clear the ARC-8 18x10.5" fine without a spacer. (On my 10.5" rims, I always run 3mm in front because of my fat tires, but the spacer is not needed for caliper clearance.)
The 9668 caliper does clear an ARC-8 18x9.5" too, but the caliper is fairly close to the spokes. I will use a 5mm spacer with the 9.5" rims.
Of course, I'm curious about braking feel too. The literature claims that pedal feel will be better due to a stiffer caliper. I'm interested to see if I can feel that.
My old AP kit had very good stopping power, so I'm not anticipating a huge change in stopping power. Both kits have the exact same pad shape. In fact, I'm just using a new set of the exact same Cobalt Friction XR2 pads because I had a new set here (in 18mm). (Later, I'll get full 25mm pads, but that won't affect performance.) If you buy a big brake kit in a production street car, the BBK has to work within the confines of the car's brake master cylinder. This means the BBK can only squeeze with an appropriate intensity that works with the car's expectations, otherwise it will trigger ABS all the time. So, as far as overall raw power, I'm guessing the new kit will feel similar. I am hoping that pad knockback is reduced with the new kit. The Bus Stop braking zone is a great place to get a sense of that.
Comparing the rotors of the two kits, the old kit had a 368mmx36mm rotor with 72 internal cooling vanes. The new kit has a 372x34mm rotor with 84 cooling vanes. Which rotor has a better capacity for dissipating heat? Who knows. I did like the idea behind the strap drive system on the old kit and thought it worked well. I'll be curious to see how the new kit's Floating Rotor design feels.
Ultimately, where a BBK shines over an OEM brake setup is thermal capacity/heat dissipation. Heat is simply the enemy in braking. Honda Accord brakes can provide plenty of stopping power for a couple brake presses. But if you go to 100mph and brake hard to 20mph 15 times in a row, you're gonna cook those brakes something awful because they're just not made to handle that kind of heat buildup. A quality BBK with race pads will handle that same situation without any drama. My old AP Racing kit never overheated or gave me a long pedal travel at any track. That's what I loved about them. This new Radi-Cal is supposed to be the next generation of braking tech. Hopefully, it will handle the heat even better.
I think the stage is set for a good direct comparison this weekend. The new kit has the same pads in it as the old kit. And I'm quite familiar with Buttonwillow. I do have decent tires with me, so once I get all bedded in with the new rotors and pads, I'll be able to push the kit harder as the day progresses.