When I first looked at the brake caliper mounting brackets, I honestly thought Jared Holstein had whittled the damn things out of an old chocolate bar. Using candy as a structural component of your car's most fundamental safety system is probably a bad idea, but I installed them anyway. Such is the sex appeal of four-piston calipers.
The brakes were an early Fastbrakes kit that paired Wilwood calipers with an 11.8-inch rotor on an aluminum mounting hat. The brackets turned out to be steel with a chocolaty coating of rusty scale and CV joint grease. They also happened to have just been outlawed in NASA's SE-R Cup series. That made the NX2000 brakes on my SE-R the stoppers of choice and rendered the Wilwoods worthless for Jared's race car which, ironically, was virtually worthless itself.
So we swapped and I strutted out into the street with my fancy new stoppers only to have the pedal sink nearly to the floor in my first panicked approach to a stop sign. Turns out the NX2000 brake system I had just swapped out had a 7/8-inch master cylinder, which is barely big enough for its 54mm single-piston calipers. Pushing four 34mm pistons takes about 60 percent more fluid, and that's just enough so that the master cylinder will bottom out before the brakes do anything decisive.
The original Fastbrakes kit used 11.8-inch rotors, which don't quite fit with our new 15-inch Motegi Trak Lites.
At the time, Jared and I shared a gritty industrial rental in a rough, third-world corner of Orange County. In truth, our 'race shop' was nothing more than 1200 square feet of filth and disarray, but in it we could find a solution to nearly any automotive problem. Lying on its side, jammed between three quarters of a Datsun 510 and a set of buckets Jared used as toolboxes, I had the skeletal remains of an old experiment. The floorpan, firewall, and several boxes of parts that had once been the 14.3-second B15 Sentra we used in the SCC Technical Assistance Program.
In one of those boxes was an almost-new 15/16-inch B15 master cylinder, just big enough to solve the problem. Voila, suddenly, I had a firm pedal and a car that locked its front brakes at the mere suggestion of deceleration.
Apparently, the Wilwoods offered up a fair bit more brake torque than the NX2000 stoppers they replaced, suddenly throwing off brake balance. Again, the rotting carcass of the world's fastest potato offered up the solution, donating its rear brakes to the cause. Both the B13 and B15 use the same size rear caliper, so the clamping force on the rotor should be the same, but the B15's larger rotor will make more torque from that clamping force, hopefully fixing the front-to-rear brake balance.
This was not so simple a swap, though. The B15's wheels have a 4x114.3 bolt pattern while the B13 used 4x100. That meant I had to re-drill the B15 rotors, or, more accurately, file each hole 7.15mm by hand.
The first time you test-fit the wheels, make sure the brake line can't touch the wheel under any condition.
The B15's beam axle rear suspension also puts the calipers on the rear of the rotor, while the B13s are on the front. They're still interchangeable, but you have to swap them left to right so the bleed screw stays on top when the calipers flip to the front. Oh, and the mounting bracket for the parking brake cable is in absolutely the wrong place and there isn't a damn thing you can do about it, except for leaving the car in gear when you park. Surprisingly, this assortment of brake junk worked well enough that I was willing, in my laziness, to forgo a functional parking brake for several years. It was only as I installed the featherweight 15-inch Motegi Trak Lite wheels, introduced in the last installment, that a real solution was needed.
Turns out the brakes didn't fit inside the new wheels. Desperate to make the photo shoot, I made them fit by spacing the wheels out 5mm and slightly re-profiling the right-hand caliper with a file. I don't recommend this solution.
Before taking on the B15 SE-R at the track, we'd need the wheels and brakes to get along a little better. SE-R Cup rules have changed since this combination was first cobbled together, and Fastbrakes Wilwoods are again the brake of choice. But the new brakes fit inside 15-inch wheels.