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I have been using their 4 piston BBK on our E46 330 since early 2016 and right off I was amazed at the difference in feel, confidence, heat resistance, and stopping power these had over good pads/fluid/lines. We've since worked with them on getting measurements and testers for a number of new fitments: FRS, C6 Corvette (above left), S197 Mustang (above right), and SN95 Mustang (AJ Hartmans's AI Mustang).
I've driven all but one of these on track already and all I can say is I don't know how I didn't move to Motorsport style calipers and rotors sooner! "Being cheap" catches up with me again, I guess? And that's what's funny. We put the Powerbrake kit on my E46 in the middle of 2016 and I'm still on the same rotors and pads, and the pads are still at 3/4 depth. And I drive like such a tool I tend to murder brakes. So in the end the total running costs per lap will be lower, even with the higher initial BBK cost.
They make a lot of different brake kits for the E46. On my 330 we used a large 4-piston caliper on a 330 mm rotor (to fit under 17" wheels). With Powerbrake's help we picked the 350mm front 6-piston brake and 350mm 4 piston rear caliper for this M3 project. This all easily fits under 18" wheels and should be more than adequate for this ~2600 pound car.
All serious cars used for track use need some sort of brake cooling, especially for the fronts. This is where you take high pressure air through an inlet, route it through tube/hose to the back of the hub, then force it into the rotor and pump it through the rotor itself. This helps keep the brake rotor cool, but also cools the hub, caliper, pads, and of course the fluid. We have made ducted brake backing plates for a number of cars and sometimes inlet duct kits as well. Super important for track use - extends the life of the pads, rotors and fluid, and could potentially save you from a crash.
First we needed to refresh the front hub bearings and install some wheel studs (I hate lug bolts). The shiny plated spindles worked great and the microscopic thickness added on the bearing surfaces didn't amount to any clearance problems with the new bearings.
On this M3 we're going to custom make backing plates to fit this Powerbrake 350mm setup that bolt to the E46 spindles both front and rear. Looking to get a 4" ducted hose for the fronts first so we will build around an 4" oval duct on the backing plate. The E46 uses a brake dust backing plate that is a funky shape and completely encircles the spindle - so to use a proper backing plate the OEM dust cover is not used.
With the 335mm tire mocked up, the calipers and rotor mounted, and the bare backing plate bolted on the spindle (above left) it was easy to see where the ducted hose flange needed to be added. This 4" oval tubing was made on the bead roller, welded up, marked, cut, and welded to the backing plate (above right).
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