With Project 325's reliability addressed in Part 2, the first performance modification was serious braking ability. Over the last few years, that has gradually come to mean big brakes for most enthusiasts: massive, 13-in. rotors (or larger) with four-piston fixed calipers, requiring 17- or 18-in. wheels. With companies lining up to provide such systems, I stuck to this project's mission of attainability and selected performance components designed to work with stock-size brakes. Big brakes work great, but the goal for this phase was to see how far one could get without that significant investment. Serious pads and fluid, braided stainless-steel lines and ducting to force cooling air to the front discs were the heart of the plan. Unfortunately, the ducting was back-ordered and didn't arrive in time to meet my deadline, but I'm pleased with the performance I've seen so far.
The trickest thing I did was swap on the rear brakes from an E36 328i Convertible. They are the same diameter as the 325 brakes and use the same pads, parking brake shoes, backing plates, brake lines and all other hardware. It's a direct bolt-on swap of the calipers, brackets and rotor. The 328ic rotor is thicker and vented, helping cooling, and the caliper has a larger piston, moving brake bias rearward just about the right amount for optimum stopping performance. This plan was hatched in consultation with Stoptech's Steve Ruiz and Centric Parts Inc. engineers. Bavarian Auto Wrecking provided used calipers as well as a replacement for a flaky headlight switch, both of which have worked perfectly.
Steve Ruiz has often mentioned the Pagid 4-2-1 compound as a "cheater" pad that offers superb characteristics, combining overall friendliness with awesome performance numbers in brake system tests. The only real downside is cost and the fact that it likes to be warmed up before being asked to work hard. Pagid reported that the 4-2-1 compound is stable up to 1,000F and loses some friction above that but does not fade until 1,200F. Pagid uses the same description for Sport street pads as for the 4-2-1 racing compound, because in many cases, they are the same. Street pads include anti-squeal shims and other required extras; racing pads do not. Pagid referred me to Bavarian Autosport, one of its warehousing distributors and a well-rounded BMW performance and accessories supplier in its own right, to provide front and rear Pagid Sport pads. Bavarian Autosport also sent new wear sensors, which should always be replaced if they have made contact with the disc.
Stoptech began assembling street-legal braided stainless brake lines to include in its big brake kits, and it was a natural step to expand the brake line activity to include stock-compatible upgrade lines. Sister magazine Sport Compact Car was happy with Stoptech lines on one of its projects, so I tried a set on Project 325.