Our biggest complaint with the 135i didn't rest with the engine but rather with the car's chassis dynamics. As one seasoned journalist put it: "It understeers like a pig." I can tell you firsthand it's nearly impossible to rotate the factory car without throwing it horribly out of shape. Couple this tendency to plow with the standard factory run-flat tires and you've got a formula for less than desirable track handling.
Madness addressed the issue with a full KW Suspension V3 coilover kit. In front, a BMW Performance brace was bolted in to tie the upper suspension together and tighten up turn-in. Adjustable camber plates were also added (set 2 degrees negative) and the front stabilizer bar replaced with a 35mm Hotchkis piece. In back, the factory bar was left in place but disconnected at one side, effectively rendering it inoperative. While we might not recommend this setup for everyday street use, it allows the rear end to be more easily unsettled, relying on the improved rigidity of the front engine to keep the chassis flat as the rear tires skate out.
The wheels and tires needed to be replaced, and Madness did it with Breyton GTS-Rs, which weigh a feathery 18 pounds each, surrounded with Continental SportContact3s. Inside those, the already beefy factory brakes were upgraded with slotted rotors, Cool Willey race pads, and stainless steel lines. The brake setup is definitely designed to be track-friendly, and you might say the tires alone could account for a 50 percent improvement in overall handling.
Inside the cabin, the controls have been altered with a BMW short shifter and sport steering wheel. A DashDAQ data display has been mounted next to the driver's A-pillar. It's a trick little piece of electronica that allows users to write their own data acquisition applications and display information with custom digital interfaces.
Having beaten the competition at its first road course event, Mehallick and the Madness crew are pretty happy with the end result. In fact, he's not even sure there's much more to be done other than replacing the suspension bushings with stiffer polyurethane units, and maybe a little bit of weight reduction. He says he's considered doing head work or playing with the turbo internals.
"I honestly don't know," Mehallick says. "Anything else could make this car a complete beast."
And as this one sits-gobs of power, improved thermal reliability, and at last, proper BMW handling characteristics-the 135i is finally something to crow about.
2008 BMW 135i
Longitudinal front engine, rear-wheel drive
3.0-liter I6, dohc, 24-valve, turbocharged. Madness cold-air intake and bypass valves, Madness front-mount intercooler, Evotech software, Titek downpipes, Madness cat-back exhaust
Six-speed manual, BMW short shifter
KW V3 coilovers, Hotchkis 35mm front sway bar, BMW Performance strut brace, camber plates
BMW Performance slotted rotors, Cool Willey pads, Madness stainless steel lines, AP Racing fluid
*Wheels And Tires
Breyton GTS-R, 8.5x18Continental ContiSportContact3, 255/35 (f), 265/35 (r)
BMW Performance carbon rear spoiler, black kidney grilles
BMW Performance steering wheel and instruments, DashDaq data display
Peak Power: 420 hpPeak Torque: 440 lb-ft*Goodspeed Performance/Madness data