a) Brakes. With the increased horsepower, stopping was now a concern. The car already had big brakes up front (tii struts, 320i hubs, 320i vented rotors, 528i calipers), so the easy upgrade was to get the rear drum brakes from a 320i. Fortunately, Ernie Bello had a suitable donor 320i, and after dodging a nest of wasps that had taken up residence in the trunk, the rear brakes (backing plates and all) were removed and installed on the M2002.
We next considered what type of shoes and pads to use. For help we contacted Larry at Carbotech Engineering (Ft. Lauderdale, FL). Larry has a lot of experience supplying SCCA cars, and was extremely helpful in sorting through all the permutations of pad compound available. For the rear drums we opted for Larry's own chelated semi-metallic material, which gives good stopping power with minimal drum wear, and is suitable for both street and track. We dropped off a set of used shoes, and Larry relined them with his material in a few days. For the front pads we decided on Hawk Blues for the track, and Repco Deluxes for the street. The Hawks' have high fade resistance, are fairly rotor-friendly once the brakes warm up, and stop like an anchor at the track. However, the combination of Hawk pads and 528 calipers now heavily biases the braking towards the front. To correct this bias, Jeff Ireland at Ireland Engineering (Duarte, CA) suggested using larger diameter (22 mm) rear wheel cyclinders from a 2800. This actually works too well, resulting in rear wheel lock-up at the slightest provocation when using street pads up front. To fine tune the bias, Jeff suggested inserting a proportioning valve in the rear brake line. We did this by rerouting the rear brake line from the master cylinder through the firewall, where it passes through and enters the driver's compartment. The brake line runs in front of the shift console, and parallel to the shift console down the passengers' side to a Tilton proportioning valve. From the valve the brake line goes through a hole in the transmission tunnel, and runs inside the tunnel, on the underside of the car, back to the tee which connects to the rear drums. The only difficulty in this installation was that in the stock configuration, the rear brake line approaches the tee from the rear of the car, and our new line approached from the front. The simple answer is to loosen the tee, and rotate it 180 degrees so that it can receive the new brake line coming from the front of the car. The real-world answer is that yes, this was done, but on a 20 year old car it involved dropping the exhaust, then the driveline, and then application of the appropriate unsuitable language before the tee would rotate. But it eventually did rotate, and we now have a brake system that is equal to the M3 horsepower, and is adjustable for bias to compensate when we switch from street to track pads.
We also designed some cooling ducts to help the front brakes out in case of over-zealous braking at the track. We cut holes in the front airdam and installed a pair of brake ducts (from Pegasus Racing), and corresponding holes were cut in the valence (which is beginning to rust anyway) behind the air dam. Ducting (3" diameter; Racer Wholesale) runs through the valence and over the lower control arm (held in place with zip ties) and ends pointing at the inside of the vented rotors (the dust shields have been removed from the front hub). At this point we realized that the tii struts have duplicate ears for bolting on the calipers, and while the rear set were used to mount the calipers, the front set were blocking about half of the possible cooling airflow into the rotor. This was rectified at Ernie Bello's tire store (West Palm Beach, FL), where judicious use of an air grinding wheel removed the offending mounting ears from the front of the struts. This really opened up the cooling path for the rotors. This braking combination provides eye-opening stopping power and no cooling problems have been encountered, even at tracks like Sebring (Sebring, FL), which is notoriously hard on brakes.
b) Suspension. The car came to us with Bilstein heavy duty shocks, and Suspension Techniques springs and antisway bars. To get more negative camber and tailor the front ride height, a set of adjustable camber plates with coilovers from Ireland Engineering (Duarte, CA) were installed. We removed the strut housing, cut off the old spring perch, and welded on the collar used to position the threaded tube for the coilovers. The camber plates required a bit of cutting to allow full travel of the adjustable bearing. The only problem with the installation was that the coilovers were really noisy on the street, making lots of moaning and clanking sounds. This was corrected by getting newer (closer tolerance) spherical bearings from Ireland Engineering, and by cutting pads from neoprene rubber for the upper and lower spring perches. Now it is as quiet as stock, with easy adjustability. We set the car for -2.5 degrees of camber, and have left it there for street as well as track. So far, no unusual wear on the tires has been observed. The original 250 lb springs that came with the coilovers were too harsh for the street, and overpowered the Bilstein heavy duty shocks, resulting in a slight bounce at each bump. To remedy the jarring and bouncing, a set of 200 lb springs were substituted, and these have proven to be just the ticket for the street-stiffer than the Suspension Technique springs, but not too harsh for commuting. In the back, Koni adjustable shocks were substituted for the Bilsteins, to allow some tuning to match the front.
Suspension update (4/98): After a year of driving, I was noticing that the front shocks would bottom out going over bumps that should have had no effect. It turns out that the 200 lb springs were too short, and the springs were collapsing at rest so that only one or two coils were available for absorbing bumps. I decided to go back to the 250 lb springs, and replaced the front Bilstein Heavy Duty shocks with the stiffer Sport models, to match the stiffer springs. I also replaced the rear Suspension Techniques springs with a pair of stiffer springs from Ireland Engineering, and set the rear Koni Shocks to their stiffest setting. There is noticeable improvement in the ride, and the car no longer bottoms out on bumps. Additionally, the Bilstein Sports don't seem as bad (rough) on the street as I had been led to believe. For me this has been a marvelous upgrade, and I can't wait to test the new setup out on the track!
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