SMB M5

Attended my first school of the season over the weekend at Watkins Glen run by the Genessee Valley Chapter and had a great time. The school was very well run and, as always, the track is spectacular. My car ('91 3.6) is set up with a Dinan Stage 2 suspension (Konis in front), RD strut tower brace, JC chip, Nurburgring front brakes (345 mm floating rotors/4 piston calipers) and UUC EVO SS. For track days I also install BFG R1 (old style) tires on the original factory wheels. Now for some observations, comments and questions.

1. With my suspension/tire combination the car handles very well on the track. Due to the size and weight of the car, it likes the larger tracks rather than smaller tracks with more turns and less straights.

2. For this track session, I installed a modified 1 piece exhaust system which runs from the header to the tips. The exhaust does not have catalyst and employs larger pipes, so it is much more free flowing. I didn't perform any other engine modifications to complement this exhaust and the result was a substantial loss in power throughout the rpm range. The car did not have any power coming out of the corners, particularly noticeable on the uphill portions. Also, on the way to the track I blew the left rear tire (fairly new Yokohama AVS S1) while doing about 80 mph. Upon removing the tire I noticed that the inner sidewall was completely demolished and saw that the exhaust pipes are very close to that tire (< 1") so I'm wondering if the heat from the pipe led to the tire damage. Before driving on the track, I wrapped that part of the exhaust with high temperature fiber and that seemed to help. For this reason, and the noise, I will probable switch back to my stock system.

3. Prior to installing the free flow exhaust, I also felt that the car seemed to have lost some of its mid range power. I had my mechanic run some tests but nothing seemed abnormal. All cylinders had a compression of at least 185 and all valves were within spec. The air intake resonance valve was also working correctly. Installed a new fuel filter and oxygen sensor but nothing seemed to remedy the situation. Could it be the ignition wires? Chip? I'm at a loss and I don't want my mechanic experimenting at $66 per hour. Any suggestions?

4. Switched from the UUC competition short shift to the street EVO model. The shifts are smoother with longer travel however, there seems to be a lot of "play" in the shifter. When in gear, I can move the shifter at least 1" to the right in any gear (don't know about 5th). Has anyone else experienced this? (Rob?)

5. Installed Porterfield R4 compound pads on the front and Mintex racing pads on the stock rear brakes. The pads and rotors held up well, but I still think that the stock front Textar pads give better feel and braking performance. For this reason, I'll probably use the stock pads for both the street and track.

6. My brake pedal seems too low when depressed for proper downshifting (ball of foot method). When I get on the brakes, the pedal is at least 1" below the level of the gas pedal. If I try to blip the gas with the right side of my foot, I have to let up on the brake to get leverage - not a good situation. I also noticed that when at rest, the brake pedal is below the clutch pedal. Does anyone else have this problem? Has anyone adjusted their brake pedal? I will have to perform this service myself as my mechanic does not want to for liability reasons.

This list is great, keep up the good work.


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Steve B
91 M5