Pocono Raceway, October 2000

I spent the weekend at a BMW driving event at Pocono Raceway. I installed a new set of Porterfield R4 race pads in front, and Kerr Friction race pads from Paul Weston in the rear. The car is the eS2, a "virtual" S2 Audi, weighing about 3200 lb. The engine is a chipped 20vt, so about 270HP. The brakes are BIRA System 2. A Tilton proportioning valve is set for full rear bias.

The track: They use a 1.4 mile infield course, which uses turn 3 (I think) of the raceway tri-oval as the "straight." My speed at the end of the straight was 115-120mph. Turn one is a very high speed right-hander, just a brush on the brakes to settle the car. Then there is just enough time to get the car straight before braking very hard for turn 2, a hard, late apex right. There are other moderate braking zones which are more quick stabs than sustained heavy slowing. The back straight was a legal passing zone, but so short that if you got the pass, you'd go inside, and have to do the left-hander at the end way off line, in which case heavy braking was necessary.

Weather: It was cold, low forties on Saturday, and the thirties on Sunday when we actually had light snow flurries. I bought a bottle of Performance Friction temp paint, and daubed the hats of all four rotors hoping to get some temp data. But the paint stayed it's native orange, meaning, I think, that the hats never got above 260F.

Impressions: The shop bedded the pads with a few 100-0 stops. I drove on them for a day. This was my first experience with race pads, and I was totally unprepared for their effect. They are far grippier (more bite) than my street pads when hot, about even when cold. The difference between the R4 and the stock pads was greater than the difference between the stock brakes and the bira setup. Initial bite was far more dramatic, and I seem to be able to activate ABS with far less pedal effort.

On the track, the pads seemed at first very grippy, locking up the front left wheel first. (I believe they were still bedding in) After they warmed up, they settled into an even predictability that was a joy to experience. At the one major braking box, I felt I was braking as late as any of the lighter, more prepared cars (the best being E30 M3s, and a slightly prepared late RX7) I was sharing the car with my wife, so it was doing essentially four 40-minute run groups per day, and there was zero evidence of fade. My wife also commented on how the brakes required less effort. I would guess I used up about 15% of the compound.

On the street, I don't yet have enough miles to make many judgments. They are noisy, but it is more of a steady high pitched squeak than a squeal. If it gets no louder I can live with it. So far I don't see much dust accumulating, but on the track I find it mostly gets blown away anyhow with my setup. They are definitely not as effective when stone cold as they are when warmed up. The "eager" feel comes back as they get warm.

More on the R4 as I gather street experience. Since this is my first experience ever with race pads, I don't have much of a reference point. But compared to the street pads, these have much more initial bite, albeit after some warm up, the feeling of more absolute stopping power. They squeak (not squeal), but nothing I can't live with. I'll keep an eye on the dust situation. They seem to wear fine, although weather conditions couldn't have been friendlier for brakes.