The San Francisco based Porsche Racing Club writes their 911 "Spec" class rules for reliability and closely matched performance. The class runs primarily with NASA events and uses Pre-1990 911 chassis. The spec engine is the 3.0 liter, but 2.7 and 3.2 versions are allowed with modifications to the induction systems that keeps everyone close to a 250 horsepower target. The rules address cams, bore, stroke, rods, heads and other parts for the three different engine sizes, and all motors must run a single spark plug per cylinder. Gearboxes are 915 units with prescribed ratios and suspension rules (keeping it mostly stock) are strict. Brake caliper, pad |
and rotor combinations are free as long as they fit in the 16" wheels. All competitors must run on the same Toyo RA1 tires, 91 octane pump gas, and the resulting battles at the front of the grid are usually close. It's interesting to see home-built and maintained 911 racers going against prep-shop built and run cars with plenty of success. Tony said, "I love watching those cars, it reminds me of watching the IROC RSR's back in the day." These 911 racers know how to keep the starts interesting too. After qualifying, the top six draw numbers from a hat to determine their starting position amongst themselves. That keeps |
things honest for sure, as does the "Trophy weight" penalty assigned to the top three cars - 75lbs for a win, 50 for second and 25 for third. The minimum weight (with driver) is 2400lbs, and the maximum "trophy weight" can't exceed 2550. As soon as a driver doesn't finish on the podium, they can lose 25lbs per non-podium finish. Sounds like fun!
above left to right: 911 Spec cars at Thunderhill, Jim Hamilton's 911 racer, and the original IROC series. |
