Sports racers definitely had the speed advantage at the 2015 25 Hours of Thunderhill, but it’s getting the cars to go the distance that proves to be the tricky part. Surrounded by, in all cases, slower cars and, in most cases, heavier cars, ESR entries have to thread a narrow-eyed needle for 25 hours straight. If they have body contact with a production car, the production car always wins. Also, getting a motorcycle-derived engine and gearbox to last 25 hours is difficult.
The fastest car in qualifying was the Team One Motorsports Radical, but that team dropped out after 381 laps. Team Gryphon Racing brought a unique car, a Slovakia-built Praga R1, a carbon-fiber monocoque chassis with a closed cockpit and reliable Renault power mated to a paddle-shift gearbox. It wasn’t as fast as the Radical, but it went the distance, picking up the win in ESR and fifth overall.
“The car was great. We had a little bit of trouble with noise regulations. We were not ready for that,” said crew chief Dusan Maly. “We spent like 25 minutes to make other mufflers. We created them here. The car is in one piece, untouched. We just need to clean it.”
Team CRE/Jackson Racing/Aim Tires’ Catfish finished in second place, some 72 laps behind Gryphon Racing, not bad for a supercharged Miata-based powertrain with a lightweight body and a 36-gallon fuel tank.
“It went really well. We had a couple of issues in the beginning. We had rebuilt an axle, and it went bad again early on in the race and we went and grabbed another suspect axle that would last the rest of the time,” said driver Oscar Jackson Jr. “After that, it went according to plan. It got a little better fuel economy than we thought, especially in the rain. Once the rain hits, your throttle gets backed off so much we were getting four hours on fuel.”
Finishing in third was the Wolf Racing GB08MJ-K20, which nailed a podium spot despite a late-night engine change.
“We did an engine twice, one on Thursday and one during the race,” said crew chief Brian Roberts. “We had a couple of big issues. We had a sound issue. We kept blowing out the stainless out of the muffler. Otherwise it was pretty good. The car is awesome in the rain. It carves well in the rain.”