25 Hours of Thunderhill

California, USA

After completing his maiden run at the 25 Hours of Thunderhill, the summation offered by 2012 World Touring Car Champion Rob Huff could be the most accurate description of the event to date.

“I’ve never done such a random race before where I’ve not exactly known everything I was racing,” he said with a laugh. “Normally, I can name pretty much everything that I’m up against, but this was the one weekend where there were four or five very imaginative pieces of kit and I had no idea what they were. And I’m not even sure the people that owned them had a clue what they were…”

The Californian endurance race, held two hours north of San Francisco, celebrated its 11th running in style on December 7-8. Huff’s factory-supported Rotek Racing Audi TT RS took outright victory, believed to be the first major enduro win for a modern front-wheel-drive chassis.

Huff, car owner Roland Pritzker, Jeff Altenburg, Kevin Gleason and Robb Holland completed 705 laps of the 3-mile, 15-turn Thunderhill road course amid freezing temperatures and occasional sprinklings of snow. The winner finished 28 laps ahead of Barrett Racing’s Porsche GT3 and 30 laps clear of Radical West Racing’s Radical SR3.

The charmingly odd pro-am event is a kindly cousin to its more famous 24-hour counterparts at the Nürburgring and Dubai, embracing multi-class racing and comically oversubscribed grids, yet the execution of the 25 Hours differs significantly once the green flag waves.

Where the ’Ring and Dubai tend to feature recognisable cars that race under guidelines conforming to the thinnest strands of logic and tradition, the 25 Hours, sanctioned by the National Auto Sport Association, does the opposite, asking a paddock filled with misfit toys and GT3 machinery alike to wage battle without contrived rules or in-race performance balancing. It’s delightfully old school, in that sense.

Thunderhill has become one of the few events where amateurs can try their hand at proper endurance racing: by welcoming some familiar names from the sport’s past and present to take part, the contest can, at times, draw more attention for who and what has been entered than the race itself.

“This really is one of the last races of its kind,” said former Ganassi Racing Indycar driver Memo Gidley, who won the race overall in 2012. “Where else can a guy build something in his garage, just for this race? If it meets one of a hundred different categories, he’s out there racing with his buddies against factory teams and pro drivers. It’s kinda crazy. We race hard and there are some really fast cars. Some aren’t, but I love it.”

The lap record went to two-time Indy 500 winner Al Unser Jr, who made his return to racing behind the wheel of the pole-sitting Wolf GB08S. The open-wheel legend led before electrical issues intervened, and hopes the 25 Hours will lead to more opportunities in 2014.

“The race was just incredible to experience,” he said. “I’ve won the Daytona 24 Hours before and done a good amount of endurance racing, but doing it at this level, with so many cars to dodge and so much of the race run in the dark… It makes you question how much you want to be out there, and I couldn’t get enough of it.”

Unser shared the track with ex-TWR Jaguar pilot and 1996 Le Mans winner Davy Jones, former factory Corvette Racing drivers Kelly Collins and Paul Edwards, Japanese Super GT driver Naoki Hattori, Formula D drifting champion Dai Yoshihara, ALMS and Grand-Am prototype regulars Anthony Lazzaro, Brian and Burt Frisselle, Michael Valiante and Mark Wilkins, and multiple SCCA champion Randy Pobst, along with other notables.

Japanese marques provided most works entries in 2013, with three turbodiesel Mazda 6s entered by Mazdaspeed, two Honda Research-run Acura ILXs and a lone Lexus IS F battling for space on the rollercoaster circuit. The remainder of the 57-car grid read like a gift to sports car anoraks.

Standard fare items like an Audi R8 LMS and a few different Porsche Cup cars represented the strongest selection of GT entries, while a healthy blend of prototypes – from Radicals to the Wolf to a Superlite SLC via Davidson Racing’s SLC derivative featuring a 6-litre Ford V8 and gearbox taken from a Panoz LMP-1 Roadster S – set the pace throughout the event.

The 25 Hours generated its usual automotive humour, with a NASCAR Truck, a twin-engined Mini, a Namazu CRE-01R (reportedly a custom-bodied Mazda MX-5), and two butchered BMW E30s of questionable provenance (sporting periscope exhausts and aluminium coachwork that clearly drew inspiration from the Mad Max movies) contributing to the Wacky Races vibe.

Despite the vast vehicular divide, Huff didn’t hesitate when asked where he wants to spend the first weekend in December 2014.

“I have to come back next year to defend my title,” he said. “The level of competition there was impressive, no matter what car or class. Everyone was there to win and have fun. And that’s what I love about stepping away from the full professional heights of motor sport. You really get that element of a positive atmosphere – the ambience of pure racing. Everywhere you walked, people were smiling. It’s a lovely way to end the season.” Marshall Pruett