GT classes take Trans-Am back to its production-based roots

Images by Richard S. James

GT classes take Trans-Am back to its production-based roots

Trans Am

GT classes take Trans-Am back to its production-based roots


With today’s tubeframe chassis and fiberglass and carbon bodies that mostly resemble street cars, it’s easy to forget that the Trans-Am Series presented by Pirelli’s roots are in production-based cars. Those that recall or have studied the history know that the famed Penske Camaros, AAR Barracudas, Bud Moore Mustangs and Brumos Porsches all started life on a manufacturer assembly line. In fact, it wasn’t until the ’80s that the tubeframe revolution began. So it should be no surprise that the series honors its past by including classes for production-based classes today.

The Super GT and GT classes, formerly TA3 and TA4, are for racers based on production cars. Corvettes, Porsches, Mustangs and more compete regularly alongside the monsters in the Trans-Am category. At Road Atlanta, in fact, the Super GT cars led much of the race on a wet track until it began to dry out. And the beauty of those classes is that the eligibility of machinery is sufficiently broad that there are hundred of race cars that could join the series at any of its weekends, either for a one-off, a regional championship or the full national championship.

Tom Herb’s Porsche 991 GT3 Cup.

“We recognize as the series was created in 1966, it was based on true manufacturer cars that had been customized for racing,” says Trans Am President John Clagett. “The GT classes pay homage to the origins of the Trans-Am Series. We’re trying to create the happiest medium of where we believe competitors that might be interested in Trans-Am will not have to do wholesale changes to their cars to come from SCCA or NASA club racing. We want to create an opportunity for people to come to the series, understand it, enjoy it and then potentially look to a future where they could be in a TA2 or even a Trans-Am car.”

The Production classes allow many car owners the opportunity to run a longer race than they might get in a club event, running a higher profile weekend. Super GT cars might come from SCCA GT-2 or Porsche Club of America/Porsche Owners Club competition, for example; the Porsche 991.1 GT3 Cup car is kind of the baseline car for the class. As series technical director Aaron Coalwell explains it, not only do those classes fit well, but also ex-pro-series cars from World Challenge GT or Grand-Am/IMSA Grand Sport, pre-2014 GT3 cars and even current cars built to GT4 specs but running unrestricted. For GT, a top-level Touring 1 car is a good fit, as are former World Challenge GTS cars and current GT4 machinery. It sounds like a wide range of stuff to manage, and it does get tricky, but Coalwell says it’s made a bit easier nowadays by access to lots of data.

“In both classes, cars are required to submit a declaration sheet and a dyno sheet, showing the power and torque, what their weight is, what gear ratios they’re running, etc.,” explains Coalwell. “I start out looking at horsepower and torque and weight, but you also have to take into account the natural abilities of the car. The Viper ACR is much heavier, but it has more power compared to the Porsche, which is lighter and has less power. But you can’t look at only their power-to-weight ratios; they’re not identical because you have to look at, say, rear-engine Porsche vs. front-engine Viper or Corvette.

“I also take into account, somewhat, who’s currently driving the car; we’ll give some variance based on driver skill and how they’re doing with that package. It’s definitely not a set-in-stone formula and we deal with every car on a case-by-case basis.”

Lee Saunders’ SGT Viper goes through tech.

The series is trying to make racing, and in particular racing in the GT classes, as easy as possible. And that goes way beyond making it so cars can cross over from other series and sanctioning bodies. It also includes mini-championships — drivers in SGT GT can compete for the North or South cups in addition to the national or West series. And it goes so far as to give teams and drivers help when necessary.

“Trans-Am welcomes a wide range of driver skill and team capabilities. We make it easy and customer friendly to come over and race, and we get a lot of comments when people do come and try it about how much they enjoy their weekend because of how easy we make it. We’re trying to get people to realize it’s not such a huge step to come and run a Trans-Am race and build up your skill. We have a staff driving coach [Terry Earwood] and myself and the other staff, we’re willing to help with the teams. If you’re struggling with something on the car, we can give advice,” Coalwell says.

Dirk Leuenberger had no previous racing experience before he decided to go racing in Trans-Am with his Viper ACRX. He’d been tracking various Vipers for years when the opportunity to buy the car came about; he wanted it, but had no idea what he was going to do with it. The friend who alerted him to it said the car is eligible to run Trans-Am, and the wheels started turning.

“I grew up watching Trans-Am in the ’60s … it was NASCAR, Indy car or Trans-Am that my dad had on television on the weekends,” says Leuenberger. “So I knew Trans-Am and had always known of Donohue and Gurney and Shelby, and I thought, ‘Yeah, Trans-Am is a great brand, a great series.’ But i didn’t know much about the racing community.”

Leuenberger hooked up with Cindi Lux and Lux Performance, which had been racing Vipers in the series for several years, got trained and licensed, and now races Super GT in the series, recently winning the race at Laguna Seca. He joins racers such as Mark Boden, Lee Saunders and Brian Kleeman in the class. The series would like to grow the class further, and is encouraging people and race shops to build cars and come race.

Dirk Leuenberger’s Viper ACRX.

“We’re trying to bring the individual development and ingenuity back in,” says Coalwell. “So in addition to the factory-built cars that are welcome, we also like to encourage race shops, if they have a car package that they have developed — say they specialize in Corvettes or Porsches or whatever — they can develop their own package and bring it to Trans-Am, and they can sell those parts. We’re really trying to encourage the race shops to develop cars like they used to develop and build before all the series went to factory-built, homologated cars.”