The ADAC, or Allgmeiner Deutscher Automobil-Club e.V., is the largest automobile club in Europe. Founded in 1903, it provides member motorists with essentially the same services that AAA does in the U.S. But quite unlike AAA, the ADAC supports motorsports activities in Germany. The organization adheres to FIA rules, which are administered by the Deutscher Motor Sport Bund e.V., or DMSB.

In 1993, the ADAC created a grand-touring sports-car series called the ADAC GT Cup. Boris Said competed in the 1993 season, driving a Callaway Supernatural C4 coupe. Said didn’t win the championship, but his daring driving style and colorful personality made him a hit with German racing fans.

The GT Cup ended in 1997 because of dwindling interest, but 10 years later, the ADAC GT Masters series was introduced. Mirroring the FIA GT3 championship format, it combines professional and amateur drivers in one racing entry. Only cars approved by the FIA are allowed to compete.

Each year 16 one-hour races are held over eight weekends. To help keep expenses down, all but four of the events are held in Germany. Each team is required to field two cars, and the grids are typically filled with 35-40 competitors.

Each race follows the same format: two free practice sessions and one 50-minute qualifying session per driver, with eight timed laps and two one-hour races. Stop-and-go penalties are administered for overly aggressive driving and pit-stop infractions. Mandatory pit stops take place for driver changes and tire-pressure adjustments, and cars must spend a minimum of 70 seconds on each stop.

In 2012, 12 manufacturers participated in the ADAC GT Masters series, yielding a wide variety of entries. We’ve provided a short summary of most of these cars in the accompanying photo captions.

Callaway Competition has been involved with the ADAC GT Masters since 2007, and captured the Team Championship honors in 2008. Last year the team entered four Corvettes, three of which were totally revised for 2012.

Modifications included relocating the clutch and flywheel to the front of the transmission, which enabled the team to move the engine down and back 1.5 inches for better weight distribution. A new open driveshaft was then installed in place of the troublesome torque tube. Moving the powerplant aft also provided extra room in the engine compartment, allowing the team to install the radiator upright for superior cooling. New ductwork around the radiator vented air through two large openings in the hood.

The LS7 engine, meanwhile, was discarded for a non-supercharged LS9 built by APP Racing Engines. The LS9 puts out similar power when equipped with the FIA-mandated restrictor, but its smaller displacement allowed for a reduction in the mandatory minimum weight of the car.

Finally, electric power steering improved the performance and consistency of these now 5-year-old race cars.

The one change that proved troublesome was a new ECM wiring system. The No. 28 Corvette had three non-finishes due to problems with the setup, which probably cost it the championship. In spite of this handicap, the car, driven by Diego Alessi and Daniel Keilwitz, was one of the fastest in the field. The pair came to the final race in Hockenheim with a slight lead in the championship, needing to finish Second or better to win.

With only a few minutes remaining, Alessi was in second place when a Porsche drove into him at a corner. The officials blamed Alessi for the collision and gave him a 30- second penalty. This effectively ended the team’s chance of winning the championship. They finished Second in both the Team and Driver Championships, behind the winning SLS Mercedes.

The ADAC GT Masters offers fans an unrivaled opportunity to watch the world’s top sports cars compete against one another. It’s exciting to see this private Corvette team running consistently near the top of the heap.