Introduced midway through the 1991 IMSA GTP season, the Toyota AAR Eagle Mk III still managed a pair of wins in its debut year. By 1993, the car had become all-conquering, winning every IMSA GTP race in which it was entered. Faster than the legendary Porsche 917/30 Can-Am car, the AAR Eagle Mk III’s 1:33.875 lap record at Daytona International Speedway’s infield road course stood for nearly 26 years, but on January 6, a 2019 Mazda RT24-P driven by Oliver Jarvis set a new benchmark, lapping the track in 1:33.398 during the 2019 “Roar Before the 24” weekend.
Officially, the “Roar Before the 24” is a test session and not a sanctioned race, so any results are unofficial. The qualifying time set by P.J. Jones – son of Parnelli Jones – in the AAR Eagle Mk III ahead of the 1993 24 Hours of Daytona still stands as the official record, but the Mazda prototypes have sent a clear message – the glory days of racing series, like Can-Am and IMSA GTP, may not be over just yet.
During its heyday, Can-Am was among the fastest and least restrictive motorsport series on the planet. Under the FIA’s Group 7 rules, engine size was unlimited, and forced induction in the form of turbocharging or supercharging was permitted. Cars needed bodywork enclosing the wheels (and, oddly enough, an unused passenger seat), but otherwise designers were given free rein to innovate. Among the most memorable cars of the era was the Chaparral 2J, which used a small snowmobile engine to power a pair of fans mounted in the car’s rear, creating a low pressure area beneath the car for added grip with no speed-limiting drag. Successfully raced just once, at Road Atlanta during the 1970 season, the 2J proved too complex and fragile to be a competitive threat.
The Porsche 917/30 at speed. Photo courtesy Porsche AG.
By 1973, Porsche’s 917/30KL was making as much as 1,580 horsepower in qualifying trim, or 1,100 horsepower in race trim. Team Penske driver Mark Donohue won six of the season’s eight races in the 917/30, while the other two victories went to similar (but less-powerful) Porsche 917/10s. Fans of other constructors or engines were left disappointed, and in 1974 new rules were imposed to limit fuel consumption. Instead of the previous two-hour race format, each Can-Am event was split into a half-hour sprint race, followed by an hour “Cup” race, but the enthusiasm that had driven the earlier series was gone. The Can-Am series was cancelled after the fifth race of the 1974 season, and fans were convinced that no series could ever rival its speed and ferocity.
It took time, but by the early 1990s few could argue that IMSA’s GTP series was a reasonable approximation. In the 1973 Road Atlanta Can-Am race, Mark Donohue qualified his 917/30 on pole with a time of 1:12.950, and set the fastest lap of the race at 1:14. At Road Atlanta during the 1993 IMSA GTP season, P.J. Jones qualified the AAR Eagle Mk III on pole with a time of 1:12.104, while teammate Juan Manuel Fangio II set the race’s fastest lap with a time of 1:13.514. In terms of sheer velocity, Can-Am finally had a rival, three decades after its demise.
The Porsche 917/30’s turbocharged flat-12 engine made as much as 1,580 hp in qualifying trim. Photo by Hoch Zwei, courtesy Porsche AG.
While the 917/30 was permitted to run a turbocharged 5.4-liter flat-12 engine, the AAR Eagle Mk III was limited to a turbocharged 2.1-liter inline four. As a result, output in race trim dropped from over 1,100 hp in the Porsche to roughly 700 hp in the Eagle, which was required to run a 52-mm air restrictor for the 1993 season. The enclosed Eagle was 138 pounds heavier than the open-cockpit 917/30, but advances in aerodynamics allowed the modern GTP car to take advantage of the “ground effect,” greatly increasing downforce while simultaneously reducing drag compared to the Can-Am Porsche.
But like Can-Am, the IMSA GTP series became a victim of its own success, compounded by external forces. As in 1973, fans grew tired of watching the same team win race after race, and privateers could no longer compete against the big-budget factory-funded squads. Across the Pacific, economic storm clouds were brewing, and both Toyota and Nissan (which bowed out of the IMSA GTP series after the 1992 season) were forced to limit their participation in global motorsports. The final race of the IMSA GTP series took place at Phoenix International Raceway in Phoenix, Arizona, in October, 1993, and – as with Can-Am in 1973 – fans swore that nothing would ever take its place.
Mazda’s 2019 RT24-P prototypes – the cars will compete in the 2019 IMSA WeatherTech SportsCar Championship, running in the DPi class. Photo courtesy Mazda Motorsports.
A single test session is hardly enough to proclaim the rebirth of North American racing’s glory days, but it does bode well for the upcoming 2019 IMSA WeatherTech SportsCar Championship season. As Jalopnik’s Bradley Brownell points out, last year’s Mazda RTP-24 prototype – which ran a turbocharged 2.0-liter four-cylinder engine, producing in the area of 600 hp – qualified ninth for the 2018 Rolex 24 at Daytona, with a lap of 1:36.633. Dropping over three seconds per lap (thanks in part to rule changes and a new series tire supplier) in a year is a major accomplishment, one that could potentially make for an entertaining 2019 season. As for other teams in the current DPi class, Acura Team Penske cars ran laps of 1:34.261 and 1:34.431, while the various Cadillac prototypes ran in the 1:34.282 to 1:35.066 range.