Originally posted by cooltouch As for the sounds of the cars, it was interesting. Almost all of the cars in the prototype class (the fastest) were turbocharged. A turbocharger really affects the exhaust note. The turbine chops it up, the result being they all sound like big vacuum cleaners as they go flying past. But there were two prototypes that had normally aspirated engines. The two Group 44 Jaguar XJR7s had NA 12-cylinder engines, and they sounded like proper race cars when they'd go howling by. Of course, the slower classes were populated mostly with V8s -- Camaros and Corvettes and Mustangs and such. And they of course added their characteristic American V8 roar to the overall noise level.
One of the many neat things about the IMSA prototype class was the diversity, chassis, makes, drivetrain layouts (mostly mid engine, but there were a few with engines in front of the driver), and the engines. Turbocharged Porsche flat 6 cylinders, Ferrari (a couple different configurations), Mazda rotary (the awesome 3 rotor 20B), turbocharged Olds Quad 4, Buick V6 (turbo and non turbo), the n/a Jag V12, and later a turbo Jag V6, Chevy and Ford stock block engines with all manner of exotic induction configurations, Cosworth Fords, the list goes on.
When they ran at Portland they didn't use the chicane like the Indy Cars did, and to stand where you could see the cars come out of the back stretch and then run down that long front straight was a hoot. Each engine singing its own song, the roar of the big V8's, the shriek of the highly strung little 4 bangers getting forced air and fuel, belching fire at every shift with that familiar chirp of the compressor blades stalling for an instant, the howl of the rotary.
And the series ran in parallel with the European and Asian endurance series, so there was a distinctly international feel to the events. Like taking an overseas trip, but only a 4 hour drive from home.
Good times.