Video: How Does a 4.0-Liter GT3 RS Drive on Worn Tires?

Leh Keen shows that he’s no slouch with a powerful Porsche in need of new rubber. On this spirited blast through Atlanta Motorsports Park, there’s rarely a moment when he’s not laying black rubber down with the aide of his 4.0-liter motor. I’d love to see view from a chase car—but finding one that can keep up with this nutcase isn’t easy to do.

Leh Keen’s quite capable of hooning powerful Porsches sideways at speed, and this is no different. While he’s not dealing with turbos in his street-driven GT3 RS, he still has 450 horsepower at the rear wheels from his custom, 4.0-liter engine built by Autometrics. The mill uses Cup S exhaust cams, big 4.0-liter pistons, a 4.0 intake manifold stuck on top, and a Gruppe M intake box. It’s not just a motor either—if “just” is appropriate here—it uses a Cup Car’s ring and pinion, an RSR’s triple-carbon clutch, and an S-Car-Go exhaust system that makes this banshee shriek:


With the power, shorter gears, and the ability to rev like it does, it has the power to overwhelm the tires at corner exits everywhere it goes. Keen’s probably not on completely bald tires here, but he puts on the right sort of dramatic show; hanging it out at every corner, and even into some of the quicker ones. It makes you wonder how much these motors go for, and whether Autometric offers any considerate payment plans. At least I’d have a smile on my face for those four-or-so decades.

About the author

Tommy Parry

Tommy Parry has been racing and writing about racing cars for the past seven years. As an automotive enthusiast from a young age, he worked jobs revolving around cars throughout high school, and tried his hand on the race track on his 20th birthday. After winning his first outdoor kart race, Tommy began working as an apprentice mechanic to amateur racers in the Bay Area to sharpen his mechanical understanding. He has worked as a track day instructor and automotive writer since 2012, and continues to race karts, formula cars, sedans, and rally cars in the San Francisco region.
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