Video: Six-Cylinder, Chain-Driven WRX Challenges Skylines at WTAC

Andy Forrest is an avid drag racer-turned-road racer who’s garnered a sizable UK following for his six-cylinder Impreza we spotted a few months ago. In the past several years, his GC8 Subaru has gone from an understated machine to an ostentatious, wide-bodied time attack chimera that’s hardly recognizable. Only the rear taillights give away hint at this once-modest Impreza’s past.

Though Forrest dominated the Scottish time attack scene with this car, it wasn’t ready for the standard of competition at the prestigious World Time Attack Challenge in Sydney. His attempts last year ended with a broken transmission and a lap time twelve seconds off the pace. Rather than throwing in the towel, the good-natured Scot went back to the drawing board and devised a few new additions to help him towards the sharp end of the pack.

Photo credit: World Time Attack Challenge

To improve the weight distribution, Forrest installed the dual-clutch transmission from a Nissan R35 GT-R. Though it’s a little on the heavy side, it’s a transaxle transmission and it frees up enough room in the cramped engine bay to allow for the hefty motor to be mounted behind the firewall; attached to the recessed bulkhead.

As the stock upright shocks aren’t great for serious lateral loading, Forrest fabricated his own dual wishbones at the rear, and still found enough room to install a massive rear tunnel for the downforce he was after. Somehow, he added a pushrod setup at the front, where the packaging constraints, thanks largely to the larger motor, were even tighter than those at the rear.

Photo credit: KYLE.ENGINEERS

At this point it makes sense to mention there’s no flat-four sitting up front. Instead, Forrest went with the 3.3-liter EG33 from the Subaru SVX, bored it out to 3.6 liters, and prepped it for boost. This year, he’s replaced the set of modestly-sized GT35 turbos with a larger single PT6870 turbo —which, due to spatial constraints, he’s mounted in the passenger footwell. Despite the size of the snail, the motor makes full boost at 4,000 RPM. The motor, facilitated 12 ASNU 1300cc injectors and a Syvecs S88 ECU, continues making serious power until 9,000 RPM, and within that range some 1,200 horsepower is made!

This sort of grunt necessitates four wheel-drive, and that itself was a serious challenge. To make room for the front differential, Forrest had to consider the crammed engine bay, the wheelbase, and the center of mass, and so he went with an unconventional approach.

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He mounted the Escort Cosworth differential behind the engine; driven by chains sourced from a 600-horsepower Harley-Davidson drag bike. As these chains only manage a fraction of the total power output, they’re hardly used except for hairpins and adverse conditions.

With all the outlandish, sci-fi bodywork, a  it’s rightly earned the nickname “Stormtrooper.” It has all the aero—including full floor, tunnels, splitter, bumper bar, and wings—made from carbon with help from AMB Aero. Proving that some serious achievements are possible on a comparatively modest budget, Forrest has risen to the sharp end of the field with ingenuity, brains, and tenacity; finishing as the fastest European entrant and just outside of a podium position.

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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