Subaru Power at its finest
by Jackie Liu
photography by Henry Z. DeKuyper
Ron Pippin, from Oakdale, California, is a pure-bred car geek. His all-star vehicle line-up includes a 2004 Porsche 911 GT3, a 1940 Ford pick-up, a 1955 Chevy street rod and so many others, he doesn't even bother to disclose them. But when you can't really autocross a classic pick-up and your Mustang won't cut it at the local time attack shootout, what do you do?
Turn your brand-new Subaru Impreza WRX STI into the do-everything supercar: aim for 460 wheel-hp, sports car-slaying handling and response, with enough room to haul kids, pets and groceries around on a daily basis. Meet the ultimate Subaru street car. The Subaru STI, whose capability is known far and wide, has earned its well-deserved accolades from a lifelong history of successful rally competition. Along with its main competitor, the Mitsubishi Lancer Evolution, the STI swam over from Japan and quickly became a hit with tuners and the coveted 35-and-under crowd who admitted to worshipping at the altar of the Gran Turismo video game franchise. With such a rabid following and more parts available than you could ever believe, the STI can be turned into just about anything.
Immediately after he bought the car, Pippin handed it over to Navid Kahangi at PDX Tuning in Portland, Oregon, a renowned Evo/STi tuner in the Pacific Northwest. The two agreed that, with Pippin's busy work schedule and limited weekend time, every second behind the wheel should be an absolute blast.
This STI had to be well rounded for every track event they intended to take part in, including SCCA Solo 2 Street Modified autocross competition and the Subiefest Time Attack event, and still be unfailingly reliable for regular street driving.With a clear plan for building the car up, and a great deal of passion, patience and support from the crew at PDX, Pippin now has an Ultimate Street Car Challenge contender and an interest to share with his 16-year-old son.
The EJ25 engine's displacement hasn't changed, but adding power made it necessary to beef up components. So PDX used Pauter rods, Mahle forged pistons and rings, ARP head bolts and ACL race bearings to button up the bottom end. Cosworth cylinder heads are used, featuring a CNC port-and-polish job, 1mm oversized valves, Cosworth double valve springs, and Cosworth titanium retainers. PDX also created a custom dry sump lubrication system to prevent oil starvation under hard cornering, and threw in a custom engine oil cooler, increasing reliability in race conditions.
A much-larger-than-stock Garrett GT3076R turbocharger feeds a front-mount Perrin air-to-air intercooler through custom PDX piping. A Perrin exhaust manifold, three-inch exhaust with high-flow cat, up-pipe and PDX downpipe improve breathing while the STI's stock intake manifold was reverse-mounted to shorten the intercooler plumbing and improve response.
An Autronic SM4 standalone ECU links injection and ignition vitals. The car now has massive 805cc/min fuel injectors, a Walbro high-flow fuel pump and Perrin fuel rails. For a little extra edge, PDX also installed a launch control feature with the Autronic ECU. The car retains its stock six-speed manual transmission, though the stock clutch and flywheel have been replaced with an Exedy twin-disc set-up.
Underneath are Ohlins coilovers, camber plates and Hotchkis anti-roll bars both front and rear. Stopping power is provided by a STaSIS Alcon big brake kit with 14.6-inch front rotors and four-piston calipers, and the grip from 315/35/17 Kumho V700 tires. We know, 315s on a Subaru-crazy.
Wearing those massive meats are custom 17x11, black three-piece CCW wheels. The exterior is finished off with an APR Performance aerodynamic widebody kit that includes front and rear bumpers, carbon fiber front wind splitter, 40 mm front and rear over-fenders, side skirts, and a huge carbon fiber rear wing. The cabin is outfitted with Recaro bucket seats, Willans safety harnesses and a TC Design roll bar. All the important stuff can be read on the Defi aftermarket gauges and heads-up display.
It took 18 months and a significant amount of effort to go from showroom stock to USCC-ready. Subarus haven't had much luck in the USCC to date, but this STI has far more than just simple bolt-ons. A built engine making some real power, a sorted suspension, and actual testing time in the autocross ranks could add up to a Subie all-rounder taking the overall win.