Motorsports showcase the technological prowess of the competing manufacturers, and Subaru’s efforts and achievements in the World Rally Championship have earned the company a loyal following. The Impreza caught Aaron Wells’ attention as he watched Colin McRae and then Petter Solberg represent Subaru on WRC podiums in the 90s and into 2000. When Subaru announced the release of the WRX in America in 2001, Wells put his deposit down. After taking delivery, he invested into his WRX with a goal of making it just like an STi. This brought him temporary satisfaction until Subaru announced the release of the STi two years later.

Text and Photos by Richard Fong

No Test Drive!?

Yes, no test drive. When the first of the STi units arrived stateside, the demand far outweighed the inventory, so each unit was sold before being test-driven. Aaron knew he would own one someday, but he wanted to know how different it was compared to his WRX. Shortly after the STi was launched, he saw one with only 3,000 miles on a used car lot. The sales manager offered Wells the test drive that sold him.

Easy On The Mods

After spending two years trying to make his WRX into an STi, Wells stated that he had no intention of modifying the engine of his new Subaru. Instead, he focused on the handling aspect, adding lowering springs, Hotchkis sway bars, heavy duty tie-rod ends, and harder urethane suspension bushings throughout. He also improved the STi’s braking performance with a set of DBA 4000 vented rotors, Hawk Performance HPS brake pads and Goodridge stainless-steel braided brake lines.

Snowball Effect

Just as sure as snow falls in Colorado, Wells could not leave the car alone. He soon grew tired of the stock setup and started looking for more power. He progressively increased power starting with an 18G turbocharger, followed by a 20G turbocharger. Finally, he decided to step up to a Garrett GT3582R with a rotated-mount configuration. At the same time, Revolutions Performance fortified the stock block with aftermarket pistons and rods. The engine was dialed in to make 527 horsepower on a Dyno Dynamics dynamometer, about 25 horsepower below what Wells had learned was the maximum threshold prior to cylinder failure. He took the STi to the Sand Hills Open Road Challenge (SORC) in Nebraska to compete in the 1⁄2-mile shootout. Sitting in second place after the first round to a C4 Corvette, he wanted to go for the top spot. He turned up the boost by 3 psi and attempted to best the Corvette’s performance, only to have the stock sleeves let go.

EJ Improvements

Undaunted, Wells brought the STi back to Revolutions Performance to be rebuilt. The shortblock was stripped down and sent to Darton International to have a set of ductile-iron sleeves installed. The block then returned to Colorado to be bored and honed to 100mm by Stan at Rocky Mountain Machine. The cylinders were then filled with a set of CP Pistons that rely on Pauter rods to make the connection to the factory crankshaft. Before completing the longblock assembly, the cylinder heads were equipped with +1mm Supertech valves, dual valve springs and titanium retainers. Kelford 272-degree camshafts were installed to deliver increased lift and duration. The heads were then secured to the shortblock by way of ARP L19 head studs.

The factory cast manifolds are joined by a GrimmSpeed crosspipe to improve exhaust flow from cylinders one and four to the Garrett turbocharger. An Ultimate Racing downpipe and Invidia exhaust route gasses from the turbine to the atmosphere. On the cool side, the compressor forces ambient air through aluminum piping to an APS front-mount intercooler before being distributed to the intake ports.