Enthusiasts have long imagined transplanting a turbocharged boxer-four from an STI into the hull of a classic Porsche for sheer novelty. While kits exist for that extreme, a different dream has taken shape: installing a six-cylinder turbo unit behind the rear axle of a Subaru WRX STI, creating a pseudo-911-Turbo without the marque’s price tag.
The effort is being led by the garage known as Smeedia. Their ambition surfaced in a video released in August, where the team outlined the goal of mounting an EG33 flat-six in the STI’s trunk. Since then, a trail of progress photos and updates has chronicled the build’s evolution.
Project genesis and inspiration
The concept sprang from a prior experiment in which an EG33 engine briefly powered the front of the same chassis, affectionately dubbed “Blu.” After running massive boost, the engine suffered a catastrophic timing error that bent two valves and warped the remaining twenty-two. The costly failure taught the team valuable lessons about balance, clearance, and the need for precise engine control, prompting the shift to a rear-engine layout.
Technical hurdles and custom solutions
Reinforcing the chassis
Placing a six-cylinder where the STI’s rear shock towers reside demands significant structural work. The rear section of the frame has already been tubed to boost rigidity, a necessity given the volume of material removed to accommodate the new powerplant. This reinforcement mirrors stock stiffness while allowing space for the engine, fuel cell up front, and a future front-end roll cage.
Drivetrain re-engineering
Maintaining the factory all-wheel drive system proved essential for handling the added power. The original six-speed transmission will stay, but a custom ring-and-pinion set is being fabricated to reverse the direction of torque, enabling the gearbox to sit on the opposite side of the engine. Custom brackets now hold the exhaust within the rear bumper crash bar, and the exhaust piping has been routed through the cramped rear compartment, illustrating just how tight the packaging has become.
Current build status and what lies ahead
At present, the engine occupies most of the trunk, and the exhaust is fully mounted. However, two critical systems remain incomplete: a dedicated harness to wire the engine to the vehicle’s electronics, and a cooling circuit capable of handling the turbo’s heat load. Both must be finished before the first start-up can occur. The project continues to generate interest on social media, and each update brings the vision of a rear-engine, turbocharged STI closer to reality.
