Subaru WRX STI Toyota V12 Swap: A Twin-Turbo Beast

Insane Subaru WRX STI Toyota V12 Swap: 1,000 HP Secret

When you see a 2009 Subaru WRX STI, you expect to hear the familiar rumble of a 4-cylinder boxer engine. But the car owned by John Proulx (@1lowrx) is hiding a massive secret. This is no ordinary hatchback; it features a wild Subaru WRX STI Toyota V12 swap that completely transforms the vehicle into a 1,000-horsepower monster.

https://www.instagram.com/reel/Cz9o0I_vYX4/?utm_source=ig_web_copy_link

The Heart of the Beast: Toyota 1GZ-FE V12

The most shocking part of this build is the engine choice. Proulx managed to fit a 5.0-liter 1GZ-FE V12 engine into the compact engine bay of the Subaru.

For those who don’t know, this engine comes from the Toyota Century, a limousine designed for the Emperor of Japan. While the original engine was built for quiet luxury, Proulx had other plans. He added two massive G30-770 turbochargers and upgraded the internals with forged rods and pistons. The result? A claimed output of 1,000 horsepower, which is roughly 700 hp more than the stock engine ever produced.

Laced with BMW Engineering

A Subaru WRX STI Toyota V12 swap creates a lot of power, and the stock Subaru transmission would likely explode under the stress. To fix this, Proulx turned to German engineering.

The V12 engine is paired with a 7-speed Dual-Clutch Transmission (DCT) sourced from a BMW 335i. This gearbox is famous for its lightning-fast shifts and ability to handle high torque. Connecting a Toyota engine to a BMW transmission required a custom adapter plate and a sophisticated MaxxECU Pro computer to make everything talk to each other.

https://www.instagram.com/p/DQZm0g4DlsA/?utm_source=ig_embed&ig_rid=58b5d413-6b83-46fe-9ede-d18a03e938bc

RWD Conversion and Weight Distribution

With twelve cylinders and two turbos, the original All-Wheel Drive (AWD) system had to go. The car was converted to Rear-Wheel Drive (RWD) using a custom driveshaft and a robust Ford 8.8-inch rear differential.

You might think that adding a huge V12 would ruin the handling, but you would be wrong. Thanks to the removal of the front drivetrain components and the heavy new rear axle, the weight distribution remains surprisingly balanced at 59/41 (front/rear)—very close to the stock specification.

Build Specifications

Here is a quick breakdown of the key components that make this Subaru WRX STI Toyota V12 swap possible:

This build proves that while the future of the STI might be electric, the passion for high-horsepower gasoline projects is still very much alive.

Also Read – Tesla Lease Price Increase – 70% Hike Coming After Christmas