Mazda RX-8 with an Audi 1.8T

Mazda RX-8 with an Audi turbo 1.8 L inline-four

The owner of this 2004 Mazda RX-8 spent three years of weekends and late nights rebuilding it from the ground up. The owner considering swapping a Honda K20 or K24 inline-four but settled on a turbocharged 1.8 L (AVJ) inline-four from an Audi A4 B6. The engine features Siemens Deka 630 cc injectors, Bosch Motronic ME 7.5 ECU, XSPower exhaust manifold, and K03RS6 turbocharger. The owner estimates the combination is good for 300 horsepower. Custom mounts place the engine further back which helped with weight balance but required some firewall trimming. He swapped the factory RX-8 six-speed to a five-speed model with an adapter plate and upgraded clutch. The car maintains stock suspension and brakes albeit resorted and/or rebuilt.

Mazda RX-8 with an Audi turbo 1.8 L inline-four

Mazda RX-8 with an Audi turbo 1.8 L inline-four

Mazda RX-8 with an Audi turbo 1.8 L inline-four

Mazda RX-8 with an Audi turbo 1.8 L inline-four

Mazda RX-8 with an Audi turbo 1.8 L inline-four

Mazda RX-8 with an Audi turbo 1.8 L inline-four

Mazda RX-8 with an Audi turbo 1.8 L inline-four

Mazda RX-8 with an Audi turbo 1.8 L inline-four

Mazda RX-8 with an Audi turbo 1.8 L inline-four

Mazda RX-8 with an Audi turbo 1.8 L inline-four

Mazda RX-8 with an Audi turbo 1.8 L inline-four

Mazda RX-8 with an Audi turbo 1.8 L inline-four

Mazda RX-8 with an Audi turbo 1.8 L inline-four

Source: RX-Klub.pl (build thread) and SopelXL via Piotr

15 thoughts on “Mazda RX-8 with an Audi 1.8T”

  1. Ive figured out how to make the plate for the gearbox but could you please tell why did you change the 6 speed gearbox whit 5 speed one and is the 5 speed from the rx8 original or you’ve used another one … if yes from what car ? Thank you in advance

    1. Because of longer gear ratios than in 6 speed.

      5 speed RX-8 gearbox is better for this engine (max 7200rpm) but in my opinion still too short 140km/h – with 4000rpm on 5 gear and max speed 250km/h. because of this i will swap rear differential from automatic RX-8 (4.3) in manual version is 4.44

  2. Hi there guys,
    i am looking to do this also.
    i have the rx8 and audi tt 230hp 1.8 20 valve engine.
    what clutch components are required for this ??
    any info would be greatly appreciated.

    Rory

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