RWD Fiesta XR2i: The Ultimate Ford Zetec Turbo Build From A UK Shed

In the heart of Britain's thriving home-build car scene, one project stands out as a true testament to engineering passion: Tobias Arkell's remarkable Ford Fiesta XR2i transformation. What began as a tidy keeper project has evolved into a monster-spec, rear-wheel-drive machine boasting a turbocharged ST170 engine, all crafted within the confines of a humble garden shed.

The Ultimate Ford Zetec Turbo Build

This isn't your average engine swap. Under the bonnet lies a meticulously engineered powertrain that prioritises response over brute force. The foundation is a rare CGI (Compacted Graphite Iron) Zetec block, known for its extra webbing and reinforced oil galleries. This unique casting provides the backbone for a high-revving package that's both stiff and durable under extreme conditions.

Mated to this robust block is an ST170 cylinder head, featuring stainless intake valves and Inconel exhaust valves. The original ST cams have been retained, while Area Six springs with reworked followers ensure everything works in harmony. With a static compression ratio set at 10.0:1, this engine is tuned for sharp response rather than lazy power delivery.

Custom rods and meticulously machined pistons complete the rotating assembly, which has been balanced to within a gram. A Ford steel crank with tweaked geometry allows the engine to chase a five-figure rev ceiling. The result? An estimated 500-550bhp on approximately 25psi of boost, delivering performance that's been proven to hold its own against a GSX-R1000 motorcycle from 30-130mph.

From Front-Wheel Drive to Rear-Wheel Drive Revolution

Perhaps the most radical aspect of this build is the complete drivetrain transformation. The original front-wheel-drive configuration has been replaced by a sophisticated rear-wheel-drive system. The current 2025 specification features a proper sequential gearbox installed under a hand-made transmission tunnel, replacing an earlier RX-8 gearbox setup.

This driveline has been carefully matched to the chassis to ensure traction can be put down cleanly rather than fought against. The focus has been on creating a car capable of speed between corners and repeatable performance on hot laps, moving beyond simple straight-line hero pulls.

Advanced Suspension and Chassis Engineering

The shell work that defined the early build hasn't been lost – it's been amplified. Seam-by-seam stitch-welding reinforces the structure, while the bulkhead has been nudged back for optimal weight distribution. The front end has been semi-space-framed to properly tie suspension loads into the roll cage.

Up front, double wishbones with inboard coilovers on pushrods have been fabricated, loosely scaled from touring car and Hoonicorn geometry. Motorsport Tools alloy hubs from an Escort Safari kit have been re-machined for custom pick-ups, while Wilwood six-piston calipers bite on 325mm floating rotors.

At the rear, the live axle has been replaced by a fully independent setup built as a bolt-in cradle with twin wishbones and dampers laid over at approximately 45 degrees, giving serious Escort WRC vibes. An R32 Skyline limited-slip differential handles power distribution, while Wilwood four-piston calipers with 310mm floating rotors provide stopping power.

Steering, Brakes and Driver Feedback

Early steering issues that once snapped a Sierra manual rack have been solved with a BMW E46 purple-tag rack fed by an electro-hydraulic pump. Brake feel has been carefully paired to the chassis balance, allowing proper trail-braking rather than tentative tip-toeing around corners.

Interior and Electronics: Race Brain, OEM Soul

Inside, a Safety Devices roll cage has been stitched into full box-section chassis rails, creating a rigid structure that fights flex as one unit. The sequential shifter sits in a tidy tunnel that looks factory-finished rather than an afterthought.

ECUMaster EMU Black, PMU16 and a digital dash serve as the car's brain, while a bias box, hydraulic clutch and hydraulic handbrake handle the serious business. Remarkably, the electric windows, door cards, headlining and even the sunroof have been retained, preserving the car's sleeper aesthetic and street-friendly soul.

Performance, Reliability and Future Developments

This build has been a learning process. An auxiliary belt mishap that once took out the oil-pump drive forced a rebuild, creating an opportunity to revise piston specifications and refine clearances. The oil system has been rethought for longevity, and fuel strategy is being pointed toward E85 to unlock more timing at the current compression ratio.

The mission remains simple: create a Ford Zetec turbo build that can run all day, not just deliver one-shot hero performances. A tighter turbo is planned for even punchier hillclimb performance, with continued chassis tuning ensuring the evolution never stops.

Ford Fair 2025 Recognition

At Ford Fair 2025, this sleeper silhouette did its best work. Forming part of the formidable Fast Ford display, the car initially drew casual glances before swarming crowds gathered as the details were noticed. The project deservedly won the "Built Not Bought" award, with recognition landing exactly where it belonged: on a Cornish shed floor transformed into a world-class skunkworks.

Why This XR2i Sets the Standard

This project demonstrates that proper engineering hasn't been replaced by CAD and catalogues – it's been amplified by skill, patience and a refusal to accept "good enough". Balanced for response rather than just numbers, designed for real-world driving rather than dyno theatre, this Fiesta represents the pinnacle of British shed engineering. From twenty paces it still reads as a clean XR2i, which is exactly why its performance hits so unexpectedly hard.

Ford Zetec Turbo Build FAQ

What is a CGI Zetec block and why was it used? It's a Compacted Graphite Iron casting with extra webbing and strengthened oil galleries, chosen for its stiffness and durability under high boost and high rpm conditions.

How much power does this Ford Zetec turbo build make? On approximately 25psi and revs just shy of 9000rpm, performance is consistent with a 500-550bhp estimate.

Is the XR2i still road-friendly? The interior retains civil amenities like electric windows and a sunroof, but the driving experience is focused on track and hillclimb performance with its sequential gearbox and competition suspension.

What's next for the build? Future plans include E85 fuel strategy, a tighter turbo for hillclimb punch, and continued chassis refinement.