Supercharged Fiesta ST150: A Force to Be Reckoned With

When the Mk6 Ford Fiesta ST150 first hit the roads in 2005, it was hailed as a significant turning point for Ford's hot hatch offerings. After a decade marked by a series of rather uninspiring warm hatches, with only a few exceptions like the Racing Puma, the ST150 arrived as a genuine contender. It possessed the power and agility to rival established performance models, signalling Ford's return to its roots of producing iconic performance cars like the Fiesta XR2 and XR3i.

This article delves into the remarkable journey of Louis Thompson, a dedicated Ford enthusiast who has meticulously transformed a Mk6 Fiesta ST150 into a breathtakingly aggressive, 300bhp-plus supercharged machine. Louis's extensive experience with Fiestas, coupled with lessons learned from numerous past projects, has culminated in what he considers his finest creation yet. The feature, originally from Fast Ford and brought to you by the words and photos of Jon Cass, explores the evolution of this formidable hot hatch and the passion that drives its owner.

The Genesis of a Hot Hatch Icon

The Mk6 Fiesta ST150, launched in 2005, represented a bold statement from Ford. It was designed to recapture the spirit of its predecessors, offering a compelling blend of performance, handling, and everyday usability. For a generation of drivers who had grown up with the legendary XR models, the ST150 was a welcome return to form, proving that Ford could still deliver a truly engaging driving experience.

Louis's Fiesta Fervour

Thirty-one-year-old Louis Thompson's affinity for Fords, and the Mk6 Fiesta ST in particular, is deeply ingrained. His formative years were surrounded by Fords, with his father’s progression through a Sierra estate, Mondeos (including an ST24), and ultimately a Focus ST, cementing a lifelong passion. "Fords have always played a major part of my life," Louis recalls, highlighting the familial connection to the brand.

Early Modifications and Lessons Learned

Upon passing his driving test at 17, Louis’s first acquisition was an insurance-friendly Mk6 Fiesta Zetec S. This initial foray into modifying cars quickly ignited a passion. "I’d soon modified it with window tints, Lexus rear lights, diamond-cut RS7s and lowered suspension," he recounts with a smile. This early experience led to a full-blown ST replica project, complete with an ST bodykit, interior, and even a tuned ST 2.0-litre engine swap. Unfortunately, this ambitious build had to be sold due to parental disapproval, leading Louis to a Focus ST. However, a twist of fate with an expiring insurance quote meant he lost out on the Focus and his deposit.

The First Supercharged Encounter

Despite the setback, Louis’s enthusiasm remained undimmed. He managed to secure a decent, genuine Mk6 ST150, which already boasted a few desirable upgrades, including a Piper exhaust system, a Dreamscience map, and a K&N filter. At the young age of 19, Louis’s modifications leaned towards the popular 'low-and-slow' scene, featuring a substantial sound system and slammed Weitec coilovers. However, this trend didn't resonate with him, and he soon reversed course. The sound system was removed, the coilovers were raised, and a significant upgrade was made: a Jamsport Stage 2 Supercharger kit was fitted, boosting the car to 250bhp. Louis thoroughly enjoyed this setup, but a new chapter in his career in the motor trade prompted him to sell the car and focus on his professional aspirations.

A Detour Through Track-Focused Fiestas

The allure of tinkering with Fords soon beckoned again. Louis found himself the owner of a Mk5 Fiesta Zetec S, a full-blown track car running throttle bodies. However, this proved to be a troublesome acquisition, suffering a catastrophic engine failure within weeks. After an expensive rebuild, Louis sold it on, a testament to the unpredictable nature of project cars.

The Mk1 Fiesta Interlude

A promotion at work and the purchase of a house, complete with a spacious double garage, provided Louis with the perfect opportunity to indulge his automotive passions further. While initially focused on motorcycles, the ample garage space inspired a new project. During a holiday, he impulsively purchased a Mk1 Fiesta online, equipped with a 1.8-litre Zetec engine and bike carbs. This Mk1, with its remarkably low mileage and excellent condition (barring minor rust patches), was meticulously cared for. However, a frustrating starting issue led Louis to a rather unconventional solution: stripping the car down to its bare essentials to make it light enough to push back into his garage. This act of practicality inadvertently sparked another full rebuild project. Louis undertook most of the work himself, transforming the Mk1 with an XR2 kit, retrimmed bucket seats, a flocked interior, custom racing stripes, and diamond-cut alloy wheels. Despite the impressive transformation, the Mk1 Fiesta eventually served as a brief interlude, being sold after a period of inactivity.

The Return of the Supercharged Dream

The memories of his first supercharged Fiesta ST150 lingered, fuelling Louis's desire to revisit his favourite model. This time, his objective was to start with a pristine example. He soon discovered a 2005 ST with an incredibly low mileage of just 18,000 miles. The car was immaculate and already featured desirable upgrades, including Team Dynamic Pro Race alloys wrapped in sticky Michelin Pilot Sport tyres, a TRC low-line kit, and a cat-back exhaust. However, it was let down by a set of substandard coilovers.

Building the Ultimate ST150

Louis's initial plan to use the ST150 as a track-ready car without major modifications quickly evolved. The under-bonnet chrome accents were removed, and during another holiday, he ordered a pair of Corbeau Clubsport bucket seats with OMP harnesses. A chance encounter with an advertisement for a written-off modified ST provided Louis with further valuable components, including a full Milltek exhaust system, an EVO 2 manifold, and a Whiteline rear anti-roll bar.

The project gained momentum as Louis contacted Jamsport, the renowned specialists for Fiesta ST modifications. Having experienced a 320bhp supercharged ST150 demo car in 2008, Louis was eager to replicate that exhilarating performance. After a consultation with Jamsport's Jamie, Louis opted for their Stage 2.5 Rotrex C30 supercharger kit. He diligently sourced all the necessary supporting parts, including an Auto Specialists inlet manifold and a genuine 60mm throttle body. Louis also undertook the relocation of the power steering pump himself, preparing the car for the supercharger installation. The build was further enhanced with 440cc injectors, an Airtec intercooler, and a supercharger oil cooler, demonstrating a meticulous approach to both performance and longevity. The car already benefited from upgraded Ford Focus ST170 front and rear brakes, a significant advantage, though the initial cheap coilovers remained a potential weak point.

Supercharger Power and Drivetrain Enhancements

With the supercharger fitted and other ancillaries in place, the ST150 underwent initial tuning. The result was an impressive 311bhp and 258lb.ft of torque, delivered through a smooth, linear power curve. Louis was ecstatic with the outcome. "The drive home was unreal, in every gear it flies and the hard-cut limiter Jamie installed set at 6800rpm sounds like gunfire!" he exclaimed. The transmission also received attention, with the ST150 gearbox being fully rebuilt and fitted with a Quaife Limited Slip Differential (LSD). To handle the increased power, a stronger Sachs 4-paddle clutch and a TTV lightened flywheel were installed.

Refining the Handling and Aesthetics

Next, Louis fitted stickier Nankang tyres for improved grip. Following a recommendation, he replaced the problematic suspension with a set of BC Racing BR-V2 coilovers, complete with camber adjusters, which significantly enhanced the car's handling. To ensure the car stood out visually, complementing its new 'jet fighter' sound, Louis added fluorescent yellow racing decals and resprayed the wheels to match.

Interior Stripped for Performance

Inside, the focus shifted to weight reduction. The immaculate 18,000-mile interior was largely stripped out, with only the door cards and headlining retained for a touch of refinement. Alongside the Corbeau seats and OMP harnesses, Louis fitted a quick-release OMP steering wheel connected to an NRG hub and a BG Racing snap-off kit, further enhancing the race-car feel.

A Testament to Dedication

This entire project is a testament to Louis's dedication and extensive experience with Fiestas. Aside from the supercharger installation, he managed to complete the majority of the work himself in his spare time, achieving this remarkable transformation within six months. "The problem I have is once I get stuck in, I start to forget about all the other things I should be doing," Louis laughs, acknowledging his intense focus. His best mate often finds himself unexpectedly drafted in for assistance, even having to pause his own Mk3 Fiesta build to help Louis, a testament to their shared passion and camaraderie.

The Thrill of the Supercharger

The supercharger itself is the heart of the ST150's appeal for Louis. "The way the power comes in, it’s more like a turbo and not your average supercharger," he explains. At 13psi of boost, the car is described as "mental," with power delivery kicking in just before 4000rpm. The addictive power delivery, coupled with the distinctive supercharger whine, consistently brings a smile to Louis's face. He recounts the joy of taking passengers out on track, invariably leaving them with broad grins.

Future Plans and Continued Passion

As with any passionate project, Louis's Fiesta ST150 is a work in progress. His future plans include the addition of an oil cooler and a rear roll cage to complete the track-focused aesthetic. He also contemplates forging the engine and installing cams, though he notes that many stock-internal STs can reliably handle up to 330bhp. For now, Louis remains content with his phenomenal supercharged Fiesta ST150, but his sights are already set on a future project: a Mk6 Ford Fiesta featuring a Cosworth YB engine, hinting at his enduring commitment to the Ford performance scene.

Key Specifications and Upgrades

Frequently Asked Questions

When was the Ford Mk6 Fiesta ST150 launched?

The Ford Mk6 Fiesta ST150 was launched in 2005.

What is the power output of Louis's Fiesta ST150?

At the time of the article, Louis's supercharged Fiesta ST150 was producing 311bhp and 258lb.ft of torque.

What supercharger kit is used on Louis's Fiesta?

Louis's Fiesta is fitted with a Jamsport Stage 2.5 Rotrex C30 supercharger kit.

What modifications were made to the drivetrain?

The drivetrain features a rebuilt ST150 gearbox, a Quaife LSD, a Sachs 4-paddle clutch, and a TTV lightened flywheel.

What are Louis's future plans for the car?

Louis plans to add an oil cooler, a rear roll cage, and potentially forge the engine and add cams.