Louis has owned and modified plenty of Fiestas in his time, and he’s combined all the lessons learnt to create the best yet; this beautifully aggressive, 300bhp-plus supercharged Fiesta ST150.

Feature from Fast Ford. Words and photos: Jon Cass

When the Mk6 Fiesta ST150 was launched back in 2005, it was seen as a huge step in the right direction for Ford. After a decade of mediocre warm hatches, with only a handful of exceptions such as the Racing Puma dripping through the mainstay of sensible motoring, here, finally, was a true hot hatch with the power and agility to match. Ford had returned to its days of dominating the streets with icons such as the Fiesta XR2 and XR3i.

31-year-old Louis Thompson has been a big fan of the Mk6 Fiesta ST, and Fords in general, for as long as he can remember. “My dad had a Sierra estate, a couple of Mondeos including an ST24 before moving on to a Focus ST,” Louis remembers, “Fords have always played a major part of my life.”

Supercharged Fiesta ST150

Once Louis had passed his test aged 17, he went out and bought an insurance-friendly Mk6 Fiesta Zetec S. “I’d soon modified it with window tints, Lexus rear lights, diamond-cut RS7s and lowered suspension,” he smiles, “this gave me the bug and I went on a full shopping spree to turn it into an ST replica.”

Not only did the Zetec S end up with a full ST bodykit and interior, Louis also swapped-in a tuned ST 2.0-litre engine too. My mum hated the thing and made me sell it, so I put a deposit down on a Focus ST,” Louis laughs, “unfortunately by the time I went to buy the car, my only reasonable insurance quote had expired, so I ended up losing out on the car and lost my deposit.” This costly episode didn’t put Louis off and he still had the funds to bag himself a decent, genuine Mk6 ST150 which already came with a few choice upgrades in place, including a full Piper exhaust, Dreamscience map, and K&N filter – so all was not lost!

“I was still only 19 at the time, so typically I opted for a huge sound system in the boot and slammed it on Weitec coilovers,” Louis laughs, “I thought it was the best thing since sliced bread at the time.” It soon became apparent Louis didn’t feel at home being part of the ‘low-and-slow’ scene so out went the sound system, the coilovers were raised and more significantly he bolted in one of Jamsport’s Stage 2 Supercharger kits. “It was running 250bhp and I loved the thing,” he remembers, “but I’d just started in the motor trade and was keen to find my own place, so I stripped the mods and sold it.”

Supercharged Fiesta ST150

Pretty soon Louis was missing having a Ford to tinker around with and before he knew it, he was the latest owner of a Mk5 Fiesta Zetec S full-blown track car running throttle bodies. “What I hadn’t realised was I’d bought a bit of a lemon and it blew up within a few weeks,” Louis laughs, “I spent another grand having it rebuilt then sold it.”

Work promotion soon came and so did a house purchase which had the benefit of a double garage. “I was into my bikes by now, but the huge garage was wasted just having a single motorbike parked in the middle of it,” Louis grins, “we went on holiday and I ended up buying a Mk1 Fiesta with a 1.8-litre Zetec and bike carbs over the internet!” The Mk1 had only 55k on the clock from new and was in great condition other than for two tiny patches of rust. “I only ever used it in the dry and polished it every week without fail,” Louis recalls, “then one day it failed to start. My garage has a bit of a slope to the entrance, and I was struggling to push it back in.” Rather than leave it out in the elements or call for recovery, Louis took his unique route of stripping the Fiesta, so it was light enough to push! “Once it had been stripped, I soon realized I’d started another full rebuild project,” Louis smiles, “I ended up doing all the work myself on that one except for the paint. It had a full XR2 kit, retrimmed bucket seats in Supersport cloth, and I flocked every part of the interior I could think of.” The Mk1 also benefited from custom Bravo stripes in an XR2 style and diamond-cut pepperpot alloys!

Supercharged Fiesta ST150

“I took it to Ford Fair in 2013, parked it up when I got back and didn’t use it again for three years, “ Louis laughs, “I ended up selling it and didn’t have much involvement with cars for a while.”

Supercharged dreams

As the years passed, fond memories of that first supercharged Fiesta ST150 returned, Louis was keen to continue from where he’d left off with his favourite Fiesta to date. “I wanted to start from scratch with a good example this time and I soon came across this 2005 ST with just 18,000 miles on the clock,” he recalls, “it was immaculate and already had these wheels, the TRC low line kit and a cat back exhaust.” It also came with a horrendous set of cheap coilovers too!

Initially, this latest ST seemed ready to take on track without having to make any drastic changes, the Team Dynamic Pro Race alloys were even wrapped in grippy Michelin Pilot Sport tyres. That plan soon changed and off came the under-bonnet chrome plates and covers and whilst on holiday again, Louis ordered a pair of Corbeau Clubsport bucket seats with OMP harnesses. “Once I’d returned from holiday, I came across an ad for a modified ST that had been written off and was being stripped,” Louis recalls, “I bought the full Milltek system from this car along with the bigger EVO 2 manifold and Whiteline rear anti-roll bar.”

Things were beginning to progress quickly and Louis was soon on the phone to Jamsport, “I’d had a test drive in one of their supercharged Fiesta ST150 demo cars back in 2008 running 320bhp and it put a huge smile on my face,” he remembers, “if mine turned out anything like that one then I knew I’d be happy.” After a discussion with Jamie, Louis opted for the Stage 2.5 Rotrex C30 supercharger kit and began sourcing the relevant parts to make the conversion worthwhile. “I found an Auto Specialists inlet for a bargain £90 and a genuine 60mm throttle body,” he points out, “I then did the relocation of the power steering pump in preparation for the supercharger myself.” The remainder of Louis’ set up is well matched; the 440cc injectors, Airtec intercooler and supercharger oil cooler demonstrating this build has been well thought out, not just for performance but to stand the test of time too. The uprated Ford Focus ST170 front and rear brakes had already come with the car, which was a huge bonus, but those cheap coilovers were still likely to let the side down.

“I couldn’t find any coilovers I wanted so I had the supercharger fitted first along with the other ancillaries I’d bought at Jamsport,” Louis tells us. After some tweaking and fettling the car made 311bhp and 258lb.ft torque with an awesome linear curve, so Louis was pleased to say the least! “The drive home was unreal, in every gear it flies and the hard-cut limiter Jamie installed set at 6800rpm sounds like gunfire! First and second gear comes and goes so quick, it feels like I should be setting off in third!” Speaking of transmission, Louis has had the ST150 gearbox fully rebuilt and fitted with a Quaife LSD while he’s also opted for a stronger Sachs 4-paddle clutch and TTV lightened flywheel.

Supercharged Fiesta ST150

Stickier Nankang tyres came next, then after a recommendation Louis replaced the cheap suspension with a set of BC Racing BR-V2 coilovers along with camber adjusters which have made a huge difference. “I still wanted the car to stand out visually even though it now sounded like a jet fighter,” Louis laughs, “so I added the racing decals in fluorescent yellow and resprayed the wheels to match.”

Inside everything has been stripped out in order to save weight as you’d expect. Gone is the immaculate 18,000-mile interior, well other than for the door cards and headlining which retain at least some refinement! In addition to those Corbeau seats and OMP harnesses, Louis has fitted a cool OMP snap-off steering wheel connected to an NRG hub and BG Racing snap-off kit.

Supercharged Fiesta ST150

This whole project has been well thought out, and Louis’ vast experience of Fiestas over the years has certainly come in handy. Other than the fitment of the supercharger, he’s managed to tackle the rest of the work himself in his spare time all 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, “my best mate often gets called unexpectedly to help out and he’s had to break away from his own Mk3 Fiesta build, we always get there in the end though!”

It’s the supercharger itself that Louis can’t get enough of “The way the power comes in, it’s more like a turbo and not your average supercharger,” he tells us, “on full boost at 13psi its mental, the power kicks in just before 4000rpm and it takes off!” Not only is the power itself addictive, the noise it makes on full boost always has Louis smiling too. “I’ve taken passengers out on track in this car and they’ve always come back with a huge grin on their face,” he adds.

Projects like this are never fully completed and Louis plans to add an oil cooler next along with a rear roll cage to complete that track car look. “I may even forge the engine and add some cams, but I’ve seen many STs on stock internals cope with up to 330bhp, so we’ll just see how it lasts,” he tells us.

He’s also got his eye on a follow up project in the shape of a Mk6 Ford Fiesta running a Cosworth YB, but for now it seems he’s quite content with his awesome supercharged Fiesta ST150.

Tech Spec: Supercharged Fiesta ST150


2.0-litre ST Duratec engine, Jamsport Stage 2.5 supercharger Kit, Rotrex C30 centrifugal supercharger, Pipercross air filter, Airtec intercooler, Auto Specialists inlet, oil cooler for the supercharger, 440cc injectors, 60mm throttle body, Milltek exhaust inc. EVO 2 manifold, mapped by Jamie at Jamsport, JS Performance power steering relocation kit, mountune short shifter, Magnecor HT leads, NGK spark plugs


311bhp & 258lb.ft


Rebuilt ST150 gearbox, Quaife ATB diff, Sachs Race Engineering 4-paddle clutch, TTV lightened flywheel


BC Racing BR-V2 coilovers with camber adjusters, Whiteline rear anti-roll bar, fully polybushed throughout, OMP front strut brace


Fronts: Focus ST170 300mm front brake upgrade with J-hook discs and Ferodo DS2500 pads.
Rears: Focus ST170 280mm rear brake upgrade with J-hook discs and Ferodo DS2500 pads

Wheels & tyres:

15in Team Dynamics Pro Race 1.2 alloys, Nankang NS2R 195/50×15 track day tyres


Fiesta ST bodykit, full TRC low line kit and rear diffuser, custom stripes, Ford Racing bonnet raisers, red and black Ford badges, front fog lights removed, Auto Specialists tow strap, 300mm sunstrip, race numbers


Corbeau Clubsport bucket seats with 3in black OMP 4-point harnesses, OMP Target snap-off steering wheel, NRG hub with BG Racing snap-off kit, most of interior stripped apart from front door cars and headlining