Thanks to a custom turbo conversion, and plenty of supporting mods to keep it all together, Nathan Birch’s little Fiesta ST produces over twice the original power output; 332.9bhp... on its lowest boost setting!
332bhp Mk6 ST was built to wow at shows and on the track.
When the Mk6 Fiesta ST first hit the showrooms back in 2005 (yes, it really was that long ago!), it was seen as a real breakthrough for Ford. There hadn’t been a hot Fiesta for far too long, but fortunately finally Ford came up with the goods in 2004 with the 150bhp Fiesta ST. The feisty little Fiesta delivered in every area, and many reckoned its capable chassis could handle plenty more power. Little wonder then, that over a decade on, we’re still seeing freshly-built Mk6 STs with over double their original power output under the bonnet.
For 25-year-old Nathan Birch, it happened to be his dad’s car that gave him the inspiration to use a Mk6 ST as a project base. “I’d had a Polo TDi for my first car, then moved on to a 1.2 Corsa SXi which I began to modify – as you do when you’re 17,” Nathan remembers, “around that time my dad bought an immaculate one-owner-from-new Frozen White Fiesta ST and I fell in love with that car straight away.”
Nathan knew full well at the time there was no way he could afford to insure even a standard Fiesta ST, but two agonizingly-long years later, he found the costs to just about be realistic. “My dad had decided to move on to another car, I knew I had to buy his
Fiesta now,” Nathan recalls, “it was a now-ornever opportunity.”
As you’d expect, the ST didn’t remain standard for long and the mods soon began. “I couldn’t help myself,” he laughs, “within a couple of months I’d fitted AP coilovers, 20mm rear hub spacers and a rear anti-roll bar, which made the car handle like it was on rails.” Nathan then moved on to the performance side of things, with a Milltek exhaust, K&N filter and 60mm throttle body all added, “it helped the engine breathe a little better and there was now an addictive burble from the exhaust along with a few pops and bangs.”
Nothing unusual so far you may think, just a scattering of well selected mods to enhance the performance of an already nimble ST… but that was soon to change. “I had a ride out in a mate’s turbocharged Fiesta,” Nathan remembers, “I was instantly impressed and knew straight away which direction to take my own car.”
In the short term, the change to forced induction had to wait, Nathan electing to enhance the subtle ST’s exterior initially. At first glance, there doesn’t appear to be any dramatic changes to the body itself other than the TRC front splitter and bonnet lip. Look closer, though, and you’ll soon spot the smoothed quick-release front bumper and smooth rear bumper. That’s in addition to the gloss black trim, window tints, halo headlights and wind deflectors which all help to make this Fiesta stand out from your average ST.
By now Nathan had full intentions of doubling the car’s original power output, so in contrast to many project’s out there he decided sensibly to upgrade the brakes in readiness. At the front there’s now ST170 300mm brakes and at the rear 280mm discs and calipers from the same donor car. These not only improve the stopping power, but also look pretty cool between the spokes of those hard as nails 7.0x16in Team Dynamics Pro Race 1.2 rims in contrasting bright red.
Now that the chassis and brakes were capable of handling plenty more bhp, Nathan began to make a start on his longanticipated turbo conversion. The rebuilt 2.0-litre Duratec now benefits from forged rods and pistons, Newman cams, ARP bolts, uprated bearings and high pressure oil pump. That’s in addition to the uprated head gasket, 660cc injectors and 19 row oil cooler – aided by the clever cooling duct located in the front bumper. In fact, everything possible has been upgraded in some way, even down to the Cosworth inlet manifold, performance silicone hose kit, relocated power steering and that unusual, but cool, side-exit exhaust!
Helping to keep the engine temperature happy there’s now an Airtec alloy radiator and intercooler in place, which also helps enhance that already aggressive front end. These additions all looked good and help give the engine bay plenty of sparkle as well as performance kudos, but the main ingredient is neatly tucked away, hidden at the back of the engine; the TD05 hybrid turbocharger.
Fitting it was far from plain sailing though, and certainly not just a case of bolting parts on to a rebuilt engine and turning the key. “After initially having the engine rebuilt with the turbo, the car kept stalling,” Nathan recalls, “after seeking advice from a couple of specialists, they couldn’t find the cause.” A switch to a GEMS standalone ECU was suggested, but the problem still persisted. “I decided to go through everything in
“The turbo has to be my favourite mod, the sound it makes is unbelievable – it sounds like a jet fighter taking off...”
“Nathan’s intentions were to build a car for track use that would look equally at home at a show, and we reckon he’s achieved his goal and then some”
the car and began swapping parts one by one with my Fiesta ST track car which I knew ran okay,” Nathan explains, “after months of head scratching it turned out to be a faulty throttle body causing the stalling issues, “I was over the moon I’d found out what it was and ordered a new 60mm throttle body and booked the car in for mapping with Darren at DWR Performance,” Nathan smiles. The result speaks for itself, with an impressive 332.9bhp at 7070 rpm on the rollers – and that’s with only 0.9-bar of boost!
Swapping the original gearbox for a stronger MTX75 ‘box along with an LSD at the same time also seemed like a sensible approach. Unfortunately, problems arose once again. This time the slave cylinder gave up the ghost after just 200 miles. “It happened loads of times too, not just once,” Nathan adds, “I was close to giving up on the whole idea and stripping the car for parts, but I’m glad I didn’t!” In the end, Nathan decided to find the root of the cause one night and took the car to his mate’s garage. “We could remove and refit the gearbox with our eyes closed by now, but this time stripped it totally down and spaced the slave out from the gearbox as it appeared to be over stroking.” According to Nathan, this is quite an uncommon problem and after remaining in the garage throughout that night ensuring all the internals remained as they should, the problem seems to have disappeared. Phew!
That just left the interior to sort and after pouring many hours and wages into the rest of the car, he wasn’t going to start cutting corners here. The full 6-point OMP roll cage dominates as you’d expect, and the Sparco Pro-2000 bucket seats with 4-point harnesses are in keeping with the functional theme. “I knew I’d have my work cut out when it came to the interior as I’d never used a welder before,” Nathan laughs, “luckily Carl at Raven Blasting Cleaning was on hand for a spot of teaching and pointing me in the right direction.” The quick-release 300mm OMP steering wheel looks right at home too and Nathan’s also flocked the dash, added gauges and his own door panels and centre console is custom-made.
All elements of refinement have disappeared, even down to the lack of stereo, heaters, and air-con. This ST is all about saving weight and going as quickly as possible after all.
Incredibly, other than the engine rebuild, wiring, and the help we’ve already touched on with the welding and gearbox issue, everything you see has been carried out by Nathan himself. And when you factor it all in, that’s a huge amount of work, especially juggling building this project around a fulltime job. “The first time I took my mate out in the car just after it went back on the road his words were ‘you have built a beast!’ and that was just at 300bhp before I’d fitted the standalone ECU,” Nathan laughs, “the turbo itself has to be my favourite mod, the sound it makes is unbelievable – it’s like a jet fighter taking off, and you get that same feeling of being pinned back in the seat as it kicks in.”
Despite every aspect of this build having been covered once – and in some cases more – Nathan’s still keen to make a few changes. A full Powerflex black series polybush kit and a swap to BC Racing or Meister R suspension is likely in the near future which should help add some camber at the front.
There may have been a few setbacks along the way, but Nathan shows no signs of slowing down and would love to take on a similar build based on a wide arch Mk1 Escort with Cosworth power next. A big challenge, but listening to his enthusiasm we wouldn’t be surprised if it happens soon.
As for the ST, Nathan’s intentions were to build a car for track use that would look equally at home at a show, effectively the perfect all-rounder, and we reckon he’s achieved his goal and then some.
TD05 turbo is at the heart of this ST’s incredible power figure
Nathan’s upgraded the suspension too, but even more chassis tweaks could be on the cards soon
With a full OMP cage and Sparco buckets, this is one track-ready Fiesta The gearbox has been replaced with a stronger MTX75 to handle the power