2.0-litre ST170 engined 400bhp 1990 Ford Sierra LX Estate

Built in a garage at home and with 400 bhp on tap, this unsuspecting Sierra estate is a perfect homebuilt hero in every way. Words Simon Holmes. Photos Andy Saunders.

SPECIAL BREW

SIERRA ESTATE TURBO TOURER ST170 turbo-powered sleeper estate.

Sometimes you find yourself falling into a project without even meaning to, but it’s often those kind of builds that turn out best. With no tune to follow, the natural process of fate will find a way of helping, which is exactly how owner Kurt Tann turned this cheap and cheerful Sierra into an awesome homebuilt street sleeper like no other. Thanks to a turbocharged homebrew special under the bonnet and an unsuspecting look both inside and out, Kurt has built a truly unique classic Ford.

As he likes a 1980s Ford, Kurt has owned a few over the years and was actually in the process of rebuilding both a Mk2 Orion and Mk3 Granada when he first heard this Sierra was up for sale.

“A friend was actually eyeing the car up and decided against it,” Kurt recalls. “He had sent me the details and after a chat I decided if he wasn’t going to have it, I had to have a look. I literally had no interest in Mk2 Sierras at all, but at £250 I couldn’t knock it for a rear-wheel-drive Ford.”

Sure enough the car appeared to be a bargain, as not only was it a really tidy example but the engine bay and interior were spotless. Aside from a couple of small bits the bodywork was decent too, plus it had every service stamp, past MoTs and a whole load of history. But although it was great buy, Kurt didn’t actually have much need for the car other than to use it for a summer.

“It sounds odd, but I actually purchased it because at the time I thought the rear end was that ugly it looked cool,” he explains. “I literally had no idea what to do with the car, as all I actually planned was to run it through summer 2015 to go to the Classic Ford Show and then sell it to crack on with my other cars.”

Rolling project

However, that soon changed as fate began to play into his hands and the car became a rolling project after a small bump while driving on ice was followed by the discovery the trusty Pinto needed attention.

“As I straightened out the damage, I found the stem seals in the original engine had gone hard,” Kurt reveals, “so I figured I’d drop a Zetec on bike carbs into it that I had sat waiting on a pallet.”

Along with a few other upgrades and additions the Sierra soon began to pick up pace, especially when a bet with a mate in the pub led to a budget-build Zetec turbo conversion. That saw a few revisions when it came to plumbing and manifold configurations but ended up making a healthy 275 bhp and led to bigger things. “When that motor died after a drag racing day out in 2019, I decided if I was going to do it again I would take the time and do it properly,” remembers Kurt. “So the ST170 turbo idea soon came about from chatting about specs with a couple of mates.”

The current build is the best yet and revolves around a heavily-reworked ST170 engine, complete with upgraded, forged pistons, steel rods and a tickled cylinder head. To go with it is a large GTX3076 turbo that much like the rest of the build has been fitted using Kurt’s home-brewed skills. For instance, the exhaust manifold is a Nissan 200SX item that has been heavily adapted to fit and the same goes for the inlet plenum, which started life on a Mitsubishi Evo and has been modified to fit the ST170 lower manifold.

“Pretty much the majority of the work was done by myself, bar a couple bits of alloy TiG welding and the odd piece of help here and there where I’ve not been able to access kit,” he explains. “The majority was done between sheds at home by juggling space.”

Other custom parts with Kurt’s input include the sump, plumbing and external oil pump set-up, although he tells us the trickiest job was something that looks much simpler. “The hardest part was actually getting the US-spec rocker cover to fit,” reveals Kurt. “It involved coupling an ST170 and US-spec Zetec cover into one.”

Essential upgrades

To continue the mixed-and-matched theme, the engine is attached to a Mazda RX-8 gearbox with an uprated clutch and powers the wheels via a proper, plated LSD. The combination is incredibly effective and Kurt says the car performs very well, so far running a best of 415 bhp and 335 lb.ft of torque.

Having previously managed a best of 13.5 seconds in the quarter mile with just 275 bhp, the new set-up is yet to be properly tested but should be plenty quicker. While the running gear has been heavily reworked and the exterior finely detailed (see boxout on page 41), the inside remains relatively standard, which was always the plan: “Anyone that’s owned a Sierra knows how comfy they are so I didn’t want to lose that and bought a scrapper GLX estate for just £40 with a mint interior, so it was a no-brainier.” Sure enough, the combination of comfort and performance make the car a joy to use and the Kurt tells us it’s at home on the road as much as it is on the strip.

“It actually drives pretty well day-to-day,” he explains. “It’s definitely still useable on the road, albeit Cornish roads aren’t the most forgiving for a lowered car but a majority of the time it’s just used for going for a drive and enjoying at the occasional drag day!”

More and more

As with any home build, there’s still more to do as Kurt has plans to tune the car further and make some improvements, as he explains. “I want to dial the VVT in and drop the exhaust housing size a bit to move the boost range a bit lower,” he reveals. “There’s also a Supra diff to go in the back end along with a spare rear beam that’s destined for the chop saw to make it fully adjustable. Plus I’d like beef up the fuel system, add some more boost and sort out a few project niggles.”

With no end in sight but more ideas in the pipeline, we expect to see Kurt developing the special brew Sierra a whole lot more in the future.

Tech Spec

• Body 1990 Ford Sierra LX Estate, strengthened rear turrets, boot floor/rear wheel well removed, Ford option front splitter. Paint: Maritime Blue with red bonnet
• Engine 2-litre ST170 engine, home-made sump, ARP bottom end studs with custom adapters to run windage tray, standard crank, PEC steel H-beam rods, ARP rod bolts, Focus RS spec forged pistons with custom valve pockets, decked ST170 block, 0.6 mm MLS head gasket, ARP head studs, ST170 head with exhaust ports flowed and polished, Peugeot 106 GTi Newman Cams 160 lb valve springs and retainers, ToyotaYaris coil-on-plug set-up, home-made external oil pump set-up, home-made water rail, Garret Gen 1 GTX3076r turbo, homemade exhaust manifold (Nissan SR20-based), homemade plenum (4G63 Mitsubishi-based), modified runner and throttle body flange to suit ST170 lower inlet, 80-mm throttle body, Siemens Deka 875cc injectors, 280 lph fuel pump, Facet lift pump, homemade swirl pot, 8 mm copper fuel lines, Zetec to Cosworth lightened flywheel, homemade 3 inch exhaust, custom US-spec/ST170 rocker cover, modified Sierra Cosworth radiator, modified RS500-style intercooler, homemade 2.5 inch boost pipes, Range Rover fans for cooling, Ecumaster EMU Classic management
• Transmission Custom Zetec to Mazda RX-8 adapter plate, Mazda RX-8 gearbox, hydraulic clutch conversion, CG Motorsport Stage 3 Cosworth clutch kit, homemade propshaft, Titan Motorsport plated slipper with adapted stub shafts
• Suspension Front: GAZ coil-overs, Mk3 Granada antiroll bar Rear: GAZ coil-overs, XR4x4 rear beam. Polybushed throughout
• Brakes Front: Sierra Cosworth four-pot callipers and discs. Rear: XR4x4 rear discs and callipers. Braided lines all round
• Wheels and tyres 7x16 inch Citroen steel wheels, with 165/45R16 tyres
• Interior Standard specification GLX trim, LD Performance dash display, Safety Devices six-point roll cage
• Thanks Massive thanks to anyone that’s had any involvement with it over the years in different ways, whether it be motivation, advice or midnight help, and especially, Phil, Tub, Ben, Shakey, Josh and Ads, my parents, and Yas

“THERE’S ALWAYS MORE TO DO I WANT TO DIAL THE VVT IN A BIT MORE, FOR INSTANCE”

Load bay now houses the battery and swirl pot for the fuel system — Kurt

plans to upgrade the latter further. Inlet plenum is a muchmodified Mitsubishi Evo item.

The current ST170-based and home-brewed engine is heavily-reworked to handle the boost, making 415 bhp.

HOMEBUILT HERO

• Initially, Kurt bought the Sierra as a (very) cheap runaround. Only later did he see its potential.
• Then, once he saw the potential Kurt got carried away, with fuel system and diff upgrades underway.
• Once done, the suspension and running gear were removed to respray the underside in body colour.
• The Mk2 Sierra was clean, untouched and more-importantly, just £250. The ideal daily driver.
• The rear beam, diff casing and fuel tank were painted or powdercoated too, for an on-point finish.
• Meanwhile, the new engine was in-progress, with the turbo sat on a modified Nissan manifold.
• The red bonnet certainly draws comments, but there’s no doubting this is Kurt’s car.
• Kurt has plans for the GTX turbo, including a smaller exhaust housing to make it more road-friendly.

THE LOOK WHY THE RED BONNET?

Although the car has a great, understated style, Kurt tells us it happened by accident, quite literally. “There wasn’t really a plan for the exterior as such,” he reveals. “But partially down to the little mishap I had, I’ve always had a soft spot for the American Moonshine Runner/Bootlegger cars; rough enough, simple and set up with a bit of poke underneath.” With that in mind, the replacement red bonnet has purposely been kept that contrasting colour and coupled with the steel wheels and sleeper style the car always gets a good reaction. “Mostly people laugh and it’s generally good really,” tells Kurt. “I think it’s down to the fact that most people can relate to wanting something similar themselves — although the bonnet can split opinion.”

Left: roll cage and GLX-spec trim? Well, why not? For the road: Sierra’s interior remains fully trimmed.Drilled bumper supplies extra air to the RS500-style intercooler. Digital display and extra gauges keep tabs on the vitals.

“THE ST170 TURBO IDEA CAME ABOUT AFTER CHATTING ABOUT SPECS WITH A COUPLE OF MATES”