After twenty years at the top and a decade since its last feature, this modified Ford Sierra Sapphire Cosworth is still pushing boundaries thanks to a new lease of life.
There are few cars that can be described as a true legend within the Ford scene, but this modified Ford Sierra Sapphire Cosworth is most certainly one of them. Owned by the equally legendary Rod Tarry and built by tuning marvel Mark Shead of MA Developments, it was the first road-legal Cosworth to crack 200mph, and despite its subtle looks it has been at the very forefront of YB tuning for over two decades. What’s more, it still is in its new guise, having been recently rebuilt and recommissioned by Mark.
Modified Ford Sierra Sapphire Cosworth build journey
Rod’s story began in 1996 when he bought the rear-wheel drive Sierra Cosworth to use as a fast road car. A 400bhp conversion soon followed and Rod enjoyed it like that until the urge for more began to build, which is a theme that propelled him throughout.
A 500bhp build followed together with uprated brakes, a bigger and better gearbox and bullet-proof diff upgrade to ensure safety and reliability. But that’s when things got a lot more serious as Rod was spurred on when he discovered he owned the fastest Cosworth around, with a top speed of 183mph, and then decided he wanted to retain that crown. So in 2003 he commissioned Mark to build a 640bhp engine with 530lb.ft of torque, together with a shot of nitrous that would see around 720bhp available – a figure completely unheard of at the time.
It was enough to keep him on top and in 2004 the car became the first road-legal Cosworth on the planet to exceed 200mph. To push the record further, a larger GT40 turbo was fitted to find 680bhp and with a 100-shot of nitrous it saw the record raised to 206mph in 2005. Still hungry for more, the development of an 800bhp engine started in 2006 and took some time to complete, but in December 2008 the new unit made 838bhp and 666lb.ft, although no more records were attempted.
Striving for greatness
What was always remarkable about Rod and his modified Ford Sierra Sapphire Cosworth was his enthusiasm and passion to use the car, and despite being in his sixties at this point he was often a regular at car meets, magazine shootouts, as well as appearing on TV. Sadly, Rod passed away in 2018 at the age of 72, before this revision of the car saw completion. He remains sorely missed within the Ford community for pushing boundaries and actively using the Sierra just as it was intended, both on the road and airfield – but his legacy lives on, as the car’s final stage was completed by Mark, who pushed on with the project together with new owner, Carl Billings, and now it’s back better than ever.
“Rod’s original goal when he set out to rebuild it this time round was simple; he wanted to go faster,” Mark recalls. “There was no figure in mind but he wanted it to be better suited to the road, with more driveability too.”
Pushing the boundaries of YB tuning
The current build has taken around eight years to complete as it pushed the limits of YB tuning further than ever before. It revolves around an original 200 block that has been linered and includes a bespoke steel crankshaft and Mark’s own specification forged pistons together with steel rods to bring capacity out to 2150cc. A bottom end girdle helps keep the assembly intact, while a Titan dry sump setup ensures it’s all well-lubricated. The head gasket arrangement is custom; the bolts to clamp it are aero-grade bespoke items, and Mark says this is about as far as you can go with a YB gasket setup.
The head has been heavily fettled and fitted with Mark’s own specification cams to help boost the huge BorgWarner EFR9180 turbo that’s fed by a twin-scroll manifold to improve spool and response. It’s governed by a single 60mm external wastegate that vents back into the downpipe and 3.5” exhaust system, before being sent into the custom Spec-R intercooler. From there, it’s pushed through to the Jenvey Dynamics plenum, which feeds four individual throttle bodies; one for each cylinder, designed to improve low-down throttle response. Fuelling is controlled by an Emtron ECU and voltage amplifiers ensure the fuel pump pressure and coil packs don’t drop during sustained periods of full throttle.
Modified Ford Sierra Sapphire Cosworth power
The dry sump setup, improved electronics and ECU upgrade with motorsport levels of safety features to automatically shut the engine down if it sees oil or fuel pressure drop were also a welcome addition at this level. There are of course other tricks to the engine build and together it works brilliantly well, as Mark reveals: “There are lots of little bits in this build that help make it a much better package overall,” he explains. “And the Jenvey throttle body setup paid off as it helped it drive nicely lower down. The headline power figure is currently 758bhp and 604lb.ft at 2.6-bar of boost on pump fuel, although it previously made slightly more power with a bigger exhaust housing. But current owner Carl requested a smaller housing to improve response on the road, which it does by spooling 400rpm earlier.”
Chassis upgrades for the modified Ford Sierra Sapphire Cosworth
A testament to how well the car was built earlier on, the rear axle remains in place but the Tremec gearbox gave up during an early mapping session. It’s now been replaced by a Tremec TKO600, capable of taking the huge torque and the original clutch setup has also been brought up to date with a custom TTV Racing triple-plate unit. Elsewhere, the original Leda coilovers have been rebuilt and re-valved by Black Art Suspension and provide a significantly improved ride, whereas the AP Racing brakes that have been on the car for many years still work well.
Elsewhere, Rod was always very particular about what he wanted from the car; it was never going to be a stripped-back, bare-bones racer with a complex rollcage to navigate, although later in the build he did have a subtle rollcage made in the name of safety. Instead, the fast road car theme always remained, which is why the original leather trim is in place and there was never anything added that didn’t need to be.
Exterior mods
Outside, the car has been given a mild freshen-up with a return to amber indicators, the front bumper has been fitted with an RS500-style splitter, and there’s a Sapphire 4×4 rear light panel.
Carl is smitten with the car and has been working through the little bits, like replacing the solid mounts with rubber items to reduce vibrations, but Mark is still open to the idea of doing the 200mph+ it did before. “If Carl told me he would like to do top speed events again then that wouldn’t be a problem; I’ve done it before so wouldn’t mind doing it again,” reveals Mark.
The fact that this car still continues to impress is testament to Rod and Mark’s vision, and we’re glad Carl is picking up where they left off.
Words: Simon Holmes. Photos: Ade Brannan.
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