Ford Focus RS: Full tech details

Ford has been producing RS badged performance models in Europe for nearly five decades, but relatively few of them have escaped from the continent.

The new Ford Focus RS is the first to be developed as a world car, set to be sold in both Australia and the USA as well as practically all points in between.

We'll be able to tell you how it drives very soon – anticipation levels are close to drooling – but before then we've been given the full tech lowdown on this 258kW mega-hatch.

The RS was engineered primarily in Europe and under the direction of Ford Performance whose engineering manager, Tyrone Johnson, is American – a mix that reflecting the car's global ambitions.

Johnson is happy to admit that the political challenge of getting sign-off on a performance special like the RS, and especially one that involved the use of a new and extremely expensive all-wheel drive system, was practically as tough as engineering it.

The original plan was that this RS, like the two previous versions, would be front-wheel drive. "But I wasn't interested in doing another front-wheel drive car with a high output," Johnson says.

"We'd done that and it had worked reasonably well, but I was determined that this one would be different."

The big difference came courtesy of British transmission company GKN, and its recently introduced 'Twinster' rear-drive system. Like Haldex, this uses a permanently rotating propshaft to take power from the gearbox to the rear axle.

But instead of one clutch it has separately controlled electronic clutches for each rear wheel, allowing variable amounts of torque to be taken by each. The system both replicates the function of a limited-slip differential, but also allows full torque vectoring across the rear axle.

Up to 70 per cent of available torque can be sent to the back, and up to 100 per cent of this can be sent to either side, with the clutches going from release to fully locked in just 0.06 seconds, says Ford.

It's this that gives the RS its much discussed 'Drift Mode', which directs torque to the outside rear wheel to overspeed it into breakaway and then moves effort as required to keep the car sliding and under control.

The Focus sits on Ford's C1 platform, originally engineered for its predecessor as well as the last Mazda3 and Volvo S40/V50. Volvo insisted that it needed the option of four-wheel drive for its C1 cars and therefore the platform has space for a propshaft down the length of the car and Ford already makes a subframe capable of holding a powered rear axle. But for that, the costs would have been prohibitive.

Looking at the underside of the RS shows what a neat implementation the back axle is. The subframe has been reinforced with new sections and some strategic shell reinforcement improves static torsional stiffness by a remarkable 25 per cent when compared to the standard Focus. An apparently small modification that, thanks to Ford's internal safety auditing, required extensive crash testing to prove it hadn't compromised the Focus's safety case.

The rear axle assembly means the loss of the stock Focus' spare wheel well (it will be squeazy-foam only), and also required the design of a unique saddle-shaped fuel tank to sit above the three-piece propshaft. Johnson says getting the cost of this signed off was the biggest challenge for the whole project.

The new all-wheel drive system adds 60kg in weight, with 25kg of this coming from the rear axle.

Power comes from a substantially modified version of the turbocharged 2.3-litre four-cylinder Ecoboost engine fitted to the Mustang. Peak power is 258kW, peak torque is 439Nm continuous, but with an 'overboost' function that increases this to 470Nm for short periods.

The RS gets a different twin-scroll turbocharger and a unique air box. It also has high-tensile cast-iron cylinder liners to deal with the higher boost pressures and a unique cylinder head.

The exhaust manages without any intermediate silencers; apparently the back box alone is enough to meet noise regulations, helped out by switchable acoustic flaps. Johnson assures us the engine has been tuned to rev harder than the Mustang's tight-feeling powerplant, with the limiter not arriving until 6900rpm.

Unlike its most obvious rivals the RS will only be available with a six-speed manual gearbox. Apparently Ford has never produced a road-going RS variant which didn't have a clutch pedal. That will obviously limit its appeal for now, but Johnson admits a twin-clutch version may follow later if there is sufficient demand for it.

Suspension has been beefed up to take advantage of the RS's increased structural performance. We're told that front springs are 33 per cent stiffer than the Focus ST's, and that the rears are 38 per cent firmer.

Two-stage switchable dampers are fitted as standard, with the firmer 'Sport' mode being 40 per cent firmer in both bounce and rebound. These will be activated in the 'Track' drive mode, but can also be manually selected through a button mounted on the underside of the indicator stalk.

Johnson says that the harder settings really are designed for use on smooth racetracks, to the extent that the car is reportedly faster around the Nurburgring Nordschliefe with its dampers left in their softer standard mode. (We asked by how much but Johnson wouldn't say; the company doesn't publicize its Nurburgring times.)

The electric power steering rack comes from a European market C-MAX and has a 13:1 fixed ratio rather than the ST's variable set-up. Apparently this has been chosen to give more predictable control when the car is oversteering.

European buyers will be able to choose between two different Michelin tyres. Pilot Super Sports come as standard, but there's also the option of track-biased Pilot Sport Cup 2s which are, according to Johnson, quick enough to take two tenths off the standard tyres' 4.6-second 0-100km/h time.

There's also launch mode.

The brakes are the most powerful ever fitted to a production Focus, with vast 347mm (13.65-inch) ventilated discs at the front gripped by four-pot monoblock callipers; they are designed to be able to run for 30-minute stints on track without fading.

Lightweight forged alloy wheels are an option, saving 0.9kg of weight per corner.

But enough of this statistical foreplay. We want to know what the new Focus RS is actually like to drive and it won't be long before we can tell you.

The new Focus RS goes on sale in Australia mid-year, priced from just $50,990. Watch this space for our first drive from the global launch later this week.