World Rally Car-Inspired Ford Focus RS

Press Release

Duratec RS Power

The very heart of the invigorating performance experience of the Focus RS is its powerful new 215-PS Duratec RS engine, which traces its roots to the Focus WRC engine design. With an air-to-water aircharge intercooler, a water-cooled turbocharger and oil-spray cooled pistons, it boosts the four-cylinder engine’s output into genuine high-performance territory.

The uprated engine delivers 65 per cent more horsepower – 215 PS at 5,500 rpm –than the mainstream 2.0-litre Duratec engine of the Focus family. The turbocharged engine also boosts available torque by 75 per cent to a peak of 310 Nm at 3,500 rpm. This heady combination gives Focus RS its punchy throttle response, exhilarating acceleration and impressive top-speed potential.

A custom-built turbocharger, the Garrett GT 2560LS, delivers the boost. It is Garrett’s first petrol engine turbocharger application to use stainless steel for the turbine housing.

The turbocharger size has been optimised to give the best possible balance between high power and good transient response. Its hardened stainless-steel turbine housing material can better withstand exhaust temperatures of up to 960º C, which the Duratec RS engine can generate.

A boost recirculation valve is used in the intake system to prevent an undesirable phenomenon known as 'compressor surge' on deceleration and to reduce turbo lag following a gear change.

When the driver momentarily lifts off the throttle a conventional turbo produces excessive boost and the control system acts to open the exhaust wastegate and slow the spinning turbo. Turbo lag is largely caused by the time taken for the turbo to accelerate up to its optimum speed again. The recirculation valve opens when the throttle is lifted, re-directing the boosted air back into the compressor inlet. This avoids the excessive pressure build-up and the wastegate system keeps the turbo spinning fast. The benefit comes when the throttle is opened again and full boost is available almost instantly.

The recirculation valve is technically superior to the often-used ‘dump’ valve as it allows the engine management system to maintain the optimum fuelling.

The EEC-V Powertrain Control Module (PCM) has several novel features to optimise the performance of the engine. It senses which gear is being used and adopts different torque curves in the lower gears to optimise traction and prevent overstressing of the transmission. It also monitors the temperature of the air entering the engine and modifies the boost pressure to deliver consistent power and torque levels for all ambient conditions.

There is also a measure designed into the unit to protect against potential engine failures from after-market ‘chip-tuning’ power modifications.

The PCM determines the required boost level, from the driver throttle input and other engine sensors, thereafter constantly monitoring the boost and adjusting the wastegate until the target pressure is reached. During this control process, the PCM is learning the wastegate characteristics, adapting to the effects of wear or manufacturing tolerances within the turbocharger. Turbocharger longevity and durability are protected by a water-cooled bearing housing, which prevents thermal degradation of the oil within the bearings when the engine is switched off whilst hot.

Vital to any turbocharged petrol engine is an efficient intercooler. This heat exchanger takes excess heat out of the compressed air from the turbocharger compressor, cooling it down and increasing its density as much as possible. The RS intercooler will deliver air temperatures typically of 40-60º C at peak power.

The 'no compromise' design philosophy of the Focus RS dictated the specification of an air-to-water intercooler. This approach also benefits the under bonnet packaging in that the charge cooler now occupies the space vacated by the standard air cleaner. This helps to minimise the intake volume between the turbocharger compressor and the engine, in order to optimise boost response. Using water as the cooling medium results in a higher thermal inertia in the system, giving lower charge temperatures and maximum performance during transient operation, such as hard accelerations.

The water circuit for the intercooler is entirely separate from the engine cooling system and has its own radiator placed in the airstream ahead of the engine-cooling radiator. The large lower grille in the front bumper positions the intercooler radiator directly in the airflow for maximum cooling effect.

To achieve the 215-PS power level, a very free flowing exhaust was imperative. However, this requirement has to be balanced against the need to reduce emissions with a catalyst system. The Focus RS meets these conflicting demands with a bespoke system that features a fast light-off catalyst close to the turbocharger, a larger main catalyst, a low-loss silencer design and a titanium-coloured finisher.

Vital lessons learned from several years of the Focus WRC programme indicated at an early stage of development that a higher-flow-rate water pump would be required for Focus RS. Consequently, a completely new water pump was designed and developed. With a power increase of 65 per cent, there is inevitably a similar rise in the heat generated by the engine. Greater coolant flows are required to remove this heat and ensure the engine does not exceed its safe working temperature limits.

Focus RS also features high-flow fuel pump and injector designs, also WRC inspired.

New forged connecting rods and pistons have been developed to cope with the increased cylinder pressures. In addition, the piston pin design was changed from a press fit to a fully floating design. Forged rather than cast, the aluminium piston is based on that used in the WRC engines for added durability. The internal compression ratio is reduced from the standard 10:1 to 8:1.

Sodium-filled exhaust valves are employed in the Duratec’s aluminium cylinder head to increase the transfer of heat away from the valve head, improving component life and reducing the risk of detonation. The valve springs are also tuned to increase the closing forces, essential to prevent the exhaust valves from leaking exhaust gases back into the combustion chamber under back-pressure. Conditions of high exhaust manifold pressure occur when the turbocharger is delivering high boost pressures, such as at peak power conditions.

To meet the demanding quality and consistency targets expected of a mainstream product, considerable engineering effort has gone into ensuring the engine can be assembled in a high-volume production facility, where continual quality checks are routine. Also, at the end of its assembly, every Duratec RS engine undergoes a hot test to assure the quality of the finished engine.

“Engineering an all-new powertrain with a 65 per cent power increase was the biggest challenge of the entire RS programme�, said Dr. Georg Heuser, Focus RS powertrain manager. “Ford's strict standards for quality and engineering excellence were applied rigorously to achieve excellent levels of driveability, responsiveness, refinement and performance. I believe this painstaking effort will set Focus RS apart from its major competitors.�

Unique Transmission with Torque-biasing Differential

Focus RS has been comprehensively engineered to transform high levels of torque into effective traction at the drive wheels. Its uprated 5-speed MTX75 transmission plays a key role in this strategy while contributing significantly to the performance feel of the vehicle.

At its heart is a race-bred Quaife Automatic Torque-Biasing (ATB) differential.

Combined with a chassis developed to use torque effectively, the Quaife differential helps Focus RS accelerate without provoking wheel spin in dry conditions. When the throttle is heavily depressed from standstill the car accelerates in a straight line. In the wet, the wheels may spin but the torque-biasing capability ensures that the car remains straight, making Focus RS a very forgiving and relatively easy car to drive despite its high-torque output through the front wheels.

Unlike the standard plate-type differential, the custom-designed Quaife differential uses worm gears to transfer seamlessly the torque between the two wheels according to the level of traction available. This ensures that it never locks up like a plate-type differential, delivering better traction for the vehicle at high power.

“With a standard differential, you have to lose traction before you regain it,� explained Kilpin. “The more sophisticated Quaife technology, which we have customised especially for this application, gives the Focus RS driver a big advantage when it comes to keeping the power on the ground and reducing the potential for understeer.�

Previous locking type differentials tended to tug at the steering wheel and produce more understeer, and under hard acceleration there was always the tendency for it to pull the wheels one way or the other.

Torque also is electronically limited in first, second and reverse gears to protect the transmission and aid the driving experience by eliminating any vicious snap of torque, thus providing an inherent degree of traction control.

The gearbox incorporates a unique set of close ratio gears developed to provide optimum performance and animated driving quality. Evenly spaced, the gearing provides the Focus RS driver with punchy acceleration, taking full advantage of the turbocharged power of the Duratec RS engine. The gear cogs are shot-peened for enhanced robustness.

“Feedback from the Focus RS WRC drivers throughout the programme was crucial in developing the 'rally car for the road' feel,� said Kilpin. “For the transmission, that dictated a choice of ratios biased towards in-gear acceleration.�

To transmit engine power into the gearbox, Ford RS engineers specified another no-compromise piece of race-bred equipment, a heavily uprated AP Racing clutch. Shift feel, another important attribute for the performance purist, was the focal point of extensive attention to detail by the Focus RS development team.

Focus RS’s Sparco solid aluminium gear selector features a short-throw shifter mechanism. It ensures an extremely positive shift feel and reduced gear lever movement, enhancing the performance driver’s feeling of connectivity with the car.

Rally-bred Exterior

With its purposeful appearance, the Ford Focus RS is immediately recognisable as a serious performance vehicle. It takes its function-driven design cues directly from a world-class motorsport competitor, the Ford Focus WRC.

The shape of the Focus RS has been painstakingly developed and aerodynamically honed to create a car worthy of the RS name. Rather than overcomplicate the styling, Ford stylists have chosen to detail forms with crisp accent lines, combining sophistication with performance engineering elements.

“Focus RS sets itself apart visually from the competition by communicating a clean, mature message, that is delivered without resort to frivolous extra forms and details,� said Chris Bird, Design Director, Ford of Europe.

While reflecting design cues from the Focus WRC, Bird and his team worked to assure that the new Focus RS would have the robustness and dependability that comes from more production-feasible materials than those found in an all-out competition vehicle like a world rally car. The result of these efforts with materials specification is a performance vehicle that meets all of Ford's production-car safety and quality standards.

Only the bonnet, tailgate, doors and roof panel remain unchanged from the standard Focus. Every other exterior panel of the Focus RS body is unique, inspired by the stance and attitude of the Focus WRC. New sheet metal for the front and rear quarter panels has been designed with wide wheel arch extensions to complement the wider track of the Focus RS, and the front and rear bumpers and sill mouldings are unique.

The body structure begins its life like every other Focus at Ford’s Saarlouis Assembly Plant in Germany. It is diverted from the standard assembly process to allow a special engineering centre to install the crucial body modifications, especially the custom-shaped rear quarter panels, which are welded in place of the standard Focus items.

Before rejoining the standard assembly process to undergo final metal finishing and the full production paint process, in which it gets its exclusive blue sheen, Focus RS is fitted with durable reinforced polypropylene moulded front and rear bumpers, side sills and a rear spoiler mounted on the tailgate.

The unique, shaped bumpers provide a distinctive look of performance with road-car aerodynamic functionality.

The rally version of the Focus is designed primarily to produce extensive downforce at speeds not much more than 100 mph. More downforce provides rally drivers with high levels of grip at the expense of top-end speed. In Focus RS, the emphasis is much more on higher speed stability. As a result, the car has been extensively wind tunnel tested using data gathered from the WRC programme.

The result of the revised exterior shape with the deeper front grille and wider footprint tyres is a drag co-efficient of 0.365.

Viewed head-on, Focus RS incorporates grille apertures similar to the WRC car, but with added Hella fog lights. Twin slots in front of each wheel arch aid in underbonnet cooling, and the radiators for engine cooling and turbocharger intercooling are positioned behind the large central grille opening.

For use on the Focus RS, the headlamp from the Focus range has been modified to remove the integral turn indicator in favour of bumper-mounted indicator lamps, another Focus WRC-inspired touch. Turn indicators are fitted with blue bulbs that complement the Imperial Blue Focus RS exterior colour scheme when they are not illuminated. These special bulbs become amber-coloured when illuminated.

Focus RS remains easy to drive despite the major external revisions, retaining highly practical ramp angles front and rear for negotiating normal driving hazards such as speed humps or angled driveways.

Other performance equipment fitted in specialist centres includes the Michelin Pilot Sport performance tyres, mated to the 18-inch O.Z. Racing wheels. Once complete, each vehicle’s suspension is minutely inspected to ensure that Focus RS’s carefully engineered geometry and optimal track settings are in compliance. It is this intensive specialist attention that mirrors Focus RS’s motorsport heritage.

Finally, each car goes on a dedicated rolling-road test before its sign-off as a Focus RS.

Competition-inspired Interior

To match its impressive all-around, competition-inspired performance, Focus RS features an interior with even more functional, motorsport-derived equipment.

The Focus RS performance driver benefits from WRC-derived elements carefully designed with simplicity, style, quality and durability very much in mind. Just three surface colours are featured throughout – black, blue and silver – punctuated by special touches that include carbon-fibre.

“The metallic elements are functional, the leather is high quality, the Alcantara is purposeful and the carbon fibre is real,� said Ford of Europe Design Director Chris Bird. “There is nothing fake about the interior of Focus RS.�

The most striking of all the interior appointments are the race-inspired seats, developed in conjunction with Sparco. Extensively track-tested to deliver just the right combination of comfort and impressive grip for spirited driving, the Sparco seats reflect the attention to quality that has permeated every aspect of this top Focus performance vehicle.

“We spent countless hours test-driving the RS seats,� Bird said. “They are not just a pretty package. Professional drivers took these seats through their paces, changing fabrics, foam densities, support structures and even logo location.�

The seats are stitched in a black leather with dramatic dual stripes in blue leather, plus carefully positioned panels of contrasting black Alcantara cushion and backrest inserts which provide extra grip, enhancing driver and passenger seat location under hard cornering.

Bold Sparco branding on the headrests and discreet RS logos embossed on the seat cushions complete the heritage link for performance purists. The Sparco seat design also features integrated harness slots within the headrests, just like the full racing version, while also providing comfort and ease of use for everyday driving. The drivers seat is four-way adjustable.

Sparco branding adorns the backrest of the rear seat, which is produced in matching hide with feature lines stitched in to identify the separate seat positions. The 60-40 split seatback design ensures that Focus RS retains all of the loading flexibility of its sibling models.

Rounding off the quality interior theme are distinctive carpet mats with subtle RS branding. Rally-inspired details continue in the unique Focus RS instrumentation design, most noticeably with the bold “blue band� graphic scheme of the analogue speedometer and tachometer dials. Each gauge features a backlit blue band on a black field, in a style closely matched to the rally car.

This exclusive instrument cluster features functionally segregated and individually framed gauges, and performance purists will also note other unique functional differences from the rest of the Focus family. These include:

• A turbo boost gauge, which occupies a prime position to the left of the tachometer. It is fitted in place of the standard water temperature gauge, which is replaced by a warning light.
• A change-up light, another feature taken from the rally car, has been added within the rev counter to prompt the driver visually to shift gear.

The steering wheel, finished in blue/black leather with an oversteer indicator stitched in, has been specially manufactured for Focus RS. Focus RS’s fascia and door panels are produced in Midnight black with blue leather inserts for the doors and rear quarters.

Neat metal interior elements geared to the performance driver include an aluminium handbrake lever, short-throw shifter knob and drilled-style aluminium pedals with rubber inserts, all specified from performance specialist Sparco. Electro-plated satin aluminium effect door handles and stainless steel scuff plates with RS lettering augment the metal theme.

The eye is drawn to another motorsport detail as the driver prepares to start the powerful intercooled turbo Duratec RS engine. It is the functional start button in Focus RS’s carbon-fibre centre console.

“The centre console was changed not just for aesthetic purposes alone,� Bird said. “The new short-throw shifter has different packaging requirements that the base console couldn’t accommodate. This also gave us the chance to integrate carbon elements and the start button.�

The carbon-fibre centre console also serves as an indication of the exclusivity of the new Focus RS. Each vehicle is individually numbered on a special aluminium plate located by the start button on the console unit.

Despite the focus on performance detail in its interior, the new Focus RS doesn’t overlook creature comforts and convenience. Focus RS retains the highly practical interior layout of the standard Focus, and boasts power assisted windows, power steering, air conditioning and Ford’s in-dash six-CD changer as part of its long list of standard features.