Fiesta ST is powered by a specially modified version of Ford’s 2.0 litre Duratec 16-valve engine, delivering 150PS and a wide spread of torque for flexibility and pulling power. The Fiesta ST gets from 0 to 60mph in just 7.9 sec and 0 – 100 km/h sprint takes 8.4 secs and maximum speed is 208 km/h.
Fiesta’s acclaimed chassis has been modified to deliver class-leading handling and roadholding for the ST. Steering is quicker acting and the brakes have improved in performance, with rear disc brakes fitted for the first time on Fiesta.
Transmission ratios in the five-speed manual gearbox have been revised and there is a new, short-throw gearshift for ultra-fast, precise gear changes.
Fiesta ST looks the part, too. A wider and deeper front grille, new bumper mouldings, discrete side skirts and a functional rear spoiler complement its low stance, and handsome multi-spoke alloy wheels with low profile, specially tuned Pirelli P Zero tyres to create a bold, performance look.
Inside, the cabin has also been given the ST treatment. Unique new front sports seats are trimmed in black leather with bold red or blue cloth centre sections and the distinctive new ST logo. ST interior detailing includes a thick, leather-wrapped steering wheel, unique gear lever, metal foot pedals and ST branded scuff plates.
Flexible performer
At the heart of the new Fiesta ST is the 1999cc Ford Duratec engine, first seen in the Mondeo and also a cornerstone of the new Focus range. The 2.0 litre Duratec engine characteristics are ideally suited to the performance Fiesta as it combines free-revving performance and impressive low-end torque for excellent all-round driveability.
These characteristics also mean that the Fiesta ST’s Duratec 2.0 litre engine can be used in a relatively standard state of tune, adhering to the Sports Technologies principles of enjoyable performance achieved without sacrificing everyday driving capability or dependability.
In the Fiesta ST the engine develops 150PS at 6,000 rpm, compared with the 145PS at 6,000 rpm when installed in the new Focus. The increased output is the result of an all-new, low-loss intake system and a new sports exhaust system that has been developed specifically for the Fiesta ST. Maximum torque of 190Nm is increased from 185Nm and the torque delivery is exceptionally wide spread with 90 per cent of peak torque available from as low as 1,350 rpm, and more than 90 per cent per cent all the way from 2,200 to 6,150 rpm.
In performance terms this means that Fiesta ST has a highly competitive 0 – 100 km/h time of 8.4 seconds and is capable of a 208 km/h maximum speed. Even more important, though, is its mid range acceleration – the true measure of ‘real world’ performance. It can accelerate from 0 - 60 mph in 7.9 secs and 80 - 120 km/h in only 11.2 secs in fifth gear.
New variable intake system
The Duratec’s sophisticated variable intake system (VIS) is the secret to its impressive spread of torque. This system uses gas dynamic effects in the engine’s intake system to tune its performance through variable intake runner lengths. This technology improves the gas-dynamics inside the intake system.
The Duratec’s VIS intake manifold achieves this by using butterfly valves in the runners. These valves are operated by a vacuum motor and split the runners into a longer part and a shorter part. They are closed at low rpm to give a long runner length, and are opened at high rpm to join all the runners to a common air chamber, which sets up a standing wave effectively to generate a shorter runner.
The lightweight, all aluminium alloy construction of the Duratec engine is the key to its successful installation in the Fiesta. The Duratec engine has a gravity sand-cast cylinder block with cast-iron cylinder sleeves cast directly into the block. An aluminium alloy ladder frame structure which carries the bottom crankshaft bearing races and a ribbed aluminium oil pan contribute further to stiffness.
The aluminium alloy cylinder head has an asymmetrical four-valves-per-cylinder layout with twin overhead camshafts driven by a silent chain drive.
Tailored installation
In addition to the new exhaust system, considerable detail engineering work has been done by TeamRS to install the larger power unit into Fiesta ST’s engine compartment. The engine, which is inclined backwards at six degrees, mates to the Durashift transmission via a new clutch housing. Its belt driven auxiliaries have been re-positioned with a rear mounted alternator and front mounted air conditioning pump.
A low inertia flywheel has also been fitted to provide faster throttle response. The Fiesta ST exhaust system incorporates a revised catalyst for reduced back pressure and a great deal of detail tuning work has been done to give the engine a suitably sporty note.
Fiesta’s Durashift 5-speed manual transmission has been extensively modified to suit its application in Fiesta ST. A short-throw gearshift is fitted to allow quick, accurate shifting, all the gear ratios have been changed, and the first, second and third gearsets have been shot-peened for extra strength.
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The TeamRS target for Fiesta ST was to create a fun to drive, rewarding and safe handling car. After nearly two years of development work, on every sort of road from twisty English country lanes to the famous Nurburgring Nordschleife, the team’s engineers feel they have more than achieved their objectives.
The Fiesta range was engineered from the start with a chassis intended to provide high standards of driving quality, inspired by the class-leading dynamics of Focus and augmented a dash of small car fun.
An exceptionally rigid body structure with ultra-stiff mounting points for the suspension and steering was the solid foundation for the team’s work. A rigid front-sub-frame carries the MacPherson strut front suspension and steering system, while the Fiesta’s rear suspension is a twist-beam system that provides accurate control of wheel geometry, has strong lateral stiffness to aid handling and good longitudinal compliance for ride comfort.
All these qualities enabled TeamRS to develop the Fiesta ST without the need for any structural changes to the Fiesta’s core suspension layout.
"The latest generation Fiesta is solid as a rock. It was the ideal basis for a performance derivative," says Ford’s Chief Engineer, Small Cars, Mark Stanton. "Fiesta ST builds on that quality and we believe it extends the strengths of Fiesta as the unquestioned dynamics leader in the segment."
Developed for handling and grip
The ST’s handling set-up has been tailored to reward the enthusiast driver and in the same time enabling relaxed driving. "What I am particularly proud of is that we have achieved its high standards of handling and grip while keeping a really good ride quality," said Ian Hull, Vehicle Integration Manager, TeamRS.
For the ST the front springs have also been considerably stiffened from 16.5N/mm of the standard car to 24N/mm, and the dampers have been recalibrated. A revised design for the front suspension knuckle provides more negative camber to the front suspension to generate more front end grip.
The rear springs also have been stiffened, from 15 to 17 N/mm, and the dampers modified to suit the ST. The twist beam axle has also been stiffened from 520 Nm/degree on the standard Fiesta to 720 Nm/deg.
The steering rack ratio for Fiesta ST has been shortened by ten per cent and the toe-in reduced, to make the steering more agile whilst maintaining high speed stability and controllability. The front sub-frame has been stiffened to enhance suspension control and to create an even more precise steering feel.
Fiesta brakes have been upgraded to match the performance of Fiesta ST. The 258mm x 22mm front ventilated discs have been fitted with larger calipers and pads from the Focus ST170.
At the rear, Fiesta gains disc brakes. Additionally, the brake system has been tuned for optimum response, achieving good initial bite followed by firm, progressive stopping performance from fine tuning of the brake booster.
ESP tuned to complement the ST
Ford’s Electronic Stability Programme (ESP) traction control system is fitted as standard in some European markets on Fiesta ST. ESP uses the individual wheel speed sensors of the ABS system together with yaw rate, steering input and lateral acceleration sensors to constantly monitor the car’s dynamic behaviour and compare it to the driver’s inputs. If the system detects imbalances, it first uses the traction control system to reduce engine power and prevent loss of traction. If it detects understeer, ESP provides a braking impulse to the inside rear wheel to stabilise the car. If it detects oversteer, a braking impulse to the offside front wheel has a similar effect.
The system has been specially calibrated by TeamRS chassis engineers to allow the enthusiast driver to exploit fully the fun to drive of ST within the safety net of the Fiesta ESP system, without the feeling of being restricted by the system.
In order to encourage use of the fun-to-drive aspects of Fiesta ST and fully utilise its chassis dynamics, the system’s oversteer control was also evolved. The result is an ESP calibration that, even under track conditions, the performance driver enjoys exploiting.
Tyre choice has been a crucial part of development, and TeamRS engineers worked closely with Pirelli to develop a special version of the tyre company’s latest high performance P Zero Nero tyre. The P Zero Nero has an asymmetric tread pattern with longitudinal channels to disperse water, optimised for position and size. The central strip is made up of continuous semi-slick elements to increase rigidity and improve directional precision whilst avoiding wheel slip during acceleration.
Fiesta ST comes with a choice of two wheel and tyre sizes, 195/45 ZR16 or 205/40 ZR17, the larger size being optional for most markets. Alloy wheels are a unique and distinctive multi-spoke design.
During the development process of the Fiesta ST a great deal of time and effort was spent ‘balancing’ the controls to create harmony between the feel and responses of the brakes, clutch, steering and gearshift. The objective was to have all these controls feel that they are a coherent part of the same car, and that they all have that essential sporty Ford feel which enthusiasts recognise and appreciate.
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