TECH SPEC
which has previously been run in Le Mans Prototypes, only with the cylinder head cover and intake manifold modifi ed to allow perfect positioning. Like its predecessor, the engine runs 4500km between rebuilds. Mated to this is a Ricardo six-speed sequential gearbox, fi tted with a pneumatic rather than hydraulic control. This new set up, developed with Shiftec, improves useability and saves weight. The self-locking limited slip differential offers four engine / transmission combinations.
The magnesium casing supports the rear suspension anchor points and has been re-designed to fi t with the new engine, which has a different crankshaft height. However, its internal structure remains the same, which has enabled teams to retain their gear ratios, offering a signifi cant cost saving over an all-’new’ transmission. The triple-plate carbon clutch also remains unchanged from the previous version of the car. Other mechanical changes
have been made to improve the performance of the car. The
suspension is very conventional, as you would expect for this type of car, using double wishbones and pushrod-actuated, two-way adjustable spring / damper units (identical front and rear). The front uses a monoshock layout familiar to anyone who has seen the version employed on the Dallara Formula 3 solution, while twin dampers are fi tted at the rear, as one might expect. However, the two-way adjustable Sachs dampers themselves are new (at least to Formula Renault) and, in total, offer a weight saving of 4kg over the whole car. Unsprung weight has also been reduced through the use of new aluminium uprights that are 65 per cent more rigid than the old units and 3kg lighter each.
WEIGHT WATCHERS Weight loss was clearly something of a theme for Dallara’s engineers and, despite the beefed-up, and consequently heavier, safety structures, the 2012 car has come in 15kg lighter in total compared to the 2011 model. Much of that weight reduction is due to an innovative electronics system, which
includes neither a starter motor or a battery. A capacitor-based electronic
control box from XAP enables temporary energy storage, smoothing the current from the alternator and keeping the on- board electronics energised for three minutes after the engine has stopped, negating the need for a battery. The loss of a starter motor has been enabled by using Formula 1-style anti-stall software loaded into the new ECU from Cosworth. Sealed and interchangeable, the ECUs can be checked quickly and easily by Renaultsport engineers to ensure equality, crucial in any spec series. That factor was key in
Cosworth winning the contract to supply the series. The English fi rm had impressed with its ECU supply to Renault’s smaller capacity (2.0-litre) spec open- wheel series when that series received its new car in 2010.
STEP CHANGE ‘The sheer number of cars involved meant it was something of a step change for us,’ explains Pio Szyjanowicz of Cosworth
Dallara T12 Class: Formula Renault 3.5
Chassis: carbon fi bre monocoque with anti-intrusion panels
Engine: Zytek ZRS03 naturally aspirated V8, 3396cc Max power: 530bhp at 9250rpm Max torque: 445Nm at 7250rpm Max revs: 9500rpm
Transmission: Ricardo six-speed sequential with Shiftec pneumatic control, self-locking LSD
Clutch: 140mm triple plate
Suspension: double wishbone with pushrod-actuated Sachs dampers
Brakes: Brembo six-piston calipers, 270 x 28mm Carbone Industrie discs
Wheels: OZ Racing magnesium monobloc Front: 12 x 13in Rear: 13.7 x 13in
Tyres: Michelin Front: 26 x 26 x13 Rear: 32 x 66 x 12
Fuel tank: 110 litres
Dimensions: Length: 5070mm Width: 1930mm Height: 1048mm Wheelbase: 3125mm Track: 1630mm (F) / 1529mm (R)
“an innovative electronics system, which includes neither a starter motor or a battery”
May 2012 •
www.racecar-engineering.com 59
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