As well as packing more raw power, the Mégane Renaultsport 230 Renault F1 Team R26, also features a Limited Slip Differential that will delight purists and everyday motorists alike.
When a car turns round a bend, the outer wheels cover more distance than the inner wheels, which means they have to turn faster. So if the inner and outer wheels were not able to turn independently, the vehicle would refuse to turn. The differential performs an essential drive-chain function in allowing different speeds of rotation for the inner and outer wheels.
However, full independence has a drawback on low-grip road surfaces. If the wheel on one side skids, engine torque will be sapped by turning this free-moving wheel, leaving the wheel on the other side with no drive. The engine will race, and the car will not move forward. Limited Slip Differential solves this problem by braking the wheel that’s skidding and transferring torque to the wheel that has grip; this greatly improves acceleration, and thus reduces the skidding. The result is incomparable efficacy, even as regards steering round bends.
The challenge facing Mégane RS 26 designers was how to fit a limited-slip differential without changing the powertrain, or the gearbox casing, or the transmission shafts, or the lubrication system.
The result is an extremely compact unit that differs considerably in design from a classic differential: instead of the usual conical sun gears we find cylindrical gears with helicoidal teeth.
When a difference in torque between the left and right wheels is detected, small shifts in the gearwheels adjust friction take-up to re-establish normal torque transfer. The effect is instantaneous, and the intensity set by design parameters such as gear helix angle and choice of thrust washers between gear shaft and sun gear. The results are conclusive: this version boasts a slight power boost, from 225 to 230 hp, and maximum torque rises from 300 to 310 Nm, but the big difference is in roadholding and traction, as evidenced by faster racetrack lap times.
Combined with the car’s famous double-axis strut suspension, the limited-slip differential gives superlative driving response, especially since the car is immune to the steering wheel reactions usually caused by asymmetrical left-right grip.
And you don’t have to be a racing driver to notice the difference; the improvement brought about by the limited-slip differential is immediately apparent to the everyday motorist under everyday driving conditions, as from the very first roundabout. The system brings a definite benefit even on models without the slightest sporting connotation.
By enhancing drive, the limited-slip differential offers an economical alternative to costly all-wheel-drive transmissions on any vehicle required to face difficult grip conditions such as snow or mud.
