Our work on MG SV had many unavoidable restrictions. Time to launch was limited and the platform was already in production Any tuning changes would cost money and create delays. However, this didn’t stop us doing the best we could.
The car allocated for chassis development work was fitted with fibreglass body panels rather than the (production intent) carbon items, so was too heavy. No matter. Out came the interior trim to get us to the predicted axle weights. The ride and handling tuning could then be conducted with confidence (albeit noisily). We all thought that the Mad Max style matt black paint finish was rather apt.
It was soon apparent that the car was too ponderous and unwilling to change direction at lower speeds. Whilst sufficient torque was available to balance the car on the throttle, there was an unsatisfying turn in phase to get through. Not agile. Not an MG sports car. Changing the balance through roll stiffness distribution gave a straightforward and immediate improvement. Time for a check at the Bruntingthorpe Proving Ground. Oops. High speed lane changes were a white-knuckle affair. The car was loose in roll and wanted to oversteer too readily. Yet the damping was too tight at lower speeds.
Time for an aerodynamic investigation. Cardboard and duct tape were used to manufacture a substantial rear wing and front splitter. Best get the assessment done before it rained. And it worked. The decent balance found at low speeds continued through the speed range, giving confidence to throw the car around and execute lane changes at maximum speed. Job done.
Not quite. Cardboard wouldn’t be suitable for production and there would need to be convincing evidence to influence the (signed off) exterior styling. Time for a late shift at the MIRA wind tunnel. Measurement of the car showed some aerodynamic lift, front and rear. I remember the lift differences (that gave a decent subjective benefit in balance and security) being expressed in terms of ‘that is only X bags of sugar.’ Still, the results led to various changes which improved the aero behaviour. One example was the change to a more open chrome mesh in the bonnet ducts. Attention to detail sweetened the handling balance consistency through the speed range.
The industry will express lift (and drag) changes in ‘counts’. How many bags of sugar were required to find the handling balance sweet spot? Not many, but every bit counts when reducing the lift count.