Chasing percentages
In 2012, Paul Nightingale of Spire Sports Cars and Tim Gray of Tim Gray Motorsport, both based in the UK, started to look at the aerodynamic development of their successful GT-3 racer for the 750 Motor Club Road Going Bike Engined (RGB) Championship, now known as Sports1000 (see figure 1).
They had already enjoyed significant success with its predecessor, the GT-R, and the GT-3 evolution, with new chassis, suspension, transmission and bodywork raised the bar again for the class, but the competition was closing the gap rapidly and so the duo turned to CFD, tunnel and track correlation to ensure they stayed ahead.
Not only did they require a step change in aero performance for the tightly regulated RGB-specification cars, they also wanted to create a version of the car using the same chassis and main bodywork panels that would be capable of competing in the 750 Motor Club Bike Sports Championship, too.
A reduction in drag on the straights and more predictable handling through the corners were key to the car’s performance
The Bike Sports class has less restrictive regulations and allows the use of bigger engines, slick tyres and almost unrestricted aerodynamic development, provided it adheres to the MSA Blue Book.
Critically for this development, Spire Sports Cars wanted costs kept under control to give new GT-3 owners the ability to upgrade from the ‘limited aero’ RGB car to a ‘full aero’ Bike Sports car in the future.
When the new generation GT-3 bodywork and chassis took over from the soon to be retired GT-R model, Spire Sports Cars took the car to the MIRA wind tunnel in the UK to run through ride height and rake changes, and get a feel for what the
