Handling has always been one of the most important features. Rear or middle engine cars with most of the weight on the rear axle, are more demanding for the driver near the critical speed. A lost of grip happens suddenly and momentum of inertia can be a big surprise for the driver. Usually these types of vehicles are understeer cars, because of the easier transient state handling properties for non-experienced drivers. But at the same time you will lose one of the most enjoyable part of mid-engine cars, the fast and accurate steering response.
RaceAbout is a car with two different characters. The first one is for normal city and public road use. In this setup spring rates and damping coefficients are lower, and wheel camber angles are closer to zero. Ground clearance needs to be bigger and brake balance is less aggressive. This setup is also used for beginners due to its understeer and more forgiving behavior. The other setup is for track use only. Suspension is stiffer and wheel angles are more tilted for maximum lateral traction. The rest of the set up mostly depends on the driver.
In the RaceAbout project we started suspension design with different simulations and calculations to achieve certain basic level and behavior. The first test drives were mostly new vehicle shakedowns to check every system and to find out something about reliability. When everything was working without problems, we could start the racetrack tests to continue suspension development work. Some improvements were done to steering geometry, rear roll-steer behavior, and rear suspension frame. The rest of the modifications were normal set up procedures such as spring rates, pitch and roll center location, ride height etc.
In 2002 we got a chance to use very advanced analysis software, and as a result, some improvements could be made to rear end behavior near the critical limit. Increased suspension a-member stiffness was a significant factor for cornering stability.
After the racetrack behavior was at the desired level, it was simpler to find the softer behavior for road use. However, the fact that RaceAbout is not a smooth road car has to be kept in mind. It is a pure driver's car where the driver takes the control and the car gives the response.
RaceAbout is equipped with an integrated data logging system, which monitors all the important data needed for the chassis set-up. The data is collected in the Motec electrical meter unit for further analysis. Data logging helps you to analyze your own driving and gives you concrete information on the effects of different set up parameters.