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The compromise for a race car can be completely different from a road car and these differences become even greater when this car is a light pickup. The target for a race car is to cover a determined distance in the shortest time and when this distance is a thousand miles, lap time is not the only objective. The compromise must include fuel consumption, tire wear, brake wear and even driver fatigue. This paper describes the full preparation, from the production vehicle to the final race car, which has competed successfully in the Brazilian 2004 Mil Milhas.

The suspension for a road car focuses in a good compromise between Ride & Handling. When this car is a light pickup, there is also an important compromise between driver and full load condition. For a race car, the suspension system must have a different compromise, were Ride is not considered, but it must be able to keep the tire in contact with the ground, transforming engine power into acceleration, brake power into deceleration and steering inputs in correct corner apex. This paper describes the suspension modification in a production Chevrolet Montana and the methodology used to specify springs, anti roll bars and dampers, which has competed successfully in the 32a Mil Milhas de Interlagos.

The system spring/damper/anti roll bar/jounce bumper must isolate the vehicle from the road inputs and keep the body in correct attitude when submitted to lateral acceleration. The calibration is performed changing one component, but the influence from the other components can result in inappropriate conclusions. This method can be divided in two main parts: stiffness calibration (without damping) and damping calibration (with the previously defined stiffness). The first part consists in calibrate the stiffness at the following order spring, jounce bumper and anti roll bar, aiming the minimum body displacements and acceleration. This paper focus in the stiffness calibration and the parameters to select springs, jounce bumper and anti roll bars.

The force x velocity graph is the most used tool for suspension damper analysis. This approach hides important information regarding the bleeds / spring / orifice combination. This paper describes the energy analysis, comparing two different damper suppliers, with comfort measurements using B&K Human Response Vibration Meter and MTS single channel Four Post system.

For high CG passenger vehicles the body control is a very important parameters for customer perception. The compromise between cornering (body roll) and uneven road (head toss) is the main goal. This paper describes how dampers, spring rate and anti roll bar can influence the desired compromise. Single channel Four Post system and vehicle dynamics measurements give the necessary support for this analysis.