Extracting the full potential from suspension modifications

Fulcrum Suspensions offer a range of techniques to improve the performance and appearance of a vehicle. Changing the springs to lower a vehicle is the most obvious way of changing a vehicle to make it ‘look good’ without spending excess money. However there are a range of other enhancement techniques that should be considered just as important in gaining better performance:

1. Maximize tyre contact through specially designed bushing hardness and shape -

Suspension modifications are often carried out to ensure maximum tyre contact patch (tyre grip to the road). Body roll, yaw, and inertia can all minimize or distort the contact patch and cause an excess slip angle which results in a vehicle traveling excessively sideways rather than forwards. Manufacturers develop bushings in a suspension system to give the driver a major focus on ride and comfort. Changing the ride height and spring and dampening rates places weight on the suspension and tyres in a different way than was originally intended. Changing the bushing to a material such as SuperPro polyurethane will give a more positive location or repositioning of pickup points to give more controlled dive or squat. Bump steer correction in conjunction with correct height and wheel alignment will give better braking and faster lap times.

2. Sensibly lower the vehicle, taking careful note of the roll centre -

Excessively lowering most street performance cars gives them a roll centre too low relative to the centre of the chassis. The results in greater body mass roll, which is the actually opposite of what most people are trying to achieve when they try to lower the centre of gravity. Spring rates are often increased to help stop the roll, however this creates a new set of issues, including loss of ride quality. A correct or higher roll centre will allow for slower body roll whilst maintaining contact patch. Centres that are too low usually deliver faster and more excess roll and distort contact patches. For normal street use, vehicles should be lowered moderately with the use of correct spring rates to balance the change, and for track work the roll centre should be changed as part of the modification where possible. Correct rake angle is also important to gives the vehicle weight transfer where needed, and minimise wheel spin. Generally vehicles have a higher rear roll centre, which allows for the rear tyres to grip more quickly when turning into a corner, therefore balancing the handling and maintaining controlled under steer to give the safest balance.

3. Install redesigned SuperPro bump stops to give changed absorption rates and improve suspension travel –

To do the job expected of a spring /bump stop/shock absorber in a suspension system, the wheel must have suspension travel. Often modifications involve excessively lowering vehicle height, which results in the spring or shock absorber having no travel and the vehicle sitting on the bump stop. This means that while driving and cornering, the vehicle will respond negatively to bumps or holes in the road. The suspension system must have ability to absorb the movement without diverting the direction of the vehicle, upsetting the body roll or loosing contact patch. It is often assumed the bump stops’ only purpose is to stop the suspension bottoming out and hitting the shock or touching the bodywork, however another important function of the bump stop is to ramp up the spring rate as a supplementary spring to gain full suspension travel.

4. Select a spring rate compatible with the vehicles mass, application and suspension geometry -

When lowering a vehicle, the wheel alignment must be recalculated individually to suit that vehicle. Manufacturers always give a tolerance for mass produced vehicles, however for individual aftermarket kits specific settings must be developed in order to gain the best results.

Finally, testing, tune testing and continuous improvements will all give results. The most important task for an owner or driver is to keep records of all changes to the vehicle, including set ups, track times etc. If the handling changes negatively then it is important that there is a documented history to fall back on.

For more information on your suspension upgrade Contact Us

Source: http://www.fulcrumsuspensions.com.au/grahams-corner.html