Lowering the Center of Gravity
Lowering the C.G. or Center of Gravity will almost always improve cornering speeds. Some exceptions are when a car is lowered beyond the desire range of suspension geometry. This will cause undesirable camber and toe changes than can and will negate any advantage gained from lowering the vehicle mass.
Depending on the vehicle, the correct way to accomplish the “ride height adjustment” differs – 914’s (all years) are like 911/930 untill 1989 in that the front two torsion bars run longitudinally and are almost infinitely adjustable. If the 11 mm adjusting bolt and cap run out of range, simply jack-up the front, unload the bar, remove the adjusting bolt, slide the rear cap off and recenter it. The rear of 914’s is coil sprung with non-adjustable perches. Struts with threaded barrels are available, however a much less expensive way to do the same would be to purchase threaded tubes. These fit over most struts and allow adjustment. If the front torsion bar size is increased to also “stiffen” or “firm” the ride, an appropriate increase must be added to the rear spring rate. If not the car will understeer or plow worse than stock.
In the rear of 911’s from 1964-1977, the only adjustment to ride height could be done in large increments (usually 1.5″) by reindexing the torsion bar spline. From 1978 to 1989 the rear has a small amount of adjustment through adjustable spring plates. In any case all 911’s with torsion bar rear suspension can take advantage of after market fully adjustable plates. These make corner weight jacking easy and very precise. All 911’s can be converted to “coil overs”; this provides the ability to make unlimited ride height adjustments as well as easy spring rate changes. 911’s respond very well to moderate ride height lowering, provided it is done along with a four-wheel alignment and wheel corner weight adjustment.
911’s after 1990 – C2, C4 and 993 can be lowered up to 1½” without stiffening; we have billet adjustable perches which use the stock springs. Lowering can also be done with shorter coil springs. These springs have about a 20% stiffer rate. This results in a lower c.g. with a slightly firmer ride, not at all harsh, very driveable and the bonus is they are within the range of the stock shocks (just barely though).