Posted 03/19/2003 7:34 PM
check out the comments in my Mitsubishi Lancer Evolution VII Rally Car Prototype Setup for a guide to setup for Rally. Also check out my Nissan GTR Vspec II R34 setup for a guide on brakes.
A quick guide for tuning road cars, keeping it short, lest this comment be too long.
Spring rates, affect transfer of weight. During braking and acceleration the weight of the car shifts. Softer front springs aids in shifting the weight to the front reducing understeer.
Shocks, see my rally setup guide above. Same effect. Softer shocks on front to remove understeer, stiffer shocks on rear to induce more oversteer.
Toe - see rally guide. 4WD and FF use -1.0 / 0.5 (front/rear) as a start. FR and RR use 0.0 / -0.5.
Stabilizers - help stabilise the car during cornering. Softer allows the car to lean into the turn giving greater grip. But too soft, causes the car to be unresponsive. Too stiff and the car is likely to drift. Use this to fine tune and remove understeer or oversteer. Eg, Car understeers too much = reduce front stabilisers or likewise increase rear stabs. Lower powered (less than 400hp) cars tend to benefit with very high stabilisers.
LSD - I find, others may disagree, that 4WD cars and low hp cars (<400hp) benefit from no or as little as possible LSD. FR cars benefit from LSD heaps. Use this to fine tune wheel spin. Watch for tire smoking while accelerating around corners. If tires smoke up, increase Accel LSD. Keep Decel LSD to around 10 - 15, too much and it induces understeer.
ASM & TCS - see rally guide above. I hate ASM, it induces understeer. Anything above 0, causes the car to behave other than it should and negates the tuning done else where. Without knowing how to tune the car use ASM, but if you know how to tune it following the above guide turn ASM off !
Downforce - Use as little as possible on tracks like Test course. All other tracks, higher front DF reduces understeer. Helps stabilise the car at high speeds. Keep front and rear close to the same figure.
VCD - only available on 4WDs. The figure in GT3 is the % amount of power delivered to the front tires. Keep it low to reduce understeer. Except for rally cars.
That should get you started. This is by no means complete, but should be enough. There is a cause and effect for each setting. Too much or too little of a setting will cause undesired effects. eg, too much front brakes and the tires lock causing understeer. Too little, and the car doesn't stop fast enough, causing the car to continue it's momentum straight ahead.