for the best 1/4mi times (400m) you need to think about what happens to the car when you launch.
I am gonna use the RGT for example (even though I have never raced one, I know the layout)
In any car, when you stomp the gas the weight of the car transfers backwards to the rear tires. In the RGT (which is rear engine, meaning behind the rear axle, and four wheel drive) you have a signifigant advantage with the weight transfer considering a good hunk of the weight is already back on the drive wheels. Here's how you should base you settings:
Get the VCD and put as much power to the back wheels as possible (ie 10%).
Then, to maximize weight transer, but still keep the front wheels planted enough to help with their 10%, raise the front end up to about half way and drop the back. (this will help put more weight on the drive tires, and it does not have an effect on your drag coef. (wind resistance) [if you see sparks raise the back and front equally a little at a time till they go away])
as far as the absorbers go just remeber that you want the rear end to "sit"
Front bound should go to about 5 or 6, mabey more (this helps keep the weight on the back during shifts)
rear bound to mabey 3 or so, mabey less (just not strong)
Front rebound should be set high to help push the front tires down a little for the 10% power they put down.
Rear rebound should be low, so as not to push the car's weight back forwar under shifting.
The rear springs need to be really loose and the front should be really stiff
camber and toe-in/out should all be zero for better tire adhesion(sp)
the downforce should be set all to lowest (downforce means drag)
then start making your runs. for tuning purposes it is best to start always from full throttle and use an auto tranny. take a couple runs to get an idea for what your base 400m time is. (this is not going to be as fast as when you use manual but it gives us a consitent shifting pattern to help us see if changes make a difference)
first thing to do is play with you tranny. you will want to be getting to the redline of either 5th or 6th gear as you cross the finish line to maximize your engine use. Remember that everytime you shift you loose a large amount of torque (hp if you want to call it that) until your engine gets revved back to peak power. watch your speedo as you do your runs, keep track of what RPM's cause the greatest increase in speed. if the acceleration dies a little before redline find out where and set that as where you will be up shifting.
Once your tranny is good enough in auto, switch to manual and see if it still runs correctly. Make any adjustments you need to get it right, usually using the final drive setting at this point is easiest.
Now comes the perfection part: when you launch you car from full throttle the engine should "bog" down to a certain RPM then kick in. (assuming TCS is set to about 5 is a good way to do this). about 500 to 1000 rpm below that point is where you want your revs right as the race starts. A split second before it is time to go, mash the gas, the car should pick up and go much better then ever before. once that is set start playing with the tcs and bring it as low as possible but with no wheel spin.
I know this was long but I hope you all learn something from this.
This is not an exact guide but more of a helper to get you started in the right direction. Just always remember, weight transfers to the back, your goal is to get as much of that weight onto the drive wheels as possible. MR and RUF's/Porsche's RR cars are the best. And give yourself a challenge and don't use 4wd, no tuning is really needed, just slam, stiffen and hit the gas.
If anyone has anymore advice or mabey corrections to my setting suggestions please post them.
(never stop fine tuning, and always save your settings)