Originally Posted by EDWARD2003
"I also prefer the smoother feel the car has with a lower roll center...it is less edgy....but can be a bit too lazy and also can have the chassis rub the driving surface."
Thanks for your lengthy yet well written input Martin.
How would you go about preventing the car from being "lazy and generating chassis scrub"? Add rebound dampening? The book mentions that "rebound damping helps control the transitional roll when entering a corner." Is this true?
How much rebound should one use on different surfaces? i.e carpet and or asphalt?
Yes...going with thicker oil, smaller holes or less holes can help reduce laziness in chicanes.. however it makes it worse in normal corners, because the car rolls slower.
Going a little stiffer on the swaybars will help reduce overall roll and thus reduce some laziness....but you will loose some lateral grip with the stiffer swaybars.
Going up on the spring rate is also an option.
In terms of how much rebound for the different surfaces....
First, I don't like to run any rebound in my shocks...ever. The purpose of the shock is to slow down the speed of the spring.... both during the compression of the spring (ie. bump) and the extending of the spring (i.e. rebound). So if you build your shocks where the shock shaft comes out on it's own after you press it into the shock cynlinder, then in my opinion you are not building your shocks correctly.
Having clarified that, lets talk about how much dampening you will want for the different surfaces. where more dampening will slow down the spring compression and rebound. The reality is there is no simple answer for this. One might think that for low grip tracks you want less dampining and for high grip tracks you want more dampening. However if you take this too far having too much dampening on high grip tracks will cause a traction roll because it is not allowing the car to roll into the carpet fast enough before it pole vaults over the outside wheels.
Also you don't want to go too thin on the oil or make the holes to big or plentiful so that you have too little dampening as that will make the car very twitchy, because it transitions too fast.
One thing to keep in mind is how bumpy the surface is. the more irregularities or bumps on the surface the lighter the dampening you will want.
Also another thing to think through is how the hole size affects the high speed bump v.s. the low speed bump. For example a thin oil with small holes tends to have a lot more dampening on a high speed bump than a thicker oil with larger holes.