MEX wrote:SnoozinEuro
and if you lower your car you will find the engine and driver and anything in the car will also head closer to the ground taking the roll center down too, and i dont know about you but ive always mounted my seats and engines as low as possible when ever ive been putting new ones in
(Disclaimer: I wanted to own you but I held back, I know im guilty of not reading posts 100% right but it seems that some people dont look into other peoples posts enough and are quick to give advice without a sound understanding of the topic in question)
Your confusing roll center with centre of gravity, your right for centre of gravity being lower, and yes that will be of some benefit to the vehicles behaviour.
The point Snoozin made about roll centre is very valid, when you lower a vehicle you change the roll centre, which is a suspension angle and alignment thing, basically you can only lower a vehicle so far before you make the car handle easily worse then stock (very generally 1-2" with an increase in spring rate is about right). The point Snoozin was trying to make (although he didn't spell it out, if you were real clued up you wouldn't need to be told anyways) is that you can only lower a vehicle slighly before you change the suspension geometry so much that you affect roll centre adversely. Very generally just to give an example that the lay men out there can appreciate, say your looking at the front mac pherson struts on a car, you have an upright coil over shock which bolts to your hub, your hub is connected by a ball joint to a control arm (which is essentially a wishbone) in a normal stance the control arm will angle down from the chassis towards the hub with the hub pivot sitting lower then the pivot point on the chassis, this is very important aspect. When the car is cornering and weight is transfered (and the car tilts onto the outside wheel, we all know what body roll is) the coil over contracts up as the spring is compressed under the load the hub follows and would you now it the control arm does to, now comes the hard part to explain, because of the angle of the control arm and the fact that outside pivot of the control arm is sitting higher it is also further out from the chassis (think of it cutting an arc) this dials in more camber to the the outside wheel and improves that tyres contact patch to suit the cars angle of roll.
The problem is when you lower a car dramatically (even 2" and its very likely your control arms will be level when the suspension is neutral) your control arms dont point down and out like they used to, they are either level or in the worse case point upwards, if the roll centre of your front suspension is like that then as that side of the car becomes loaded mid corner you decrease your negative camber and subsequently the cars contact patch.
To sum things up roll centre is not to be confused with centre of gravity.
Now please, I seriously hope you read his post wrong, cos at least thats better then being wrong
and remember people the only thing worse then being wrong is to be wrong and argueing your point and passing off bad advice
