Okibi wrote:I know Matty is full bottle on this stuff but until anyone can present a logical explanation as to why the rear sway bar isn't working as it should then i'll stick to my guns.
Weight transfer is a function of centre of gravity height, cornering acceleration and track width. It has (almost) nothing to do with body roll - a go-kart still gets weight transfer occurring.
Weight transfer happens from the inside to the outside pair of tyres during cornering. Whether it goes to the outside front or outside rear is a function of the relative roll stiffness of the suspension at each end. Say you had an infinitely rigid rear suspension, then all the weight transfer would occur to the ouside rear wheel, and none to the outside front.
A sway bar is in effect a roll-stiffener for that end of the car. Yes it reduces roll stiffness, but (as said) that has very little impact on weight transfer*. But it does mean that more weight transfer happens at that end of the car.
Adding a rear sway bar (increasing rear roll stiffness) is going to want to cock the inside rear wheel up. This has two effects in this case:
1) the inside rear becomes unweighted, so it has less traction, and with an open diff you then have less ability to accelerate the car.
2) the outside rear gets more weight on it. Tyres have a coefficient of friction that decreases as you put more weight on them. So the upshot is the rear has less grip (and at the same time the front gets more grip because there is less weight transfer going on there) - so you end up with oversteer.
Conversely, removing the rear sway bar gives the rear more complaince, so weight transfer goes more to the outside FRONT tyre, and the opposite to the above happens (more grip at the inside rear, less weight on the outside rear).
*increasing roll stiffness can improve overall grip because you decrease the camber change on the tyre, an effect which improves their traction, but with double wishbones this is a minor effect.
