Posted 30 July 2005 - 03:17 PM
Will is talking about front sway bars.
JWX are you saying put a bigger bar on the front than on the rear?
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Cut and Paste from a post I made in 2003
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Sway bars are put on a car to limit the roll angle of the car during lateral acceleration and deceleration.
Since tires develop the maximum amount of traction when they are perpendicular to the ground (and the tread is parallel) that’s what you’re going after. Subarus are notorious for little to no usable camber adjustment. It has an innate inability to keep the outside front tire perpendicular to the ground during corners. In fact, they are forced to positive camber setting when pushed hard. Understeer.
Standard Subaru engineering.
It’s also a safeguard when Japanese manufacturers brought over cars to the US. The average driver can control understeer, not oversteer. Domestic cars too, for that matter.
Sway bars increase roll stiffness and they are, by far, the cheapest and easiest modification to increase roll stiffness on a Subaru. When you turn your car, one wheel will be up because of compression and one will be drooping down. The sway bars limit the roll angle of the car by using torsional stiffness to resist one wheel going up and the other going down.
If a car has understeer, too much of the load is on the front outside tire. By increasing the size and effectiveness of the REAR swaybar, some of the load can be transferred during cornering to the outside rear tire.
This will decrease the load on the front tires and make the car handle in a more neutral fashion. The very opposite is applied when increasing the front.
The stiffness of a swaybar increases very quicky as its diameter is increased. The stiffness is a function of the diameter to the fourth power.
For example: A 1 ¼” diameter swaybar is 2.44 times as stiff as a 1” swaybar.
A 1mm change will change the understeering characteristic of the wagon enough to notice. Especially in sharp, on throttle turns. Let’s not forget about weight transfer. Get that long wheelbase car nose high in acceleration, with the weight transferred to the rear, then cut the wheel. Push.
Panic, jump on the brakes, overload the fronts, transfer weight off the rear. Push.
A rear swaybar will help balance out the weight in a lateral manuever by not letting the trailing wheel get too high and thus not help with traction. It will help take the load off the fronts, too. Jay
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Will, why would you want that big of a swaybar on the front? What's the rest of your set-up and how does it accomodate such a big bar in the front without adversely affecting turn in? Or where you just surprised that Whiteline made anything for theses models?
Brian, IIRC the 20mm bar is from the rear of the XT6.
Tizzle, If you lower the roll center of these cars it has more of an effect on the body motion than doing anything else. Shorter springs with higher ratios and appropriate rebound and damping combined with correct swaybars would be the way to go.
Regards,
Jay