Last weekend we brought in the Subaru Legacy Spec B into the shop for a suspension update. As you may recall from our previous entries, our adventures with this car started with swapping out the stock rear anti-roll bar with one from Perin. This helped to reduce the amount of body roll that was in the car as it came from Subaru. The Spec B came with Bilstein struts but the springs allowed for excessive body roll.
We were reluctant to swap out the spring for some shorter ones because their installation would result in lowering the car’s roll center as well. What happens then is that while the center of gravity is lowered the roll center gets too low and produces understeer to a higher degree.
Whiteline came out with a kit to compensate for the drop in the roll center when STi springs were installed. That consisted of revised lower ball joints and tie rod ends that brought the lower control arms and tie rod geometry up where is belongs.
While the car’s handling was sorted out by all these changes the rear bar was acting up by causing a bind as the suspension went through its full range of motion. So off we went to find a better solution for an anti-roll bar. We found the Cobb makes a set of bars for both the front and rear of the Spec B that were tubular in design. Tubular bars are particularly nice since they are lighter in weight, yet provide just about the same roll stiffness as a solid bar. Keeping weight off the car is a goal that should always be kept in mind especially unsprung weight. Since most of the work of an anti-roll bar is done at the outside diameter of the bar, making it out of tubing is the most efficient design.
The Cobb bars were a perfect fit, too. To get to the stock front bar the splash pan had to be un-bolted as well as a stamped metal brace. The front Cobb bar came with new bushings and brackets that had grease fittings installed. Synthetic grease was the only kind to use as regular grease would be flushed out with water.
The rear bar replaced the Perin bar and included reinforcements to ensure that the mounts wouldn’t flex as torsion was put on them during normal suspension movements. It also had grease fittings built in to the mounts.
The results was a noticeable improvement to the handling and feedback that a driver feels. The only downside was the noise from the bushings. Even though we applied a very liberal coating to the inside of the bushings they still squeaked. So we ordered up a synthetic grease gun kit from the folks at Green Grease. That should quiet things down.
With the warning about the noisy bushings the Spec B was returned to the owner who was very impressed with the handling improvements. He also found the bushings too noisy, but is willing to wait for the Green Grease to arrive and solve that problem.
Thanks to Tim Supples for the photos!