I heard reports that my car's front inside tire was coming up off the ground in a slalom at a recent auto-X. I don't like the sound of this and I think I may have created an imbalance in my car's suspension by installing the cusco rear sway bar and the Helix endlinks. I have the sway bar on the firmest setting. I like my absence of understeer very much, but I think I may have over done it in the back, i.e. I don't think you can just throw on a super stiff sway bar and expect the car to behave more like RWD.

Questions

1) What exactly (if anything) is wrong with my setup? Why?

2) What is the best way to fix without changing my rear sway bar set up? -or- Should I just loosen the rear bar up a little?

3) What effect would a front sway bar, rear strut bar, front strut bar and front x-brace have on my handling? Would they keep my tires more firmly planted?

It's a 2003 WRX with otherwise stock suspension.

Thanks

 

a front sway will not produce the results that you want. you'll experience more understeer, and chances are good that you'll be lifting the inside front a good bit more though slalom sections or tight turns.

depending on whether or not you were on the gas while lifting the wheel, a whiteline ALK may or may not help. if it doesn't help with wheel lift, it'll certainly improve the front end grip on corner exits.

i don't think that strut bars will have much of an affect on your setup, since you're still running the stock springs and struts.

solid front and rear endlinks would also be a good idea.

 

The ALK sounds good, I don't completely understand what it does, but there are plenty of threads about that. I've got the solid rear endlinks, but wouldn't the front endlinks effectively make my FSB more stiff? Accomplishing the opposite of what I want. I think I'm asking for the best of both worlds here. Or maybe I'm getting too theoretical? Someone please enlighten me.

I was most likely on the gas when the wheel came up,

 

front end links won't make the front bar feel stiff, it'll simply make the front bar more responsive. basically, you're eliminating play in the bushings and getting more front end feel.

 

Depending on your classing and the latest rules the ALK might not be legal for auto-x. I've read that although a stiffer front sway bar generally will increase understeer, the Impreza is a slightly different animal. Because it is a strut type suspension it gains positive camber as it rolls. This is opposed to a double wishbone setup that usually gains negative camber as it rolls. Thus a stiffer front sway bar that reduces roll would decrease positive camber gain, improving the tire contact patch and decreasing understeer. I haven't experienced this so I don't know that it's true, but I've read it from several (seemingly) reliable sources and it makes sense to me.

 

Is it the front or rear inner wheel that is lifting during turns? I'm trying to picture how you can manage to get the front wheels up in the air during turns. If it's your rear tires going off the ground, stiffer springs and struts would help decrease nose dive and keep your car more planted on the turns.

-Soren

 

It definitely was the front. I was making the transition from left to right in the slalom, as I was getting back on the gas. My back tires have been known to come up off the ground too, but I understand this phenomena a little better.

 

The ALK basically works by increasing the caster on the front. Increased positive caster generally means that you have a different camber application angle, and (in practical terms) you can get on the throttle a little earlier coming out of corners. The flipside of this is that the car's steering won't be quite as twitchy when you're entering the corner, but most people don't seem to mind a bit of loss in corner entry steering response when the payoff is earlier throttle application at corner exit.