If you've ever thought about changing the handling characteristics of your Impulse JI to help reduce it's tendency to oversteer, you've probably looked at the parts installed and wondered if there's a way to tighten the front up/loosen the rear, or if there's an aftermarket solution. Well as far as I know, for the most part were all out of luck on the latter, but the good news is that the front bar is in fact adjustable to two discreet settings with the OEM setup being the softer of the two. Altering the setting isn't exactly the easiest method compared to other adjustable swaybars, but it's a simple operation and only requires removal of the front wheels and the use of an open end 14mm wrench and another 14mm wrench or socket. (You'll probably need a jack too . . .)
With the car jacked up and properly supported by jack stands with the front wheels removed, what you'll be doing is removing the end links from the sway bar and L-arm. In OEM configuration they should be mounted toward the inboard side. You'll need to use the open end wrench on the stud side of the link while loosening the nuts with the other wrench. Once removed, just flip it around so that it mounts on the outboard side of bar L-arm bracket. Reinstall the nuts and torque to spec (19 lb-ft per the service manual). Put the wheels back on and take it for a spin! Too easy.
To enhance the stiffness even further, it's possible to shim the lower mounting of the end link out even further (about 1/4") with a few properly sized washers. (Shimming the top mount won't do anything except increase the possiblity of interfering with the brake caliper at full steering lock.)
Well you may already be thinking at this point that the engineers didn't intend this setup to be adjustable in this manner, but the fact remains that it is. Repositioning the lower end of the link further out on the L-arm increases the working radius and hence the range of motion transmitted to the swaybar. With a 1/4" shim, the working radius of the swaybar link is increased from 8" to 10" - A 25% INCREASE! Now consider that this increase is applied to each side - THAT'S 50% MORE STIFFNESS!!!
Well I can't speak for the difference this alteration makes for the handling of the Impulse XS, but I like what it's done to my RS. The front no longer seems to mush into the corners like it did before, and since I've got a bit more than stock power available, it also helps to keep the inside rear wheel from lifting and spinning in hard corners. The car still has the tendency to oversteer a bit as well in medium to high speed corners which came as a surprise to me given the amount of increase in stiffness. Even in low speed corners understeer has not seemed to increase (I suspect that it helps keep a more ideal camber angle).
If you haven't already replaced the stock rubber bushings with polyurethane bushings, start there. A noticeable increase in stiffnes can be felt from doing this alone, and the bushings rarely cost more than about $10/set. They are easy to install and don't require removal of the swaybar (a job you really don't want to do on the front of these cars). Be sure to use a good bit of grease inside the bushings to keep them from squeaking though.
If that still isn't enough, get out your wallet cuz whatever you do next aint gonna be nearly as inexpensive. You'll either need to pay for a custom bar, or put in some stiffer springs. Nobody currently manufactures a front bar for these cars - although they may be available soon through Bill's. (As of July 19, 1997).
Some of you may be wondering if a similar procedure can be done to stiffen or soften the rear bar. It can't be done as easily. As far as softening goes, it really can't be done without putting in a smaller bar. Some increase in stiffness can be attained by swapping the bushings out as well, but beyond that, the only other solution with the OEM bar may possibly be to shorten the end link arms and drill new holes.
Although the above mentioned procedure should not cause any interference problems, it is still using parts in a way in which they may not have been inteded to be used. I.e. the extra force placed on the end links may be too much for them and they may buckle in extreme cases. It hasn't happened yet on my car and most likely it wouldn't be a catastrophic failure (like a tire blowing out), but this alteration does increase the stress on the links and as such, this procedure should be performed as always -
Thank you for your support . . .