By: Ron Lee
The factory stock 5.0 Mustang is a blast to drive, delivers more bang for the buck than any other car, but it does have some serious handling deficiencies. The Mcpherson strut front suspension, while cheap, reliable, and lightweight, has major shortcomings in keeping up with a more serious sports car (Corvette for example). The unibody construction (also cheap and lightweight) allows the suspension pick up points to flex which also limits handling. Traction is highly limited, probably in an attempt to reduce warranty costs for Ford. Maybe the most serious problem with the suspension is the way the rear axle will hold the road to the maximum point of adhesion and then will snap the car into a spin if you go past that point (without any warning). Incidentally, that maximum point of adhesion varies widely with the circumstances. There are many ways to improve and correct these shortcomings. As always, how much you correct will depend on how much you want (or can afford) to spend.
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First, you need to decide what your goals are and then if your budget will support those goals. If not, lower your goals somewhat or lengthen the time frame allowed to save the money required. If you want a drag race type car, and not a road race type car, then stop reading here and go read the Traction 101 article instead. The "typical" Mustang handling improvements include adding braces (subframe connectors, strut tower brace, and G load brace) and replacing a few select pieces with improved aftermarket pieces (springs, struts, shocks, polyurethane bushings, sway bars, rear upper and lower control arms). I can tell you from experience that you will notice the difference in the handling of your Mustang from each and every one of those items as you change them out. More serious Mustang handling improvements include a torque arm rear suspension and a tubular front suspension. A torque arm suspension is about the best rear suspension system around, but will run you at least $1000 before you're done. The torque arm will greatly increase handling, traction, and give feedback on what the rear suspension is doing. The minuses include the cost, reduced ground clearance, and that it normally requires fairly stiff (about 350 lbs/in) rear springs to operate correctly. A tubular front suspension will increase handling further and reduce front end weight by about 65 pounds, but will also run you at least $1000 before you're done. There are other slick suspension systems such as the Bart Works SLA (short and long arm) front suspension which is about the best available, complete with a nice price to go with it. This all said, read and think awhile before you make any decisions.
I personally think the first thing you should do to improve your Mustang's handling is to replace the rear upper and lower control arms. This will not eliminate any chassis flex, but it will eliminate most of that "rebound" from whipping the rear end around (spinning the tires through a corner and then letting them catch can cause a "rebound"). It will make your rear suspension more predictable and the sudden snap into the 360 degree circles will be largely gone (except at extremes). It will also provide valuable feedback to you as you drive the car on what the rear suspension is doing. Typical prices for rear upper control arms are about $100 while rear lower control arms will set you back about $175. I personally like the Steeda heavy duty rear upper control arms ($110) or any of several makers of the adjustable rear upper control arms (about $200). Most of the lower control arms are very similar except that Steeda has come out with one made from aluminum to save weight. Both can be installed in your driveway with the upper control arms being the more difficult, mainly to remove the old axle housing mounted bushings. Remember that removal of the lower control arms requires the removal of the coil springs which can be very dangerous. One final comment about rear lower control arms is that some (Megabite, South Side Machine, and Lakewood for example) come with lowered pickup points which will increase traction and lower the rear of the car. To a point, this is a plus for handling at the same time. You will have to do something to level the car unless you like the rear to be lower than the front (not me).
After that, I definitely recommend installing the subframe connectors, strut tower brace, and G load brace in that order. Get a pair of subframe connectors that include the double arm brace that bolts to the seat mounting bolts (most do). Get a 4 point G load brace versus the 2 point version. The G load brace may not clear a tubular front suspension or long tube headers, mine didn't. The subframe connectors must be welded on. Don't kid yourself, a bolt on pair of subframe connectors also requires welding if you want them to last more than a few corners. Remember to paint (with a high quality primer paint) where the welding removed the paint unless you want your prize Mustang to rust underneath you (bad choice). Even that lowly G load brace will surprise you in how much difference it will make to your car's handling. Prices for these parts are about $100 for the subframe connectors, $130 for strut tower brace, and $50 for a G load brace. You can get them in chrome moly steel for a little more. Chrome moly steel is lighter in weight than the standard steel while retaining the same or better strength.
You will be surprised how much of a difference just these relatively simple and easy changes to your Mustang will make in the way the car handles, while largely retaining your factory ride. I was impressed with my Mustang after these few changes. For about $600, plus some time to install the pieces, and the handling was much improved over the factory setup. Read the next article if you want more.
©Copyright 1998 Ron Lee