5.0 Mustang & Super FordsHow To Chassis Suspension
1996 Ford Mustang Cobra Alignment - Steered Straight
Adjustable caster/camber plates give more control, so use it wisely
Horse Sense: To find an alignment shop that's comfortable working with adjustable caster/camber plates, start with your local Mustang club. The members should be able to tell you where they've had good luck in the past.
You can't just throw a pile of high-priced engine parts together and expect to safely make big power-you definitely shouldn't expect to win races. Even amateur racers know that fine-tuning the engine combo correctly with the right injectors, fuel pressure, and timing is just as important. The same is true for steering and suspension. Lowering springs, upgraded struts, and even tubular A-arms can be added, but without the right alignment, the job is only half-done. Factory alignment is great for everyday street driving, but more is needed for aggressive street driving, road racing, and drag racing.
The inside treads on our car's front tires were worn to the cords because of a terrible alignment. Before heading to the alignment shop to get it fixed and back on the road, we interviewed Chuck Schwynoch, CEO of Maximum Motorsports. He gave us his recommendations based on the racing and product development the staff at Maximum has done throughout the years.
Keep reading to find out how the conversation went.
5.0&SF: We're going to install Maximum Motorsports' caster/camber plates on one of our project Mustangs. What alignment settings do you recommend?
Chuck Schwynoch: On a stock Mustang, only camber and toe are adjustable. With Maximum Motorsports' caster/camber plates, caster becomes adjustable, and a much wider range of camber adjustment is possible. The OEM alignment specifications were determined by studying the driving habits of the average vehicle owner. They almost never meet the needs of the performance-minded Mustang owner.
5.0&SF: Do the different cars (Fox, SN-95, New Edge, S197) benefit from different settings?
CS: Yes. Fox chassis Mustangs should have as much positive caster as possible. For the '94-'04s, C/C plates make it possible to adjust in enough positive caster that bumpsteer should be altered. Unless you're going to deal with the resulting bumpsteer issues, stick with 4.5 degrees of caster, which is about the halfway point of available adjustment on the Maximum Motorsports caster/camber plates.
The S197 chassis that debuted in 2005 is completely different. The camber and toe advice detailed previously for the different situations is about the same for the newest Mustang. One difference is the S197 chassis has a lot of caster already, so it's not really necessary to add more. At Maximum Motorsports, we've nearly finished the design for our caster/camber plates for the S197.
5.0&SF: What about the Mustang's suspension makes these settings necessary?
CS: The basic Fox/SN-95 Mustang chassis was designed in the '70s. It was never intended to be a high-performance sports car chassis with an emphasis on good handling. The extreme alignment settings are essentially a Band-Aid for the car having too little camber gain during body roll, not enough Ackerman steering geometry, or positive caster, and too much front weight bias. The faults are part of the package; the car has a modified MacPherson strut suspension designed for a family car. The Mustang frontend lacks grip, and so it tends to understeer. The rear suspension design is another story.
5.0&SF: Is it necessary to get your Mustang aligned after you lower it?
CS: Yes. The act of lowering the Mustang causes the camber to become more negative. Not only does the camber need to be corrected, but so does the toe setting. When camber is changed, whether from lowering the car or because of an adjustment made during the alignment procedure, the toe setting will change.
5.0&SF: Do your alignment recommendations change for lowered cars?
CS: No. Ride height doesn't have much effect on the basic alignment that works well for each car in the different situations outlined. The effects of lowering do, in turn, affect what settings can be reached. When the car is lowered, the camber becomes more negative, and the entire range of available camber adjustment will shift toward more negative. Lowering causes the caster reading to be more positive. It also lowers the roll center, which affects the camber change of the front tires during cornering, as well as the tire temperature profile. If you're setting camber based on the temperatures, the static camber setting might be slightly different.
5.0&SF: Are there any other built-in advantages to using the MM C/C Plates?
CS: They give the strut a solid, precise, non-flexing, and low-friction mount because they replace the stock rubber mount with a spherical bearing. On lowered Mustangs, they allow for an increase in bump travel. You're also able to to install a front coilover conversion kit with the plates.
5.0&SF: Before we head to the alignment shop, we've always wondered: Is it possible to mark MM plates somehow, making it possible to toggle back and forth between street and race alignments?
CS: Yes. You can make changes to the camber and mark the plates. Remember that changing the camber will also change the toe setting. The steering rack attaches to the spindle in front of the wheel center, making the Mustang a front-steer car, thus increasing negative camber. That causes the toe setting to move toward toe-out. Some people have found that adjusting their camber to the more negative setting will cause their toe setting to move from the preferred toe-in of a street car to the preferred toe-out of a track car. You'll only know by measuring the toe before and after adjusting the camber.
5.0&SF: I read on the company's Web site that it's important to do one part of the alignment after another. Can you clarify that for the readers?
CS: Camber must always be set before setting the toe, because any change to camber will alter the toe setting. Caster should be adjusted after camber, as it's measured by extrapolation from the difference in camber as the tires are steered.
With all those tips in mind, we took our project Cobra to Dan Wolfson at DB Performance for the installation of the Maximum Motorsports caster/camber plates. We then took the car to Inver Grove Ford for an alignment based on a recommendation from the local Mustang club. As it turned out, Technician Dustin Milbrandt is a Mustang enthusiast, so he knew how to handle the adjustable plates. In fact, his Rio Red '98 GT was featured in our Oct. '06 issue ("Blame it on Rio," p. 104).
Now it's time to drill the fourth hole for the Maximum Motorsports caster/camber plate. Set the factory strut plate on the strut tower and rotate it 180 degrees from its original position. Align the holes in the plate with the inner edge of the factory bolt slots. Scratch or draw an outline of the new hole in the strut tower. Move the plate so the holes line up with the outer edge of the factory adjustment slots and trace the hole again. Notice that the two marks intersect (upper left).
Use a center punch to designate the intersection of the two marks. Drill a 1/8-inch pilot hole on the punch mark, and then follow up with a 13/32-inch bit. You may need to clean the edges of the new hole.
Compress the strut and move it out of the fenderwell. It won't be easy. Remove the lower strut plate.
This is the factory upper- (left) and lower- (right) strut plates. You won't need factory plates with the Maximum Motorsports version.
Remove the plastic dust boot, and then remove the bump stop found underneath (shown). This is a good time to swap in new struts.
Cut the steel clamp that holds on the top of the dust boot.
Lubricate the new Maximum Motorsports bumpstop and install it onto the factory dust boot. Use a heavy-duty zip tie to hold it in place.
Install the dust boot and the new bumpstop onto the strut shaft. See the Maximum Motorsports instructions or Web site for advice on what spacers to use above and below the bearing plate. Since this car has the stock ride height, we put four spacers on the strut rod. Later, we put one above the bearing plate.
With the strut out of the way, install the Maximum Motorsports lower plate so the studs stick up through the holes. Maximum suggests using a bit of silicone to hold the lower plate in place. Put a 1/4-inch-thick washer on each stud.
Set the main plates on top of the washers; the odd nubs on each plate go to the front and outside of the engine compartment. Install a set of the thinner washers and nuts on the studs in the lower plate.
Put on another set of thinner washers and bearing plates on the main-plate studs. The bearing plates are reversible left to right, depending on the amount of camber needed. Since this is a street car that doesn't need much negative camber, Dan recommends installing the plates in the positive position with strut rods nearer to the outside of the engine compartment.
Compress the strut and put it back in place with the rod running up through the bearing plate. If your car has the stock ride height, put one spacer on top of the bearing plate and tighten the bolt.
If this car were lowered, we would've utilized the measurement of the original height of the strut rod. In that case, add the correct amount of spacers so the strut rod is higher than the original dimension by the amount the car is lowered. Check the hood clearance. If it's less than 1/8-inch, reposition the spacers to give the clearance needed.
Camber can usually be set to -3/4 degree. Better cornering can be had with more negative camber, such as 1 degree or more, but at some point, tire wear will become uneven and excessive on the inside edges. In some situations, the wear might be excessive even at only 3/4 degree of negative camber. How negative the camber can be before poor tire wear begins is dependent on a number of factors: tire size or brand, the particular driver and driving technique, and the types of roads driven on. Someone who drives mostly on freeways will get better tire wear with less negative camber than someone who drives on twisty mountain roads. The primary focus on a street-driven car is generally to set camber to get the most tire longevity, not the ultimate cornering grip. Adjust camber to be as negative as the car will tolerate while still providing adequate tire life.
Toe will be set to a slight amount of toe-in, and the factory specification is fine. This keeps the car stable for easy street driving. An improper toe setting, whether toe-in or toe-out, will cause excessive tire wear. When diagnosing tire-wear problems, look at the toe setting-not just the camber setting.
The caster setting depends on the basic model. Fox-chassis Mustangs have different requirements than SN-95s. The '79-'93 Mustangs should have as much positive caster as possible, which is typically in the neighborhood of four degrees. With the '94-'04 Mustangs, there's enough adjustment range when fitted with MM caster/camber plates to have more caster than is desirable for a street-driven car. Usually increasing caster to a setting of about +4.5 degrees works well. Additional caster creates a problem with bumpsteer, as the steering arm on the spindle rises with increased positive caster. That raises the tie rod, altering the amount of bumpsteer. More caster would still be OK if you're willing to measure and adjust the bumpsteer.
On a street-driven car, it's common for alignment shops to adjust the passenger side to a slightly more positive setting than the driver side. A car tends to pull toward the side with less positive caster. By adjusting the caster so it has a slight pull to the left, the tendency for the car to be forced to the right by the crown of the road will be counteracted. Caster split-the difference in caster from one side to the other-of less than 1/2 degree isn't likely to be noticed by the driver, and yet it's enough to counteract most of the pull from the road crown.
The thing to keep in mind is that caster measurement is mostly an approximation; it's not directly measured to provide a definite, absolute number, as camber is. Caster measurement is basically an extrapolation made by measuring the difference in camber with the wheels steered first in one direction, then in the opposite direction. There are a lot of factors that can affect caster measurement, and therefore the resulting number. For example, any rake to the car will affect the caster measurement, as will changes in ride height. Probably the biggest variable is the competency of alignment technicians, and their proficiency in the use of the equipment. On any individual car, the more important thing is the change in caster from the stock setting that's made, not the final number.
The amount of negative camber on a road-raced car can become aggressive. As much as 3.5 degrees isn't unusual for some tracks. The camber is usually set to what works best at a particular track, and is usually different from side to side to optimize the car. Taking tire temperature, checking tire pressure, and keeping an eye on tire wear will guide toward the best camber setting. On our road-race Mustang, we may change the alignment before every session for a particular track. We pay as much attention to the wear pattern as the tire temperatures. Usually, the alignment that produces the best handling also has the most even tire wear.
The toe is set to toe-out, making the car respond more quickly when turning in for the corners. The amount typically ranges from 1/8 inch overall to as much as 1/4 inch, depending on the track. Excessive toe-out makes the car unstable at speed and darty under braking. It will also increase drag on the straights and increase tire wear. It takes experimentation to find the best setup for a particular track.
For a road racer, caster is increased compared to what a street car has. Any car that is road raced should have the bumpsteer measured and adjusted. Since that takes care of the bumpsteer issue, caster can be set to as much as 8 degrees positive. More positive caster causes more negative camber when you need it. The caster setting affects the camber when the front tires are steered, while the car is cornering-but not when the tires are steered straight ahead. There is a tip-over point at around +4 degrees of caster. Above that amount, the camber becomes more negative on the outside front tire, as it's steered during cornering.
In this application, the most important thing is straight-line stability. Everything should be focused on that.
Camber should be set at a minimum, between 0 and -1/2 degree. As the front of the car rises, it will move toward positive.
Caster should be set just as with a street-driven car: increased to a more positive setting than stock, but not enough to cause a bumpsteer problem. Serious competitors realize that even in drag racing, the suspension alignment is as important as anything else. To keep good straight-line stability, drag-race cars should have the bumpsteer measured and adjusted to the minimum amount. When that happens, the caster can be set to as positive as possible, whether it's a Fox or SN-95 chassis.
The toe setting should be slightly toed-in, again to enhance straight-line stability.