Installing QA1 Double-Adjustable Shocks And Struts On Our ’11 ‘Stang

At the track, suspension and setup can truly make or break your performance, and a point comes where the OEM shocks, struts, and springs outstay their usefulness. This is particularly true if you’re trying to put a considerable amount of horsepower and torque to the ground, and with so much potential on tap with the 5.0-liter Coyote engines in today’s late-model Ford Mustangs, this is ever more the case for true enthusiasts, who are consistently wringing far more power from their pony cars than they came stock with.

QA1’s struts and shocks feature double-adjutable control, allowing you to dial-in the compression and rebound for a given combination or environment. These offer a significant upgrade to the stock parts on a Mustang, which offer no adjustability at all.

Along with on-track performance, a well-tuned suspension can also make all the difference in the feel and handling on the road. That said, with fully double-adjustable shocks and struts out there on the market for the Mustang, you can have the best of all worlds at the turn of a dial, allowing you to dial-in the suspension to any given environment or type of use in short order.

The team at QA1 Precision Products offers just that with their double-adjustable Mustang shocks and struts that are not only entirely user-adjustable, but are direct bolt-in replacements for the OEM pieces on the 2005 and later S197 Mustangs, making them easily user-installable, as well. In this text, we’ll be taking a closer look at the Mustang offering from QA1 and guiding you through the installation and setup processes, with the help of QA1’s own Dave Goldie.

Here’s the rear shock under our 2011 Mustang — part of the three-link system the late model Mustangs sport, with the independently-mounted spring on the axle tube. With the new adjustable shock from QA1 installed, we’ll be able to tune the rear of the car to help plant the tire better upon launch. As a side note, we’ll be utilizing the very same Ford Racing lowering springs that are already on back of the car.

The QA1 Package In-Depth

The S197 Mustangs come from the factory with coilover-type MacPherson front struts, with a three-link system out back utilizing a non-coilover shock with independently-mounted springs on the axle housing, similar to the way to the 1979-04 Fox body cars that preceded them were built.

What the QA1 offering for the Mustang presents is a number of performance-minded features, not the least of which is the option for a true coilover front strut setup, with height adjustability.

The model we’re using is QA1’s twin-tube, double-adjustable shock that has a complete coilover conversion using a coil, which is designed with high performance use, both on and off the track, in mind. They feature a lightweight steel construction, are re-buildable and re-valvable, and present a staggering 324 different valving options. The struts can be optioned with different springs depending on your needs, and in our case, we opted for a 10-inch, 250 lb. spring to give us a nice solid ride.

In the rear, we’re going to continue utilizing the existing lowering springs that we have in the car, and combine them with QA1’s lightweight aluminum, double-adjustable twin-tube Stocker Star shocks, which feature deflective-disc valving and 18 levels of damping, all controlled through the use of the two accessible dials on the shock body.

The primary feature of these shocks and struts, of course, is the double-adjustability, which allows one to independently take control of both the compression and rebound, so whether you’re tuning for the drag strip, a track day on a road course, or simply for highway driving, the ride is right at your fingertips.

“The factory struts are non-adjustable, so they basically are what they are,” says Goldie. “If it works for you, so be it, but in situations where someone wants to change the performance of their vehicle’s suspension, an adjustable shock or strut is one of the easiest ways to increase the performance.”

“The adjustable valving allows you to change the settings, to move from something like a street performance setting, or to something more suited to drag racing, where you might have a softer rebound and a firmer compression, as drag racing-style cars typically have,” explains Goldie.

Here’s the assembled coilover strut from QA1, which will allow us to adjust the ride height as needed. These can be purchased with or without the coilover conversion, if you so choose.

As well, the coilover system up front offers some advantages over the non-adjustable spring on the OEM struts from Ford.

Says Goldie, “With our front strut coilover package, it allows the user to adjust the ride height on the front. For some, the stock ride height is acceptable, but for others, they like to change the height as they need. Lowering the cars is the most popular route, and not many people raise their vehicles, of course, but the coilover allows you to change the ride height and get a stance that you like. You can also pick out a spring rate that’s suited to your combination.”

Compression And Rebound

The compression damping of a shock or strut is the controlling of the energy absorption when being compressed, in effect, controlling how the shock absorber compresses when the tire is being loaded or hits a bump. Rebound, meanwhile, controls the extension of the suspension and the rate at which is returns to its normal position after compression takes place. By adjusting the ‘C’ and ‘R’ knobs, the oil flow inside the unit is altered to allow or inhibit the motion of the shock absorber.

As Goldie shares, the softer spring that we’re using on our car is a boon to the overall weight transfer, and is also a great spring for every day driving.

Likewise, the caster/camber plate that’s used in conjunction with our new struts allows for a means of a more precise alignment, with a solid bearing on top versus a COM isolater-type bushing that comes from the factory, giving a more solid feel going down the road. By design, the bearing gives an improved distribution of load and reduces wear and “sloppy” bearings that cause road noise and poor handling. QA1 has tig-welded the bearing housing to give the plates strength and longevity, which is what you’d expect from a quality aftermarket part.

Like the front struts, the rear, non-coilover shocks allow you to adjust the valving, using the clearly-marked knobs, for different purposes, be they street, strip, or road course. As Goldie tell us,” everyone has a different performance level, so the adjustable shocks allows the owner to adjust the setting that works for their situation. Whether it’s a stick car or an automatic car, you can adjust the rebound to suit to your type of combination and the horsepower rating.”

The Installation And Setup Process

Our assembly process begins at the front of the car, which is a little more tedious than in the rear, with the spindle, the strut, the caster/camber plates, and of course, the alignment all part of it.

After removing the wheels as the obvious first step, we unbolt the strut from the spindle, all supported with a jack so it doesn’t fall to the ground. With the strut hanging loose, you can then unbolt the caster/camber plate assembly and drop the entire strut assembly out. To install the QA1 components, we first mate the spindle and the new strut, secured using two nuts and bolts, just as with the stock struts. We then utilize a jack to help us lift the strut up into place and compress it so that we can bolt it to the newly-installed, QA1 caster/camber plates. Once you’ve got the brakes, wheels and tires back on the car, you’ll want to perform an alignment job there on the lift, or dial it in close and then take the car to a local service shop to have this done.

Here’s the entire package that we’ll be installing, including the set of struts and shocks, along with the coilover conversion package, the coilover springs, and the new caster/camber plates.

In the rear, the panhard relocation bracket has to be disconnected first, as it sits in the way of the shock bolt. From there, we use a jack to support the rear end and unbolt the factory shocks — one bolt on each side of the axle and a nut that goes on the strut shaft on the topside, inside the trunk. From there, it’s a matter of installing the new QA1 shocks in the reverse process.

We begin up front by removing the spindle from the strut, and then, with the suspension held in place with a floor jack, unbolting the factory strut from the caster/camber plates at the top of the shock tower. At this point, the assembly can then be removed.

QA1 provides a few baseline settings for the shocks and struts to get you off the ground and running, but as Goldie tells us, trial and error is the best medicine to find just the right valving. In general, the higher horsepower cars require strong compression and rebound settings, particularly on the rear, which affects how hard the car hits the tire at launch. If the shock is too soft (in essence, the suspension moves easier) this can tend to drive the tire down into the pavement much too hard and ‘flatten’ out the tire, taking it out of round. Likewise, if the setting is too high, making the suspension a bit on the stiff side, the tire won’t strike the pavement hard enough to make it plant.

With the new caster/camber plates from QA1 installed, we can begin bolting up the new coilover struts, repeating the process of removal of the factory strut in reverse order. We eyeballed the alignment well enough to drive the car to a local alignment shop to get the car dialed in nice and square.

The new rear shocks use the same mounting location as the stock shocks, with a nut that locks the shock shaft from inside the trunk.

On the front, higher rebound settings (extension of the strut) is often needed to control how much lift the front of the car is getting, and also may be needed to control how the vehicle comes down from a wheelstand, as Goldie shared with us.

“A single adjustable strut works as a 50/50 valving, so you can change the valving at the softest setting to a real soft, simultaneous compression and rebound, and then as you dial the valving up, it goes from say a 10/10, to a 20/20, and so on, “ Goldie Explains. “But the double-adjustable is for the more hardcore guy or gal that might want a firmer compression and a softer rebound. You can run the rebound between 0 and 6 and the compression higher, maybe between 6 and 12, as an example.”

Like the factory shocks, the QA1’s have a simple eyelet at the bottom for mounting to the rear end housing.

From there, you can go out and make a pass, and if the cars wheelstands or picks the wheels up, you’ll want to add a little more rebound and compression,” Goldie continues. “Whether you’re going out there with a 300 horsepower car or one making 800, there are enough valving options to accommodate the different horsepower levels and how they’ll respond on the starting line. There’s really no need to get hung up on the adjustments — you just make a run, you see what it does, and adjust from there.”

Whether you’re going out there with a 300 horsepower car or one making 800, there are enough valving options to accommodate the different horsepower levels. – Dave Goldie

A stick shift car, as Goldie explained to us, will generally require more rebound in the shock to a manage the torque and horsepower going through the drivetrain from what’s typically a harder-leaving car. An automatic won’t leave as hard in a vehicle with similar horsepower, unless it’s running a high-stall converter, thus requiring a little less rebound. Likewise, a slick tire will often necessitate a little more rebound, as you don’t have to strike the tires as hard to plant them compared to a radial tire.

Track Testing

We began our track testing with two clicks on the rebound and five on the compression up front, with opposite settings in the rear (five rebound and two compression). After a couple of hits, we ended up tightening up the compression in the rear, as the car was striking the tires too hard and spinning them right at the hit. At eight clicks, the car did a much better job of transferring the weight without hitting the tires.

The Results

We went a best of 11.15 in the quarter-mile, with a sixty-foot clocking of 1.67. The best sixty-foot time we ever ran in the Mustang before was a 1.69, one time. Typically our 2011 Mustang averaged in the 1.73-1.75 range, so with a reduction of .07 for our first time out with the new QA1 suspension, we were impressed. Typically, a reduction in one tenth from your sixty-foot time will net an increase of 1.5 to 2-tenths on the top end. We are fairly certain that with some more seat time with the the suspension that we can easily dip into the 1.50s.

We left things alone from our initial settings on the front, where we simply wanted the shock to extend enough to allow for optimal weight transfer to the rear tires when we dumped the clutch. If the rebound were set too loose, it would allow the car to run down the track with the nose in the air, so there’s a delicate balance there to make the car transfer weight at an adequate rate on the starting line without the rebound being so tight that the nose drops too quickly at launch and doesn’t help to plant the tires.

What a set of double-adjustable shocks and struts offers is unparalleled control of the performance of your vehicle, regardless of the horsepower, the tire, or the environment — something that your stock Mustang suspension simply does not provide. Not only can you dial the performance in for a given use — perhaps competing at a local street night at the drag strip — but you can easily switch back to settings more suited for a Sunday drive with the turn of a dial. And what QA1 has done is deliver a high quality, long-lasting, easy to tune set of products that will have your Mustang riding smoother, planting the tire better, or cranking it’s way around corners at speed better than you ever could’ve imagined with your stock suspension parts.


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About the author

Andrew Wolf

Andrew has been involved in motorsports from a very young age. Over the years, he has photographed several major auto racing events, sports, news journalism, portraiture, and everything in between. After working with the Power Automedia staff for some time on a freelance basis, Andrew joined the team in 2010.
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