As a whole movement of doorslammer racers have proven over the last handful of years, a world of potential exists in a stock suspension-equipped vehicle when not only planned out and constructed accordingly, but fine tuned with an astute attention to detail. Because much like a full-on race suspension, several elements exist in stock and stock-style suspension systems that can make or break the performance of a car, regardless of whether it’s producing 300 or 3,000 horsepower.
For those of you out there with ten second and quicker Mustangs or those with such cars on the drawing board, suffice it to say, you’d like to get the most out of your investment, and cutting corners or overlooking things in the suspension department isn’t going to get you there. Many misconceptions, outdated thought processes, and pure oversights exist regarding the preparation of a stock suspension Mustang, and to rectify that, we’ve compiled a list of suspension pointers and tuning techniques to cater to everyone from the beginner to the seven-second showmen. And to do so we turned to one of the experts in the field.
Dave Zimmerman, the man behind Team Z Motorsports in Taylor, Michigan, is without question one of the most knowledgeable and experienced individuals in the racing suspension business – especially when it comes to our beloved Mustangs – and so when we set out to provide our Late Show-like Top 10 list, there was simply no one better for the job.
From the home office in Taylor, Michigan, here ladies and gentleman is tonight’s Top 10 list.
1. Do it right the first time
The racing hobby certainly isn’t cheap by any stretch of the imagination, and everyone has a budget, but selecting the proper suspension components the first time may end up saving you a few dollars down the road when you have to buy it a second or third time. This tip rightfully sits at the top of our list.
“In all my years in this business, I’ve never seen a person want to go slower,” said Zimmerman. “Speed is addicting, and you’ll never hear ‘I’ve gone tens and now I want to go twelves.’ Remember that what you choose for a ten second car probably wouldn’t work on a seven second car, but what you’d use on a seven second car would definitely work on a ten second car.” As Zimmerman instructs, plan ahead and decide the ultimate goal for your vehicle and choose your parts wisely. A hundred dollars more spent up front could save you a thousand or more later.
2. Going solid and adjustable in the ear.
Sure, the suspension system under your Mustang is no slouch, but it was designed for ride comfort and quality, not for ultimate performance on the racetrack. If you want to get the most out of your Pony car, you need to think solid and adjustable.
Adjustability is the name of the game in a rear suspension setup if you want to go fast in a stock suspension car.
As Zimmerman explained solid bushings won’t deflect like a rubber or urethane bushing, plus solid bushings and hiem joints won’t absorb energy upon launch, thus transferring more power to the ground. Thinking solid in terms of parts is also key, as components made from materials such as 4130 chromoly are less likely to stress or deform under the load of high RPM launches.
If traction and straight line acceleration are your goals, adjustability is a must. If you can move your instant center and adjust the pre-load and pinion angle, you have the foundation for a well-functioning suspension. The downside to solid bushings is an increase in noise and vibration. But if are serious about drag racing and straight-line performance, you’ll need to suck it up to get a lower e.t.
3. Suspension geometry
As mentioned above, the Mustang stock suspension leaves some to be desired, but that doesn’t mean ample potential doesn’t exist. By using a four-link calculator and plotting out the geometry of the suspension as it came from the factory, you’ll find that the instant center is either behind the axle or never intersects at all. This is far from optimum for drag racing purposes.
Achieving an optimum instant center, which a vehicle from the factory often lacks entirely - is key to making a stock suspension race car hook well and run fast. The instant center is the point in space where the upper and lower control arm would intersect.
“In a stock suspension mustang, geometry is everything. It’s the difference between getting down a track when others are struggling, or complaining like everyone else that the track sucks,” states Zimmerman. “Usually, the first thing most racers do is lower the car and put bigger tires on it, but this causes a shift in the geometry as the instant center moves from behind the rear axle to well in front of the rear axle and lower in the car. This is better than behind the axle, but it’s far from ideal.”
Changes such as these lead to inconsistency and instability at higher speeds, and many try to correct such issues with band aids that fail to actually correct the geometry. If they were to go straight to the source first, short times would improve and the car would exhibit better stability and consistency characteristics. Because geometry is important, be careful of adjusting your ride height, and if you add an aftermarket rear end, think about housings that allow you additional mounting points for your lower control arms. More than anything, work with a single suspension guru to help you building an integrated system.
4. Anti-roll bars
When used correctly, adding an anti-roll bar to your Mustang will improve your sixty-foot times and how your car handles down track.
Anti-roll bars act to reduce the body roll experienced upon the launch, caused by torque and the rotational forces of the driveline.
The primary purpose of an anti-roll bar is to reduce the body roll on launch caused by torque and the rotational forces of the driveline. It also serves to help plant both rear tires to the pavement evenly. He doesn’t feel it’s a pre-load device, as Zimmerman argues emphatically, although some use it to do that. “If your car is heading left or right, you’ve got other issues, so don’t try to fix it by adding pre-load in your anti-roll bar; this will only cause premature wear and possible part failure. Find the problem before it finds you.”
Use your anti-roll bar for its intended purpose and it’ll reward you handsomely. The downside of an anti-roll bar is that it’s really not designed for street use. For street/strip cars, you can disconnect the anti-roll bar before you hit the street, and re-connect when you hit the track.
5. Lighten that Front suspension
As anyone with any understanding of weight and the laws of gravity is aware, increasing a vehicles weight transfer to the rear tires goes a long way to improving traction. And one of the best ways to accomplish this on a stock suspension Mustang is by swapping out the stock K-member and A-arms for lightweight, tubular versions. And while you’re at it, toss the heavy stock springs in favor of an adjustable coilover kit as well.
You may not think it, but an aftermarket front suspension is about weight and weight transfer. Disposing of the factory shocks will remove a significant amount of weight, and the adjustability of coilover and shocks will assists in weight transfer upon the launch by leaps and bounds.
Not only will a coilover setup shave some 60-80 pounds of rolling weights off your race cars thighs, but these adjustable options allow one to achieve the proper spring length and spring rate for controlling the front end rise and weight transfer to the rear suspension, as well as front ride hight adjustments and corner pre-load. A few other advantages – more header clearance, ease of working on your car, and our favorite – it just looks bad ass.
6. Picking the Right Shocks and struts
With the tire and suspension technology that exists todays, shocks and struts play a very important role in a stock suspension setup, and Dave says that adjustability is desirable. The days of cheap drag shocks and high performance are generally gone, and if you want to get the most out of your suspension, you’ll have to go this route. “I generally recommend a good single adjustable strut that will help you control the rise of the front end, but can be adjusted to be very stiff if needed.” For those of you with nine second and quicker cars, double adjustable rear shocks are the way to go, while a good single adjustable will allow you to control the rebound if you’ve got a high nine to low ten second car. “Remember that high dollar rear shocks that have multiple, ultra fine adjustments work great on a chassis car but really aren’t necessary on a stock suspension car,” continued Zimmerman.
Adjustable rear shocks are simply a must for any hardcore street or strip ride looking to find the true performance potential of their vehicle.
Zimmerman also suggests avoiding stock location rear “coil over” conversions for your suspension, as bolt-in shocks aren’t designed to work with a coilover body, “There are too many issues to get into, so save your money and your time,” claims Dave. Selecting the right shocks and struts will go a long way toward helping you to get every last horsepower to the ground and and accomplish it much sooner on the race track.
7. Springs – Pick the Right Ones
For many Mustang enthusiasts out there, selecting the appropriate springs is like voodoo. Thanks to Al Gore’s invention of the internet, a wealth of information on spring selection exists right at ones fingertips, but like anything else, you’ve got to dissect the good from the bad. For Springs 101, there are two primary types of springs that most will use on their stock suspension Mustangs: a stock-type spring or coil-overs.
On the front end, if it’s traction and straight-line acceleration that you’re after, forget about stock-type springs. Coilovers not only allow for ride height adjustments, but you can also dial in the optimum spring rate and length to get the weight transfer just right. If you want control over what the nose of your does and when on the launch, coilovers are your answer.
Moving to the rear of the car, if you car isn’t equipped with coilover shocks, the stock spring actually works quite well. Team Z has used an old, high-mileage V8 spring with a single coil removed that has provided great results on mid to low eight second cars. If you opt do the same with your car, keep your spring-chopping to a single coil.
Selecting the proper springs can be like voodoo to many first-time car builders, but thanks to the internet (and this guide), information on this very topic is right at your fingertips.
If however, you’re using a true coil-over (not a retro fit) rear shock, your choice of springs becomes very important. What you’ll need is a spring stiff enough Zimmerman is quick to remind our readers that in the overall cost of building a race car, springs are rather cheap and many racers carry spares.
A common misconception that creeps into many discussions about springs is that longer, lighter springs store energy. But our expert views this is a myth that needs to be silenced. “A spring can only store the amount of energy that’s placed against it in the form of front end weight. Over the years, as suspension and tires have improved, the need for longer and lighter springs has diminished, and I’ve all but transitioned away from the 14″ springs on the front for drag racing vehicles and the results have been amazing.”
8. Torque Boxes – Fix ‘Em Up!
Torque boxes don’t usually receive the attention that they deserve, but they play an integral role in making a suspension system work. The transfer of energy from the suspension goes through the torque boxes, which are essentially thin, stamped steel.
The transfer of weight and energy goes right through your torque boxes, and they should be checked regularly for cracks or other signs of stress of wear.
When Team Z builds a stock suspension race car, a good amount of time is invested in the torque boxes, stick welding them into place, plating them, and even tying bars into the upper torque boxes to keep them from moving. For those of you building or assisting in the buildup of your own cars, be sure that you too invest time in welding and plating your torque boxes, and inspect them regularly for cracks.
Remember that all rotational energy harnessed by the suspension is passed through the torque boxes as your Mustang launches and powers its way down the race track.
9. Square Your Suspension
So you’ve selected and ordered all of your suspension components, you’ve torn all the boxes open like a little kid on Christmas morning, and everything is bolted into place on your car. Now what?
With the installation process complete, now it’s time to insure that everything is straight and the rear end is square, and the quickest and easiest way to do this is with a process called triangulation. Per Webster’s Dictionary, triangulation is the process of determining the location of a point by measuring angles to it from known points at either end of a fixed baseline.
Using some not-so-scientific methods with a pencil and a tape measure, one can check to ensure their housing will be centered and square in the chassis and ready for setting of the pinion angle and installation of the anti-roll bar down links.
When performed properly, you can be certain that your rear end and suspension are centered and square to the car. “When we build a car, one of the first things that we do is determine the centerline of the chassis and mark it in as many places as we can. This both gives us a center line to measure and build from and, once the car is completed, we always have a center line marked to measure while setting the car up in the shop or at the track,” says Zimmerman.
One of your multiple centerline markings should always be done 24″ to 30″ in front of the axle to serve as the reference point for other measurements. Once you have this point, measure from your left rear lower control arm bolt to your center point and then repeat the process on the right side. Adjust both the upper and lower control arms until the left and right sides measure exactly the same. At this point, your rear housing will be centered and square in the chassis and ready for setting of the pinion angle and installation of the anti-roll bar down links.
Moving to the front of the car, Zimmerman recommends visiting a competent alignment shop. The build tolerances on a race car isn’t that tight, but with the rear of the car squared up, the front can be easily aligned.
Some recommend the ‘X’ measuring method for squaring a car, which means measuring from the left front grease zerk to the right rear lower bolt and repeating it for the opposite side. But as stated above, working off the centerline with the triangulation method is a better, more accurate method.
10. The Biggest Loser: Stripping Weight
Again, anyone with an elementary school science class under their belts can figure this one out. The lighter a moving vehicle is, the faster it’s capable of going. They’ll crank out quicker short times because there’s less mass to accelerate, and the reduces weight will show itself at every increment on your time slip thereafter.
Unless you’ve already got a bare bones car, removing weight is one of the cheapest ways to find that all important elapsed time. All it takes is some work cutting and grinding any unnecessary metal or extras like sound deadeners, wiring, insulation, and the like. If you can find 100 places to remove one pound, you’ve just made your car quicker and your suspension work just that much better.
Even if you plan on class racing your car where weight limits are in place, getting the car itself as light as possible is a huge advantage, as you can then add ballast in all the right places to make your suspension and therefore your car perform to it’s greatest potential.
From Paper To Practice
So what does this expertise and practice in suspension setup and tuning look like in the real world? To illustrate that, let’s take a look at two similar yet very different ends of the Team Z spectrum.
Brandon Alsept earned the NMRA Pure Street championship in his Team Z-built ’98 Mustang in 2008 and is consistently among the class’ elite year in and year out. His Mustang is motivated by a 4.6L 2V combo with Trick Flow cylinder heads and topped with an Edelbrock Victor Jr. intake and a carburetor.
Up front, Alsept’s machine features Team Z’s K-member, adjustable and narrowed A-arms, and Caster Camber Plates, along with Strange Engineering struts mated with a set of Hypercoil springs. And moving to the back of the car, you’ll find Team Z’s re-located upper control arms and lower control arms, along with one of Zimmerman’s anti-roll bars. The shocks are QA1 double-adjustable pieces that sport a set of stock springs that Alsept modified himself by removing roughly one and half coils. Pure Street rules allow for relocation of the control arms on the housing side, thus the only worked performed to the body side has been reinforcement of the torque boxes.
Brandon, who now competes in Mean Street on the NMCA side, has been as quick as 9.72 at 137 mph and 9.86 at 135 in official competition, with a best sixty-foot of 1.27. The car is undergoing a swap to a Team Z Outlaw Stock Suspension 9-inch setup for better gear selection to the get the short times under 1.30 on a consistent basis.
Now we steps thing up a couple of seconds and take a look at the Super Street Outlaw and Drag Radial machines of Chris and Brian Tuten, respectively.
Brian (left) and Chris Tuten.
Both of these cars that have run with the NMRA and at other small tire venues feature Team Z-built chassis. Chris’ ’87 Mustang sports a 25.3 chassis with a Team Z 9-inch housing and complete front and rear suspension. Chris has been 7.02 at 202 mph in Super Street Outlaw trim and was the first racer in the category to top the double-century mark with the 358 cubic inch small block Ford with a 98mm turbo traveling through a pair of 28 x 10.5’s. Zimmerman and crew are in the midst of updating the chassis and installing a monstrous Alan Johnson 481X powerplant with a pair of 88mm turbos that should certainly give the car a workout.
Brian, meanwhile, has a 25.5 chassis under his ’91 Mustang with a Team Z 8.8 housing and the full Team Z treatment in the front and rear suspension department. Brian has been in the 7.60’s in the 275 Drag Radial category and won at Maryland earlier this year with his 358-inch, 88mm turbo combination.
With stock suspension race cars covering the quarter mile these days in well under seven seconds and at over 200 miles per hour, it’s clear that the tireless efforts of suspension wizards like Dave Zimmerman have closed the performance potential gap between chassis and stock suspension cars considerably. And as cliche as it sounds, the sky really is the limit for a stock-type suspension race car when careful consideration is taken to choose the right parts and perform the right steps in the building, preparation, and maintenance of such a vehicle. And whether your ride is a heap of tubing and parts on the jig or a seasoned warhorse, it’s our hope that the guide above will get your machine on track to perform at its best.