Team Z Motorsports, based in Taylor, Michigan just outside of the Detroit and Dearborn auto manufacturing hub, has become one of drag racings most renowned and respected chassis shops and component manufacturers, with a strict attention to detail that rivals anyone else in the business. Company founder Dave Zimmerman has maintained a solid focus on the suspension side of things with a complete line of suspension and chassis components to compliment their full-on car buildups. And thus, in order to get the most out of our Fox body, who better to not only pick the brain of but put our newfound knowledge to practice with than Zimmerman and company.

The 9-inch housing that we've received for our Fox body is based upon Team Z's standard 9-inch housing, but features the added upper and lower control arm mounting points featured on their higher-end Outlaw housing.

Team Z recently supplied us one of their trick 9-inch rear end housings that’s based upon Team Z’s standard Mustang Bolt-in Ford 9″ housing but features the adjustable upper and lower control arm mounts found on their upgraded Outlaw Stock Suspension Bolt-in 9″ housing. In this article, we’ll show you everything you need to know about the Team Z housing, along with outfitting our rear with a set of 35-spline Strange race axles and a 35-spline spool.

This trick Team Z 9-inch sports axle tubes constructed from 3", .188" wall thickness 4130 chromoly tubing for superior durability.

9-Inch Fox Basics

“The 8.8 housings are kind of fragile: they won’t handle 800 to 1,000 horsepower reliably, and so a lot of people are shying away from the 8.8’s,” said Zimmerman. “But the cost of the nine-inch is typically outrageous, and so with this housing, we targeted the in-between market there: somebody that doesn’t want to spend the money on an Outlaw fabricated 9″ housing, that wants the lighter weight of the 8.8 and the reliability of the nine. That’s what we’re going after.”

The housings’ center section is fabricated through a process known as hot stamping, where the metal is heated up until its cherry red and then stamped into shape. In using this method, the material becomes so strong that according to Zimmerman, one would be hard pressed to even cut on it. This process is one that many OEM manufacturers are using these days on their hydroforming materials. The axle tubes are constructed from 3″, .188″ wall thickness 4130 chromoly tubing.

While the longevity and reliability of this 9″ housing is certainly one of its strongest (no pun intended) attributes, what the suspension wizards at Team Z have focused most on and what they believe sets this particular housing apart from its competitors is its geometry. And it’s this geometry that will benefit us in wringing the most out of our Fox body Mustang.

Zimmerman's 9-inch creation sports multiple pickup points top and bottom for making ample adjustments to your vehicles instant center.

Fox Body 9-Inch Geometry

“The geometry on the upper control arms in our new housing is ideal,” explained Zimmerman.”We have multiple pickup points on the top, and most 9-inch housings out there don’t have the correct pickup points. With the multiple pickup point options, you can raise or lower the car, and while no one would ever raise it, if you lower the car, you have the ability to adjust the upper control arms. And the same goes for the lower control arms as well – we have four pickup points on the lowers for adjustability.”

“On many aftermarket 9-inch housings, as you begin to lower the car and the upper control arms are in the location that they end up on a 9″, what most often becomes the case is a very short instant center in the car,” explained Zimmerman. “That tends to cause a car to hook well in the first 20 to 30 feet of the racetrack, but once the power begins to come in, it’ll unload the chassis due to the both the short instant center and the high anti-squat value.”

The instant center of a suspension system is the point in space upon which the suspension links  – in this case the control arms – meet.

Because the motiion of the wheel and tires are restricted by the links of the upper and lower control arms, the motion of the wheel and tire forms an imaginary arc in space with an "instant center" of rotation at any point along its path.

To get a better idea of what instant center looks like, grab a pen and a napkin and first draw the rear wheel and the center point of the axle. Then draw a line from where the lower control arm mounting point on the housing is to the mounting point of the lower control arm on the chassis. Finally, draw a line right down the center of the rear end housing to the front of the car. With those drawn, locate the point at which these two lines intersect, and you’ve found your instant center. Obviously finding the instant center of your actual car is going to require more than a pen and a napkin, but you get the idea.

The further back and higher in the car that this intersection point is, the faster the rear tires will plant to the pavement. The tradeoff is that the tires also unload quicker. Thus, a fine line in discovering the happy medium between these two action exists in setting up the control arms on your car in order to get the tires planted and keep them planted. The Team Z Fox 9-inch housing allows you to optimize this geometry whether you’re running 10’s or 7’s.

The further back and higher in the car that the instant center "intersection" point is, the faster the rear tires will plant to the pavement. The tradeoff is that the tires also unload quicker.

The anti-squat value mentioned previously is an element related to instant center and is designed into a rear suspension link setup to combat a cars natural tendency to squat under acceleration. By strategically placing the instant center at a certain height in relation to the cars’ center of gravity, you can control just how much the car squats or lifts. The higher in the car that the instant center is located, the higher anti-squat value, and the lower it is the less it has. Because weight transfer in drag racing is critical, finding that fine balance between lift and squat is crucial when setting up the car. Generally, a very high instant center will tend to lift the car and affect traction in the front part of the track.

As mentioned previously, the multiple lower control arm mounting points on the Team Z housing makes it possible to move and lengthen the instant center to achieve what Zimmerman calls a “more efficient instant center.” In our Mustang, the ability to adjust the instant center will not only improve our short times on the dragstrip, but also effect how the car handles down track. “It definitely makes the car more stable going down the track with the correct instant center in it,” Zimmerman explained.

“If you drop the ride height, and mini-tub the car, and have it slammed to the ground, at that point, the lower control arm becomes more critical because you don’t want the lower control arm pointing down in the front. This will lower your instant center and basically just ruin your traction.” “We’ve built plenty of cars and I can’t even count the number of stock suspension cars that I’ve set up. I’ve got a window that I like to work within, and with the pickup points on this housing, one will be able to achieve a very good instant center for just about any ride height of car.”

Getting Strange: 9-Inch Axles And Spool

In order to get our new Team Z housing suited up and ready for installation into our Fox, we’ve got some other essentials it’s going to need for proper working order: namely, a set of axles and a spool.

For the center section, we’ll be using a 9-inch Ford nodular piece, mated with a new 9-inch Ford Pro race 35-spline spool from Strange Engineering and 3.89 gears from Motive Gear. The new spool is of chromoly forging construction, making it “one of the lightest spools on the market,” according to Strange’s JC Cascio. This particular spool weights in at just 8.2 pounds. These race-intended spools allow for the use of larger axle splines, and it’s lighter and stronger design improves ring and pinion life by providing for a more rigid gear mounting.

The new components going into our rear end buildup, including 35-spline axles and spool from Strange Engineering, a 9-inch Ford nodular center section, and large rotor Wilwood disc brakes.

Also from Strange, we’ve installed their Thru-Hardened Hy-Tuf 35-spline Pro Race axles. These axles are made from an ultra-strength alloy steel forging, which was actually developed for highly stressed landing gear in military aircraft.The combination of Hy-Tuf and thru-hardened heat treament not only equips these axles with superior torsional strength, but is also very lightweight – perfect for the drag racing applications for which they’re designed.

The specific axles that we’ll be using measure 30-inches for the left and 27 on the right, with 1/2-inch wheel studs, ball bearings, and the works. Both the axles and the spool are available from Strange as part of a 33 and 35-spline package (Part # P2007).

While our Fox body is a nine-second car, and would hold up well with a 33-spline setup, we opted to go the 35-spline route not only for added peace of mind, but for future-proofing, as well.

“Based on the weight, horsepower, and application of the car, 33-spline axles probably would’ve been fine, but by going with the 35-splines off the bat, there’s more strength there for upgrades down the road should a power adder come into play,” explains Cascio.

Dave Zimmerman and his Team Z posse are intently focused on the suspension side of things, perhaps more than any other house of speed in the Mustang market. And this new housing resting under our Fox body puts on prominent display the results of the homework they’ve done and the expertise that they’ve acquired, leaving little doubt that our Mustang will hook with the best of them.