Inside Afco’s New Drag Racing Fox-Body Mustang Struts
When it comes to drag racing — stock usually sucks. In this case, we are referring to struts on the classic Fox-body Mustang. As you well know, the Fox platform is an amazing platform for drag racing, but replacing your struts with aftermarket units designed to provide maximum traction is a necessity. For street/strip cars, you need to make sure to aid quick weight transfer to the rear tires to prevent tire spin, but you also want a safe shock that work on the street. There are a number of offerings on the market, but one company – Afco Racing – decided to put it’s extensive experience to the party by introducing a brand new Mustang strut. Let’s take a look.
Afco’s latest offering for the Fox body and SN-96 (79-04) Mustang is part #30022, and is a non-adjustable front strut that features Afco’s secret (and guarded) valving technology for street/strip use.
“Afco shocks are engineered based on hard data, plus feedback from racers,” said Eric Saffell of Afco. “We also use the latest data acquisition software, because through this process we can create quantitative values to be obtained by a given design.” What that means in laymen terms: Afco used hi-tech 3D modeling and analysis to design the Mustang struts. Then, before they sold any, they tested them in real Mustangs on the road and on the track.
Anatomy of a Shock
Even with street/strip cars, struts are often overlooked when it comes to performance tuning. A properly designed strut not only functions better, but also enhances traction. When matched with a properly setup performance suspension, the entire car will weight transfer correctly, giving you the best ET, which translates into the win light at the end of the track.
There are few aspects you need to know about how struts work before buying a high-performance strut. Inside the strut body, fluid passes through a series of holes and valves. This controls the movement of the suspension as it travels up and down. Rebound is how the shock controls the speed at which the shock opens. For drag racing, the front shocks should extend quickly to facilitate weight transfer. Compression is the opposite, the rate at which the shock compresses
Valving ratios are expressed in compression/rebound. The valving in this strut is an Afco exclusive blend of soft rebound dampening to promote weight transfer with “BNC” bounce control compression Afco offers. When talking strictly drag race duty, the most common valve ratio for the front is 90/10. This provides a fast rebound with the most resistance to compression, which is nice your car hangs front wheels; softening the landing means less chassis (and driver) shock.
Afco uses an innovative variable valving system called Velocity Sensitive Valving. Essentially this means that the speed at which the shock piston is moving alters the amount of rebound and compression. At faster speeds, such as the instant the car launches, the shock moves quickly, to help facilitate weight transfer. As the car gets moving, the piston in the shock moves much slower. This is when the VSV design stiffens up to control body roll. Because of this, each adjustment has a larger effect on the shock’s behavior, so a small tweak works better than a big change.
For our Mustang, this new shock features everything you could ask for in high performance street/strip struts. While these struts are non-adjustable; they have been configured for the vast majority of street/strip rides. In fact, one racer on a forum recently reported 1.2X 60-foots even with the non-adjustables.
Coil-over struts add another aspect to the tuning of the vehicle. With the ability to change the spring rates and ride height, you can overcome just about any adverse track conditions. Not only that, but just about any Mustang looks great with a lowered stance. Add in the adjustable caster/camber plates, and you have the ultimate in suspension tuning at your disposal.
We opted for the whole enchilada- Afco’s Fox Body Mustang struts (#30022) for 1979-2004 Mustangs, coil-over sleeves (#29022) and the Afco caster/camber plates (#40022). Once they arrived, we spent a day installing them onto the Mustang. The installation is quite simple, especially with the coil-over option. Without the coil-overs, compressing the spring in the pocket is a tricky task, often requiring a spring compressor. Since the spring is incorporated in a coil-over shock these are much easier and safer to install.
The end result is pretty impressive, fits good and looks great.