S197 Mustang Rear Suspension Upgrades- Rearing To Go

Horse Sense: If you look closely in the background of our photos, you might see a photo of the No. 37 Steeda race car. Dario Orlando was kind enough to let us have some seat time with him in that Fox racer when it was new. We went 6,000 rpm in Fourth gear while it was fitted with 2.91 rear axle gears-do the math and get a shock. The occasion was an SCCA mini-enduro at Daytona and we used a stock seat. Yikes!

It makes no difference that the S197 Mustang is the best-handling, stiffest-chassied Mustang by a long shot, the aftermarket is always ready to make it better. As if to prove the point, we've previously shown Steeda's front suspension gadgets for the new Mustang. This time, we're presenting Steeda's matching rear suspension improvements for street-driven S197s.

Central to Steeda's S197 rear suspension mods is this combination of a billet-aluminum lower control arm and a U-shaped extended mounting bracket. The bracket lowers the rear of the arm to provide a more aggressive, harder biting, on-throttle traction hit.

These upgrades are a mix of chassis stiffeners and, more important, geometry changers. The geometry products are replacement control arms and brackets for the three-link suspension. Their purpose is to increase rear axle traction-the cat-on-carpet traction the drag boys call bite-when the throttle hits the floor. These pieces are likely most effective for the sharp throttle blasts featured in street driving or at the strip, although they'll certainly drive the rear axle into the pavement no matter where or when the power is applied.

As the newest Mustang has but a single link between the top of the differential and the chassis, Steeda's adjustable street upper control arm third link replacement is also a single piece. It's fabricated of stiffer materials and supported by stiffer bushings than the stock piece to reduce flexing under heavy load. Furthermore, it's adjustable for simplified pinion-angle adjustment.

Steeda notes that the third link is street friendly, even though it has stiffer-than-stock bushings. A sophisticated three-piece urethane bushing design is the reason. There is also a Competition Upgrade Kit for the third link if you have to have more. The upgrade kit substitutes an all-metal rod-end bearing for the urethane bushing. It transmits some clank and road hash into the driver compartment in trade for more precise axle location. It's best used on race cars and Saturday night shakers.

It's true that S197 Mustangs are stronger than earlier Ponycars, but when hitting with big power, extra bracing is a good idea. It's also likely to help in the long-term integrity of the chassis. Steeda's frame and torque-box braces are built from 4130 chrome-moly plated with yellow zinc. They're supplied with the necessary hardware (the chassis already has the required holes) and bolt between the inner and outer frame-rails. They should be welded into position for maximum benefit.

Steeda uses the more descriptive and traditional trailing arm designation for what Mustangers commonly refer to as rear lower control arms. Steeda's arms are whittled from billet aluminum and can be had with either streetable urethane ends or racy rod ends. Steeda says both styles are stiffer than the stamped-steel stockers, thus reducing wheelhop and aiding in precision.

Interestingly, Steeda offers the lower controls arms badged either as Steeda or Ford parts under the Ford's Official Licensed Product program. Steeda is also quick to point out that the company was the first to the market with an S197 rear trailing arm, a product of unusually close ties to Ford for an aftermarket tuning house.

There's another twist to the Steeda trailing arm story: they're required if you also want Steeda's lower trailing arm relocation bracket. This is a U-shaped stamping that lowers the control arms' rear-mounting point below its stock location under the rear axle. This changes the instant center of the rear suspension and gives the trailing arms on-throttle bite, the sort of grip more traditionally associated with ladder bars.

To disperse the extra loads the more aggressive trailing arms impose, Steeda offers the three-point framerail and torque-box brace. This is a welded 4130 tubing and plate. It ties the inner and outer framerails of the Mustang together and communicates at its third point with the trailing arm attachment point. Thus, it passes the loads from the control arms into the chassis without overloading the chassis pickup point.

Together, these parts fortify the S197 for hard acceleration action. To show you how they're installed, we followed along as Steeda fitted them to customer cars at the Pompano Beach campus. It's how the best get better.