Last month we rebuilt the ailing suspension of our Project Diplomat with the promise that we still had a few tricks up our sleeve to better the performance of our '89 M-Body. As you will see, Ma Mopar's basic design is a sound one that we did not alter a lot. In other words, we didn't reinvent the wheel; we simply made it roll better. but, there are some weaknesses that dogged Chrysler, particularly with the early Diplomat/Gran Fury platforms, where extreme usage by law-enforcement agencies uncovered a glaring flaw in the construction. Despite the fact that certain detractors dismiss the transverse torsion bar system out of hand, we feel that such negativism is unwarranted.
The transverse torsion-bar suspension was debuted with the introduction of the '76 Dodge Aspen and Plymouth Volare F-bodies. Police agencies were faced with patrol cars whose front suspensions sagged over time, causing uneven tire wear (from negative camber), poor high-speed handling (from toe-out), and severe brake pull (also from toe-out). While the sagging suspension wasn't a unique event in and of itself, it was quite rapid, particularly under aggressive braking. Plagued with alignment issues when pushed to their limits by law-enforcement agencies, the problem was found attributable to K-members produced from inferior materials on foreign soil. In M-Bodies and F-bodies, the K-member serves a multipurpose function and is responsible for cradling the engine and locating the suspension, steering, and brakes. The tumor was supposedly removed and the situation rectified by the '88 model year--two short years before the end of the Chrysler pursuit vehicles. But we're not going to get sentimental on you; we're simply going to celebrate the era by making our Diplomat into what it could have been with a little more development. these problems were not that prevalent with civilian versions of the M-Bodies because they generally weren't driven with as much gusto as police cars.
In the first installment, we had to make sure our foundation was solid. We returned to Sleeper Suspension Development to let owner Jim Sleeper loose with his bag of tricks. With some carefully crafted modifications, the lightly regarded transverse torsion bar suspension can become a heavy hitter in terms of street hook.
Handling of any car is going...
Handling of any car is going to be questionable at best without a front sway bar. Quickor sent these trick sway bars, measuring 1-1/4 inch and 7/8 inch, front and rear.
(above & below) The original...
(above & below) The original police-issue sway bar measures a whopping 1-1/8 inches, but we went one better with the Quickor 1-1/4-inch unit. We made the decision to stick with the original rear sway bar for testing purposes. It's Fat City back here with the factory-issued, police-package rear sway bars spec'ing at a chubby 1 inch in girth.
Quickor Suspension sourced...
Quickor Suspension sourced Energy Suspension for the polyurethane swaybar bushing kit included with the new sway bars.
(above & right) While we were...
(above & right) While we were at it, we decided to strengthen the lowercontrol arms on project Stealth Bomber by boxing and gusseting them.Here, Jim Sleeper makes a template pattern. The templates are used todraw patterns on a 3/16-inch steel plate. Then a plasma cutter isemployed to cut out the pieces.
We welded a nut on the backside...
We welded a nut on the backside of each outboard control-arm brace toreceive the strut-rod link--but more on that later.