Though most hot rodders won't admit it, the light-duty truck is the ersatz hot rod of the '90s. You know, V-8 motor up front, rear-wheel drive, a trunk bigger than Arizona, and more emissions-legal speed parts available for it than you can shake a stick at. It's the family vehicle that hauls you, your kids, and your tools during the week and pulls your boat to the river on the weekends. But after a couple of years, even with religious maintenance, the handling characteristics can become torpid and the ride soft and unsure. Nobody but a couch potato likes to drive a couch, so follow along as we instill the reflexes of a Corvette in our daily driven work truck.
Suspension modifications are a multistage affair. To a serious performance addict, the first stage is to replace all the OEM rubber bushings with ones made from polyurethane. The second stage is to lower the center of gravity and to tighten up the four corners. Stage three is to get the power to the pavement and look good doing it.
Rubber deflects and compresses under load and makes the bushings do the work of the suspension components. With 75,000 miles on my 1991 GMC shortbox, the ride and the handling had gone way south. Even with fairly new shocks, response was vague. We took the truck to Energy Suspension for a full-boogie bushing rebop. Energy has been manufacturing its own polyurethane for 20 years and has an in-house R&D department. Such close proximity allows Energy to index its hardness factor (durometer reading) to a specific application.
In the reassembly process, the Energy Suspension technicians prelubed all rotating surfaces with Teflon-based grease.
First the technicians tore down the front- and rear-suspension assemblies and replaced all the rubber bushings (including the transmission mount) with polyurethane. The results were noticeable immediately. I could feel the road again. Gone was the knuckle-under mush from the outside wheel. Gone was the excessive sway and overall bucket-of-manure sensation I'd been getting from the seven-year-old rubber components.
Handling was creeping back with a vengeance, tighter and more positive than ever. The front sway bar was working as designed, and thanks to the Teflon-based lube Energy used during reassembly, the system's squeaks were erased. In short, Energy's bushings make a remarkable difference in handling and the ability of the suspension to absorb road-surface irregularities.
An Energy poly-bushing's ability to withstand greater loads without deflection is demonstrated by the use of a press required for installation.
Step two entailed lowering the ride height and improving the handling. We entrusted this to Hotchkis Performance, and the company installed its Sport Truck Suspension Handling Package composed of high-quality steel parts, which are CNC machined, tig welded, and powdercoated in glossy black. Polyurethane bushings, Grade 8 fasteners, grease fittings, and detailed instructions are all part of the package.
The new hardware produced a 2-inch drop in the front and a dramatic 4-inch drop at the rear. A 1 7/16-inch-diameter (1/4-inch wall) hollow sway bar, variable-rate coil springs, and CNC-machined tie-rod sleeves led the way. In the rear, new leaf springs lowered the center of gravity and work with a solid 7/8-inch-diameter sway bar. To inhibit side-to-side motion, Hotchkis connected the axle to the frame with a Panhard rod. Installed properly, the Panhard rod is parallel to the axle to minimize movement. In addition, a built-in overload leaf spring helps retain towing capabilities while increasing load capacity. Bilstein dampers, specially calibrated for the mission, put a serious edge on the handling threshold. We let the stuff settle in for a week and then met the Hotchkis staff at Santa Anita Raceway's northside, lot six, where the boys had laid out a 600-foot slalom course. Timing lights and a laptop computer kept times honest. Baseline data was established in the company truck, a bone-stock GMC shortbed that differed from mine in color only. The staff's best time was 8.42 seconds at 48.76 mph. With the suspension kit, my ersatz hot rod's quickest and fastest effort was 7.12 seconds at 57.6 mph. Quite a significant improvement.
A couple of months after the install, I was invited to the First Annual Hotchkis Performance On-Track Day at Buttonwillow Racetrack to feel firsthand what kind of improvements its products provide in an all-out environment. After a thorough safety inspection, Camaros, Mustangs, Impalas, and a lone GMC negotiated two separate track layouts. A 1.4-mile course filled the morning's activities; after lunch, a 2.7-mile layout held our attention.
It's one thing to hot rod around town and roar through SoCal's canyon roads, but it's something else altogether to be wearing a helmet, going flat out, and four-wheel drifting through a long sweeping right hander in a 1/2-ton pickup that shouldn't handle that well. We held back nothing and drove to find the absolute handling limits. The truck handled like a big go-cart, and with the supercharger whining and lighting up both rear wheels via the Auburn differential just past every apex, we were convinced that fun can be awfully serious.
Though many hot rodders don't believe in turning left or right, it's a great comfort to know exactly how your vehicle will handle next time you get into a dicey situation on the freeway. As Hotchkis' Paul Yniguez so eloquently put it, "Now you got something going on down there!" He's right.
The difference between the OEM rubber (left) and the Energy Suspension bushing (right) is readily apparent in these front-spring isolators.
Hotchkis Performance Test Data 600-Foot Slalom
Stock Modified Stock '97 Shortbed Chevy Mike's Standard Cab Shortbed Stock Tires Hotchkis Suspension and BFG Sport Truck Radials (285/60R16, 315/55R16) Tire Pressure-Front: 42 psi; Rear: 28 psi Run Seconds MPH Seconds MPH 1 8.1 50.5 7.72 53 2 8.07 50.4 7.33 55.8 3 7.72 52.8 7.2 56.82 4 7.71 52.8 7.58 54 5 8.06 50.76 7.17 57.1 6 7.64 53.4 7.12 57.6 7 7.71 52.8 7.2 56.82 8 7.25 56.4 9 7.19 57 53.4 Best 57.6 Best 51.92 Average 56.06 Average 4.20mph faster than stock
