It's all about the feel, baby. Unlike dynos that can objectively measure improvements in engine performance, discerning the handling characteristics of a car's chassis requires a well-tuned hiney. Naturally, this makes suspension tuning particularly challenging. For a racing vet like John Hotchkis, however, it's second nature. Over the years, he's competed in Formula 3, SCCA Trans Am, the 24 Hours of Le Mans, the 24 Hours of Daytona, and the 12 Hours of Sebring. Now this is a man who knows how to make sense of the tugs and pulls a car exerts on his back, bottom, torso, and hands, while powering through corners. His latest development mule--an almost all-original '70 Challenger T/A--is about to help unleash loads of lateral grip on the Mopar faithful.
Although the bulk of Hotchkis' parts development has been dedicated to GM machines since the company's inception, John admits that he's had a soft spot for Mopars since he was a kid. "I wasn't old enough to drive them when they were new, but I've always thought that Chrysler made some of the fastest and best-looking muscle cars of the era," he opines. While the Challenger certainly whets his Mopar appetite, it serves a more practical function as well. "In the past, a lot of Mopar guys were traditionalists who weren't into Pro Touring or heavily modifying their cars, but I think the market is changing now. The owners are getting younger, and a lot of them want things like fuel injection and improved handling. These guys aren't content sitting around in lawn chairs at shows anymore. They want to go out and drive their cars."
Since the goal was to develop parts, not restore a car, John started out with a completely finished Challenger. Other than a set of Hooker headers and a Tremec TKO five-speed trans, the car was entirely stock when purchased. Having found the perfect test bed, John wanted to dramatically improve the car's handling while keeping things as simple as possible. "Many Mopar owners we talked to recognized the handling deficiencies of their cars, but at the same time they didn't want to cut up their cars and make permanent modifications to them either," John explains. "With that in mind, we decided to design a completely bolt-in suspension system. This approach was much more time consuming, but in the end we felt it more directly addressed our customers' needs."
By today's standards, the Challenger's combination of front torsion bars and rear leaf springs seems downright archaic, however, John says tremendous improvements are possible even with simple hardware. "You don't have to go all crazy with a coilover setup in order to have incredible handling. Torsion bars are extremely efficient, and in fact, Porsche used them through much of the '80s," John explains. Beneath the front of the Challenger, Hotchkis designed and installed new tubular control arms, tie rods, strut rods, torsion bars, shocks, and a bigger sway bar. Out back are Hotchkis leaf springs, spring relocation mounts, shocks, and a beefier sway bar. "Our front upper A-arm changes the camber curve when the suspension compresses to dramatically improve cornering grip. It also increases caster for better straight-line stability. Our tie rods virtually eliminate bumpsteer, and our leaf spring relocaters raise the front of the spring to greatly reduce rollsteer."
At the end of the day, the suspension tweaks are good for a 10-mph improvement through the 600-foot slalom. That's drastic in anyone's book, and John says the results are attributable to the company's racing heritage. "During the track and on-road testing phase, you need to have a keen sense of how a car turns in, transfers weight, and manages power application on corner exit. All that's impossible to do unless you have a racing background," he says. "Our chief engineer is a championship-winning autocrosser, so we definitely have a depth of minds on how a car feels in the corners. It may take us longer to bring a product to market, but once we do, we have absolute confidence in it. We're just really excited about finally entering the Mopar market."
One of the only visual cues...
One of the only visual cues that separates this Challenger T/A from a stocker are the 18-inch Forgeline ZX3R wheels. Since the car sees lots of time on the autocross, a set of StopTech brakes scub off speed.
From the factory, the Challenger...
From the factory, the Challenger T/A was rated at 290 hp, but actually produced 20-30 hp more. The functional scoop feeds the air filter, which seals up against the bottom of the hood.
To keep things simple, the...
To keep things simple, the Hotchkis E-body suspension system uses a beefier torsion bar while retaining the stock K-member. The company may develop a coilover system in the future, but first wanted to show what can be done with a suspension system that still looks stock. Suspension parts are also available for B-body Mopars as well.
|BY THE NUMBERS |
|'70 DODGE CHALLENGER |
John Hotchkis, 44 * Santa Fe Springs, CA
|Type: ||stock Chrysler 340ci small-block |
|Induction: ||Chrysler Six Pack |
|Exhaust: ||Hooker 1¾-inch long-tube headers, |
stock mufflers and side pipes
|Transmission: ||Tremec TKO five-speed manual, Hurst shifter, Centerforce clutch |
|Rear axle: ||stock Chrysler 8¾-inch rearend, 3.90:1 gears, Sure Grip differential |
|Front suspension: ||Hotchkis tubular upper- and lower control arms, |
heavy-duty strut rods, lightweight tie rods,
torsion bars, shocks, and sway bar
|Rear suspension: ||Hotchkis leaf springs, shocks, |
sway bar, and subframe connectors
|Brakes: ||StopTech discs front and rear |
|WHEELS & TIRES |
|Wheels: ||Forgeline ZX3R |
18x9, front; 18x10, rear
|Tires: ||Yokohama Neova 265/35R18, |
front; 295/30R18, rear