2005 Mazda RX-8 - Geting A Grip On Grip - Project RX-8

Moton Club Sport dampers solve the 8’s rear grip problem.

By David Pratte

Hey, an actual tech story about Project RX-8! That’s right, boys and girls, the 8 is officially back in action now that the lame owner (that’s me) has finally regained enough Achilles’ tendon function to abuse it on the street and around the racetrack. First on my to-do list was to find a cure for the unpredictable rear grip I’d been fighting with at the track.

On the street, the 8’s handling and overall ride quality was excellent with BC Racing’s entry-level BR coilover system, but at the track the short rear dampers were running out of travel, which meant the rear suspension was spending too much time on the bumpstops. This resulted in an unpredictably tail-happy Mazda. After trying to work around the problem with stiffer spring rates and alignment settings (and disconnecting the rear antisway bar), ultimately we knew the only real solution was to get some dampers with more travel.

For this we turned to Moton, a company with a long and storied history in the world of motorsports (with wins at Le Mans and Daytona), opting for the more affordable but still highly sophisticated Club Sport line of two-way adjustable dampers. These bad boys have separate rebound and compression controls, where each of the seven adjustment levels result in significant changes in damping behavior. We also like the fact that Motons are capable of handling a wide range of spring rates, so you can run as mild or as aggressive a spring setup as you want without having to re-valve them or worry about them prematurely wearing out.

As for spring rates, we opted for a middle-of-the-road approach of 700 in-lb front and 350 in-lb rear Hypercoil springs (sourced from Paragon Competition), a setup that’s stiffer than most RX-8 autocrossers use, but softer than what you would typically find on a World Challenge or Grand Am RX-8. For a STX street tire setup, these spring rates are probably a little too firm for optimal tire performance (and ride quality on the street is a bit harsher than our previous setup), but should work very well with the stickier race rubber we’re planning to use now that we’re targeting SM class for SCCA Solo 2 action and Modified/Limited class for time attack.

As some of you know, Moton was recently acquired by AST (a high-quality damper/coilover kit manufacturer from the Netherlands), but you’ll be happy to know that the Moton line, including the Club Sport, will continue to be produced under the new ownership. As Brian Hanchey from AST USA told us, “The Club Sport name is going to continue as the two-way solution for Moton. It will be made with Motorsport parts, but we felt that it had such a strong name that the brand needed to continue. We also have some exciting new changes that we will announce later this year, based on lessons we’ve learned in Grand Am and via customer requests.”

By David Pratte
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