The Ro-Spit has spent the summer with Steve Eckerich in North Carolina, autocrossing and receiving some more sorting. As we are planning on adding a turbocharger this winter, we wanted to further fine tune and strengthen the rear suspension and driveline.
To this end, after careful testing, we realized that we were getting excessive rear camber change because the upper locating link is mounted to the differential itself. This differential is mounted in the original factory Spitfire rubber mounts, which were flexing under the high-g loads attributed to autocrossing. Steve re-engineered the rear suspension so the upper locating link now mounts to the frame instead of the differential.
At the same time—to take the added horsepower of the impending turbo conversion plus our new wider Panasport wheels and Hoosier tires—Steve redesigned the rear hubs and carriers to accept larger Mazda Miata hubs and bearings. Our old GT6 roller wheel bearings have now been replaced with super slick and much stronger Miata sealed wheel bearings at the rear.
We also weren’t completely comfortable with our GT6 stub axles, as they were quite thin after machining them to fit the spline of the Mazda RX-7 half-shaft. To fit these new Miata hubs within our Fiat X 1/9 rear disc brake rotors, we only had to slightly machine the hub around the outside.
Initial testing has shown this to be a far superior setup, but we will test further and continue coverage of this project in the magazine shortly. Our plans for 2002 include further autocrossing, drag racing and ultimate victory at the Beech Mountain Hill Climb.
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