With a rolling chassis ready, matching the skin of the RX-8 was the next task at hand. Worth sourced a Mazdaspeed carbon-fiber RX-8 shell to cover the chassis. Dzus fasteners were chosen to secure the panels to the frame. These fasteners allow for quick removal of panels to service vital engine and chassis components. A Pettit Racing custom-designed rear wing adds downforce to the rear of the chassis. This wing was specially designed with a “break-away” feature. In the case of a spin, this feature allows the wing to pivot on its hinges, flipping up to act as an air brake. The wing can then return to its normal position once the car is moving in the right direction.
Cameron Worth’s break-away wing design is meant to serve as an air brake in case the RX-8 spins and ends up facing the wrong direction.
Making It Go
Propelling the RX-8 around the track is a fully-built 20B three-rotor engine. Cradled in the engine bay, the normally-aspirated engine features peripheralported housings with semi-direct injection. Machined to Pettit Racing’s specifications, the 9.4:1 compression rotors turn a two-piece eccentric shaft. Incoming air flows through a trio of 51mm velocity stacks feeding TWM 60mm throttle bodies. A six pack of Nippondenso 437 cc/min fuel injectors provide fuel for the fire, while NGK plugs receive ignition energy from six factory 13B trailing coils. Burnt gases are expelled through a Pettit Racing 321-stainless steel, 3-into-1 exhaust manifold. To orchestrate fuel and spark events, Worth installed a MicroTech LT12 engine-management system. With the chassis strapped to a Dynojet dynamometer, Worth optimized the fuel and igniton tables of the MicroTech LT12. At 9,800 RPM, the 1,962cc rotary mill generated an impressive 456 horsepower to the wheels. That breaks down to 228 horsepower per liter.
In a 2,200 lb. chassis, 456 horsepower gives this RX-8 an incredible power-to weight ratio. To harness the power efficiently, a Tilton Engineering 5 ½-inch tripleplate clutch and flywheel transfer the power from the eccentric shaft to the transmission. The reduced rotational mass of the smaller diameter clutch improves engine response. The transmission, a Jerico Racing 5-speed gearbox, features ultra-short ratio gearing for quick shifting around the track. A Pettit Racing aluminum driveshaft joins the transmission to the 4.4:1 final drive in the rearend. Inside the carrier, a MAZDASPEED 1.5-way limited-slip differential divides the power between the rear wheels.
Reduced Heat Signature
The high-revving rotary generates a substantial amount of heat on the track. Therefore, Worth looked to several heat dissipating implements to control engine temperatures. A Griffin aluminum cross-flow radiator rejects the heat built up in the coolant, as the custom Pettit Racing air separator tank purges any pockets of air within the cooling system. In addition, dual Mocal oil coolers cool the crankcase oil while a System 1 remote oil filter with external oil pressure adjustment simplifies filter changes and allows for oil pressure to be optimized to the demands of the 20B engine.
Held Down By The Man
With the project complete, Worth and his team prepared for competition. Initial testing of the platform and engine proved to exceed original expectations. There was a shining bright light of optimism for the coming race season. But only months before the start of the new racing season, Worth was handed some bad news. Despite having consulted with Rolex Cup technical advisors through every part of the original frame construction, some of the rules had changed after the RX-8 had been completed. Left without any time to reconstruct portions of the chassis and reposition the engine to satisfy the new requirements, Worth’s extensive efforts ended up being a lost cause. Worth stated that according to the racing series, this carbon-fiber beauty was branded an outlaw, not allowed to compete in the Rolex Cup series. Soured by the situation, Worth recently sold the RX-8 to a racing team in Guyana, South America. Now this Rogue Racer will wreak havoc on Guyana’s hottest asphalt.
