Splitdorf magneto information site and forum board for vintage motorcycle magnetos.

Contents • • • • • • • • • • • • Development history [ ] In 1993, Bill Riley began initial work on a design for a to meet the 's (IMSA) World Sports Car regulations. The new regulations, announced during the 1993 and intended to be debut in the, sought low-cost open-cockpit prototypes to replace the expensive closed-cockpit GTP models used in the. Riley & Scott, already experienced constructors in the, were looking to enter the sports prototype category of motorsports. The new car, known as the Mk III, featured a radical design with tapered rear sidepods that flowed into the rear wing mounts.

This opened a large amount of empty space around the rear wheels and exposing much of the floor of the chassis. For cooling were all placed at the front of the car, under a simple sloping nose.

Interest in this design was however low, and Riley & Scott did not construct a car for the 1994 season. During that same year, contracted Riley & Scott to aid in improving the team's current WSC car, a DR3 chassis with a engine. After completing the improvements for Dyson, Bob and Bill Riley returned to their Mk III design with new knowledge from their Dyson experience.

After the Mk III was redesigned, Riley & Scott were able to convince Dyson Racing to replace their Spice-Ferrari with two new Mk IIIs for the. Bill Riley's redesigned Mk III was simpler in its design, allowing more variety for customers as well as a low cost. Although the extreme aerodynamics of the original design were gone, the car was conceived to be fast enough to compete for overall wins. The redesign and eventual construction of the first car took only four months.

The chassis featured a with panels made of. Behind the cockpit the engine bay was designed to be large enough to allow for a variety of engines, mostly the of,, and that were common amongst IMSA GT. All cars used a 5-speed. The suspension consisted of with attached by a pushrod. A system was also part of the standard Mk III. The redesigned carbon fiber and bodywork of the Mk III was developed by aircraft designer, who assisted Bob Riley in using early programs to refine the aerodynamics of the new car. Final aerodynamic testing was performed at a.

The nose of the final Mk III was very similar to the original design model from 1993, featuring a nose which sloped downward towards a extended from the front of the car. In the center, a wide intake allowed air into the mounted flat under the nose.

The air exited the radiator from two openings on top of the nose and in front of the cockpit. Between these exit vents, teams had the option of installing extra headlights for night races. A circular duct was placed on either side of the radiator intake to allow air to the front brakes for cooling. Behind the front wheels the bodywork was now relatively square and flat, with full sidepods running the full width of the car. A rules-mandated full width was positioned behind cockpit. Positioned under the roll hoop was an arched intake for the engine.

On the sidepods several square holes were created in order to allow teams to adjust their cooling and aerodynamics dependent upon circuits and conditions. The squares could be filled with bodywork of various shapes and sizes effectively closing or opening the holes as much as the team wished.