The main aim of CR04 was to make a simpler, lighter and easier to build car than the others as the main problem in previous years was that the cars had suffered from reliability issues and a lack testing due to long development times.
To improve the car it was decided to, for the first time, use an Aprilia SXV 550 V-twin engine as this engine weighed only 27kg compared to the 60-70kg for a typical 600cc in-line four cylinder motorcycle engines used before. The chassis was designed to comfortably and safely accommodate a range of drivers, meaning that the car was easier to drive than Cardiff's previous entries. The chassis was a full-monocoque constructed from aluminium sandwich panel. This is a material Cardiff has used extensively and has gained experience in its use from previous cars. The engine was fitted with a Suter slipper clutch which allows the engine to "free-wheel" on throttle closing, enhancing the drivability of the car by reducing the severity of the engine braking. CR04 retained a short wheelbase and narrow track width in order to negotiate the tight autocross and endurance course using less steering angle and a smaller turn radius than is possible on the longer and wider cars, a benefit found to outweigh the slightly increased load transfer. The rear track of the car was slightly narrower than the front, to avoid the driver clipping a cone with the rear wheels in slaloms.
Unfortunately CR04 was only completed midway through the Formula Student event so a good result was not expected. A number of problems were discovered on the track which the team managed to overcome to get the car running for the endurance event. The car survived until the half-way pit stop; however, the car was excluded due to a brake fluid leak. Although the team did not achieve a record result, they learned about the many practical problems in the design and construction of complex machines, experience they took forward into the design of the next car.
Body: Aluminium honeycomb monocoque
Brakes: AP Racing, Brembo calipers
Suspension: Front and rear a-arm, pull rod actuated
Tyres: Hoosier C2000 R25B
Wheels: 3 piece, Keizer rims, custom centres
Engine Name: Aprilia SXV 550 V-twin
Engine type: SOHC fluid cooled two cylinder four-stoke
Engine Capacity: 553 cc
Bore & Stroke: 80 x 55 (mm)
Compression Ratio: 12.5 : 1
Inlet: Wave tuned carbon fibre plenum (side fill)
Injection: Stock injectors
Exhaust: 2 into 1, stainless steel, Quill tri-oval silencer
Drive Train: Student designed aluminium spool
Final Drive: 2.925:1