MAZDA RX-8

A sports car like no other

The Mazda RX-8 is the fruit of great effort and passion put forth by the entire Mazda team, from R&D and manufacturing to sales and marketing.

It offers customers the driving pleasure and technical innovations they expect from Mazda, including a rotary engine. To date, the Mazda RX-8 has been received many awards from all over the world, winning RJC Car of the Year 2004 in Japan, 10 Best Car for Car and Driver magazine in USA and the Wheels Car of the Year in Australia. In addition, the RENESIS, which powers the RX-8 and is the only mass production rotary engine in the world, was named International Engine of the Year 2003 and RJC Technology of the Year 2004.

Advanced front midship layout

The RENESIS is a naturally aspirated engine, and its height, excluding auxiliary equipment, is approximately the same as the transmission. Furthermore, the intake unit is mounted away from the power unit, towards the front of the vehicle. In addition, the height of the oil pan is reduced to about half of that of a conventional design. All these factors allow the RX-8's engine to be mounted 60mm further aft in the vehicle, with the dashboard being located 80mm forward. The engine is also placed 40 mm lower than the RX-7's.

Use of the advanced front midship layout, location of the plastic fuel tank between the wheels and other measures assure an ideal fore-aft weight split as well as a 5 percent lower yaw inertia moment than the RX-7. Locating the engine lower and further aft in the body also yields a lower center-of-gravity for the vehicle which, together with the wide track specification, has a cumulative effect in assuring high roll stiffness.

The RX-8's exceptional cornering and stability realize a class of handling that keeps the car perfectly attuned to the driver's intentions. And the advanced front midship powertrain layout, low center of gravity and 2700 mm wheelbase also bolster the RX-8's straight-line stability.

Highly rigid body structure and all-new chassis

To realize the exceptional driving performance of a sports car, engineers devised a suitably rigid underbody frame and cabin reinforcements to give the RX-8 a body that, in terms of rigidity and low weight, surpasses those of comparable sport sedans of the same wheelbase.

The upper part of the transmission tunnel is a rigid closed section high-mount backbone frame running horizontally from the front of the vehicle to the rear and joined to the main frame in both the front and back. The underbody makes maximum use of high tensile strength steel in critical locations to assure sufficient rigidity. The optimized layout and large sectional area ensure a highly rigid vehicle, and the advanced front midship powertrain configuration enables installation of cross members connecting the frame in the engine compartment, adding rigid lateral support to the front suspension.

In addition, three cross members are fitted across the lower open end of the transmission.

The RX-8 also uses a high rigidity construction for the side paneling of the door openings. Tailored blank construction method, formed from five steel sheets of optimal thickness welded together, provide ring shaped frame components for local reinforcement where needed for the side panel inner. The panel inner is also tailored blank, formed from three steel sheets, to provide added stiffness to the door opening and cabin.

The low hood design enabled by the advanced front midship powertrain layout of the RX-8 allows the use of Mazda's newly developed in-wheel-type, double-wishbone front suspension. Upper and lower arms are mounted on a highly rigid sub-frame, and the long arms ensure linear alignment changes with jounce and rebound of the front wheels. To obtain linear control of compliance behaviour in response to input of external forces, upper and lower arm bushings have been given a new zero-stopper clearance structure.

Additionally, the front suspension employs monotube gas-filled dampers with large diameter pistons, and the damper lever ratio (the ratio of damper stroke verses wheel jounce/rebound.) has been raised to improve damping efficiency. These measures assure sufficient damping force even with slight piston strokes and realize close compliance with the road surface over a wide range of surface conditions.

The RX-8 employs an advanced multi-link rear suspension system. The long links are optimally arranged to maintain correct geometry and compliance to keep tires in stable contact with the road at all times and achieve superior handling stability, ride comfort and low road noise. Coil springs are located below the floor in the rear of the vehicle, and spring lateral force against the damper rod has been reduced to minimize friction. As with the front suspension, gas-filled mono-tube shocks with a large diameter piston are used for the rear suspension. The rear suspension also uses a newly developed six-point rubber mount system for the sub-frame. This arrangement assures rigid support for the links as well as a more comfortable ride with low road noise.

Additionally, the RX-8 is equipped with newly-developed electric power rack-and-pinion steering that transmits just the right amount of road information back to the driver. The sports suspension version, fitted with large 18-inch tires and aluminum alloy wheels, incorporates large-diameter ventilated front disc brakes and provides ample stopping power for sports driving.