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The Mazda RX-8 is a sports car manufactured by Mazda Motor Corporation. It first appeared in 2001 at the North American International Auto Show. It is the successor to the RX-7 and like its predecessors in the RX range it is powered by a Wankel rotary engine.
The RX-8 was designed as a front mid-mounted, rear-wheel drive 2+2 coupé. The car has a near 50:50 weight distribution, achieved by mounting the engine behind the front axle and the gas tank ahead of the rear axle. Weight is trimmed through the use of materials such as aluminium (hood, rear doors and trunk), and a carbon fiber composite driveshaft on the manual gearbox car; designed in an attempt to reduce rotational mass connected to the engine. The rest of the body is steel, save for the plastic front and rear bumpers.
The car features a pair of rear-hinged "freestyle" doors (similar to suicide doors) in order to provide easier access to the rear seats. The RX-8 has no B-pillar between the front and rear doors, with the leading edge of the rear door acting as a 'virtual pillar' to maintain structural rigidity. Because of the overlapping design, the rear doors can only be opened when the front doors are open.
The RX-8 is powered by a 1.3 L (1,308 cc) naturally-aspirated Renesis rotary engine, which features newly designed side intake and exhaust ports, versus peripheral exhaust ports of its predecessor the 13B-REW. The engine is smaller and lighter than previous rotaries, primarily due to the lack of a turbocharger and associated parts. Because rotaries have multiple combustion chambers per rotary, the displacement of all the combustion chambers must be measured for true displacement. When measured fully, some describe the engine as displacing it comes out to 2.6L (2 full rotations of the eccentric shaft). However, the engine is classified by most sanctioning bodies and regulatory commissions as 1.3L.
The engine is designed in various configurations for different models, but in its most powerful setup develops 250 PS (247 hp, 184 kW) at 8,500 rpm with a sustained redline at 8,500 rpm, peak redline of 9,000 rpm and fuel rev limit/cut-off at 9,500 rpm. It won the International Engine of the Year and Best New Engine awards in 2003 and holds the "2.5 to 3 liter" size award for 2003 and 2004.
The power is delivered to the rear wheels via a five- or six-speed manual gearbox or a four- or six-speed automatic through a torque sensitive limited slip differential (which is standard with manual, and optional for automatic, models). The six-speed automatic was introduced in model year 2006 to replace the four-speed.
In late 2003 Mazda issued a press release stating that the actual horsepower of the RX-8 could be up to 5% less than previously advertised. Mazda offered to buy back any of the affected vehicles sold in the United States. Those who chose to keep the cars were given other incentives such as free maintenance, parts, and accessories. Independent engine-dyno testing has shown the engine to make approximately 217hp, however.
In August 2006, Mazda announced that a miscalculation with oil metering had led to the engines in a few RX-8s to experience problems with severe power loss and rough idle. Mazda voluntarily recalled all 2004 and 2005 and some 2006 models to test for this problem, and all engines that failed a vacuum test were replaced at no charge, even if the car was out of warranty. The catalytic converter and leading spark plugs were also checked and replaced as needed. Mazda extended all recalled vehicles' drivetrain warranty to 5 years/60,000 miles. Most affected vehicles were in hotter climates, and were exposed to high traffic, low rpm driving and long idle periods. Mazda estimated that less than 1% of engines needed to be replaced. For vehicles that did not require an engine replacement, Mazda updated the PCM to provide more oil injection at idle and under low rpm driving. Wikipedia |
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