Friday 12 April 2013
The Mazda RX-7 is a sports car produced by the Japanese automaker Mazda from 1978 to 2002. The original RX-7 featured a 1146 cc twin-rotor Wankel rotary engine and a front-midship, rear-wheel drive layout. The RX-7 replaced the RX-3 (both were sold in Japan as the Savanna) and later replaced all other Mazda rotary-engine cars except the Cosmo.
The original RX-7 was a sports car with pop-up headlamps. The compact and lightweight Wankel engine (rotary engine) is situated slightly behind the front axle, a configuration marketed by Mazda as "front mid-engine". It was offered as a two-seat coupé, with optional "occasional" rear seats in Japan, Australia, the United States, and other parts of the world. These rear seats were initially marketed as a dealer-installed option for the North American markets.
The RX-7 made Car and Driver magazine's Ten Best list five times. 811,634 RX-7s were produced.
Series 1 (1978–1980) is commonly referred to as the "SA22C" from the first alphanumerics of the vehicle identification number. This series of RX-7 had exposed steel bumpers and a high-mounted indentation-located license plate, called by Werner Buhrer of Road & Track magazine a "Baroque depression." In Japan it was introduced in March 1978, replacing the Savanna RX-3.
In May 1980, Mazda released 2,500 special North American models known as the LS (Leather Sport). This package was essentially an uprated GS model with added LS badges on each B-pillar, special striping, and LS-only gold anodized wheels (with polished outer face and wheel rim). All LS editions came equipped with special LS-only full brown leather upholstery, leather wrapped steering wheel, leather wrapped shift knob, removable sunroof, LS-specific four-speaker AM/FM stereo radio with power antenna (though listed as a six speaker stereo, as the two rear dual voice coil speakers were counted as four speakers in total), remote power door side mirrors, and other standard GS equipment. Two primary options were also available; a three-speed JATCO 3N71B automatic transmission and air conditioning. Other GS options such as cassette tape deck, splash guards, padded center console arm rest and others could be added by the dealer. The LS model was only ever available in three different exterior colors: Aurora White (1,000 made), Brilliant Black (1,000 made) and Solar Gold (500 made). Production estimates in parenthesis are widely accepted estimations per color, though no official production records are known to exist or to have been released, aside from the total combined production figure of 2,500 units.
The Series 2 (1981–1983) had integrated plastic-covered bumpers, wide black rubber body side moldings, wraparound taillights and updated engine control components. The GSL package provided optional four-wheel disc brakes, front ventilated (Australian model) and clutch-type rear limited slip differential (LSD). Known as the "FB" in North America after the US Department of Transportation mandated 17 digit Vehicle Identification Number changeover. For various other markets worldwide, the 1981–1985 RX-7 retained the 'SA22C' VIN prefix. In the UK, the 1978–1980 series 1 cars carried the SA code on the vehicle VIN but all later cars (1981–1983 series 3 & 1984–1985 series 3) carried the FB code and these first generation RX7's are known as the "FB". The license-plate surround looks much like Buhrer's "Styling Impressions."
In Europe, the FB was mainly noticed for having received a power increase from the 105 PS (77 kW) of the SA22; the 1981 RX-7 now had 115 PS (85 kW) on tap. European market cars also received four-wheel disc brakes as standard.
The Series 3 (1984–1985) featured an updated lower front fascia. North American models received a different instrument cluster (the NA S3 RX-7 is the only rotary-engined car to not have a centrally mounted tachometer). GSL package was continued into this series, but Mazda introduced the GSL-SE sub-model. The GSL-SE had a fuel-injected 1.3 L 13B RE-EGI engine producing 135 hp (101 kW) and 135 lb·ft (183 N·m). GSL-SEs had much the same options as the GSL (clutch-type rear LSD and rear disc brakes), but the brake rotors were larger, allowing Mazda to use the more common lug nuts (versus bolts), and a new bolt pattern of 4x114.3 (4x4.5"). Also, they had upgraded suspension with stiffer springs and shocks. The external oil cooler was reintroduced, after being dropped in the 1983 model-year for the controversial "beehive" water-oil heat exchanger.
The 1984 RX-7 GSL has an estimated 29 highway miles per gallon (8.11 litres per 100 km) /19 estimated city miles per gallon (12.37 l/100 km). According to Mazda, its rotary engine, licensed by NSU-Wankel allowed the RX-7 GSL to accelerate from 0 to 50 (80 km/h) in 6.3 seconds. Kelley Blue Book, in its January–February 1984 issue, noted that a 1981 RX-7 GSL retained 93.4% of its original sticker price.
In 1985 Mazda released the RX7 Finale in Australia. This was the last of the series and brought out in limited numbers. The Finale featured power options and a brass plaque mentioning the number the car was as well as "Last of a legend" on the plaque. The finale had special stickers and a blacked out section between the window & rear hatch.
The handling and acceleration of the car were noted to be of a high caliber for its day. This generation RX-7 had "live axle" 4-link rear suspension with Watt's linkage, a 50/50 weight ratio, and weighed under 2,500 lb (1,100 kg). It was the lightest generation of RX-7 ever produced. 12A-powered models accelerated from 0–60 mph in 9.2 s, and turned 0.779 g (7.64 m/s²) laterally on a skidpad. The 12A engine produced 100 hp (75 kW) at 6,000 rpm, allowing the car to reach speeds of over 120 miles per hour (190 km/h). Because of the smoothness inherent in the Wankel rotary engine, little vibration or harshness was experienced at high engine speeds, so a buzzer was fitted to the tachometer to warn the driver when the 7,000 rpm redline was approaching.
The 12A engine has a long thin shaped combustion chamber, having a large surface area in relation to its volume. Therefore, combustion is cool, giving few oxides of nitrogen. However, the combustion is also incomplete, so there are large amounts of partly burned hydrocarbons and carbon monoxide. The exhaust is hot enough for combustion of these to continue into the exhaust. An engine driven pump supplies air into the exhaust to complete the burn of these chemicals. This is done in the "thermal reactor" chamber where the exhaust manifold would normally be on a conventional engine. Under certain conditions the pump injects air into the thermal reactor and at other times air is pumped through injectors into the exhaust ports. This fresh air is needed for more efficient and cleaner burning of the air/fuel mixture.
- engine: 4 cylinders
- capacity: 1308 cc
- horsepower: 135 HP
- gearbox: 5+1
- top speed: 195 km/h