Mazda RX7 History (1978-1985)
Article by Mark Trotta
In addition to it's unique rotary engine, the RX7's chassis/layout was also unique; a rear-wheel drive platform had the motor positioned slightly behind the front axle, marketed by Mazda as "front mid-engine".
Production of the Mazda RX7 began in 1978, first reaching American shores in 1979.
Wankel Rotary Engine
Rather than a crankshaft connected to reciprocating pistons via connecting rods, rotary engines have three-sided eccentric rotors, which spin around a central shaft. This design eliminates most of the moving parts found in a conventional piston engine.
Although German engineer Felix Wankel was the originator of the rotary engine, modern rotary engines are of a second design known as KKM (Kreiskolbenmotor) engines, credited to Hans Dieter Paschke.
First Rotary Engine Car
In 1961, both Japan-based Mazda and German-based NSU signed contracts to develop the rotary engine. Although Mazda produced an experimental rotary-powered car that year, NSU was first to market a rotary-powered automobile (1964). In spite of the engine's impressive power and smoothness, poor reliability and fuel economy made them unpopular.
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Mazda Rotary-Powered Cars
Mazda's first rotary engine car was the 1967 Cosmo Sport. About 1,500 of these vehicles were built between 1967 and 1972. Shortly after, Mazda began installing rotary engines in other models, including the RX3.
Based on the RX3 chassis, early RX7's had MacPherson front struts and coil springs with a straight rear axle. This setup kept production cost down, but still gave spirited handling. Disc/drum brakes were fitted front/rear.
First Year RX7
First offered in Japan in 1978, the RX7 was a direct replacement for the Mazda RX3. It was produced in two variants; a two-passenger hatchback, and a 2+2 hatchback with "occasional" rear seats. American markets only saw the two-seat coupe; the four-seat versions were available in other parts of the world. Both models were sold in Japan as the Savanna.
The RX7 was first available in North America in 1979. Under the hood was an 1146cc twin-rotor rotary engine (designated 12A), producing 100-horsepower and 105 lb-ft of torque. a four-speed manual transmission as standard equipment, consumers could opt for a five-speed manual or three-speed automatic at extra cost.
Consumers had a choice of trim levels, including the S and GS models, with the GSL to follow. The GS package included the five-speed gearbox and a rear anti-roll bar.
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The first-series "SA" RX7 (the first two letters of it's VIN tag) was an instant success, unlike the rotary-powered coupes that came before it. The smooth-spinning rotary engine was light and compact, approximately one-third of the size of a piston engine of equivalent power. It's smaller size allowed a lower center of gravity, as well as a desirable 50/50 weight distribution.
In 1980, electronic ignition replaced the previous points-based ignition. Also that year, Mazda built 2,500 LS models for the U.S. market, featuring a sunroof, leather interior, and gold alloy wheels.
The first series RX7, produced from 1978 through 1980, is commonly referred to as the 'SA22C' from the first alphanumerics of the vehicle identification number.
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1981 Mazda RX7
The second series RX7 featured many improvements, including integrated plastic-covered bumpers and a reworked front spoiler. These lowered the car's drag coefficient and measurably reduced front-end lift.
New interior upholstery options were added, the dashboard was redesigned, and rear taillights were a now a "wraparound" design. Also new were the wide black rubber body side moldings.
The four-speed manual gearbox was dropped for 1981, and the gearshift on the five-speed box was mounted closer to the driver. While slightly longer overall, the second-series RX7 was 135 pounds lighter in U.S. trim.
RX7 GSL Package
A new optional GSL package featured 14-inch alloy wheels and four-wheel disc brakes. Unfortunately, the four-wheel discs were packaged with a sunroof and power windows, which added weight, making the car slightly over 2,400 pounds.
The Series-2 RX7's are commonly referred to as the 'FB' cars.
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85 MPH Speedometer
In September of 1979, the U.S. National Highway Traffic Safety Administration (NHTSA) passed a bill which stated that all car, pickup truck and motorcycle speedometers were to display a maximum speed of 85 miles-per-hour. This mandate ended in 1981 after much debate and little proof it actually did anything to change driver behavior. The 130 mph speedometer returned to the RX7 in 1982.
Read: 85 MPH Speedometer Law
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Mazda RX7 (1982–1983)
While 1982 was basically a carryover year, 1983 brought a new Limited Edition model.
Limited Edition RX7
Loaded with expensive extras as standard equipment, the Limited Edition package included 14-inch aluminum wheels, air conditioning, cruise control, sunroof, and cassette deck with a 7-band equalizer. Limited Edition models were finished in Chateau Silver paint with red striping. Reportedly just 5,000 were produced.
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Model year 1984 saw a new four-link rear suspension. Curb weight was now slightly under 2,500 pounds.
The GSL-SE was first offered in 1984, with fuel injection as standard equipment.
13B Rotary Engine
While the 12A engine was still being produced, the new 13B rotary went into production. Essentially a 12A engine enlarged to 1.3 litres, the 13B produced about 30 percent more power.
The optional 135-horsepower, fuel-injected 13B engine was first offered in the optional GSL-SE model. The optional four-speed automatic replaced the three-speed automatic (no automatic option with the GSL-SE).
1984 RX7
The 1984 model year featured four-wheel disc brakes with larger rotors. Rear trailing arms were mounted 20mm lower for improved handling. An interior redesign gave longer-wearing materials, and a new front valence panel had twin lower grilles to aid front brake cooling.
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End of First-Gen RX7
From 1978 to 1985, a total of 474,565 first-generation RX7's were produced, with 377,878 units sold in the United States.
During 1985, RX7 production switched to the all-new FC series, a heavier, though more capable car powered exclusively by the 13B engine. The second generation (FC series) was manufactured between 1985 and 1992. A third generation of RX7's (FD series) were built from 1992-2002.
With over 811,000 units sold between 1978 and 2002, the Mazda RX7 is the best-selling rotary engine powered car in automotive history.
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RX7 in Competition
For twelve consecutive years (1982 to 1993), Mazda RX7's dominated the IMSA GTU class (up to 2500cc), including Daytona's 24 Hour endurance race. They finished first in 100 IMSA races, which is more than any other make or model.
RX7 At Bonneville
In 1978, a California-based company called Racing Beat brought an FB RX7 to the Bonneville Salt Flats in Utah. This specially prepared RX-7 came away with a new Class E Grand Touring Cars record of 183.904 mph. The old record of 167.208 mph was held by a Corvette.
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First-Gen RX7 Buyers Guide
The first generation Mazda RX-7's are affordable and fun to drive. Engine performance is good, with some lasting to 250k miles.
If you want for the most performance for the buck, look for a 1984 or 1985 GSL-SE model in good condition. A good way to check the health of a rotary engine is to do a compression check.
Rebuilding an old 12A rotary engine is becoming challenging, since rotor housings are no longer available from Mazda, and good used ones can be hard to find. If you're so inclined, an early 13B engine will swap into a 12A car with minor modifications.
NOTE: The Wankel engine design burns oil as part of it's combustion process, and synthetic oils are not recommended.
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