Mazda RX7 History (1979-1985)
Article by Mark Trotta
As an alternative to V8 power, the rotary-powered Mazda RX-7 debuted in 1978 for the 1979 model year. The chassis/layout was unique; a rear-wheel drive platform had the motor positioned slightly behind the front axle, marketed by Mazda as "front mid-engine".
Wankel Rotary Engine
Instead of having a crankshaft connected to reciprocating pistons via connecting rods, rotary engines have 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 Mazda and 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.
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. The first of these would became available to U.S. markets in 1971.
First Year RX7
The 1979 RX-7 was a direct replacement for the Mazda RX3. Both models were sold in Japan as the Savanna. Under the hood was an 1146cc twin-rotor rotary engine (designated 12A), producing 100-horsepower and 105 lb-ft of torque.
Base transmission was a four-speed manual, with a five-speed manual or three-speed automatic available at extra cost. An optional GS package included a rear anti-roll bar and the five-speed gearbox.
Based on the RX3 chassis, the RX7 had MacPherson front struts and coil springs with a straight rear axle. This setup kept it inexpensive to produce, but still gave spirited handling. A disc/drum brake combination was fitted front/rear.
The first-series "SA" RX7 (the first two letters of its 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.
The RX7 was offered as two-passenger hatchback. and as a 2+2 hatchback with "occasional" rear seats. It was offered in America as the two-seat coupe only, the four-seat versions were available in other parts of the world.
Mazda RX7 (1978–1980)
The first series RX7 is commonly referred to as the "SA22C" from the first alphanumerics of the vehicle identification number. 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.
Mazda RX7 (1981–1983)
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. Also new were the wide black rubber body side moldings. New interior upholstery options were added, the dashboard was redesigned, and rear taillights were a now a "wraparound" design.
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. The Series-2 RX7's are also referred to as the FB cars.
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 2400 pounds.
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
While 1982 was basically a carryover year, 1983 brought the Limited Edition RX7, featuring special silver paint, red pin-striping, and 14" x 5.5" BBS-style alloy wheels.
Mazda RX7 (1984–1985)
The third series RX-7 featured a four-link rear suspension. Curb weight was now slightly under 2,500 pounds. North American models received a different instrument cluster.
13B Rotary Engine
With the 12A engine 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 with GSL-SE model. The optional four-speed automatic replaced the three-speed automatic (no automatic option with the GSL-SE).
The 1984 model year brought other changes. Four-wheel disc brakes featured larger rotors for better stopping power, and the 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.
2nd Gen RX7
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.
3rd Gen RX7
The third and last generation RX7's (FD series) were built from 1992-2002. With over 811,000 units sold, the RX7 is the best-selling rotary engine powered car in history.
First Generation RX7 Buyers Guide
The first generation SA/FB RX-7's are still fun and affordable. From 1978 to 1985, a total of 474,565 first-generation RX7's were produced, with 377,878 units sold in the United States. Engine performance is good and some have been known to last up to 250k miles.
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.
The Wankel engine design burns oil as part of it's combustion process, and synthetic oils are not recommended.
If you want for the most performance for the buck, look for a 1984-1985 GSL-SE model in good condition. A good way to check the health of a rotary engine is to do a compression check.
Mazda 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.
Read: Sports Car History