The Legendary RX-7
It would be impossible to discuss the RX-7 without talking about its engine. A Wankel rotary engine. What is a Wankel rotary engine? The rotary engine works of the geometric principle of inscribed triangles inside of an epitrochoid figure. As the triangle-piston rotates it creates three areas inside of the compartment. The faces of combustion occur around the outside of the triangle as it spins. The rotary engine was invented by German engineer Felix Wankel when he was a teenager. Didn’t get around to actually marketing the engine until after World War II, while he was working for a motorcycle names N.S.U. (Nebraska State University) holler. In 1959 N.S.U. invited a group of engineers and leaders of the automotive industry from around the world to see Wankel’s rotary engine. One of the men was Matsuda, head of what was then called Toyo Kogyo and they had made their money creating auto-rickshaws and later trucks, under the name Mazda-Go. Matsuda loved the Wankel. He immediately licensed it from N.S.U. and brought the prototype to Japan. In 1961 told his Chief engineer that it needed to be reliable and production ready as soon as possible. Within the first of running the prototype, the motor ceased. Within a few days it had blown itself up. The main problem was the tips of the triangular-piston. As it spun around it left chattering wear marks on the inside of the chamber. Using graphite from the pencil leads they created apex-seals. And they gave the rotor smooth movement around the chamber without chattering.
When all was said and done after 80 prototype cars, Mazda released the Cosmo Sport 1 10, in 1967. Their very first rotary- sports car. The Cosmo and the rest of Mazda’s rotary fleet sold really well, until the gas crisis hit. In 1978, the markets had recovered enough for them to debut their new rotary sports car. The Mazda RX-7.
The RX-7, known as the Savanna in Japan, was meant as a direct replacement for the RX-3 series. The RX-7 ended up indirectly replacing all of the other rotary cars, except the Cosmo. Mazda retired everything else in 1977. It was inspired by the Lotus Elan and the first series was a light, two seat coupe. Mazda called it front mid-shift-rear-drive, since the Wankel 12A engine was sitting slightly behind the front axle. This gave the car a low center of gravity and good weight distribution. While the engine was definitely light and it packed quite a punch. The RX-7 could go from 0 to 60 in 9.2 seconds, and ran at 100mph at 6,000 Rpm. Unlike a normal reciprocating engine, the rotary needed to be driven to red-line on a fairly regular basis. Mazda actually recommends running it to red-line in order to both clear out the carbon deposits, and to keep the oil at the right temperature and viscosity. Series 3 saw the introduction of the 1.3-liter, 13B engine. The RX-7 was already becoming a darling of the club racing level. It was fast and very light. And it handled beautifully. As long as you had fuel in tank, because if you had an empty tank it wouldn’t spin.
In 1985, Mazda redesigned the RX-7, and the second generation was born. This time they took inspiration from the Porsche 944 and the RX-7’s were closing to a touring car with sport’s car highlights than the first generation pure sports car. The series 4 produced from 1986 to 1988 came standard with the 13B-DEI engine. With a turbo version available with 189 horsepower. Mazda also finally around to upgrading to rack and pinion steering. Which greatly what could politely be called its tendency to over-steer. It also traded out the clunky drum brakes for discs, and the Series 5 inched up the horsepower to 160. And finally to 200 with the introduction of the Turbo II. Even after adding a convertible top, the best RX-7 was yet to come.
In 1992 Mazda released the futuristic looking third gen Series 6 RX-7. Finally embracing its sports car identity it came standard with a 13B-REW sequential twin-turbo engine. The twin-turbos had been designed in part by Hitachi, and worked together to give smooth acceleration. The first turbo supplied extra torque at low rpm’s, which had always been an issue for the rotary engine. The international community was going to have to satisfied with this last imported version. Due in part to Japanese financial crisis in the 90’s. Ford took over as a controlling interest in Mazda in 1996. The Series 7, released soon after was only available in Japan and Australia. It’s final iteration, the Series 8, was released in Japan only with a myriad of upgrades. More efficient turbo chargers, better intercooling and radiators, new lighting design, more comfortable seats and more power.
Mazda did introduce the RX-8 in 2003 and we got it. For many Mazda fans, the heavier less sleek and less powerful RX-8 was no substitute for the Legendary RX-7. The engine was more fuel efficient and had better emissions rating, but at the cost of less torque. Problems with failure on the apex-seals. And in some cases on the first generation cars, total engine failure. Even increased fuel efficiency couldn’t save the RX-8 from the economic crash of 2008. And it was retired in 2012. While the RX-7 is no longer in production, it has left a lasting impression in the automotive world and in all of our hearts. The RX-7 has a constant presence in the 24 hours of the Le Mans endurance race. The RX-7 dominated the IMSA GTU series for 10 years. From 1982 though 1992. And won more IMSA races than any other model. Even few years Mazda teases us with news of a new rotary or a new RX-7. But so far they’ve not returned their classic. Here’s hoping that one day they’ll make it efficient enough to pass new emissions standards and still retain the pure fun of the old one.