Toyo Kogyo displayed more faith in the rotary Wankel type engine over the years than any of the other major car manufacturers in Japan, Europe or America. Indeed by late 1978 the company was celebrating completion of its one millionth rotary powered car since the first Cosmo sports model of 1967
While it was undoubtedly true that Mazda's first essays in rotary power, like the RX 3, were less than impressive, there was no denying that the engine had come of age in the RX-7. When it was introduced in the USA in 1978 it created an instant sensation, and Road and Track magazine even dubbed it the best sports car available under $7000.
Some of the appeal was no doubt generated by the very attractive European-style body. It was in its specification and performance, however, that its real appeal lay. The engine was a twin rotor unit rated at 2.3 liters, much smaller of course than the equivalent 2.3-liter conventional in-line, vee or horizontally opposed engine.
It spun very easily up to 7000rpm, the point where it produced its maximum output of 130 bhp. Although this was hardly world shattering, it did confer a very brisk performance on the small 2 + 2; 120 mph could be attained easily. The engine was front mounted and drove the rear wheels in the time honoured manner, it was, however, so compact that it was possible to site the engine well back in the chassis to give an extremely good weight distribution.
Suspension was by MacPherson struts at the front with an anti-roll bar, and by a live rear axle located by no less than four trailing links, a Watts linkage and an anti-roll bar. Oddly enough the steering was not by the more precise rack and pinion system, but by a recirculating ball, although, in mitigation, it is true that the latter system had become much less vague over the years.
One of the penalties of the early rotary engines was their thirst for petrol; by 1978 it seemed that Mazda at least were beginning to come to grips with the problem. The overall consumption of the RX 7 averaged out in the region of 23 mpg, and while this was by no means good it was acceptable in a high performance car, and what was equally important, it had been achieved within the confines of .Japanese and American legislation on exhaust emissions.
Mazda RX-7 Quick Specifications
Front mounted Wankel type with 2 co-axial, 3 lobe rotors. 573 x 2cc (35 x 2cu in). Maximum power (SAE) 130bhp at 7000rpm; maximum torque (SAE) 1051b ft at 4000rpm; light-alloy block with cast-iron rotors. 2 main bearings. Nikki downdraught carburetor.
Single dry plate clutch and five-speed manual gearbox. Ratios 1st 3.67, 2nd 2.22, 3rd 1.43, 4th 1.00, 5th 0.82. Hypoid bevel final drive, ratio 3.9:1.
Front-independent by MacPherson struts and anti-roll bar, rear-live rear axle with four trailing arms, Watts linkage, and anti-roll bar.
Discs front and rear. Dual hydraulic circuit. Servo assisted.
5in x 13in.
185/70 x 13in.
2 door, 2/4 seat. Integral.
Dimensions and weight:
Wheelbase 95.3in; track-front 55. 9 in. rear - 55.1 in; length 167.9in; width 65.0 in; height 49.6in; weight 2400lb; turning circle 31.5ft; fuel tank capacity 14.5 gal.
Maximum speed 120 mph: acceleration 0-60 mph 8.7 secs; fuel consumption approximately 23mpg.