Mazda RX-7
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The new RX-8, as mentioned, as powered by a 1.3 liter RENESIS dual rotary
engine. This engine, unlike a standard piston controlled combustion system
does not use a system of valves and pistons within the engine to introduce
the flow of air and fuel into the engine for the combustion process, but
instead a system of triangular rotors that spin within the engine housing.
Instead of valves that open and close to let in the air and fuel, as well as
to release the exhaust from the cylinders, this engine does not have valves.
As the rotor spins in the housing, the direct intake and exhaust ports are
controlled by the motion of the rotor blades against the housing as it moves
through the 4 steps of combustion. The air and fuel enter the chamber, and
at that point, the engine is at it's first step. The rotor then pushes the
air and fuel to the second step, the compression step. Once the air and
fuel have been compressed, they are moved to the section that contains the
spark plugs, and there the third step of the process takes place, which is
detonation, and from there, the rotor enters the exhaust port area, which is
the fourth and final step of the rotor combustion process. One advantage of
this engine style is that with fewer moving parts, there are less parts to
fail, and with the lack of connecting rods, this engine is able to build
it's power at a very high RPM range, and redline on the new RX-8 is an
astonishing 9000 RPM.
When this new car was envisioned by the Mazda corporation designers in 1969,
they wanted a car built strictly as a sports car, and only for the rotary
engine platform. This first project was named the X020A, but the worldwide
fuel crisis of 1973 put an apparent end to the development of anything that
was not strictly an economy car. But, in 1975, the engineers set back out
on developing a sports car from Mazda. This project, entitled the X605, was
to be built strictly for the Wankel rotary engine design, and while it would
not have massive amounts of torque and horsepower like the American
performance cars, the tiny engine stature would allow for far greater
aerodynamics and lightweight construction. While it would take some five
years of development for the X605 to be released to the public, sometime in
March of 1978 the first officially named Mazda RX-7 rolled off of the
assembly lines in Ujina, Japan.
While the body styling was unique to the
new RX-7, the under carriage parts and engine had been seen before in the
less performance oriented
Mazda models. Those previous uses of the rotary
engine allowed the Mazda engineers to work out the bugs before sending them
across the world to the US market. Originally they had planned to insert
the 13B rotary engine, but due to the rising cost of fuel, and the seeming
limited availability of fuel, they opted for the economy of the 12A over the
higher power output of the 13B rotary in the first offering of the RX-7.
This carbureted 12A rotary engine offered the driver 105 bulk horsepower,
which was actually increased from the previous usages of the 12A. The
suspension was not specially developed for the RX-7, but rather refined from
other, older models of Mazda. The relatively tiny stature of the rotary
engine allowed for a much lower hood line, as well as a low sitting front
fascia, which nearly comes to a point. The windshield and roof line were
also tested heavily in the wind tunnel to yield the lowest possible
coefficient of drag without making the interior head room seem ridiculously
cramped. The headlights are a hideaway flip up style which helps to bolster
the already excellent aerodynamic effect of the front end. All of these
features put together help the first generation RX-7 to yield a minute 0.36
coefficient of drag, which was as good as the
Porsche 924 of that era, and
even with the headlamps open, the coefficient of drag only increases to
0.38, which is equivalent to the drag of one of its nearest competitors, the
Datsun 280Z.
Aside from its light weight and aerodynamic styling, it had a
few external features that helped it stand out from the American cars of
that era, yet, match Japanese competition. The most obvious of this is the
location of the side view mirrors. Most American cars have the mirrors
mounted on the A pillars, but the RX-7 has them instead mounted along the
top of the front fenders, about half way between the door and the front
bumper. The braking systems were not as refined as many had hoped, with
disc brakes in the front, but with drum brakes in the rear. Steel wheels
measuring thirteen inches tall and five inches wide were standard, but an
upgrade option of thirteen inch tall and five and a half inch wide aluminum
alloy wheels could be chosen.
The demand was so great for these first
issues of the RX-7 that prices were being jacked up as much as twenty five
hundred dollars over sticker price. This insane demand for the new Mazda
sports coupe allowed the Mazda Corporation to see the need to make a
whopping 140,000 units by the end of the 1979 model run. The 12A was the
standard offering of the RX-7 until 1983 when Mazda introduced the 13B
rotary engine to the RX-7 for the American market. This engine was only
offered in the high line RX-7 at first, which carried the model line name
GSL-SE. This model packed 135 bulk horsepower, and if chosen, this
particular package also included four wheel disc brakes and limited slip
differential. All of these first generation RX-7s featured 8000 rpm
tachometers, 130 mph speedometers, and a combination clock / fuel level /
water temperature gauge. Thanks to the overseas support in the performance
department, the RX-7 proved to be very successful in many racing series both
Stateside and abroad. Other than the addition of the 13B engine option,
very little changed on the first generation RX-7 during its life span with
the exception of slight changes like moving the side view mirrors to the a
pillar, and even with the huge popularity of the car, Mazda was looking to
improve on it, and late in 1985 Mazda released the next installation of the
RX-7 story, the 2nd generation RX-7.
