@wheelsaustralia 33
W
HAT YOU are looking at here is a chimera; an
alien shape that could never be replicated today.
The low bonnet and cowl would never pass
pedestrian safety legislation now. Those would
have to be raised, with fresh air over the top of
the engine’s hard points. With it, the seating
position would inch up by a commensurate amount and that would
require a higher roofline. Because of that, the beltline would have to be
elevated to prevent the glasshouse looking gawky. That, in turn, adds
sheetmetal between the beltline and wheelarch tops, so the wheels
need to get bigger and heavier to maintain proportion. And then you
realise there’s no chance of replicating the purity and balance of the
beautiful FD RX-7. This moment will never happen again.
It’s hard to know whether this pleases Wu-Huang Chin or not. The
Taiwanese designer was part of the Mazda North American design
team that won a shoot-out against a home team from Hiroshima. Many
aspects of the Japanese proposal would end up recycled into the MX-3,
but the American design was something very special.
“I first started working on the third-generation RX-7 in 1988,” says
Chin. “Soft, organic aero shapes were the trend of the time. Our goal
was to develop a timeless design along the lines of the legendary Ferrari
and Jaguar sports/racing cars from the 1960s. We pictured in our minds
this car being presented at the Pebble Beach Concours 20 years later.
However, we did not want to borrow any heritage from others; instead
we looked at the Cosmo Sport, the first- and second-generation RX-7s
and tried to continue this Mazda rotary heritage.”
It’s hard to overstate how radical the engineering was here. The FD
RX-7 and Cosmo shared a sequentially turbocharged rotary engine,
the first production cars after the Porsche 959 to offer this tech. The
engine was pushed deep and low into a gaping transmission cone for
a surface-skimming centre of gravity. Long before the company’s ‘gram
strategy’ on the MX-5, Mazda sought to slice weight out of every RX-7
component. The brake pedal is a tiny aluminium tile, drilled 12 times to
further shave weight.
Even the spark plug leads were trimmed to save weight. The
dimensions were kept compact; shorter, wider and lower than its
predecessor with tighter overhangs and 20 percent better torsional
rigidity. For some sort of perspective, the 1230kg Type RZ model is a
yawning 311kg lighter than a modern Supra. As far as contemporary
benchmarks, the initial power-to-weight ratio was within two percent of
the Ferrari 348 and two percent better than the aluminium-bodied, and
far more expensive, Honda NSX.
The fundamentals were near perfect. Light weight, a low centre of
gravity, fully galvanised body, aluminium double wishbones front and
rear, vented disc brakes all round and a clever Power Plant Frame (PPF)
that used high-tensile steel to effectively make the engine, gearbox,
Torsen differential and rear axle into one unit. An allied benefit of the
PPF was additional crush resistance that then permitted the fitment
of a larger 76-litre fuel tank without risking it being pierced by the diff
housing in the event of an accident. Together, the PPF, the rotary engine
and gearbox totalled a mere 374kg.
The twin Hitachi HT12 turbo set-up was fiendishly difficult to
calibrate. It required 67 vacuum hoses to finally ensure that there was a
smooth handover from one to the other, pressure bled off the primary
blower pre-spinning the secondary turbocharger to 140,000rpm
before chiming in at an engine speed of just over 4000rpm. Stung by
accusations of rotary engine unreliability, Mazda punished the 13B-
REW engine in testing, running one unit at 8000rpm for six months
while another was accelerated from tickover to 7000rpm constantly
for three months. Another test involved taking the engine to its heat
threshold and switching it off to see if the turbochargers would cremate
themselves, over and over again.
The car first launched worldwide in 1992 and there were three sub-
generations of the FD. The Series 6 ran from 1992-1995, followed by a
lightly modified Series 7 from 1995-1998. The Series 8 was a Japanese-
market-only swansong from 1998-2002 but included the desirable Type
RZ and Spirit R models. Wheels tested the RX-7 in October 1992, putting
it up against the BMW 325i, the Nissan 300ZX and the Subaru SVX, but
as far as dynamics were concerned, it was soon apparent that it was a
mismatch. As Mike McCarthy said, “For sheer grunt and go, the RX-7 is
streets ahead” and he noted that “the RX-7’s chassis dynamics are mind-
boggling. Nothing here comes close.”
Australia received the very special RX-7 SP in 1995, produced to
homologate vehicles for the Australian GT Production Car Series and the
Bathurst 12 Hour. Only 35 were built in 204kW/357Nm guise, and for
many, this is still the ultimate production FD. Selling here for $99,790, itWHY
BUY?(^428) OFFICIAL 50:50 ’92-’95
FD
RX-7
SALES
IN
AUSTRALIA WEIGHT
DISTRIBUTION
PRODUCTION
RUN
KERBWEIGHTOF
R X-7S P CONSECUTIVEBATHURST12-HR
62,627 1218kg WINS
THE GOOD
Organic styling; purity of purpose;
rev-happy power delivery;
driver-focused cabin;
competition pedigree; rarity
THE BAD
Many are neglected; complex
twin-turbo mechanicals; requires
regular maintenance; cheap interior
plastics; half-baked auto; rarity