I have been waiting to drive this car for years
and it does not disappoint. Lower-slung and
dinkier than it appears in pictures, the 110S is
cosy but not cramped inside. The décor of func-
tional black finish and generously abundant and
cleanly calibrated instrumentation is along
1960s Jaguar and Lotus lines.
There is excellent 360º vision, and with a
well-spaced pedal, steering and gearchange
relationship you instantly feel that you are in
a sports car. And that is half the battle won.
In the interests of low-down torque, smoother
idle and part-throttle characteristics Mazda had
a preference for straight inlet porting rather than
NSU’s autobahn-friendly peripheral ports. The
Cosmo is as happy to potter at low speeds as it is
to sing around to 7000rpm with that smooth
hum that can only be a rotary engine. Those revs
would give you 120mph in top, but it’s more fun
to flick through the indirect ratios in the delight-
ful ’box with its stubby lever and slicing action.
With a slight rearward weight bias (the
compact engine is mounted well back in the bay),
the Cosmo is a really agile, go-where-you-point-
it car with light and neutral steering, lots of
adhesion and very little body roll. The ride is
firm and flat, which confirms the car’s sporting
rather than gran turismo aspirations.
If it’s hard to think of a Japanese car I’d want
more than a 110S Cosmo, then the appeal of the
Citroën GS Birotor is a little more difficult to
fathom – though appeal it certainly has in spades.
Its commercial failure was one of the deciding
factors in Citroën’s bankruptcy (and subsequent
124 Classic & Sports Car September 2019
takeover by Peugeot), not so much on the basis
of those 847 cars but because of its joint invest-
ment with NSU in a company called Comotor.
The two firms plotted to build rotary engines
in a new factory 30 minutes east of Luxembourg,
Citroën having satisfied itself of the feasibility
of a Wankel-powered car by doing a dry-run of
267 specially adapted Ami coupés fitted with a
single-rotor 49bhp engine. Known as the M35,
these were handed out to ‘special customers’ for
evaluation between 1969 and ’72, complete with
a window sticker advising other road users.
With its various external drives for the hydro-
pneumatics, the Birotor’s peripheral-port engine- transversely mounted and mostly obscured by
the spare wheel – looks different externally to the
Ro80 unit. Internally it is identical to the
German, the lower power rating of 106bhp
presumably down to tune and losses associated
with the brake and suspension pumps.
With a three-rotor CX prototype waiting
in the wings, it’s odd that Citroën chose the
compact three-year-old GS as the basis for its
first rotary vehicle when, presumably, buyers of
the bigger car would have been more open to the
idea of a more powerful and technically advanced
engine. Even if it was rather thirsty.
It’s not even as if much of the Birotor is inter-
changeable with a standard GS; beyond the
obvious flared arches and five-bolt wheels, much
of the suspension and underpinnings are unique
to the car or shared with the CX. The front
disc brakes being outboard, rather than inboard,
was just one of many differences.
CITROËN GS BIROTOR
Sold/no built 1973-’75/847
Construction steel monocoque
Engine iron-block, two-rotor 995cc Wankel,
with two Solex carburettors
Max power 107bhp @ 6500rpm
Max torque 101Ib ft @ 3000rpm
Transmission three-speed semi-auto, FWD
Suspension independent, at front by
wishbones rear trailing arms; hydropneumatic
self-levelling f/r
Steering rack and pinion
Brakes powered discs
Length 13ft 6^1 / 4 in (4120mm)
Width 5ft 4^3 / 4 in (1644mm)
Height 4ft 6in (1370mm)
Wheelbase 8ft 3^1 / 4 in (2522mm)
Weight 2513Ib (1140kg)
0-60mph 13.3 secs
Top speed 109mph Mpg 20-22
Price new £3000 Price now £30,000From top: hydropneumatic
suspension ensures gliding
progress; chocolate brown
seems the default choice.
Opposite, clockwise from
bottom right: distinctively
styled trio; spartan NSU
cabin; Cosmo has the most
exotic feel; quirky GS
with single-spoke wheel