1975 Nissan AD-1 Concept

Mid-engined styling concept featuring a cantilever roof design. The AD-1 was based on the F10 1400 Cherry and appeared at the 1975 Tokyo Motor Show. Many Nissan enthusiasts regard it as a significant loss that the Mid-4 concept of the late 1980's never reached production, despite extensive development and some very favorable reviews in the media. However, the Mid-4 wasn't Nissan's only still-born mid-engined sports car. A Decade earlier, in 1975, the Nissan AD-1 had gone on public show for the first time at the 21st Tokyo Motor Show. The AD-1 was a neatly styled, aerodynamic little two-seater coupe with a mid-mounted transverse engine, similar in layout to Toyota's MR2, which wasn't launched until some nine years later.

The AD-1 was styled with the help of wind tunnel research to achieve the best aerodynamics possible, something they achieved admirably with a mere 0.26 Cd, remarkable even by today's standards. The low drag, allied to the low curb weight of just 740kg, would have helped the car give a lively performance while still retaining a relatively small and economic engine.

While today the technical details of the chassis might not seem adventurous, it was quite a high specification for a small Japanese car in 1975. In the AD-1, this was a 1.4 liter overhead valve A14 engine equipped with electronic fuel injection. Cooling the unit via long pipes to a small front-mounted radiator meant the body sides could be kept free from unnecessary air intakes. At the same time, excess engine compartment heat was vented through grilles in the engine compartment cover behind the rear window. The AD-1 was also equipped with a five-speed gearbox. Underneath the car was suspended by McPherson struts all around and featured dual circuit four-wheel disc brakes.

The AD-1 featured a lift-out roof panel and a fold-down rear window in a special cantilever design roof, eliminating thick front pillars. Outside, the car featured a luggage compartment at the rear and more storage under the bonnet at the front and behind the seats inside. The doors featured a simple released button with a hand cutout, rather than full door handles, similar to the design used by Renault on many models at that time. Unusually for a Japanese car of the period, the AD-1 also featured chrome, door-mounted mirrors rather than the more common fender-mounted mirrors used on most Japanese production cars of the day. This was possible due to Nissan's previous work with Experimental Safety Vehicles (ESV's), the color-coded, impact absorbing bumpers, and the well-protected, mid-mounted fuel tank.

The interior of the AD-1 was functional rather than highly equipped. Its most notable feature was the sports seats, which were "infinitely adjustable" with an adjuster to alter the front of the seat squab and the normal recline adjuster and a separate one to change the angle of the upper half backrest and headrest. The frame-less door glass were open-able with manual winder handles.

The intriguing thing about the AD-1 is that although it is usually regarded merely as a styling exercise, it does appear to be an almost completely production-viable car. Unlike many concept cars, it features details such as badges, locks, and side repeaters… all items are usually left off of concepts to avoid spoiling the lines. Inside, the car looks like a production model and lacks the futuristic appearance seen on most concepts. It's also likely that the AD-1 that appeared at the 21st Tokyo Motor Show was not the only AD-1 built, as can be seen by the differing interiors and body colors shown in the two pictures above. This all leads one to wonder if this car was more than just a proposal? Maybe Nissan was close to building it for real, just as they were a decade on with the Mid-4? I guess we will never know for sure. Still, either way, it was probably a great opportunity lost for Nissan, especially when you consider the success of one other very similar design from the same period, the Fiat X1-9.

Source: www.conceptnissan.com; ratdat.com

Images: www.conceptnissan.com