Guide: Dome Zero
Background
The Dome company was founded in 1975 by Minoru Hayashi who wanted to build road and racing cars. He already ran Hayashi Racing in Osaka which was a successful supplier and manufacturer of parts for both street and competition cars. Among the components made by Hayashi Racing were steering wheels, seats, shock absorbers and alloy wheels.
Minoru Hayashi had dabbled in car building since the mid-late 1960s. His most notable creations had been Honda 600-based specials like the Karasu, Tojiro and Macransa.
The new company was based in a corner of the Hayashi Racing plant. Work on the forthcoming road car began in 1975 and the Dome Zero was unveiled at the Geneva Motor Show in March 1978.
Hayashi planned a short production run to fund a Le Mans campaign which had been a long-held dream for him and many of his employees.
Chassis
Despite its radical appearance, the new car’s construction method was fairly conventional.
The Zero was based on a steel semi-monocoque with square tube front and rear subframes. It had a wheelbase of 2400mm, mid-longitudinally mounted engine and rear-wheel drive. The bodywork was glass-reinforced-plastic.
Suspension was fully independent with double wishbones, coil springs and Hayashi Racing shocks.
Anti-roll bars were fitted at either end and Girling disc brakes to each corner. The discs were ventilated at the front and solid at the back (where they were mounted inboard).
The cast alloy wheels were manufactured in-house and had a 13-inch diameter at the front and taller 14-inch diameter at the rear. They were shod with Dunlop Super Sport tyres (185-60VR13 and 225-55VR14 respectively).
Several off-the-shelf components were used to include a steering rack from the Honda Accord, caliper assemblies from the Subaru Leone and halfshafts from the Toyota Cressida.
Engine & Gearbox
It also made sense to source the engine from an outside manufacturer. For the Zero prototype, a 2.8-litre Nissan straight-six was selected.
The two-valve Nissan L28 motor was water-cooled with a single-overhead camshaft, cast-iron block and aluminium alloy head. It was the same unit found in the C130 Laurel and displaced 2753cc thanks to a bore and stroke of 86mm and 79mm respectively.
Compression was set at 8.3:1 and a trio of twin choke Solex C40 carburettors were installed.
In this configuration, the Nissan engine produced 145bhp at 5200rpm and 166lb-ft at 3600rpm.
The gearbox was a five-speed manual ZF 5DS-25/2.
Bodywork
Styling was handled in-house by Dome chief designer, Masao Ono. Although its appearance was largely derivative, the Zero’s build quality was very high for a prototype.
The wedge profile was reminiscent of Bertone’s Lancia Stratos Zero from 1970. Amber light covers below retractable main units were clearly influenced by the Mercedes-Benz C111 while doors that swung outwards and upwards on hydraulic struts were not dissimilar to Bertone’s Lamborghini Countach.
Another Bertone design to inspire the Dome Zero was the Marzal concept of 1967 which similarly featured glass window panels in the doors.
Aside from its front wheelarches, there were practically no curves anywhere on the Japanese car. Instead, the Zero was a mix of flat surfaces and sharp angles.
It already looked a little dated by 1978 as top European designers were beginning their transition to the boxier style that came to define the 1980s.
A forward opening rear hatch revealed the engine and a small removable luggage box that was mounted over the transaxle.
Interior
Inside, the good standard of fit and finish continued.
Heavily reclined seats were upholstered in light green suede. Grey suede was used for the dash, doors and headliner.
Plush grey carpet covered the sills, floor and rear bulkhead. The sills themselves were extremely wide with the right-hand side home to a curiously shaped gear lever.
Behind the twin spoke Hayashi Racing steering wheel was a full complement of digital instrumentation. A second bank of touch controls was located to the driver’s right. Dome had clearly gone for a state-of-the-art ambience but cockpit space for anyone approaching six foot was extremely limited.
Weight / Performance
Although the power output was moderate, the 920kg Zero had a power-to-weight ratio that matched Porsche’s 911 and the Lotus Esprit. A turbocharged engine would most likely have been used for production which would have made the Zero a very quick little car.
Performance figures were never published but in this normally aspirated configuration, top speed would likely have been around 140mph with a 0-62mph time of about seven seconds.
Launch
The Zero prototype was unveiled at the Geneva Motor Show in March 1978.
While the car garnered a lot of attention, it quickly became apparent the Japanese Ministry of Transportation would not approve it for sale on safety grounds. The rules were very strict for domestic manufacturers and Dome did not have the funds to sustain a lengthy road certification process.
However, the Zero’s popularity in Japan led Dome to sign a number of deals with toy manufacturers that licensed the car’s appearance. This proved sufficiently lucrative to enable Dome to open a new head office in Kyoto, develop a second prototype for the international market (the Zero P2) and build a Group 6 racing car to contest the 1979 Le Mans 24 Hours (the Zero RL).
Text copyright: Supercar Nostalgia
Photo copyright: Dome - http://www.dome-museum.com
