DeLorean DMC12

The DeLorean DMC12 was, ambitiously for a scratch-built car, designed to surpass the contemporary Corvette of the era in every aspect; safety, handling, comfort, practicallity, performance, fuel economy, aesthetic appeal, longevity, reliability, and price. Most remarkably, it very nearly worked; achieving all goals bar the latter.

The car was the dream of John Z. DeLorean, an affluent manager at the worlds largest car manufacturing company: General Motors. Having experience with large-scale automobile production, John DeLorean was convinced that he could build his dream car in sufficient numbers to compete effectively with the Corvette, GM's sports car for the masses. To do this, he would use state-of-the-art production techniques, and a purpose-built high-tech assembly factory.

The exterior of the vehicle was intended to be unique, featuring, at the desire of John DeLorean, gullwing doors and an unpainted stainless steel body. The car was to be rear-engined, as opposed to the desirable mid-engine configuration, to increase interior room and simplify construction. In its original design, the car was to use a new composite material called ERM, or Elastic Reservoir Moulding, which was to form the entire body-chassis structure. The design would have been very similar to the old fibreglass Lotus Elite; front and rear subframes would have mounted the suspension to the body-chassis. However, the ERM process failed to achieve design goals and more conventional glassfibre reinforced plastic, or GRP, was used instead.

By this time, engineers from Lotus were brought in to refine the design and manage the production process. Like many Lotus cars of the time, the DeLorean was given a steel backbone chassis to increase rigidity, instead of seperate front and rear subframes.

In its final configuration the DeLorean DMC12 was designed and constructed in three stages: First, the backbone chassis, which tied together the suspension and driveline components, was assembled. The chassis, a Lotus-developed double wishbone box-section, made of conventional steel, was covered in fusion-bonded epoxy to prevent corrosion. The GRP body, which incorporated sections of expanded poyurethane foam for added strength and safety, was then mounted to the chassis. The foam also dampened vibration and road noise. Finally, the GRP moulds were covered with stainless steel body panels. Each stainless steel panel which formed the outer skin of the DeLorean was comparatively simple in shape, and none were coated, instead each was given a simple brushed finished. The shape of the exterior was penned by the italian design master Giorgetto Giugiaro.

- Relatively heavy gullwing doors were counter-balanced with cryogenically preset torsion bars (manufactured by Grumman Aerospace) and gas-charged struts. They were reached while seated by hanging lanyard attached to the handle and extended outwards only 11 inches (264 mm) to aid parking. They incorporated smaller electrically operated windows within the main window, as the angle was too great for the main window to slide into the door frame.

- Rear engine layout with PRV V6 engine. 35/65 F/R Weight distribution. Non-power assisted rack and pinion steering.

- Mechanically fuel injected all alloy oversquare (91x73mm) 90-degree 2.85 litre V6 engine made only 97 kW (130hp SAE) at 5500rpm and 208 Nm (153 ft lbf) at 2750 rpm, in part due to emissions requirements. SOHC and 2-valve per cylinder. The radiator was front mounted. 12 L/100 km

- Available with a 5-speed manual or 3-speed automatic transmission.

- Originally the emphasis was on safety. Longevity, reliability, and ease of service were also selling points.

- Roomy comfortable leather cabin with enough space for a bag of golf clubs behind the front seats. Trunk was in the front and accessed by the tilting front panel, which was an almost completely flat section of reinforced stainless steel. Indentations under the roof panels of the gullwing doors increased headroom.

- Fully adjustable seats and a tiliting telescopic steering wheel. Electric windows and mirrors. Dolby noise reduction system.

Blow moulded fuel tank resided in the front under the trunk, wedged between the front forks of the chassis.

- Production total of about 8583 cars.

- The DeLorean had a rear glass window (with an electric heater defogger!), and although the plastic louvers were primarily a design feature, they also sucked out hot air from the engine compartment and reduced window glare.

- The aerial for the radio was originally imbedded in the windscreen surround, but this proved inadequate; later models had conventional telescopic antennaes under the rear louvers.

- Even the exhaust system was fully stainless steel to prevent corrosion.

- The suspension system consisted of unequal length wishbones at the front and compliant diagonal trailing radius arms with upper and lower links (i.e. multilink) in the rear. 10.7m turning circle, 3.2 turns lock to lock?. An overall steering ratio of 14.9:1, giving 2.65 turns lock-to-lock? and a 35 ft (10.67 m) turning circle.

- Wheels were cast alloy, 14 inches with 195/60 tires at the front and 15 inches with 235/60 tires at the rear. This disrepency in tire sizes front and rear was to minimize the inherent oversteer caused by the rear-engine layout and worked quite well.

- Unlike most exotics, the car borrowed a lot of its parts from other marques, ensuring replacement and repair was not an issue.

- Some concerns were raised about the evacuability of the car after it had been rolled onto its roof. In practice however, the windscreen could be easily kicked out.

- The engine and transmission was shared with the contemporary Renault 30. However, in that car the engine was ahead of the transmission which drove the front wheels. For the Rear-engined DeLorean, the whole unit was turned 180 degrees which required the crownwheel on the differential to be flipped over to ensure the wheels did not turn backwards.

- Although the rear engine layout was used to good effect in many Porsche's, the lotus-tuned DeLorean did not handle quite as well. Because the cabin was so big, necessarily to accomodate tall people comfortably along with their golf clubs, the engine and fuel tank were pushed out to the edges of the car, creating a high rear-based polar moment of inertia which negatively affected handling, specifically turn-in and response.

- Although the sporting nature of the car was heavily criticized, the car made more sense as a luxury grand tourer for the american market and ended up being quite reliable.

- Lotus was brought in to further develop the car and to assist in the pre-production process. This is one reason the car shared many similarities with the Lotus Esprit of the era. Both were also designed by Giorgetto Giugiaro.

- PRV engine was a 'odd-fire'? uneven ignition timing design, with crank-pins 180 degrees apart?

- The stainless steel body panels were a problem to repair as the repair job could not be covered over with paint. Originally this was seen as not a problem as it was expected that damaged panels could be simply replaced, and this would have been the case if the original dies had not been thrown into the atlantic ocean after the collapse of the company, as the panels could have been relatively easily and cheaply made.

- The engine output, originally set at 170hp, due to recent emissions requirements requiring the EFI system to be detuned and catalytic convertors fitted, ended up at 130hp.

- The square headlights were required by US legislation and in order to attain the minimum height, the front suspension was raised a few inches.

- The moral of the DeLorean story was that a great car was very nearly successfully designed and marketed from complete scratch.

- Flip up gas cap just ahead of the windscreen for adding fuel and window washing fluid. Only available for 1981 models.

Early models had a dedicated fuel filler cap just in front of the windscreen. Later models required the trunk to be opened to gain access to the fuel inlet.

In a very late stage of development, the front suspension was raised to comply with the required minimum height of the headlights.

All text copyright of Michael J. Bloxham.

If you would like to use any of these materials, contact me first at michaeljbloxham@yahoo.com