The time machine went through several variations during production of the first film, “Back to the Future”. In the first draft of the screenplay, the time machine was a laser device that was housed in a room. At the end of the first draft the device was attached to a refrigerator and taken to an atomic bomb test site.
Ultimately, five real DeLoreans were used in the filming of the trilogy, plus one “process” car built for interior shots. In the off-road scenes in the third film, a modified-for-off-road VW Beetle frame was fitted to the DeLorean with the whitewall tires and baby moon hubcaps. A seventh DeLorean was also used in the filming; however, this one was merely a full-sized, fiberglass model used for exterior shots where the vehicle hovers above the set as well as when the actors interact with the vehicle.
Director Robert Zemeckis said in an interview that the idea was scrapped because he did not want children to start climbing into refrigerators and getting trapped inside. In the third draft of the film the time machine was a car, as Zemeckis reasoned that if you were going to make a time machine, you would want it to be mobile. The specific choice of vehicle was a DeLorean DMC-12 for the purposes of it looking like an alien spaceship due to its characteristic gullwing doors. However, in order to send Marty back to the future, the vehicle had to drive into a nuclear test site. Ultimately this concept was considered too expensive to film, so the power source was changed to lightning.
When the filmmakers arrived at the point where the time machine would be built into a car, the art department was instructed to come up with designs for the DeLorean. Andrew Probert was the first artist to explore the subject (before Ron Cobb joined the production), but his designs were deemed “too perfect” for the look the producers wanted, which was to make it look as if it had been built in a garage by Doc Brown. The idea was that it had been constructed with parts found in a hardware and electronics store, so it couldn’t look too sophisticated. It also had to look dangerous, as Producer Bob Gale noted in the DVD commentary for Back to the Future. The task was undertaken by Ron Cobb who added the coils to the back of the vehicle. The nuclear reactor was also a design choice made by Cobb. This choice proved to be important, given the direction the script had taken. Cobb complemented the nuclear reactor with one vent on the back of the car, since it was generally known at the time that nuclear reactors had vents. Once Cobb had left the production, the producers wanted to balance the design with another vent, keeping a symmetrical aesthetic. Probert was asked to step in and he brought the design to its final form. At the end of the first film of the trilogy these vents become the propulsion system for the improved DeLorean, which now had hovering abilities and could reach the time-traveling speed of 88 miles per hour flying. The production design team added other buttons and lights inside the car to make it look more appealing and complex in order for the audience to have something attractive to look at.
Rather than use the sound of the stock V-6 DeLorean engine in the film, the sound of a V-8 from a Porsche 928 was used.
Different parts from three 1981 DeLoreans were used in the first film. Liquid nitrogen was poured onto the car for scenes after it had travelled through time to give the impression that it was cold. The base for the nuclear reactor was made from the hubcap from a Dodge Polara. Aircraft parts and blinking lights were added for effect. In one of the first scenes, carbon dioxide extinguishers were hidden inside the DeLorean to simulate the exhaust effect. Ultimately, five real DeLoreans were used in the filming of the trilogy, plus one “process” car built for interior shots. In the off-road scenes in the third film, a modified-for-off-road VW Beetle frame was fitted to the DeLorean with the whitewall tires and baby moon hubcaps. A seventh DeLorean was also used in the filming; however, this one was merely a full-sized, fiberglass model used for exterior shots where the vehicle hovers above the set as well as when the actors interact with the vehicle.
Rather than use the sound of the stock V-6 DeLorean engine in the film, the sound of a V-8 from a Porsche 928 was used.
From: wikipedia.org
