Scans

Here is a picture of the Legend Industries twin-turbo setup. This picture is from Stainless Steel Illusion on page 110:

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caption: The twin-turbo engine developed for DMC by Legend Industries. R & T editor John Dinkel drove the car and calls it "fantastic," comparing acceleration to Porsche 930 Turbo. (DMC)

Text from the book:
Turbocharging From Legend Industries
Another change, one that was being looked into even as the De Lorean was starting production, was adding some power to the PRV V-6 engine. With the automotive magazine road tests showing 0-60 mph times between 9.5-10.5 seconds for the stainless steel sports car when all the car's serious rivals were in the 7.5-8.5 second range, the need was obvious. The owners may not go that fast themselves, but they do read the automotive magazines to compare acceleration figures and then it matters.

From the start of the engineering program for the De Lorean there had been interest in a turbocharged engine as a natural route for the company to follow in looking for more horsepower. There was already a De Lorean version of the V-6 with a pair of turbos on display with the car when it was shown in the National Automobile Dealers Association meeting in January, 1980.

With Mike Loasby and the rest of the DMC engineering staff already busy with other projects, De Lorean again decided to go outside for help in developing the turbo version of his car. Legend Industries of Hauppauge, New Your, already had an excellent reputation for their turbocharging systems. They were the company retained to turn the aging Fiat spider 2000 into a pleasant 1980's sports car with one of their turbo installations. The car De Lorean asked Legend to develop was to have added horsepower, to be produced without a great sacrifice in fuel economy. DMC also wanted a turbo that provided a wide power band, and not the sort of peaky surge of power one gets in a Porsche 930 Turbo. Naturally, the turbo system couldn't do anything to cut into the De Lorean's durability, and it had to be easy to service.

The Bosch K-Jetronic fuel injection already on the V-6 was a natural for the turbo installation, so that wasn't changed. Legend then added a pair of I.H.I. (that stands for Ishikawajimi-Harima Heavy Industries, so you know why they just use their initials) RHB52 turbos. A pair of these was preferable to one larger turbo because their small size made packaging easier and Legend was able to tuck them down low near the exhaust ports, keeping exhaust valve-to-turbine and compressor-to-intake-valve distances as short as possible. Small turbos also meant less rotating inertia, which helps response time. Between the turbochargers and the throttle body of the fuel injection is a pair of intercoolers. These cool the air headed for the engine and are helpful because a cooler, dense charge is more efficient and keeps combustion chamber temperatures down, which helps prevent destructive detonation in the chamber.

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The standard PRV engine

The DeLorean chassis

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Scans from Various Sources