Scans taken from Porsche Turbo.
Say the words Porsche and turbo, and most enthusiasts will conjure up images of the 911-based Porsche 930, or its racing equivalents, the Porsche 934 and 935. The history of forced-induction Porsches goes back far earlier than this, as author Randy Leffingwell details in Porsche Turbo, his latest effort for Motorbooks.
Cutaway drawing of the Porsche 917-10.
When the Commission Sportive International changed the rules of the World Championship of Makes for the 1972 season, reducing maximum displacement to 3.0-liters, Porsche found itself at a distinct disadvantage. The Stuttgart automaker had sunk a tremendous effort into developing the Porsche 917’s Type 912 engine, which itself had grown in displacement over the years from 4.5-liters to 5.0-liters. Not willing to start again, Porsche instead turned its attention to the (almost) anything-goes North American Can-Am series, dominated by American V-8s.
The Porsche 935.
In early going, Porsche found itself at a distinct horsepower disadvantage, and Porsche engineer Valentin Schäffer was given the directive to address this. His first effort was a 180-degree 16-cylinder engine, based upon the Type 912 with an additional pair of cylinders grafted to each end. Though the resulting effort produced 760 horsepower, it proved to be heavy and incapable of generating higher output numbers. Adding more cylinders was clearly not the answer, so Ferdinand Piëch directed the engineer to explore turbocharging as an option.
The Porsche 930, initially sold here as the Porsche 911 Turbo Carrera.
The result is racing history. By the time the 917 racing program wound down in 1973, the twin-turbo 917/30 was producing as much as 1,400 horsepower in testing, which translated to a consistent 1,200 horsepower in racing trim. Porsche’s philosophy has always been to adapt lessons learned in racing to its street cars, and in 1975 forced induction found its way into the company’s flagship 911.
As with other books penned by Leffingwell, Porsche Turbo is well-researched and beautifully illustrated, with factory photos, engineering drawings and cutaways helping to tell the story of Porsche’s forced-induction development. The 256-page hardcover book covers racing cars, street cars, and prototypes, from the early 1970s to the present day, and is a must-own for fans of Stuttgart’s highest-strung thoroughbreds.
from Hemmings Daily - News for the collector car enthusiast http://ift.tt/1NDww6K
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