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Porsche’s Seven Speed Gearbox, Explained 7
Sep
Posted by Kurt Ernst in Automotive, Automotive Help, Kurt, Manual Transmission, PDK Gearbox, porsche, Technical, Transmission, video on 09 7th, 2011

Seven and eight speed gearboxes are the way of the future, since they offer up a blend of both performance and fuel economy simply not possible with five and six speed transmissions. Porsche is the first manufacturer to release a seven-speed manual transmission, and adding the seventh gear allows the automaker greater flexibility in improving the new 911’s performance while meeting ever-tightening U.S. and E.U. fuel economy requirements.

The seven speed pattern is your typical “double H” of a six-speed, with another “half H” added to accommodate the seventh gear (which is located to the right of fifth gear). Gears one through six are close-ratio, designed to maximize acceleration, while the seventh gear is essentially a tall overdrive, designed to reduce engine speeds at high vehicle speeds. In other words, only one to six will be used when driving in a spirited manner (since top speed is achieved in sixth gear), while seventh gear will be used exclusively on the highway (or faster secondary roads) to boost fuel economy.

Porsche’s PDK dual-clutch automatic is also now a seven-speed, with the same “overdrive” feature as the seven speed manual gearbox. As with most dual-clutch manumatics, the PDK will serve up the fastest lap times, since it executes gear changes much faster (and smoother) than a human being can. The trade off is the man-machine interface, and I’ve never driven a shiftable automatic (including Porsche’s PDK) that I prefer over a manual transmission for sheer entertainment value. Props to Porsche for offering customers the ability to choose, instead of just jumping on the flappy-paddle-shift bandwagon.

Source: You Tube via Left Lane News







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