Porsche 911 Turbo

摘要

111,508 Our 911 Turbo's wastegate turns out to be good only for the waste bin. Even after just a few weeks, the 911 930 Turbo has become part of the family, lurking in the garage, all arches and testosterone. Once I'd got it home, I pretty soon got stuck in to sorting out the most urgent job: a wastegate exhaust leak. When Autofarm (from whom I bought the car) ran the car through an MOT for me prior to doing the deal, the leak was picked up. With the Porsche up on their lift, it was easy to spot the blowing joint. Turbos are split into two parts. On one side, a turbine is driven by the energy of the hot exhaust; on the other lives a compressor, whose job it is to force air into the engine, which in turn generates more power than a naturally aspirated engine could manage alone. A wastegate is really just a big safety valve, triggered at a certain boost pressure to allow exhaust gas to bypass the turbo or, in this old timer's case, vent it to the atmosphere through its own tiny silencer. Without a wastegate, the boost pressure would climb unchecked until the engine exploded.