(also known as; full-throttle shifting
, or speed shifting
) is a method of shifting used with manual transmissions
to reduce the time where the driving wheels are not powered.
Unlike a normal gearchange, or "Granny Shifting" with a manual transmission, in a powershift the driver does not let off the accelerator. The clutch
is briefly depressed while the shift lever is rapidly shifted into a higher gear, keeping the engine in its power band
. This helps the car accelerate faster, but increases the wear on the clutch and the transmission beyond normal levels and shortens the expected life of these components. Flat-shifting may also increase fuel consumption. In most cases, there is a method of cutting the ignition and/or fuel delivery, in a similar fashion to a rev-limiter, which prevents the engine from over-revving when the load from the transmission is removed. Many aftermarket engine management systems provide this functionality as either a standard feature or as an option, usually combined with launch control
The technique lends itself especially well to sequential transmissions as found on motorcycles and race cars.
This can also be achieved by means of electrically, pneumatically or otherwise powered gearbox accessories, for example in racing (to get even faster shift times) or to support disabled motorists who cannot use the limb in question. In... Read More