Ram air

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As a ram-air (literally ram air) engine intake systems are referred to motor vehicles whose suction openings are arranged so that, by the dynamic pressure , a running wind engine charging and thus an increase in performance is achieved.


2010 Porsche 911 GT3 RS - Flickr - The Car Spy (12) .jpg
Ram air hood on the hood of a Porsche GT3 RS . The flow towards the scoop takes place ...
2010 Porsche 911 GT3 RS - Flickr - The Car Spy (10) .jpg
... via the head wind , which can build up a lot of back pressure on the bonnet , especially at high speeds , and consequently also improves cooling and air intake.

At high speeds, ram-air systems feed more air into the combustion chambers for combustion, which means that more gasoline can be burned, which leads to an increase in output.

The ram air openings required in addition to the cooling air openings can, however, at the same time worsen the vehicle's c w value . This puts the effect into perspective insofar as the greater air resistance increases quadratically with the speed , but the increase in performance due to the ram-air effect only linearly. This is particularly important in connection with the hoped-for effect, since it only becomes significant at high speeds, i.e. in the area in which aerodynamics play a steadily growing role. In order to increase the speed from 300 km / h to 400 km / h, a significantly higher increase in performance is necessary than for the increase from 200 km / h to 300 km / h. This effect can no longer be achieved through ram-air effects alone, so that ram-air systems cannot replace other measures to increase performance, but can only supplement them.


In modern motorcycles with ram-air systems, the inlets are usually attached to the face of the front fairing with low resistance. In some ram-air systems, the air is supplied through flared intake ducts , which is less aerodynamically efficient.

In prototype racing series such as Formula 1 , vehicles are often designed with large, forward-facing intake openings that use the ram-air effect. In Formula 1 in particular, regulations stipulated perforation of the airbox in the 1990s in order to limit the performance of the vehicles.

See also


  • Richard van Basshuysen, Fred Schäfer: Handbook Internal Combustion Engine Basics, Components, Systems, Perspectives. 3rd edition, Friedrich Vieweg & Sohn Verlag / GWV Fachverlage GmbH, Wiesbaden, 2005, ISBN 3-528-23933-6