Freestyler800sxr
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 Erstellt: 01.01.08, 11:53 Betreff: Re: Unterschiede Drypipe/Wetpipe |
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There's a bit more to a wet pipe, or at least to a B-pipe. The water doesn't just keep the exhaust temperature low, but it allows you to adjust it. An aftermarket exhaust seeks to help extract gases out of the cylinder by setting up a standing wave in the chamber (anyone remember their high-school physics?!). As the exhaust pulse heads down the chamber, part of it gets reflected and heads back upstream. A performance exhaust makes sure that the chamber length is tuned to the length of the shockwave so when it hits the manifold so it pulls gas out of the cylinder, rather than pushing it back in.
So far so good. The trouble is that the shockwave changes wavelength with frequency (revs) which means that an ideal exhaust would also change length - tough to do!! The relationship is:
wavelength = frequency/speed
(where speed is the speed the wave travels through the exhaust). So the tuned exhaust is set to a length depending on the wavelength, but as you see it can only be tuned at a specific frequency (rev setting). Here's the cool part: the speed of the wave is a function of the temperature of the exhaust gas, and that's what the B-pipe relies on.
It goes something like this: The chamber length is fixed, but the user may want the exhaust to be optimized for higher or lower revs. Freestylers want all the power down low, for example. So by adjusting the amount of water injected, you can set the temperature and hence the speed of the wave, meaning that you can, in turn, tune the wavelength for different frequencies.
In English: cooler gas - exhaust optimized at lower revs and vice versa. Pretty clever
Hallo,das war mir soweit auch schon klar,aber wird die Abgastemperatur/Schallgeschwindigkeit bei der Drypipe über die Mantelkühlung realisiert......wäre doch viel zu langsam von der Ansprechgeschwindigkeit,oder???
Grüsse,Andy
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