I saw mention in a past post where someone said regarding the diverter valves he had upgraded on his TT, "And I love the sound they make"

What sound do they make? Do they go pssss when you come off the boost?

Chris Barton

 

It is hard to describe in words...but it is like a "dweeep" sound. Very cool!

 

Hi Turbo Chris,

The make a "vaguely" similair sound to the blow off valves (at least from the inside) do on other cars. It's barely noticeable in "stock" form and when coming off of hard boost. With the EVO intake the sound is a little more pronounced obviously... However the main reason to replace them is even if your car is stock they have failed over time. The have a rubber boot/seal that tears just a tad and then there goes your boost and smoothness... The billet ones have a piston and don't have that issue

http://www.sharkwerks.com/products.php?pid=30

 

Think of a Diverter Valve as being a BOV that does not vent into the atmosphere. Rather, it vents back into the intake. A BOV vents back into the atmosphere, so you hear the sound more as there is nothing to really "muffle" the sound.

However, if you have a diverter valve that vents back into the intake and you have a free/cone/open intake, you will more easily hear the rush of air as it is vented back in.