View Full Version : Reduced Boost after APR DV install
snoopra
October 26th, 2007, 05:29
Guys and Gals, I need your knowledge once again. I just completed a diverter valve upgrade (APR product) and now boost is reduced and there's a low humming sound that seems to be coming from the DV's when accelerating/changing gears. Any thoughts?:vhmmm:
r1nga
October 26th, 2007, 13:26
Guys and Gals, I need your knowledge once again. I just completed a diverter valve upgrade (APR product) and now boost is reduced and there's a low humming sound that seems to be coming from the DV's when accelerating/changing gears. Any thoughts?:vhmmm:
Had the same on a Subaru in a past life (before the image of them crashed.....!) and was due to a weak or badly fitted spring, resulting in a bad seal when not doing its DV thing. Sounded like a cow moo-ing or the noise when blowing over the top of a glass milkbottle. Would ask for a new set I'd say.
Phil G
UK
snoopra
October 26th, 2007, 14:46
Sounded like a cow moo-ing
Phil G
UK
That's exactly how it sounds! I'll give APR a call today. Thanks Phil
Hy Octane
October 26th, 2007, 18:13
May have installed it backwards.
snoopra
October 27th, 2007, 06:21
May have installed it backwards.
High pressure side points forward and low pressure side points down. Vacuum connection pointing up, right? Tech dept told me to send them back for inspection/repair/replacement, said it could be a loose brass seat or defective spring. I'll post an update when I reinstall them.
snoopra
November 22nd, 2007, 15:49
Got the same DV's back, one with top scratched, still making the mooing sound! W#T@F?
snoopra
November 22nd, 2007, 15:53
Anyone have the OEM set I can borrow for testing since I kinda broke my originals while removing them?
jtessman
January 7th, 2008, 21:51
did you ever resolve this?
snoopra
January 8th, 2008, 17:27
Ya! took out the R1's and installed OEM 710's!
jtessman
January 8th, 2008, 18:11
I replaced my stock DV's with the R-1's as well. I have noticed the "honking" effect as well but other than that they are working great. I only get "honking" on low partial throttle conditions which would indicate that they are doing their job. Usual case is pulling away from a light with someone slow in front of me where I have to really lay off the throttle. The turbos are spooling up and generating more boost than the engine requires. I can get rid of the sound by modulating the throttle up or down. Snapping the throttle shut from high load conditions doesn't generate any noise. Anything other than that and they are perfect.
The one thing I did do while installing them was to zip tie the vacuum lines to prevent leaks. The crip on devices that Audi used require a special tool that I had no patience for.
The sound has to be caused by the escaping air passing over the diaphragm and causing it to resonate.