New DV's = Odd Noise

[saulcupra]

Morning all

Had my car serviced and health checked at Unit 20 last week (oil/filters/Box/Diffs) all ok and no errors anywhere (bar a leak from oil cooler and weepy RMOS)

I fitted some new panel filters over w/end, all fine.

Then I replaced the Forge/CC DV's (Yellow Spring) with stock 710N units.

Now, on light/half throttle at 2-3K I get a weird noise, bit like a kazoo blown by an asthmatic, or maybe a resonance type noise.

Im presuming its something to do with the new DV's, ive searched and read a comment by Grizz that the 710N's can make a strange noise on the RS6.

Anyone care to enlighten me? The old Forge DV's are filthy, I have my gun cleaning oils etc so ill give them the once over if I need to put them back on.

NB Car is mapped by unknown at the moment, we think its a piggy back or new eeprom that's been put on as it wont take a new Revo map over the top.
This will be sorted sooon with new eeprom properly fitted.

TIA

[IanH755]

Have a look at this thread as I also replaced my DV's, air fters etc and get a strange noise - http://forum.rs246.com/viewtopic.php?f=2&t=109261

[Shoppinit]

Usually it's the forge DVs that make the honking noises.

Could it be fluttering that you're hearing? Maybe there's a vac leak somewhere or you've got a faulty N249.

[saulcupra]

its hard to explain (what noises aren't)

there was no noise with the forge ones on, will try and get a recording

unless ive pulled a hose somewhere, but power seems as was before

[Shoppinit]

I'm wondering if the problem isn't downstream of the DVs. Maybe the forge ones weren't working (seized?) and you didn't know it (wouldn't necessarily affect the absolute power you make - more of an issue for gear changes). Clean up and lube the forge ones to see if once working you get the same noise.

A recording would be good.

[saulcupra]

EDIT

got it as an mp3 or a 3ga file, but cant find anywhere to hose it?

any ideas?

soundclip (if the link works) 6 seconds in, then a little bit after that also

[IanH755]

Wouldn't play for me (Media player or VLC).

[ahoooga]

I got the following from that link

[IanH755]

I'm uploaded a vid of the noise my car makes into my thread above if you want to compare.

[saulcupra]

edited above post to remove the link

ian, sounds very similar to mine!

can email you the file if you want?

[saulcupra]

thanks to ian for hosting!

6 seconds in

www.ianhenshall.com/moose2.mp3

[saulcupra]

cleaned, re-greased and re-fitted the forge DV's and sound has disappeared

odd but I suspect not threatening!

[Shoppinit]

Maybe that's why the RS6 uses the 710P instead of the 710N. I've always wondered what the exact difference is (if any).

[sweegie]

The 710N has a stronger spring at the very least, but I'm not to sure on other construction differences.

FWIW I put 710N's on my car and have had honking noises at light loads ever since. The new 710N's are made by Keyser, not Bosch, and don't suit the RS6 IMO. I had to play around quite a bit with the N249 settings to quieten things down. 710P's will be going back on the car shortly.

HTH

[Shoppinit]

Interesting. Maybe what people are hearing is flutter when the load conditions on the valve spring are borderline.