Was doing a logged run .... and I heard a very noticeable whistle sound coming from the engine bay when I came off boost.

Opened up the engine bay and noticed that this hose has a play of around 2-3" ...

Could it be also the DV's?

Also attached the actual log itself ...

Thoughts?

 

yes. replace... ( or.. could be the ps steering reservoir pump whistling too )..

but i'd guess dv's first.

 

What about that hose on the picture?

 

sorry, beyond the limit of my experience. if it's like a "honking" it';s most likely the dv going bad. if it is a WHISTLING that can be eliminated by depressing the clutch, then it;s the PS res valve whistling 996t oddity # 39. most of us have switched out the res by now or previous owners may have since it was so common. there is a TSB on that one if you search, you'll find it in here.

good luck w it.

 

The whistling sound would just show up after coming off boost ...

 

those are the conditions present when it ( ps res whistling ) happens. hot engine after spirited driving. it's a valve inside the res itself that resonates/vibrates unwittingly and annoyingly. read up on the power steering pump reservoir issue.. and see if if it sounds like it mirrors your issue. best i can do.

 

Mine was making a whistling noise coming off of boost as well. Also noticed it would over boost to 1.5 bar (I have an EPL tune, set to I believe 1.2 bar). Read up that if a hose pops off the N75 valve overboosting can happen.

Well I looked and no hoses popped off, but I found a split in the Y-pipe that the DV's connect to. This explained the whistle, and the over boosting because the N75 valve feeds off of this Y pipe.

 

I didnt notice anything overboosting ... just the whistling noise when coming off of boost ...

 

Anybody know that hose one the picture? Anybody?

TIA !

 

plastic hose in your hand is not the cause of your noise.

 

I figured that pretty much ... but I'm still curious what this plastic hose is though ...

Whats your vote on the noise? DV? N75 valve?

 

DVs are easy enough to check and are known to make noise when they go bad. N75 wouldnt really make noise. Check DVs and the F-hose. do yu have stock DVs? if so i would just swap them anyway, its much easier if u lower the motor, very tight space. also pneumatic pliers make this job much much easier.

 

I'm having the exact problem. Noise only off throttle after boost. Recent work done: turbos, 1 bar WGs, coolant tank, GT2 slave conversion & new P/S pump. Pressure tested system at 25 psi no leaks.