Hi Guys:

just upgraded to the AP DV's with the f hose. I noticed that there is a loud whistling noise when the boost kicks in. Is this normal?

 

Yo Jeff..

i think its your turbos whistling...

i hear a similiar sound from my evo dv's

 

I have AP DV's and mine don't make a noise, except at idle when cold, then they make a honking sound noise, which I need to get investigated. When it's been running 30 or seconds or so it's gone.

 

Simon, what turbos you running?

 

Stock turbos, not x50. I have a softronic flash, nothing fancy. The weird noise only lasts about 30 seconds, goes when you rev a little, like 2k RPM
And sounds "stereo" so I'm thinking both are doing it.
Everything else seems OK, holds one and runs strong enough.
Just thought it was a little odd.

 

I get the whistling too...X50 flashed car. I think it started when I replaced the diverter valves...or maybe it was the Europipe...can't recall. They call it the turbo "whoosh", and it's normal. I like it. Sounds like a 747 getting ready to roll. It's different than the honking noise Simon talks about. Honking usually means you have a bad diverter valve...the diaphram is torn...needs replacement.

 

porsche came out with a bulletin in 02 about a honking sound from the dv's, their fix was a replacement with a brass washer in by the diaphram. never heard a sound from fvd or champion, don't know about the ap's

 

The so-called "fix" isn't worth messing with. The OEM part is a cheaply made plastic valve that's known to fail when the diaphram tears. That creates the honking sound. Just replace it with an FVD, Bailey, Forge, EVO or other good billett valve. Buy one with the metal tube that comes off the top at a 90 degree angle rather than straight up. Makes the install much easier in cramped space.

 

are you losing boost?

 

I will have to have someone in the car to record the sound.

 

we need to pressure tets the car...

 

will see you tomorrow afternoon. Beers?

 

I've replaced my DV's with an upgraded BOSC DV. I've also noticed a high pitch wistle pop sound between shifts under hard accelleration at around 3000 to 4000 rpm. It also coincided with an chip tune. So, perhaps it is a result of that much more air being sucked in.

I know... it's the large vacume being created behind the car from sheer acccelleration

 

maybe not buy cheap stuff in the future?

 

The Agency Power valve is made here in Arizona by the same manufacturer who makes a couple of other company valves which are on probably over 4000 different Porsche, Audi, and VW. The valves feature a CNC machined aluminum piston with nylon washer for absolutely no piston play or leaking. The F-Hose is a 4ply silicone which is much thicker and durable then the stock unit. Being "Cheap" would be absolute incorrect. Seems there is another problem. Remember that this car received GT28 turbos and a bunch of other mods at the same time. So diagnosing by the noise is tough.