[lawwailok]

sorry guys, this may be discussed before but i tried to search and couldn't find the answer for a few days.

current mod: cobb S1+, ets fmic, bmw pe, stock airbox with drop in filter.

symptom: when doing WOT, boost beyond ~12psi and upward, there's a "air-ish" or a soft flute sound. normal driving or boost stays low, i do not hear it, it only occurs when boost getting high. i tried stage 0 stock map tonight, max boost was 8psi only, i do not hear that noise at all.
then flashed back to S1+, once it gets to high boost, the sound comes back, it is not super loud but you can hear it when windows are down. i know how the turbos sound in stock boost and high boost. definitely that is not the turbo spooling sound for sure.

i logged the car and boost is up to spec, no drop or any weird activities. datalog shows what it should be in all parameters. any idea of what could be? thank you guys!

[Syndicategt]

Originally Posted by lawwailok

there's a "air-ish" or a soft flute sound.

What kind of "soft flute" are we talking about? Like a Skin flute? If so, that makes more of a soggy-ish sound

[branabolic]

how long since your fmic install? mine had a very slight leak at one of the connectors because it wasn't on all the way and it sounded like a faint whistle. also, could be your dv's. check your fmic connections though.

[lawwailok]

Originally Posted by branabolic

how long since your fmic install? mine had a very slight leak at one of the connectors because it wasn't on all the way and it sounded like a faint whistle. also, could be your dv's. check your fmic connections though.

the fmic is about 1 year old or less. and yes, i was advised maybe the stock DV too.. i'll try to find time to jack up my car to check connection. thanks

[itsmeek]

I know we don't have bov's, however in other turbo cars- this may be a sign of your bov leaking pressure.

[gtaccord]

Sounds like a leak somewhere to me.

[Syndicategt]

Check your hot side of the FMIC, sounds like it might have slipped off. I've had it happen, they car usualy didn't boost over 8 psi (never thew a CEL).

[lawwailok]

Originally Posted by Syndicategt

Check your hot side of the FMIC, sounds like it might have slipped off. I've had it happen, they car usualy didn't boost over 8 psi (never thew a CEL).

weird that i logged 5 times and boost is up to par. no boost leak, car pulls strong..

[Tzu]

Log WGDC, as it can sometimes indicate a leak where the turbos are working harder to overcome.

Also, pretty easy to pressurize the hot side of the intercooler and listen carefully. If it is indeed as loud as you say, then you should be able to hear/feel it fairly quickly.

[lawwailok]

Originally Posted by Tzu

Log WGDC, as it can sometimes indicate a leak where the turbos are working harder to overcome.

Also, pretty easy to pressurize the hot side of the intercooler and listen carefully. If it is indeed as loud as you say, then you should be able to hear/feel it fairly quickly.

WGDC both are at ~40 ish from my cobb logs. no weird activites throughout the logs.

[Jeff@TopGearSolutions]

Is it like a high pitch squeal? That's usually a boost leak.

I would start by checking and re-tightening connections at the FMIC.

If that doesnt fix it you may need to do a boost leak test under pressure or simply start replacing stock parts, I.e. stock DV system. (worst case scenario).

[Rotorocious]

Did it sound like a leprechaun flute?

[lawwailok]

Originally Posted by Rotorocious

Did it sound like a leprechaun flute?

how does a leprechaun flute sound? not too familiar with that..

[Syndicategt]

Originally Posted by lawwailok

how does a leprechaun flute sound? not too familiar with that..

Little higher in pitch than the skin flute.

[335(EX)(EYE)]

Originally Posted by Syndicategt

What kind of "soft flute" are we talking about? Like a Skin flute? If so, that makes more of a soggy-ish sound

[Jeff@TopGearSolutions]

Instead of guessing you can just look and see if your WGDC are elevated through logging

I cant recall if skin flutes actually make any sound..... ZING

[lawwailok]

Originally Posted by Syndicategt

Little higher in pitch than the skin flute.

maybe sounds like a little like the skin flute? i guess.... it's not high pitch... but not loud.

Originally Posted by Jeff@topgearsolutions

Instead of guessing you can just look and see if your WGDC are elevated through logging

I cant recall if skin flutes actually make any sound..... ZING

WGDC are at ~40ish during WOT.

[branabolic]

Ive never heard a failing dv on my 335 as I put in forge dv's within 1000 miles of brand new. however, my fathers 996 turbo dvs started failing shortly after he flashed it and they made almost like a horn sound. my money says its probably your dv's. good luck with it though.

[lawwailok]

Originally Posted by branabolic

Ive never heard a failing dv on my 335 as I put in forge dv's within 1000 miles of brand new. however, my fathers 996 turbo dvs started failing shortly after he flashed it and they made almost like a horn sound. my money says its probably your dv's. good luck with it though.

um.... i don't say 100% horn sound, but it's a low volume some kind of air pressure deep-medium tone kind of sound... sorry guys i'm not good at describing and explain how the sound is like. but the sound frequent does not change i can ensure that. like how when turbo spool, you can tell when it starts and stops, the beginning and ending frequency are different.

but this sound has only one flat tone... no changing during from start to end.

[lawwailok]

also, since the stock DV re-route the air back to the intake pipe, shouldn't it be making any noise if it leaks?

[Orb]

Originally Posted by lawwailok

um.... i don't say 100% horn sound, but it's a low volume some kind of air pressure deep-medium tone kind of sound... sorry guys i'm not good at describing and explain how the sound is like. but the sound frequent does not change i can ensure that. like how when turbo spool, you can tell when it starts and stops, the beginning and ending frequency are different.

but this sound has only one flat tone... no changing during from start to end.

Had this just last week.. Turbo DP clamp was loose.

[Syndicategt]

Want me to give it a once over this weekend? Shoot me a text.