How To Get Flutter Noise ???

[MADVR4]

thraka.... depends on what ur using ur car for aswell.... a drag car wouldnt need a BOV becoz u lose less boost between gears.... a BOV will get rid of 99% of air b4 u change gear.... without it a BOV u will hold the boost so in turn its actually better for drag cars...

any VL turbo that is running 30psi.. would be a drag car....

and VL's flutter becoz most of them put a huge F**king intercooler on them and pod filter...

to matty intercooler has alot to do with flutter.... more air flow.... im running 2.5 piping and a 600x300x75 cooler no BOV and a pod on EVO MAF it flutter like a VL turbo.....

its each to there own on the subject no point arguing it.... some mechanics say dont use one... some say it will kill ur turbo... ive been running mine now without BOV for a pretty long time with no side effects....

but also running no BOV means when dragging ur gear changes must be quick as f**k otherwise ur turbo will bog basically....

i dont think its fair to say it will kill ur turbo... becoz alot of people dont run then and have no issues.... let every1 have there opinion maybe with some proof and thats that...

cheers Grant-

 

[joe-ness]

dude just run a pod and a plumb back bov .......gees and you other fags make another thread and argue in there

 

[JAP63]

im running the factory blow off valve....now if i just had a pod filter installed would i get some flutter...

Not really,i ran this for a while,the standard blow off valve,despite its hard springs seems to work at just about any Rpm,i think it has to do with the fact it has a small recirculation hole for the diaphgram,

so in short,u probly wont get a flutter noise with the stock B.O.V and a pod.

 

[rob323]

If you want flutter (aka compressor surge), then run with no bov, or put a blocking plate between the bov and the flange on the intake pipe or shove something in the hose that goes from the bov back to the intake.

if you want the whoosh noise of a bov, even a K & N insert in the standard air can will allow you to hear it.

 

[kaotik]

Evil_Mx6 if u wanna run a pod with no air canister and still use the stock AFM then grab yourself one of these http://cgi.ebay.com/ebaymotors/Raci...tegoryZ38634QQihZ010QQitemZ200029123984QQrdZ1
and and yes, its for a hyundai but its the same AFM as im sure alot of u know, early hyundai's sported trendy mitsu motors so to answer ur question, this should solve ur problem, dont know if it will give u flutter but it will house the stock AFM inside just like the canister only it will give better air flow, hotter air flow but better none the less. 8)

 

[Evil_Mx6]

thanx heaps mate, but i have done a bigger cooler now and got a blow off which is a bit tight with a pod runnin....i will post pics up wen i get the chance for all 2 see 8)

 

[MADEVO]

so do u have flutter now??

 

[Evil_Mx6]

ye mate its fully dosin now hahahah
makes me laugh everytime....
tu tu tu tu tu tu tu...........

but under full accelaration the blow off just goes whooosh....

very happy

 

[MADEVO]

hence my frontmount theroy!!

 

[kayarubin]

my car sorta has the combination of the 2....the BOV actually flutters in conjunction with the compressor surge!!

i must have got it right coz yeah at the higher rpm u can just hear the bov fluttering like a normal one going off but fluttering but lower rpm its more of the compressor surge choo choo choo sound! 8)

turns so many heads....and especially in the good ol' Nimbus! 8)

but yeah ive set it to have more air escaping with just the constant whoosh to have better response changing gears just drivin around normally instead of the turbo bogging down every time i shift normally!

cheers!

kaya rubin.

 

[tharaka]

my car sorta has the combination of the 2....the BOV actually flutters in conjunction with the compressor surge!!

i must have got it right coz yeah at the higher rpm u can just hear the bov fluttering like a normal one going off but fluttering but lower rpm its more of the compressor surge choo choo choo sound! 8)

turns so many heads....and especially in the good ol' Nimbus! 8)

but yeah ive set it to have more air escaping with just the constant whoosh to have better response changing gears just drivin around normally instead of the turbo bogging down every time i shift normally!

cheers!

kaya rubin.

flutter is compressor surge

 

[kayarubin]

yeah but thats what im saying!...my bov goes off between the compressor surge as opposed to just the sound of the compressor surge!

unless that happens anyway?? :?

cheers!

 

[NE DAY]

You could of just put a bottle lid in between the factory BOV and cooler pipe.. Works well with the K&N replacement filter. Very high pitch dose.


Mitch.

 

[danielb]

Just some stuff i would like to add:

Older turbo cars, such as the CA18DET S13s didn't come with a BOV at all.

I remember there was a discussion on the ausrotary forum about this, and someone scanned in a segment from the series 5rx7 owners manual, which stated that the purpose for the BOV was for emission control and to reduce intake noise (i.e. flutter)

 

[AUSVR4]

aluminuim untake pipe, pod filter, stock bov and ~5 psi or less = flutter

 

[kayarubin]

i think flutter killed my turbo...coz it spun the nut off it and the nut went straight into the fins at really high speed! an ~800 dollar mistake that was!! :cry:

but yeah!...im with the guys that are saying that blow off valves are for prolonging the life of your turbocharger! and im gonna set mine as loose as a goose when i get my new turbo for sure!! i really do think that with old turbos u need a bov...coz it can spin the turbo backwards at such a massive rate from going 150000 rpm that it could just spin the nut off like it was a wheel nut!

i wouldnt make ur car flutter at high boost or at any boost coz it just shits all over ur reliability! if ur turbo has done 120000 kays like mine did!...heres a pic of the comp wheel:

 

[Skuz]

TAKEN OFF NISS SIL.COM

All of this works quite simply under constant acceleration:
Air comes in, is compressed to the set boost level, intercooled, used by the engine, and the exhaust keeps the turbo spinning.

It becomes more complex when you start changing throttle settings.
If the throttle is wide open, and you're at full boost accelerating, then close the throttle (for a gear change, or back off) suddenly the turbo is pushing against a closed throttle, and at the same time the engine has stopped producing exhaust gas, so the turbo starts to slow down.

Now that there's a whole intake system full of compressed air with nowhere to go, and the compressor is not being driven by the turbine - so it can't hold the same air pressure that it did while spinning flat out. The air will start to flow the other way, which means going backwards through the still spinning compressor.
This is where compressor surge comes into play. The compressor is still trying to pump air, but at the speed it's going it can't provide as much pressure as there already is in the pipe.

This causes the compressor to "stall". Stall is a misleading turn used here, because it doesn't mean stall as in to stop spinning. It's the aerodynamic stall, like a plane that's tried to climb too steeply, or has slowed down too much to maintain lift.

The smooth air flow through the compressor blades is broken up, and some of the air will flow back out through the compressor, making a hissing noise.
Centrifugal compressors work on a "squared" relationship for speed vs flow / pressure, so if the turbo slows down to half speed it will only be able to hold a quarter of the boost pressure.

The "chopping" or "fluttering" sound is caused by the accoustic effects in the intake system, determined by the size and length of the piping / cooler.
Rather than air constantly flowing back out of the turbo it tends to come out in bursts, triggered by pressure waves in the piping hitting the compressor.

Generally though the flutter is the sound of the pressure wave cause by the throttle closing bouncing back and forth between the turbo and the throttle plate (the longer the pipes the slower the flutter).
Every time the wave hits the turbo it causes the compressor to cavitate, which makes the noise.

It's not the blades chopping the air making the flutter. Since the blades are spinning at 80000+rpm you wouldn't be able to hear the individual "chops"

If you listen closely you'll actually hear a more constant hiss sound at higher boost levels and rpm when backing off. (ie, a "whooosh" rather than a "chop chop chop")

The loudest flutter tends to occur at lower rpm and boost levels of only slightly above atmospheric pressure (0psi). This is partly because the sound is "chopped" up more noticeably, and partly because the rest of the car is making less noise at lower speeds. This is also where it's least damaging.