Verify How Flutter Works

[baby34]

Hi, I'm curious about how flutter actually works...............

Okay, i know in order to get the flutter noise you need to blow off the stock BOV, doing this f**ks the turbo though right?

ANOTHER way i think of doing it getting a pod filter/front mounter intercooler (does this produce flutter?)(my mates r34 has pod filter and intercooler & reckons this is why it flutters but i tell him that i think his BOV of blocked off)

So what im trying to ask is there a SAFE way to get a car to flutter without damaging anythin?

& also, do ATMO BOV's do this? and is it bad for the car?

can anyone confirm how this works?

Thanks.

& yes (flame suit on)

but i do wish to get a few genuine answers.

Edited August 12, 2010 by richar

[RB25PWR]

Hi, I'm curious about how flutter actually works...............

Okay, i know in order to get the flutter noise you need to blow off the stock BOV, doing this f**ks the turbo though right?

ANOTHER way i think of doing it getting a pod filter/front mounter intercooler (does this produce flutter?)(my mates r34 has pod filter and intercooler & reckons this is why it flutters but i tell him that i think his BOV of blocked off)

So what im trying to ask is there a SAFE way to get a car to flutter without damaging anythin?

& also, do ATMO BOV's do this? and is it bad for the car?

can anyone confirm how this works?

Thanks.

& yes (flame suit on)

but i do wish to get a few genuine answers.

About blocking the bov. Some people say it does nothing to the turbo, some do. Both appear to have good arguments... however in my opinion if you're running standard boost or not going crazy I personally don't think you'll do a lot or any damage to the turbo. However that's based on very little...

A pod filter will just increase the induction noise, so whatever bov or setup you have, whatever sound it's going to make... you'll just hear it louder than the std airbox - I don't think the intercooler has any affect on that

A safe way? lol why do you want hektik flutters? Girls don't think you're cool, guys don't think you're cool. The only person who will think they're cool is you...

Fitting an atmo bov will just make your call stall, unless you have an aftermarket ECU or some shit

Others will jump in and probably give you a bit better info but that's all i know

[89CAL]

stock turbo - dont do it. Theres arguments as said that will support both cases but I really think if you block it off completely it will destroy your turbo.

intercooler may make the flutter sound different but thats about all

End of the day... if you really want it to flutter, get a pod and get a good aftermarket bov that you can plumback and set the spring so it will flutter at 5psi or something.

But seriously.... its alot of trouble for nothing....

[The Mafia]

a safe way to make it flutter?

Seriously, you actually want to look like a dickhead?

f**k, I swear the threads in this section get stupider by the week.

[The Dan]

The flutter is the sound of the air bouncing back and forth between the turbo and the throttle plate but also circulating through the BOV.

Blocking the BOV off gives what they call a 'dose' which is even more gay.

Agree with above, good arguments either way but in my opinion Nissan (and every other car manufacturer who runs a turboed performance car) didn't spend millions of dollars developing a car if it didn't need something. Rally car drivers use them......for a reason.

There is more argument that it gives better performance than protecting your turbo.

On a side note, it is a well known fact that the best way to get flutter is to paint a butterfly on your bonnet. You can also paint a flower, which will attract bees and give you the same result but the butterfly is the loudest

[FineLine]

The flutter is the sound of the air bouncing back and forth between the turbo and the throttle plate but also circulating through the BOV.

Blocking the BOV off gives what they call a 'dose' which is even more gay.

Agree with above, good arguments either way but in my opinion Nissan (and every other car manufacturer who runs a turboed performance car) didn't spend millions of dollars developing a car if it didn't need something. Rally car drivers use them......for a reason.

There is more argument that it gives better performance than protecting your turbo.

On a side note, it is a well known fact that the best way to get flutter is to paint a butterfly on your bonnet. You can also paint a flower, which will attract bees and give you the same result but the butterfly is the loudest

Keep up with the times Dan. the newest bestest way for flutter is to put foolly sik "My Family" stickers on your car.

[The Dan]

Keep up with the times Dan. the newest bestest way for flutter is to put foolly sik "My Family" stickers on your car.

I f**ken hate those!!! In fact I'm going to make my own set to take the piss.

[FineLine]

man...woman....pigeon.

[l0WRB]

kinda hard 2 stop the dose noise even with a bov on your bigger turbo setups like gt3582r + 4" intake setups and 20psi, mine sorta doses but the bov goes off aswell. argh well.

[R3N3]

i think it also depends on you BOV. some blow off valves come with different springs, which i think its so you can "tune" the BOV to your car, i could imagine that if you were running a bov with a 15psi spring in it on a stock engine will give you flutter, as the bov will only open slightly if at all. dunno if im right or wrong, just how i thaught it works

[paulr33]

the bov is designed to open when the pressure in the throttle body area spikes well above the normal range

so if you have 10psi in the pipework and you close the throttle body (ie gearchange) the throttle body closes and pressure spikes its ass off

this is when the bov opens and dumps the pressure back into the front of the compressor wheel

if the spring is too tight or no bov, the BOV does not open, the pressure spikes its ass off and collides mid air with itself

the flutter noise is the air going back and forth in the pipework.

for mythbusters fans go talk into the back of a desk pedestal fan when its on full speed

youll notice as you talk your voice becomes chopped and you sound funny

this is the same thing but amplified in your pipework when you close the throttle body and have no BOV or a mega tight spring

the end result with no BOV or a tight spring is the air collision symptom we all know off

this in turn can place stress on the compressor wheel as the compressor wheel can stall or recieve unstable compressor speeds

this is also known as compressor surge. compressor surge occurs when pressure past the compressor wheel exceeds what its compressor can actually supply

ie in the best efficiceny the map dictates it can flow 14psi of air at blah blah, but when you close the throttle body and have no bov lets say pressure spikes to 40psi

the compressor cannot supply this pressure so it surges and will either stall or recieve survere shock on the shaft and wheel

this is usually related to mangled compressor wheels, mashed blades, ripped apart shafts etc due to high speed shock or stall

now i know billions of dudes go oh but ive run no bov for 27 years on 342psi on my vl turbo

yep thats great, but each time you gear change no only does it stall the compressor it places wear and tear and you slow down the compressor for zero gain

revent the excess pressure back to the front of the compressor to maintain momomentum

[maddowse]

it amazes me how people think because they them self dont like something then anyone who thinks different must be a moron !!! me personaly i like my car to be silent so the cops leave me alone !, but i can garente if i had a turbo at 18 or even 22 i would have loved to have flutter and neons and fully sick 22's , as im sure all you realy cool older blokes (that tell people what they have to think is cool or not) did some pritty wankish things to your cars or bikes when you were younger !!!

give the bloke a break and some advice to achive what he wants who cares if you dont like it as hes not doing it to impress you !!!

man these fourums just get meaner and meaner i wish the people who run this site would do something about the bullying !

[Basti]

The only person who will think they're cool is you...

the only person that matters you mean?

it amazes me how people think because they them self dont like something then anyone who thinks different must be a moron !!! me personaly i like my car to be silent so the cops leave me alone !, but i can garente if i had a turbo at 18 or even 22 i would have loved to have flutter and neons and fully sick 22's , as im sure all you realy cool older blokes (that tell people what they have to think is cool or not) did some pritty wankish things to your cars or bikes when you were younger !!!

give the bloke a break and some advice to achive what he wants who cares if you dont like it as hes not doing it to impress you !!!

man these fourums just get meaner and meaner i wish the people who run this site would do something about the bullying !

what he said.

[Trozzle]

If my stock BOV makes a VERY loud whoosh sound when I close the TB, even in neutral if I rev it (sound is coming from the pod filter) would this indicate there is either something wrong with it, or it has been blocked off/fked with for hektic dose?

Another problem I've noticed is if I'm cruising in any gear except 5th, slightly positive manifold pressure, and let off the throttle enough to drop boost below -5mmHg, it feels like I've completely let the throttle off and immediately put it back on enough to not be decelerating...this REALLY pisses me off, as it make it hard to accelerate up to say 100kph in 4th, then let off when I get there without changing to 5th....it's a massive jerk on the car.

Would just go out and buy a GTR bov, but haven't seen any for sale

Also I'm running 11psi if that makes any diff.

[maddowse]

i forgot to add a guy at work has a vl turbo running 14psi and no BOV at all and i asked the same question as i thought it did damage but the car has done 60,000 without a BOV and is still running 250kw so i guess its all personal how you want your car done listen to Joe blow !! just do what you want after all thats how we all learn so we too can become arrogant stuck up know alls like most the people on this forum !!!

[maddowse]

If my stock BOV makes a VERY loud whoosh sound when I close the TB, even in neutral if I rev it (sound is coming from the pod filter) would this indicate there is either something wrong with it, or it has been blocked off/fked with for hektic dose?

Another problem I've noticed is if I'm cruising in any gear except 5th, slightly positive manifold pressure, and let off the throttle enough to drop boost below -5mmHg, it feels like I've completely let the throttle off and immediately put it back on enough to not be decelerating...this REALLY pisses me off, as it make it hard to accelerate up to say 100kph in 4th, then let off when I get there without changing to 5th....it's a massive jerk on the car.

Would just go out and buy a GTR bov, but haven't seen any for sale

Also I'm running 11psi if that makes any diff.

with a pod on you will hear the BOV every time u put you foot on the accelerater and off again , even if u slowly toe tap it .

the other think your talking about is your compresion in your engine that slows you down when you back off just select 5th for 100kms it will save fuel any way , so no i personaly dont think you have a problem

[Trozzle]

Nah it aint engine braking, it's seriously like I fully lifted off the throttle, then put back on enough to maintain current speed - but I DIDN'T fully lift off, only enough to come off boost and open the BOV.

idk, I'll rip the BOV off when I change the turbo next weekend and see what the dealio is.

EDIT: It's like I hit R&R when it happens, or like I have an atmo BOV, so the extra fuel going in when I let off throttle causes loss of power for a split second

Edited August 13, 2010 by Trozzle

[Birds]

the bov is designed to open when the pressure in the throttle body area spikes well above the normal range

so if you have 10psi in the pipework and you close the throttle body (ie gearchange) the throttle body closes and pressure spikes its ass off

this is when the bov opens and dumps the pressure back into the front of the compressor wheel

if the spring is too tight or no bov, the BOV does not open, the pressure spikes its ass off and collides mid air with itself

the flutter noise is the air going back and forth in the pipework.

for mythbusters fans go talk into the back of a desk pedestal fan when its on full speed

youll notice as you talk your voice becomes chopped and you sound funny

this is the same thing but amplified in your pipework when you close the throttle body and have no BOV or a mega tight spring

the end result with no BOV or a tight spring is the air collision symptom we all know off

this in turn can place stress on the compressor wheel as the compressor wheel can stall or recieve unstable compressor speeds

this is also known as compressor surge. compressor surge occurs when pressure past the compressor wheel exceeds what its compressor can actually supply

ie in the best efficiceny the map dictates it can flow 14psi of air at blah blah, but when you close the throttle body and have no bov lets say pressure spikes to 40psi

the compressor cannot supply this pressure so it surges and will either stall or recieve survere shock on the shaft and wheel

this is usually related to mangled compressor wheels, mashed blades, ripped apart shafts etc due to high speed shock or stall

now i know billions of dudes go oh but ive run no bov for 27 years on 342psi on my vl turbo

yep thats great, but each time you gear change no only does it stall the compressor it places wear and tear and you slow down the compressor for zero gain

revent the excess pressure back to the front of the compressor to maintain momomentum

Agreed! I hate the old "I've been driving for blah blah and I've had no troubles". It's as good as saying "I drift all the time on the road but I've never crashed so should be sweet bro". Some stuff doesn't happen until way down the track and some never happens, that doesn't mean it can't. You notice though, that these people are very very quiet when it does finally happen to them

give the bloke a break and some advice to achive what he wants who cares if you dont like it as hes not doing it to impress you !!!

man these fourums just get meaner and meaner i wish the people who run this site would do something about the bullying !

I call bs, he's doing it to impress other people, just like most aesthetic/aural things people do to their cars under the guise of doing it for themselves...otherwise he'd put a CD of fluttering noises into his head unit and listen to that without making everyone else listen to it...

But I agree these forums are getting meaner, that or the population of stupid threads is on the rise. People tend to be snapping at people in the first post these days. It used to be after 20 replies or so!

[wolverine]

as im sure all you realy cool older blokes (that tell people what they have to think is cool or not) did some pritty wankish things to your cars or bikes when you were younger !!!

Yep, and we were called wankers by the old guys.

So we shut our traps, listened up and accepted good advice without compounding our youthful stupidity by backchatting.

I agree about the bullying it needs to be looked at but it comes from frustration of long termers that this topic has been discussed to death and a simple search will answer nearly any question you can think of. If noobs need more info, adding a question to the old thread makes more sense than opening another which adds to the burden of further searches.

[Basti]

...backchatting....

you're ancient broooo!