Flutter dump

[XB-16-AX]

OK. I understand what you're talking about. Some of the air goes out the BOV and some goes back through the compressor wheel.


But you are using the term waste gate and screamer pipe when they have nothing to do what we are talking about.

Also, don't try and fxuking big note yourself and talk about how long you've been in the scene.

I know xunts that have been in the modified car scene for 30 years and still don't understand shit. It's all right not to know everything, you've just gotta admit it

Thnx mun.

Yeh i just prob got confused with the terminology and shiet.

Nah no big note. Just saying incase people think im a troller or 101% dont know shiet.


Nomsayin?




Regards

Ryan
xoxoxox

[Jccck]

Nomsayin?

I think you need to stop saying 'Nomsayin' personally.
And holy hell i had to re-read this thread twice to make sure i wasn't corrupted by any of the Screamer Pipe nonsense (And i feel like a total jerk saying that word in a thread about Flutter and further confusing the issue)

Plenty of info here though, some is good.. Some is alright i guess.
But i still don't understand this;

I've got a TiAL Q Sport 50mm BoV.. 11PSI Spring (Which is the correct pressure based on my In/HG Vaccum at Idle) And i'm running Wastegate Spring of 9PSI (Gauge confirms 9 also)
So my car goes 'Flutter Flutter Flutter Chhh" when i get off the gas mid-throttle.
And at WOT/Full Boost it's a quick "Chhh"
Yet at low RPM (less than 3000, my turbo isn't even making boost yet?) it has a very quiet and slightly slower "Chhhh" noise (No flutter that i can hear though!)
Kinda suggests i have enough pressure/vacuum in combination to open the BoV enough to let the air out.
So if it happens as it should at low rpm/no boost and high rpm/full boost.. Why not at mid rpm/mid boost?

And it's said here that if i don't like the flutter.. Install a Plumbback?
TiAL BYPASS 50mm BOV is the choice, with 11PSI Spring and 1.5" Outlet.

But what i don't understand is.. How changing my BOV to the Plumbback will STOP the Flutter?
Or doesn't it stop it? It just stops the noise because it's all fed back into the intake?
So i still have this 'flutter' but i just can't hear it?

If that's the case.. Is it impossible to stop the flutter when i get off the pedal at a mid-RPM / mid boost level?
Ofcourse i'm talking within reason, because if i put a 6PSI Spring in my BoV it would just open.. But it wouldn't suit the Vacuum and the BOV may creep open during high boost? So that's out of the question.

[DLO01]

Depending on the type of plumback, you'll still get the flutter. We are still talking response time of the Bov, so depending, you'll still prol get it. On the other note, a plumback is supposed to make the blow off quiet. But contrary to popular belief, this also is not always the case and you'll hear the blow off as well. In this case though the sound instead of going directly from bov to atmosphere, it goes bov, plumback pipe, intake pipe and then sound out the intake arm (pre turbo) and out the filter. The sound is less that if 'directly' to atmosphere of course, but you can hear it noticably. This really depends on your (mainly on custom) setups, bigger pipe sizes and shorter lengths. Of course on a OEM turbo setup, you cannot hear the bov blow off cause of the narrow pipe sizes, mazes of pipes, lengths and the effort to 'design' out the noise emission.

[Jccck]

Alrighty, well the pre-turbo intake is very short and sweet.. Airbox top is mounted on a custom base too (Rather high flow, lmao)
Legality is moreso what i'm aiming for, and if the sound is muffled a fair bit then it's a win also.

From what TiAL says, these BOV's are extremely responsive.
And the control hose to the Intake Manifold (Using the PCV Inlet) is absolutely huge (5/16th ID iirc?)
Guess i'll find out when it arrives and i install it.
Cheers!

[mugen_ctr]

Depending on the type of plumback, you'll still get the flutter. We are still talking response time of the Bov, so depending, you'll still prol get it. On the other note, a plumback is supposed to make the blow off quiet. But contrary to popular belief, this also is not always the case and you'll hear the blow off as well. In this case though the sound instead of going directly from bov to atmosphere, it goes bov, plumback pipe, intake pipe and then sound out the intake arm (pre turbo) and out the filter. The sound is less that if 'directly' to atmosphere of course, but you can hear it noticably. This really depends on your (mainly on custom) setups, bigger pipe sizes and shorter lengths. Of course on a OEM turbo setup, you cannot hear the bov blow off cause of the narrow pipe sizes, mazes of pipes, lengths and the effort to 'design' out the noise emission.

Adding to this, if u ever driven a Stock evo/S15/GTR/Wrx etc etc... u will barely notice it, infact when i last drove my brothers old car, s15, i really didnt notice it at all :/

Alot of stock BOV are designed to leak on low level boost as it makes it easier to open... I remember modding a stock GTST bov to stop it leaking on low boost... well to say, it did work... but it was hella cheap ahahaha...

IMO, if u want a good BOV, stick to OEM bov, either weld on a flange an wack it on or do some other way, aftermarkets aint designed for DD, hence why its RACE/RALLY use only.

[xenonkuraz]

Wow I've started a great debate here. Didn't mean to get an education on flutter/compressor surge/screamer pipes/etc. I just wanted to know why my SSQV being a SEQUENTIAL valve would STILL flutter at LOW rpms (sorry sticky caps lock button )

I'm used to it now and it doesn't bother me as much and weirdly...

it now only flutters on COLD STARTS

when the car is warm it will VTA 99.99999999% of the time even if I'm hitting .01 bar boost.

Thanks to everyone for the friendly and intuitive replies.

I learnt a fair bit going through the pages, especially the difference between flutter and compressor surge. That video really helped (never heard such a noise before).