[Mk2] [Turbo] why doesnt my Tial flutter

[LuizeGT]

just curious, not too clued up on external wastegates but was just wondering what makes them flutter cos mine doesnt. thought it was one of the perks of having external wastegates

[wadeski]

if you mean the fluttering sound you get on overrun like a WRC car, its not really a sound you want, its your turbo stalling. Your recirc valve / blow off valve is built to prevent this from happening.

It causes a lot of wear to your turbo.

[RyanRs]

As wadeski says, the fluttering noise is caused by the compressed air in the boost pipes working back out through the compressor while the compressor is still trying to pull air in. the cause of this? well, while on boost the engine is supplying sufficient energy to the turbo to enable it to compress air at high pressures, but when you come off the throttle, that energy is greatly reduced and the turbo no longer has the drive to keep the air compressed at that pressure and therefore the pressure leaks back out. -This causes the flutter noise.

However, as much as many people say that this is damaging to the turbo -as it causes rapid deceleration of the shaft and elevated pressure on the fins, it has never actually been proven! And therefore is more of a myth. Although ,Surge at high boost levels while still on boost however HAS been proven to be very damaging and that is what anti-surge housings are designed to eliminate.

[mr2nut123]

I've got this on mine. I've been told that some bearings need replacing after about 50k but as it's a rollerbearing it's much safer than using shaft turbos. It sounds awesome on high boost.

You will only get this noise with external wastegates and no bov. Alternatively, you get it a lower boost slightly with an SSQV bov

[RyanRs]

No, its nothing to do with the external wastegate. Its purely air back tracking through the compressor the wrong way!

Take any turbo powered motor and remove/block off the BOV/DV/Air bypass valve and it will also make this noise!

[LuizeGT]

oooh right, i knew that was the case with turbo stall but for some reason i always thought external wastegates make a flutter. i dont know why either

[wadeski]

if you have a screamer pipe, they can make a noise at full boost?

[castrolfan]

i got this on my gt4 after i fitted a very big intercooler
if i let off the gas very quickly the ssqv would dump the air but if i let off very slowly the ssqv would stay shut and i got the turbo chatter noise... it is a cool noise

[Wingers]

if you have a screamer pipe, they can make a noise at full boost?

I've got a screamer pipe and can confirm that it makes "a noise"
To be more specific it makes 110 noises from about 5m away...

Wingers

[mr2nut123]

if you have a screamer pipe, they can make a noise at full boost?

I've got a screamer pipe and can confirm that it makes "a noise"
To be more specific it makes 110 noises from about 5m away...

Wingers

Oh yea!

[jimGTS]

sure does
especially a 48mm one!


http://www.youtube.com/watch?v=1y8W_WvLjpE


have now gone back to running no bov now tho....