The flutter sound

[GiJOr33]

it's a blow off valve... sits just before the throttle body on the R33 inlet pipe. It has some pipe that comes off the outlet and goes back in down near the air filter before the turbo, but after the air flow meter. It also has a small hose that goes to the inlet plenum that opens the valve when you take your foot off the accellerator

[DJ984]

BOV = Blow off Valve; Basically it either releases (atmo) or re-directs (plumb-back) the pressurised air from the inlet pipes when off throttle....

in more detail:

atmo; sends the pressurised air out of the intake pipes to the atmosphere (goes wooosh... lol)

plum-back; puts the air back through the turbo.....

i thinks that's about right.... if any one wants to elaborate you're more than welcome....

[R33_BO]

OK...I said it was a stupid question!!! So i take it that the fluttering sound is bad and that i should look into fixing it.....however my blowoff valve sound like it is working OK. Also sometimes when i apply full load to the engine, my car kinda stutters and jutters and then fangs....

[GunMetalR33]

how much do SSQV's cost? $300 + I would assume. Too much money for some stupid sound. I would rather spend that on an EBC

[R33_BO]

BTW Thanks for de-stupifying me GiJoR33 and DJ984

[DJ984]

sounds like pinging.... dyno's are great to test all that.... most likely something simple....

as for the BOV, you can tighten them to only go off above certain pressures/revs...I've done that with mine, which makes it flutter under about 3500 RPM then go whooosh above....

[GunMetalR33]

R33_BO:

It sounds like you have a BOV that vents into the atmosphere. This means that when you change gears and alike your BOV realises air outside the air intake, which means that your engine thinks you have more air in the air intake then there actully is. It does this through your AFM (Air Fuel Meter, the thing Connected to your air Filter - black box thing). Not all cars have these so they can run atmospheric BOV's but unfortunatly Skylines do...

You should look into getting a stock BOV on your car and all should be fine if the BOV is your problem...

It could be other things, dirty AFM etc...

[GR33DY]

my car makes the fluttering sound just recently... it just happened after i upgraded my air filter form the standard box.. beofre i did change the air filter to a trust (airinx), it was just making thew woooshhh sound... now with the filter on, it goes tshh tshh tshh tshh... is that a bad thing?

[TasR.X]

a porsche in targa was making a very bad fluttering noise and the night after i heard it i saw that they had taken the old turbo off and were most likely going to replace it with a new one.... so 'cool fluttering' noises = bad :Bang:

[Guest INASNT]

the flutter is ok, but if u want to be fully sick and have the dut dut dut dut sound then get a nice big turbo like a 3040 run it at around 1 bar with no bov at all and u will be fully sick. I did this with mine for about 2 weeks till i found my gtr bov's. It sounds good but farks the turbo bearings and tip of the comp wheel if u run like that for a long time.

Just like everything else u will get bored of the fully sick sound after awhile

[GR33DY]

am i getting the what the flutter sound is?? lol! i know it may seem like a stupid question.. because the flutter sound happened when i put my new air filter on.. does that mean i should take it off??? i dont wanna wreck my turbo

[nitemare5]

the sound youre hearing is not caused by the pod filter, but you can hear when you fitted the pod because standard box filters the noise. The flutter noise is caused by either you've blocked your bov, or you have an aftermarket bov setup with a hard spring, causing compressor surge.

[GR33DY]

i do have an after market bov set up, BLITZ, as well as a front mount intercooler... is that ok?? im not fussed abt the sound so is it ok?

[GunMetalR33]

my car makes the fluttering sound just recently... it just happened after i upgraded my air filter form the standard box.. beofre i did change the air filter to a trust (airinx), it was just making thew woooshhh sound... now with the filter on, it goes tshh tshh tshh tshh... is that a bad thing?

How does it go again?

[Guest INASNT]

i do have an after market bov set up, BLITZ, as well as a front mount intercooler... is that ok?? im not fussed abt the sound so is it ok?

do u enjoy the stalling problems associated with the blitz bov?

[GR33DY]

the sound goes woosh shh shh shh shh... Never stalled on me, and no idle problems or nothing.. People say on the nissan silvia forums that the flutter sound is becuase when u take ur foot off the accelarator the turbine wheel spins backwards thus cutting back through the air making the flutter sound, or something like that iforgot exactly.. im so confused now lol..

[pinoi_boi_r33]

mate the wheel will not spin backwards. It may slow down do to the pressure applied but turbo rewind is a myth. Think about it ur turbine is spinning over 10,000rpm for max .5 seconds when u change gears it won't cause the wheel to slow down to a halt then start spinning backwards in that amount of time. There was a really good article on autospeed about it was ages ago tho.

[GR33DY]

yeah but there was like 4 pages of ppl saying that it was spinning backwards and everyone was agreeing..

[GiJOr33]

that's why the skyline forums is better than the silvia forums... cos at least here we know what we are talking about!!!

What happens is the pressure wave reflects off the closed throttle and back towards the turbo. When it reaches the turbo, the spinning wheel chops the pressure wave (also referred to as compressed air). That is the sound you hear. It could also be you BOV opening and closing (like mine does)... unless you have removed it

[LastTemptation]

wat do u need to block or disconnect to get the flutter... is it a thin hose or the fat one that connects to the stock blow off valve?