davidgoodwin1803

hi guys, when my turbo starts to boost very first starts it flutters quite a bit before it goes in to full boost, do all scoobys do this as my other wrx i had before did the same thing.

once it goes in to full boost it is less fluttery but is stll there.

thanks

mikey2

iTrader: (1)

what do you mean by fluttering?? mine goes straight up do delays and no stuttering at all.

Skooby53

iTrader: (1)

Is it only when warming up? What year is it?

davidgoodwin1803

its a 1994 sti and it does it all the time not just when cold.

if i was driving in 3rd for arguement sake @ 2500rpm and coasting and i pressed the throttle just a bit it would start making a fluttering noise as if the turbo was about to boost then not and then boost but rappidly causing the fluttering noise.

Thanks david

smokingkills

iTrader: (3)

I had the same problem & I replaced the recirc valve with a forge recirc, its now cured.

rigga

iTrader: (4)

Dont happen to have an induction kit fitted instead of the standard airbox by chance?????

STI_Baly

iTrader: (23)

Sounds like compressor surge, check your dump valve there's issues with it.

In other words, it could be a faulty dump valve which is causing the turbo to stall. This could lead to long term problems with the turbos life expectancy too. (if it is surge)

Good Luck

Baly

davidgoodwin1803

No induction kit but a pipe cross pannel filter and i am using a blitz BOV

STI_Baly

iTrader: (23)

My turbo dont hesitate or stutter a single bit, as soon as the boost gauge comes out of negative pressure and exceeds atmpsheric pressure its full bore!

Good Luck David sorry i couldnt be of anymore help.

Baly

53

iTrader: (41)

Blank it off !

djmisio85

Isnt compressor surge when you come off the gas, then the air that is usually recirculated, or dumped by the dumpvalve, is going back to the turbo, causing a rally flutter.......

But this guy seem to be talking about a fluttering noise when hes stepping on the gas....

finalzero

I get this when I am accelerating gradually from 2k rpm onwards, around 3k you can here a distintive flutter sound coming through the dash where the turbo is in the engine bay.

The sound goes away as more boost comes on tap, not noticed it after 4k rpm, boost pressure seems fine and car pulls well.

I have a VF28 turbo, could it be a tell tale sign the turbo is on it's way out?

davidgoodwin1803

my problem is the same as finalzero.

could it be the turbo on its way out. the car has covered 88,000 miles

Martin typeR

I have exactlly the same proplem too, same turbo VF28.

Mine only started happening after a remap and boost was turned up.

finalzero

Hmm they are known to be a bit fragile at times, might be worth getting our turbo's checked.

What is a good upgrade/replacement for the VF28 that will drop straight in?

davidgoodwin1803

once the turbo has gone in to full boost it does seem to stutter hardly anything but i can feel it.
could it not be the standard boost controller, it pulls really well but i can make out a stutter when it is pulling from say 3,000rpm - 6,000rpm

thanks

mit

iTrader: (10)

Exactly the same with mine! I fitted a de cat downpipe,and now get a whistle/high pitch tapping sound when on low boost,stopping on full boost. I was thinking of fitting a better recerc dv,any one know a good one that won't kill my wallet? The sound is the same as when changing gear,when dumping the boost.

Mit

scooby46

iTrader: (2)

Hi, i get exactly the same as above except ive got a 95 sti with a tdo5 turbo - my turbo runs a treat, its done 68,000 miles

peepiggly

Similar problem here, but tends to be when asking for some power in second the car feels like someone is braking hard then letting go a few times its judders that much then she just pulls away.

terzo320

i had the same problem,got rid of the dump valve and is fine now

Martin typeR

I have the standard dump valve and still have this problem, could it be that its faulty?

Jay m A

iTrader: (2)

Are you sure you guys aren't just hearing the wastegate?

davidgoodwin1803

it may well be the wastegate but it souldnt make noise during boost but only when it opens when you releas the boost.

i think some how the wastegate is not closing properly like it should, i am not sure why yet but it feels to me and sounds like the wastegate is instead of closing straight away as it should, it is flapping quickly making the ch ch ch ch ch ch ch sound as it boosts.

Thanks David

greerwrx

iTrader: (1)

I have this on my 2006 wrx. 2.5l.

I have been trying to find out what it was for ages. the car is standard, apart from an exhaust.

No one could tell me, prosport said the car was ok, and a couple of scooby garage said it was fine.

when it was standard it was not as bad, when i put the exhaust on it was loud. I then did a search on NASIOC, as they have had the 2.5 engine for ages, and their is about a 100 posts about the wastegate, making all the noise, and it get louder when you fit an exhaust /downpipe.

They explain its due to the wastegate opening and closing, while trying to make boost, and what you need to do, is tighten the actuator rod, as their isnt that much back pressure in the exhaust now.

dont know if this is right, but im going to ask prosport when i next go.

my car flutters between 2-3k rpm before it hits full boost, and it always has done this since new.

since the exhaust its very loud and i get some looks, when im driving round town, and its fluttering away.

well im hoping this is the case, and what they say is right.

ill try and find the link to the threads

Jay m A

iTrader: (2)

Sounds like you're describing the dump valve there, not the wastegate. The wastgate regulates the boost, so as soon as you approach target boost the wastegate will divert some of the exhaust gas and bypass the exhaust turbine. This is done at a certain duty cycle and does sound like a flutter.

rbaz

iTrader: (1)

Mine has a VF28 on it and just before it hits full boost its noisy but I think its just spool up noise.

greerwrx

iTrader: (1)

Well this thread from NASIOC says that the wastegate controls boost, and is what i have put my noise down too.



FAQ: Wastegate Flutter AND YOU! - Newbies & FAQs - NASIOC

greerwrx

iTrader: (1)

Turbo flutter - Newbies & FAQs - NASIOC

Fangoria

iTrader: (1)

Anyone ever hear almost a loud whistling noise when coming on Boost - I have this when accelerating which goes away once I reduce the Boost pressure
That for me is compressor surge though not wastegate noises

mikey2

iTrader: (1)

Simple fact is, the wastgate wont stutter or flutter, when you get a chance, try pulling the wastage open, it wont happen, the actuator holds it closed quite well. The fluttering is either the dumpvalve sound as it dumps, or the compressor stalling. If you want a definitive answer to what compressor stall sounds like, disconnect your dumpvalve and go for a run, that will give you an answer.
Its not good for the turbo at all, imagine going from say 30-40 thousand rpm to nothing or maybe reverse in a fraction of a second, the forces are huge, and can either shear blades or snap the turbo shaft. A little stall/surge is ok, but it will mean you have to spin the turbo up through the next gear, so sacrificing performance.
On that note, you will not hear the wastegate opening or closing, and its not a whistle, a whistle is either the compressor spinning up or an air leak.
The turbo will not stall or surge while you are accelerating either, as far as i know, its not physically possible.
Hope this brings some light to people