Ian

iTrader: (10)

hi on my scoob i have the decat downpipe, H&S back box, and a bailey vta dv, and a ota pannel filter

when i was driving today with the windows down, i could hear the DV nice and clearly but also noticed after it a sound that i would say is close to the sound of the air filter chatter, bit was like a much quiter and softer sound of the dv.

me car is a 1999 sti

any ideas ppl?

Stiver3

Don't know if this is correct, but it could be linked to the dump valve, my forge dv chatters very quietly when i lift off the accelorator so this could be what yours is doing, not a problem though.... Or it could be the wastegate, but i doubt it...

(yeh yeh, i know i have got a dv, but then i am from essex )

Anders_WR1

iTrader: (8)

If your STI has the cold air induction kit fitted before the air box, it could be turbo sucking air through the intake under the front of the bonnet. I notice it on my car when I pull around 0.5 bar around town in third gear.

Anders

BenGee

iTrader: (1)

ive got this to on my95 wrx was told its the turbo stalling and the air cutting through the blades.

Could be wrong tho

morpheous

iTrader: (9)

I have this but i have no d\v

BenGee

iTrader: (1)

Me neither mate thats prob why your getting it. The air being pushed back through the turbo hitting the splines and causing the chatter you hear.

And you should have a d/v! well just the plastic recirculating one as standard

Ian

iTrader: (10)

but wouldnt the vta dv stop the turbo from staling, as thats what they r ment to do, where a re-cire dv puts the air back into the system?

BenGee

iTrader: (1)

yeah i believe a vta d/v probably would get rid of most of the excess air but i believe even with any kind of dump valve or bov some air will always get back in anyway

A recirculating valve as you say just recirclates the air and does just as good a job as a vta.

The turbo always stalls between gear changes, a d/v just helps it to keep spooling i think as all the excess air build up is released

im not 100% on what i say myself tho so probably is just all gobble dee gook just what ive read about and heard

ALi-B

iTrader: (1)

As mentioned in one of the posts above, Sounds like your DV is causing it.

The DV doesn't actually stop compressor stall, it just dampens the shock waves produced by the butterfly snapping shut by venting the pressure.

What happens in most cases of crap/badly adjusted DVs is:- After lifting off, the DV opens, the pressure drops, the wastegate shuts and the DV shuts, turbo still spinning so pressure builds up again, so wastegate opens again, and DV open again too...repeat about 50 times a second And that is what your chattering noise is, so either adjust your DV, or put a decent one on (i.e original).


I hear countless scoobies doing it....And I just shake my head and ask why would somebody want to mess up a perfectly fine standard setup?