simscooby

At the risk of getting slated for having a car with a dumpvalve (I only say that cause I'm new on the forum and don't know how people feel about them on here) could you please tell me how I could get a particular sound from mine.

Currently my dump valve sounds normal, with the sort of high pitched hiss you get. But I'm really after the sort of fluttering sound. I dunno wether this can be achieved from just changing the dump valve or you get this sound as a result of somthing else on the engine.

Below is a vid of the sound I'm after. Bear with me cause the vid is quite long. At 2mins 6 sec there is a drive by clip and that is the sound I'm after.

any Ideas, many thanks

YouTube - MR WRX 03 Subaru Impreza WRX

AlanPPP

iTrader: (2)

Nice vid

AlanPPP

iTrader: (2)

Somthing to do with the wastegate i think? External wastgate??? lol i'm sure i'm wrong.

cos500

My cossie used to sound just like that, had nothing to do with the dumpvalve, it had a group A k&n filter on it and that used to give it the sound u speak of, the car didnt have a dumpvalve.
On the impreza well the older models anyway, you have to be careful of the MAF as they dont like cone filters, this could lead to engine damage.

[Davey]

Thats compressor surge / wastegate chatter (depending on which side of the fence you sit on).. Theres an aussie tunning company (APS I think) that does a twin scroll 'rotated' turbo conversion, it uses an external wastegate, its an aussie vid so might be that setup?

[Davey]

Garrett turboed fords seems to have extreme amounts of compressor surge/wastegate chatter sounds.. God knows why, but they sound AWESOME

I also think the TMIC on the impreza doesnt help because there isnt as much air getting 'chopped up' if that makes sense?

L33_WRX

I love the chatter sound too - I've got a Forge unit fitted to mine which the majority of the time gives the usual 'PHSST' sound but I've found at night (when it's quiet) when shifting and touching the throttle in a certain way I can hear a slight chatter - just wish it was louder and occured all the time :-)

rossi_p

iTrader: (26)

The flutter is wastegate chatter and for that you need to take the DV off.

I may be wrong though....

[Davey]

That statement is going to start an argument

simscooby

So your saying if i get the DV off then I'd get that sound. I'm no expert but if i did that then my car would be just like any other turbo scooby and they don't all chatter like the one in the vid??

It's a shame really cause that sound is AMZING but i guess if it was as easy as getting a different dv then you'd hear a lot more cars with that sound, which you dont.

Brun

If you removed your dump valve then your car would not be like most Scoobs as every Scoob is fitted as std with a dumpvalve
No dumpvalve possibly puts the life of your turbo at risk. You may get away with it on a TD turbo as they are regarded as quite sturdy - not recommended on a VF turbo though

sob

have looked into this myself,you need to take off any dumpvalve and block off all pipes and hole in intercooler,this forces the boost back through the turbo and the noise is the boost being 'chopped' by the compressor blades from what i understand,simple!you'll just need to replace the turbo more often! used to get it on my rst cabby when the hose blew off my dumpvalve,

GazTheHat

Bingo!

Some turbos run fine without one.

L33_WRX

has anyone tried the above? if so, get some vids posted up - I'd be interested to hear what a scoob sounds like with it done

Kjartan

Mine had that sound when I had my old 2l engine in it and a pipercross filter was awesome I also had a blitz bov

Mr Brannen

had it on my cossies,just take the DV off

L33_WRX

is this bad for the car in anyway? why do subaru fit them if they are not really required?? to stop that flutter sound???

L33_WRX

i guess if you tighten the BOV spring a bit you will get a flutter at lower levels of boost

pitcha44

if you want that chatter sound take the dv off. i was getting it last week because my dv was stuck shut but make sure you have funds to replace the turbo as it will go bang. or to do a propper job get a new turbo setup with external wastgate as this is what the rally guys use.

pitcha44

if you want that chatter sound take the dv off. i was getting it last week because my dv was stuck shut but make sure you have funds to replace the turbo as it will go bang. or to do a propper job get a new turbo setup with external wastgate as this is what the rally guys use.

YouTube - Top Gear - Prodrive P2 (the most crazy little car)

1min 15 in to the clip

OcTag3n

iTrader: (4)

There is a common myth in the automotive world about so called "wastegate chatter" or "turbo flutter", a noise created on lifting off the throttle in a turbocharged car.
The noise is in fact the air compressed by the turbo passing back through the compressor wheel of the turbo after the airflow is abruptly halted by the throttle plate closing. This is also known as Compressor Surge and over time can result in significant damage to the turbocharger. Surge puts an enormous amount of stress on the compressor wheel and thrust bearing which causes them to fatigue and eventually fail. To avoid this damage, turbocharged cars will use a dump valve, which allows the extra pressurized air in the intake out. However, in some cases, i.e. where it doesn't open fast enough or is set up to only react to high boost, some chatter will remain.
The chatter noise is very noticeable on WRC Rally cars, where no BOV is allowed.

simscooby

I think basically the moral of the story is you can do it "fairly" easily but you'll need deep pockets cause it's just gona wear ya turbo out quicker. I think I'll stick with my dv lol