Fluttering Dump Valves

[spraggol]

Turbos are new to me so I apologise if this question sounds silly..

How come some dump valves make a fluttering noise when releasing pressure and some make a single whoosh noise?

I was totally against fitting a chav blow off valve an hour ago but after hearing a mates fluttering Evo tonight I want one!

[CAVEMAN]

I am pretty sure the 'fluttering' noise is not the dump valve, whatever kind it is.

The 'fluttering' noise is down to the air hitting the turbine blades causing it to stall.

The older style WRC cars all made this noise too.

[spraggol]

So basically any dump valve making a fluttering noise isnt letting the air escape quick enough and backing up which is bad ... ?

[hightower]

i have not long fitted a HKS SSQV and i love it.

[CAVEMAN]

in my opinion any dump valve letting air out of the system is bad...regardless of the noise it makes.

I can't remember the exact cause and physics of it all, but I am sure if you search the old tin ternet there will be lots of similar stuff posted up.

short answer is don't do it as they sound crap and don't improve things...

[Clark]

the likes of an RCM induction kit etc will give you similair noises

[spraggol]

Clark how much did you pay for your RCM and have you got any videos of what it sounds like?

[Clark]

Whatever price it is on the RCM website - I cant remember now, maybe around the £150/200 mark? Not the cheapest available but it's a great piece of kit.

I've no videos as the car is 45 mins away in storage for the winter so I cant take any just now. It sounds awesome though, you get a huge "ssssssssshhhhhhhhhhhhhhh" noise (people always turn round and stare at this point ) as you begin to accelerate in pretty much any gear and then when you back off you get the fluttering noise coming back through the filter

[dynamix]

in my opinion any dump valve letting air out of the system is bad...regardless of the noise it makes.

I can't remember the exact cause and physics of it all, but I am sure if you search the old tin ternet there will be lots of similar stuff posted up.

short answer is don't do it as they sound crap and don't improve things...

Agree 100%