Acoustic valve...

[mattjk]

Has anyone tried widening the hole on the side of the PH2 airbox or is that a pointless exercise.

 

[JonC]

Bare in mind that the induction hose to the throttle housing is only around 70mm (I think, the aftermarket samco hoses slightly bigger 80mm) so you'll hit a point of diminishing returns from using bigger hoses to the airbox which could affect performance negatively. I'm by no means an expert, this is just my opinion.

 

[FeelX]

You're welcome Mauricio,

I don't know the weather in Mexico but if you're running it in hot weather you might get some more heat soak then running in the winter. In holland it's usually 0-5 degrees in the winter

Best thing is to get a duct there that allows air from outside the enginebay to the airbox. You could also make up an airduct that directs air from the lower front grill, up/right to behind the headlight. (this will only work when driving)

The lower CAF I did not change since it was difficult to get to and also to fit. However I think it might bring something. (more noise anyway )

 

[jack_davey]

I removed my acoustic valve today and extended the standard air feed with some K&N hose then cabled tied it to the vents at the bottom of the arch liner. Have noticed the engine breathes much better and accelerates quicker, induction noise is also louder.
I've done a BEng course in motorsport engineering and I can tell everyone that this is a beneficial modification, costs nothing too!
Oh and to the person who said the engine was mapped to run with it on, the ECU will almost certainly compensate for it being removed.
When you think about it, the air entering the inlet is going to vary in temperature (especially in the UK), colder air is denser, the ECU will therefore be programmed to inject more fuel when the air is colder/denser.

 

[Jamesstone]

Had a read through.. & erm.. where is this valve located, in the main caf?? may remove it too, sod the enviorment, pay enough in tax & fuel to keep my peace of mind lol

 

[JonC]

The valve is located behind the front passenger side wheel arch lining. Theres a guide on the ClioTrophy.co.uk forum here:
http://cliotrophy.co.uk/forum/viewtopic.php?f=2&t=1592&st=0&sk=t&sd=a&hilit=acoustic+valve&start=60

 

[Jamesstone]

Thanks for the link jonc, will have to check out the power diffrence on my rs tuner power analyser as one of the guys off there said he lost power according to removing it , not interested in it for noise, power flow & soon to buy decat will be more than loud enough lol, just looking to improve the torque

 

[sammyhale22]

How can you lose power removing it?? Some guy on another thread has proven it does nothing apart from make the car quieter! lol. I would have thought it simply acts as a dampener on the inlet sound, reducing the induction roar. If you look at it you will see its a plate inside a pipe(bit like butterfly), and surely that plate must be causing some drag on the air being sucked through the pipe?

 

[GodSpeed]

IMO what you may loose with removing the valve is low rev torque. However this is assumin the valve is closed at low rev.

By the way it is not strange that the valve did not react when tested through the revrage if you did not drive the car. If Im not wrong the vaccum builds under load. No load very low vaccum = open valve.