How do exhaust valve controller or cutout work ?

[Simon99]

Hey guys, I know this might have been asked before, if not here, on other forums, but I really can't seem to find an answer to the following question :

"Is an exhaust valve controller or cutout supposed to reduce or increase noise ?"

Now at first I thought it was an hole that could either be opened manually or electronically (with the correct device) to reduce noise and to be closed when you want the full exhaust sound (by creating 2 holes for the pressure to leave the system, therefore reducing the noise at the back of the car), but after reading through some stuff, it seems that a device like that would increase the noise, as it would create what is considered a leak (if I'm correct) and therefore releasing the gazes under the car (without it passing through resonators and such).

If someone has the answer, it would be appreciated, as I'm wondering if this could be an option to reduce noise in a possible complete exhaust system this summer ( Vibrant 4-2-1, HFC, Borla CBE). Thanks alot for your time !

For those who are wondering what I'm talkin about, here are some examples:

Apexi Electronic Exhaust Valve Control http://www.nengun.com/apexi/exhaust-control-valve


Jegs Manual Exhaust Cutoff http://www.jegs.com/webapp/wcs/stores/servlet/m20ProductDisplayView?catalogId=10002&parent_category_rn=10245&top_category=10245&categoryId=11529&langId=-1&productId=751312&storeId=10001&pgGrp=catNav

[Thrizzl3]

it increases noise.

you want your car to sound like this?
http://www.youtube.com/watch?v=fcfvGygc3Po

[leecheefoto]

You weld a y pipe

It's usually located in replace or after / before the resonator.

There's a butterfly valve that restricts airflow

You use a switch to open the valve causing more sound and gas to leave the y pipe before the muffler.


No it won't reduce your current noise

[KING1307]

if you have any questions about it let me know, ive been running one for 2 years now.

[Simon99]

if you have any questions about it let me know, ive been running one for 2 years now.

Well, seeing how it doesn't reduce the noise, I just have one .. Why ?

[loki]

Well, seeing how it doesn't reduce the noise, I just have one .. Why ?

more performance with a more free flowing exhaust with a turbo application, when you want that power. But quiet(er) if you're not under heavy boost

[The Wolf]

more performance with a more free flowing exhaust with a turbo application , when you want that power. But quiet(er) if you're not under heavy boost

This is very important.

[standsideways]

This is very important.

Why cant they all be like you? :)

[KING1307]

more performance with a more free flowing exhaust with a turbo application, when you want that power. But quiet(er) if you're not under heavy boost

you said it

[Simon99]

So if I got this straight, you would open the valve under heavy boost to increase the flow and close it when normal driving to reduce the noise a bit ?

[KING1307]

So if I got this straight, you would open the valve under heavy boost to increase the flow and close it when normal driving to reduce the noise a bit ?

I have essentially two options, either open; which is completely straight piped from the turbo, or loud as some may say. Then theres closed; where it flows through the stock system and is quiet as some would say. Couldnt stand the sound of a sport exhaust groaning 24/7. I dont open it under high boost only, ill let the car run for about 5 mins before I really push it, just to allow to computer to slightly adjust for the change in back pressure.