Active Exhaust Cutout Valves - now with videos!

[Rusty]

Anyone know much about these? I was having a look as one would fit perfectly in place of a centre silencer under the back seats

A brief search yesterday didn't yield much so I thought I'd see what yous lot know

Seems that as well as the noise hilarity there is the additionaly advantage of reduced back pressure so performance increase is a possibility...

[add]

Anyone know much about these? I was having a look as one would fit perfectly in place of a centre silencer under the back seats

A brief search yesterday didn't yield much so I thought I'd see what yous lot know

Seems that as well as the noise hilarity there is the additionaly advantage of reduced back pressure so performance increase is a possibility...

i'm sure i saw someone using one on motorgeek,think it was on that biturbo v8 coupe

[Fat Audi 80]

I believe the RS4's RS6's run them, so you could try liberating one from an old system off one of those. I am not sure how they work, but would imagine it is electronically controlled based on engine revs and actuates a flap in the exhaust...

[Rusty]

I've seen a few on the net. They are a butterfly valve, like a TB, and are controlled either electronically or by vacuum/boost pressure. They seem to cost about £200 but that seemed a little steep. Will have to look when I'm on my computer not my phone...

[Rusty]

These are also called an exhaust cutout (valve).

Here's a place in Australia, Hyperflow. Not sure why the prices are $0, might have stopped doing them?

Here's one from AET Turbos, it's rather pricey! Linky.

Can't say I care for much more control than on or off, all this constantly variable stuff just costs money. Ideally it'd be boost controlled and that's it. A solenoid or two to control operation and a bleed valve to control boost going to the valve would give complete manual control for a fraction of the cost.

This is more like it, quicktimeperformance in the US. $215 for the valve and $120 for the controller. Also available on the bay from Nemesis Performance, prices in £ are about the same as $.

And somewhere in Canada, buickgn.

Autospeed Articles here and here.

McCord Power Plate here too, $129!

[S2central.net]

Wasn't this discussed a while back ?

They are used on the RS6 for sure - more about sound control on that machine for envirocrap.

I looked at one briefly as an idea to integrate with a scream pipe - but figured it was gonna need an expert welder / fabricator to do a nice job - and the cost is not insignificant as you have found.

I supsect you are right that some simple boost control of the valve operation would be sufficient - could be made even simpler though if the valve could be directly controlled by a solenoid... Then just wire up to switch that says 'scream' on it for when the mood requires !

[Rusty]

The QTP stuff is moved by a motor and can be controlled to give constantly variable opening by an ECU output or the QTP controller. There are alos some available that are controlled by a boost actuator like those use on WGs for internal WG'd turbos.

I'm quite interested in this, I've got to go back to get a flexi fitted so could have a small centre box fitted and then have a bypass valvew and 3" pipe to vent the gases away from anything important, I'm thinking a Diseasel style bend pipe in the void under the back seats. The disadvantage is a touch more weight, 5kg maybe, but the advantage would be OE silence on a cruise and IMSA howl on a thrash

Edit:- There is a cavern of space under the driver's side rear seats, perfect :mischeif:

Wasn't this discussed a while back ?

It would seem so, here, I even replied... Brain is rather akin to Emmental at the mo, lots going on and not eneough energy to keep the grey matter ticking along...

[shark_90]

As most people who have these generally remove the vacuum pipe and block it to keep it open, I have to ask: Why would you bother?

[Rusty]

A few reasons. Track day noise regs, motorway cruising on longer journeys, e.g. 500 miles to the 'ring, subtlelty around where I live so that I don't P the neighbours off or draw too much attention to 'just an old Audi'. The list could go on... oh, and some are electronically controlled so you can set them on, off or anywhere inbetween using the controller.

[s2_bo]

You could also do this manually with a simple butterfly valve, i have one fitted in my chimney flue on the wood burner, you just open it by turning the handle 90 degrees,

Wouldn't be as fancy but would be much much cheaper and easier to install too.

[Fat Audi 80]

/\ That is not a stupid suggestion... I like that idea.

[shark_90]

You could also do this manually with a simple butterfly valve, i have one fitted in my chimney flue on the wood burner, you just open it by turning the handle 90 degrees,

Wouldn't be as fancy but would be much much cheaper and easier to install too.

Is the exhaust note any better with the valve open Bo?

[Greg_S]

Something like this would probably suffice

http://cgi.ebay.com/ECLIPSE-3-BV-AD-...742.m153.l1262

[BRY]

Something like this would probably suffice

http://cgi.ebay.com/ECLIPSE-3-BV-AD-...742.m153.l1262

It would be a bit heavy

[Rusty]

You could also do this manually with a simple butterfly valve, i have one fitted in my chimney flue on the wood burner, you just open it by turning the handle 90 degrees,

Wouldn't be as fancy but would be much much cheaper and easier to install too.

You can just get the Y piece and a planking plug, this would do the same thing but wouldn't be adjustable.