My 3" custom exhaust with spring loaded flapper valve
Biggest thing that sold me on the one I got was the completely bolt-in install. No cutting/welding/etc.
Also it shouldn't cost even a single hp in backpressrue, since it doesn't use exhaust pressure to open.
I would also have "settleed" for a vacuum operated setup, except the quality ones are absurdly overpriced, and most of them are cutouts, which is not what I'm looking for.
I'll post results after it comes in.
Also it shouldn't cost even a single hp in backpressrue, since it doesn't use exhaust pressure to open.
I would also have "settleed" for a vacuum operated setup, except the quality ones are absurdly overpriced, and most of them are cutouts, which is not what I'm looking for.
I'll post results after it comes in.
That doesn't work quite as well on boosted cars 
And actually a whole lot of these "boring" cars use electric motors, and they fail quite often
Yup. And again, this is much easier cause I don't have to hack up my $1300 exhaust to put it on.

And actually a whole lot of these "boring" cars use electric motors, and they fail quite often
Yup. And again, this is much easier cause I don't have to hack up my $1300 exhaust to put it on.
My B6 S4 had vacuum-operated exhaust flappers. They were ECU-controlled with solenoids, and the reservoir for them was buried in the trunk somewhere. It eventually started leaking so I disconnected them and that left the flappers open all the time, which was still substantially quieter than the Miata. 
I'm pretty sure the C7 S6 has the same system, but I haven't needed to go looking for it.
Vacuum actuators are actually a decent solution for this kind of occasional thing, because they're simple, powerful, cheap, and have minimal moving parts.
--Ian

I'm pretty sure the C7 S6 has the same system, but I haven't needed to go looking for it.
Vacuum actuators are actually a decent solution for this kind of occasional thing, because they're simple, powerful, cheap, and have minimal moving parts.
--Ian
More simple and less moving parts than the valve I ordered?
lol
You all know I've liked that whole idea for a long time now, in fact I've made a few threads about it along the way.
Scottiac made sure to derail each of them
(but seriously, I like vacuum activated flappers. just not gonna happen this time)
lol
You all know I've liked that whole idea for a long time now, in fact I've made a few threads about it along the way.
Scottiac made sure to derail each of them

(but seriously, I like vacuum activated flappers. just not gonna happen this time)
If you're a German OEM, needing to meet German idle noise laws, but still want your car to make good power and sound fast at WOT (and fake out the emissions test!), a passive spring-actuated flapper isn't gonna cut it.
--Ian
--Ian









exactly my point