Braineack

iTrader: (62)

add splitter box, attach to regular throttle cable

...oh wait...

JasonC SBB

What's the advantage of a complicated setup vs a simple spring?

codrus

Never use one part when three will do! Use a vacuum motor!

--Ian

18psi

iTrader: (76)

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.

JasonC SBB

Have you seen my actual measurements? IIRC it was 0.3 psi. And that's with the stiffer of 2 springs.

sixshooter

iTrader: (12)

Ya know, back when I was a boy the muscle cars had vacuum operated valves on the mufflers to open them up when the throttle was opened.

Braineack

iTrader: (62)

They still do on "boring" cars...

18psi

iTrader: (76)

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.

Braineack

iTrader: (62)

my dad's bimmers all had wastegates on their exhausts.

codrus

That's what vacuum reservoirs and check valves are for, same as on an NA car.

--Ian

Braineack

iTrader: (62)

this is from a 330i:







oh but it don;t work on boosted cars he says....



takes a look at the 335i exhaust:






#boringcarsmatter

18psi

iTrader: (76)

Lol @ "vacuum reservoirs" on a Subaru/miata custom exhaust system

Braineack

iTrader: (62)

ever seen a VICS IM?

18psi

iTrader: (76)

What is the fascination with vacuum and overcomplicating the everliving crap out of things?

oh that's right you're a mercedes driver now

codrus

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

18psi

iTrader: (76)

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)

codrus

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

18psi

iTrader: (76)

Why not?
I didn't get the spring flapper, but the manual valve, but now I'm curious why you think that. The mitsu evo and many others do this very successfully

Braineack

iTrader: (62)

im driving a 2015 c300 right now, wanna talk about over complicating? it took me a few minutes to get it out of park.

18psi

iTrader: (76)

exactly my point