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I am working on putting together some vacuum actuated exhaust cutouts and am not sure what actuators to buy and where to buy them. Could someone on here give me some ideas or tips? I just want the type that require full vacuum (as in WOT) to operate. Thanks for any help.

Irish350

iTrader: (14)

idk what you need, but im interested in seeing how this turns out. i was gonna do an ecutout but vacuum would be cool too

eseibel67

iTrader: (10)

Sounds like you are trying to rig up and "automatic" cutout. I don't think you're going to be happy with the results by using vacuum for this.

Irish350

iTrader: (14)

whys that? the corvettes with the sport exhaust (or whatever) option use a vacuum actuated butterfly valve

garys 68

iTrader: (1)

There are lots of vacuum actuators in the AC sytems of cars. C3 corvettes have them for headlights and wiper doors. Sounds like a trip to the junkyard is in order.

1logote

Yeah I first saw one of these on here a couple of years ago. Was pretty cool..only opened at WOT. It looked like a 4wd hub actuator or a headlight door actuator to me. We will see I guess. There are a lot of examples all over the internet and people using BOVs, wastegates, and semi truck PACBRAKES...whatever that is. There is a company in Australia that makes them as a full kit but I have some old QTP first gen ecutouts that was thinking on salvaging.

1logote

This is a pic off this forum from a while back...

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just saw this...wish i was rich....http://forums.vwvortex.com/showthread.php?4736638

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I may use this....kinda pricey tho. http://himni-racing.com/index.php?ma...oducts_id=1838

1logote

http://www.spracingonline.com/store/...___3_inch/3673

basically exactly what im trying to do...without spending 700 bucks

jimmyblue

iTrader: (11)

Been wanting to do the same thing more or less for a
while now.

I bought a whole box of vacuum biscuits off eBay for
real cheap. They have about a 1" stroke so the bellcrank
would have to be about like that. Getting the spring
right, is the trick. The actuation time through a long
hose may be a bit slow.

However vacuum is not necessarily the signal you want.
Sure, it's there for you at WOT. But it's also easy to drop
to low vacuum in normal driving especially on a M6 car
or even an A4 with crappy trans tune and a stockish
stall speed.

You depend on vacuum to -close- the cutout meaning
a pretty light spring will be needed for it to be closed
at "near zero" vacuum. Otherwise you may have accept
a part-open cutout at heavy part throttle.

Most E-cutouts seem to have a series resistor for motor
stall protection. If you made a "smart" electrical drive
that energized the motor witl full voltage but only a
long enough time to ensure full-open (my McCord has
a limit switch that could be used to stop cycle, do not
know about others) you could forego the resistor and
get much better actuation time. And you could base
it on something more sensible, like TPS voltage, or
some combo like (TPS > 4.5V AND MAP > 4.0V) etc.
You're talking under $20 in parts to do this, less if you
have a deep "junk box", to an existing electric cutout.

I have found some cheesy linear actuators inside
CD-ROM drives that seem capable to pull a crank
too, and can take 12V applied and work with a
spring return. But they are not environmentally
robust.

A Ford door lock servo sure would pull well enough
and if run off a WOT switch, ought to survive a
fair duration of 12V applied. These are under $20
on eBay and are fairly weatherized.

1logote

I read that like five times and finally think I got it...lol. Interesting for sure. As far as door servos (maybe for shaved doors?) I would think they would work...but getting them to energize at the right time with maybe a physical contact switch at the TB linkage would be a little easier?

with the vacuum actuator/switch i was under the impression that the spring closed the cutout and the vacumm opened it. Do i have that backwards?

jimmyblue

iTrader: (11)

You have high vacuum at closed throttle and no vac
at WOT. So "do nothing" has to cause the cutout to
open.

Tricked-Out-Toy

iTrader: (4)

Heres mine also been designing a cutout to use vacuum that will bolt to a standard 3 bolt cutout flange. I have a prototype sitting on the shellf waiting to get tested but ive been to busy and dont have a car with a cutout already installed... The ones in the pictures below use a throttle body off a caddy, theres a straight piece of piping inside the muffer with perferations, when the butterfly is open it bypasses the muffler and goes straight out the tip. when the butterfly closes the exhaust travels on the stock muffler exhaust path. This setup completely eliminated the massive drone I had with cooks axleback.

1logote

Okay so it is the spring that basically does the work that opens the butterfly and the vacuum that collapses the spring and closes the butterfly?

Tricked-Out-Toy

iTrader: (4)

BTW there is still enough vacuum to keep them closed at WOT. Im also working on a controller that will allow you to either have them open or closed all the time OR have them open at a user adjustable RPM set point. Its a pretty pimp setup and the wife LOVES being able to open them up around town but close it up on the long road trips.

Tricked-Out-Toy

iTrader: (4)

There is no external spring needed since the vacuum acuators have a spring inside that once no vacuum is present has plenty enough force to close the cutout.

1logote

Okay so it is the vacuum that opens the cutout and the spring that closes it? thats what i originally thought

Tricked-Out-Toy

iTrader: (4)

you can do it either way. I have it setup where vacuum closes it so when you first fire the car up its loud and nasty. You can very easily swap it so vacuum opens it. The TB/cutout really doesnt care which way you plumb it.

2002_Z28_Six_Speed

iTrader: (19)

More pictures. Very interested. I am not sure how this works though. Shouldn't the cutout and vac act be placed before the mufler?