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Old 12-21-2016, 03:06 PM   #7
geraintthomas
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Join Date: Nov 2015
Location: South Wales, UK
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Quote:
Originally Posted by The Radium King View Post
depends on how you want it to function. vacuum are (a) faster, and (b) good for a lot more operations before they die. if you just want if on sometimes, off sometimes, then electrical will work fine.

if you want it to work like porsche oem you want vacuum. here's why - the porsche units activate with every blip of the throttle - cruising at 3k rpm - valves closed. rpm gets over 4500 or so (ie, you are hard on it) then valves open up (better sound, less back pressure for better performance). so, you need them to work fast, and you seen something that is good for hundreds of thousands of operations.

wiring is easy either way. electric is power and a switch. vacuum is easy too. your car already has a vacuum system. one of the vacuum actuated things on the car is the flapper valve on the resonance tube - it actuates at around 4500 rpm (can't remember the exact value) - the exact thing you need for the exhaust (and for the same reasons, btw). the vacuum system on the car feeds into a electrically-actuated vacuum switch, where the ecu sends the open/close signal. so, you can tap off the vacuum line that is feeding the resonance flapper so that your exhaust goes when the flapper goes, or you can get a second vacuum switch and tap off the ecu signal going to the resonance flapper. the benefit of the second approach is that you can put a switch on it so that you can turn off the exhaust if you like.

seach 'cut out' on ebay - most folks just put a cut-on on their exhaust to bypass the muffler altogether, so that is how the pruducts are marketed.
Great stuff. The only issue with this is that the exhausts are never fully on, and require throttle for the valves to open up. My desire is to have them act like electric ones. Open or closed, and they stay open or closed until I decide otherwise. I think it may be too hard to do this with a vacuum system.

But it's finding an electrical valve that's around 1" size. It seems impossible, because space is quite tight as you can see from the photo.
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