Cut outs
#1
Pro
Thread Starter
Cut outs
So
I've been watching Bitchin Rides on discovery. They did two cars adding cut outs with a push button on the dash. Has anyone ever put a cut out system on a 928? I started my car once with the exhaust off and it made the hair on my neck stand up! I'm thinking this might be a project I wanna do!
https://www.quicktimeperformance.com/OVAL/
I've been watching Bitchin Rides on discovery. They did two cars adding cut outs with a push button on the dash. Has anyone ever put a cut out system on a 928? I started my car once with the exhaust off and it made the hair on my neck stand up! I'm thinking this might be a project I wanna do!
https://www.quicktimeperformance.com/OVAL/
#2
Administrator - "Tyson"
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My 79 had a two stage muffler I can open / close on the fly.
Open is un-muffled off the headers. I almost never close the valve.
Todds Turbo also has a secondary exhaust he uses when pulling into the shop at night so he doesn't disturd the neighbors.
Open is un-muffled off the headers. I almost never close the valve.
Todds Turbo also has a secondary exhaust he uses when pulling into the shop at night so he doesn't disturd the neighbors.
#4
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#5
Pro
Thread Starter
Would it be OK to put them in the Y pipe before the catalytic converter or because my O2 sensor is in the CAT I have to do it afterwards?
Last edited by sstrickstein; 11-04-2015 at 04:15 PM.
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#9
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Thread Starter
So I had the car on the rack today. The big pipe between the cat and the resonator is the place. But it's right in front of the transmission. Angle the cut out down and to one side?
#11
Captain Obvious
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#12
Administrator - "Tyson"
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Here is mine, it's packed full of fiberglass muffler material.
Sounds like this:
Sounds like this:
#14
Nordschleife Master
An opinion:
I like the muffler bypass system such as that in Hacker's photo.
These sort of valves should be operated automatically based on something like throttle position and rpm in N/A motor or something like exhaust manifold pressure or intake manifold pressure in a turbo system. With the turbo system its especially easy to just have pneumatic actuation at the cutout valve. I guess that for N/A car you could set the diaphragm such that a spring tries to open the cutout and the intake manifold vacuum closes it. At WOT, there's no intake manifold vacuum and the spring opens the valve. At idle there's significant vacuum and the valve is closed.
That way, you don't have to remember to push any buttons, the car is automatically reasonably quiet if you're not driving it hard. And since the muffled exhaust tract flow plenty for the low boost and/or low rpm operation, you literally lose nothing in terms of performance.
I like the muffler bypass system such as that in Hacker's photo.
These sort of valves should be operated automatically based on something like throttle position and rpm in N/A motor or something like exhaust manifold pressure or intake manifold pressure in a turbo system. With the turbo system its especially easy to just have pneumatic actuation at the cutout valve. I guess that for N/A car you could set the diaphragm such that a spring tries to open the cutout and the intake manifold vacuum closes it. At WOT, there's no intake manifold vacuum and the spring opens the valve. At idle there's significant vacuum and the valve is closed.
That way, you don't have to remember to push any buttons, the car is automatically reasonably quiet if you're not driving it hard. And since the muffled exhaust tract flow plenty for the low boost and/or low rpm operation, you literally lose nothing in terms of performance.