Z06 Exhaust valves always closed (mod) Perf decrease?
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Z06 Exhaust valves always closed (mod) Perf decrease?
I like quiet cars. I was thinking of disabling the opening solenoid on my Z06 to always put the flow through the mufflers. Has anyone dyno'd a vehicle like this? What, if any real performance changes wold be experienced?
I don't want to do it if it will really cost me some HP at the rear wheels but somehow I think GM only added the "dual-mode" to make the car louder.
Thanks for any feedback!
Leif
I don't want to do it if it will really cost me some HP at the rear wheels but somehow I think GM only added the "dual-mode" to make the car louder.
Thanks for any feedback!
Leif
Race Director
Joined: Mar 2005
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From: Austin Texas
The dual mode on the '08 and up C6 LS3 is 6HP, GM has to verify that with the Feds. So 6HP from going to a free flowing 2 outlet exhaust from a single outlet exhaust.
Your guess is as good as mine as to the gain from a 2 outlet slightly resricted exhaust to a free flowing 2 outlet.
Your guess is as good as mine as to the gain from a 2 outlet slightly resricted exhaust to a free flowing 2 outlet.
Melting Slicks
Joined: Nov 2007
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From: Chattanooga TN
I like quiet cars. I was thinking of disabling the opening solenoid on my Z06 to always put the flow through the mufflers. Has anyone dyno'd a vehicle like this? What, if any real performance changes wold be experienced?
I don't want to do it if it will really cost me some HP at the rear wheels but somehow I think GM only added the "dual-mode" to make the car louder.
Thanks for any feedback!
Leif
I don't want to do it if it will really cost me some HP at the rear wheels but somehow I think GM only added the "dual-mode" to make the car louder.
Thanks for any feedback!
Leif
Thread Starter
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Yeah, that Sunset Orange device is prob just a simple garage door circuit tied into a relay that either allows or forces the stock valve open...at least that's how I'd build it. That's the one that you use your homelink buttons for-right?
Race Director
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From: Daytona Beach FL
If you don't want them to ever open, just leave the TC on and never exceed 3,500 RPM.
You can also keep the valves closed above that RPM by never exceeding more than 25% throttle.
Bob
You can also keep the valves closed above that RPM by never exceeding more than 25% throttle.
Bob
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From: Southeast TX
I like quiet cars. I was thinking of disabling the opening solenoid on my Z06 to always put the flow through the mufflers. Has anyone dyno'd a vehicle like this? What, if any real performance changes wold be experienced?
I don't want to do it if it will really cost me some HP at the rear wheels but somehow I think GM only added the "dual-mode" to make the car louder.
Thanks for any feedback!
Leif
I don't want to do it if it will really cost me some HP at the rear wheels but somehow I think GM only added the "dual-mode" to make the car louder.
Thanks for any feedback!
Leif
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disabling the opening solenoid on my Z06
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Run the ZR1 mufflers !!!!!!
When the valves are closed, the ZR1 mufflers are a lot quiter than factory Z06 mufflers (but a lot louder when they do open under WOT)
As was mentioned above, keep rpm's below 3500 RPM, or under 25% throttle to keep the valves closed at all times.
When the valves are closed, the ZR1 mufflers are a lot quiter than factory Z06 mufflers (but a lot louder when they do open under WOT)
As was mentioned above, keep rpm's below 3500 RPM, or under 25% throttle to keep the valves closed at all times.
Drifting
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From: STL MO
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I had a similar experience to Old Motorhead, when i did my first pull with my NPP mufflers closed I put down over 30 rwhp less than with them open. Mine are 2 1/2 inch vs your 3" version though. I also use the Sunset Orange creations system so I can run open or closed regardless of throttle input.
Melting Slicks
Joined: Nov 2007
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From: Chattanooga TN
In my case it's the module you use when you don't have the GM factory vacuum system setup and want to add NPP exhaust without the hassle of installing GM's setup or Billy Boat's knockoff of it.
It's so easy even an old C2 owner can do it too...
Team Owner
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From: Springfield MO
If you don't want them to open, then jam a toothpick in the butterfly valve. That will keep the spring from opening the valve when there is a loss in vacuum(that holds then in the closed position).
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Bill
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The dual mode on the '08 and up C6 LS3 is 6HP, GM has to verify that with the Feds. So 6HP from going to a free flowing 2 outlet exhaust from a single outlet exhaust.
Your guess is as good as mine as to the gain from a 2 outlet slightly resricted exhaust to a free flowing 2 outlet.
Your guess is as good as mine as to the gain from a 2 outlet slightly resricted exhaust to a free flowing 2 outlet.
Doug in Fla (GTOdoug) dyno'ed his stroker with the Z06 exhaust open and closed and it was a staggering 30rwhp difference. A stock exhaust on a base car far outflows a closed Z06 exhaust.
On my FI car it was night and day. It felt like 50hp.
Last edited by SpinMonster; Mar 4, 2012 at 09:57 PM.
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