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Old 04-05-2019, 07:37 PM   #147
KingLT1


 
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Drives: 2016 1SS NFG A8
Join Date: Aug 2017
Location: 46804
Posts: 7,559
Quote:
Originally Posted by 70chevelleSS View Post
While I have not noticed the noise that yours makes, I have noticed that my valves don’t shut 100%. Essentially I can put mine in stealth mode, and still get some flow on the outer pipes. It gets quieter if I cover the outer pipes with my hands. I assumed this was just the nature of these valved exhausts, but it could be related to the problem you are experiencing.


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It is but mine don't close as far as they do on initial startup after I have driven it and that is when they start making the hissing noise. If I use a screw driver I can push them closed 1/16" or so and the hiss goes away, then the sound is similar to what you describe.

I'm going to try some stuff in the exhaust valve tuning and see if I can fix it. It almost seems like the valves need to be turned a tad further then the controller is turning them in order to seal. I am going to try using a value higher then 100 in the closed cells and see what happens.
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2016 NFG SS A8/Whipple 2.9/Fuel System/Flex Fuel
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