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Free Exhaust Mod!!


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  • 10 months later...
On 11/18/2017 at 1:19 PM, pl8man said:

Rotate counter-clockwise. I used long machine screw w/ nut.

IMG_0001.JPG

Man, I wish mine was as accessible as yours appears to be!  I used this same screw in this same location, but on my 2017,  I have MUCH less "access" to get the nut on the screw. 

So I had to simultaneously:  1) hold the valve in just the right open position so I could turn the screw  2) hold the nut in the perfect orientation with some needle nose pliers  3) turn the screw until it caught the nut.   

 

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2 minutes ago, kevinfranklin said:

Man, I wish mine was as accessible as yours appears to be!  I used this same screw in this same location, but on my 2017,  I have MUCH less "access" to get the nut on the screw. 

So I had to simultaneously:  1) hold the valve in just the right open position so I could turn the screw  2) hold the nut in the perfect orientation with some needle nose pliers  3) turn the screw until it caught the nut.   

 

So what you are saying is you got it done, just needed three hands to do it.  :)

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The round-headed valve clamped open:

 

182337-0781638a757049815f22f3a8dc72e44b.jpg

 

NOTE: Fully clock-wise and clamped as shown in pmot1200's March 26 post in the thread "Exhaust Adaptive Valve" in this forum.

Edited by BigBlueLB756
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On 11/18/2017 at 2:19 PM, pl8man said:

Rotate counter-clockwise. I used long machine screw w/ nut.

IMG_0001.JPG

I did the exact same thing with mine after seeing your post.  I have zero drone, and I do notice a louder tone at a cold start.  Other than that, I haven't noticed too much difference.  I think it's time to remove the flapper and muffler and have a pipe added...

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  • 4 weeks later...

For those that welded/clamped open the flapper or cut it out completely, did you notice a performance difference or a stumble in the engine and exhaust when starting it up or revving it a little at idle?

 

I have a 6.2L with a supercharger and tied mine open for a few days. The performance (mainly throttle response) took a hit and there was a stumble while giving it a slight rev at idle. Maybe a back-pressure issue...?

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11 hours ago, Mileguru said:

I have a 6.2L with a supercharger and tied mine open for a few days. The performance (mainly throttle response) took a hit and there was a stumble while giving it a slight rev at idle. Maybe a back-pressure issue...?

You have a 6.2 with a supercharger? In a truck? That must be fun!! I want one!! 

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On 11/1/2018 at 8:24 AM, FAST380 said:

You have a 6.2 with a supercharger? In a truck? That must be fun!! I want one!! 

Yep, very, VERY fun. I'm still trying to figure out if tying the flapper open robs you of some low end torque though.  Or maybe I'm having a problem because the truck has a supercharger with a Magnuson tune so any little change that produces a small of amount of negative effect is amplified and felt more than it would have been in a stock truck.

Edited by Mileguru
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  • 2 weeks later...
On 10/31/2018 at 11:41 PM, Mileguru said:

For those that welded/clamped open the flapper or cut it out completely, did you notice a performance difference or a stumble in the engine and exhaust when starting it up or revving it a little at idle?

 

I have a 6.2L with a supercharger and tied mine open for a few days. The performance (mainly throttle response) took a hit and there was a stumble while giving it a slight rev at idle. Maybe a back-pressure issue...?

Mine runs no differently w/ the flapper bolted open.  Only difference I've noticed is a little bit louder at startup when I auto-start it in the barn, and a SLIGHT helicopter sound under light acceleration in V4 mode.

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  • 2 weeks later...
  • 1 year later...

Hello all. 
New to the forums and this is my first post. 
The other day I was at the airport to do an oil change my plane and when I was safety wiring the oil filter I had an idea. 
Took my safety wire and crawled under the truck and tied open the valve on my 2017 Denali 6.2L.

It sounds so much better now ... doesn’t sound like a Prius anymore. 
The engine is finally breathing.     Does anyone hear any other engine noises that they are not used to hearing when they clamped the valve open?

4170CBEE-4E1E-489C-97CE-DCC0B8A8A526.jpeg

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