Exhaust Adaptive Valve

[Guapoh]

Wow, cool info. Just joined this forum this morning in advance of my delivery of my custom built to order 2014 Sierra All Terrain 6.2.

 

Will certainly do this on day one until my aftermarket solution is in place.

[jmitchell]

I have a 2015 Tahoe and have the same squeak or whistle noise coming from the exhaust only when going from V4 to V8. Thanks to this forum, I'll be fixing this annoying problem tonight!!! Thanks for the info guys.

Edited June 26, 2014 by jmitchell

[DranoSnake]

so I have a Borla Cat-back exhaust, would i still have the flappy flap valve?

[2016 Sierra Owner]

If you had the exhaust put on at a muffler shop. More than likely they took it off. The valve is just in front of the axle on the passenger side.

[f8l vnm]

Man you guys are awesome with this info. Can't wait to try mine on 14' 6.2

[Sermed]

i put the clamps on , and i love it, specially when i start the car and when i am slight over raving it on the streets

[chuckl1218]

so I have a Borla Cat-back exhaust, would i still have the flappy flap valve?

In the exhaust system thread there is a discussion about the Borla exhaust. The GMPP Borla exhaust system purchased from GM dealers does have an adaptive valve, but it is a different version than in the stock GM exhaust. The Borla exhaust system from Borla does not have the adaptive valve.

[f8l vnm]

Hey guys how much is this flapper have to be tightened down? I'm trying this on mine but even with a clamp it doesn't seem like it's tightened much , if any. Any advice or suggestions?

[JAF1]

I didn't have the right size hose clamp so I used a nail instead. Just thought I would share.

 

[f8l vnm]

I didn't have the right size hose clamp so I used a nail instead. Just thought I would share.

 

Can you please take a side shot ? Would like to see how much room in between is left once it's all the way open. Thanks

[JAF1]

Can you please take a side shot ? Would like to see how much room in between is left once it's all the way open. Thanks

Not sure exactly what you're asking. I simply twisted the valve open and wedged a nail in between the two square flanges. I was going to cut the nail off but it just worked out that it sits on top the pipe. Took a few different nails to find the right one.

[f8l vnm]

Thanks man I appreciate the help. Just trying to figure out if this valve twists closed or needs to be hammered straight down. I tried mine and I heard this whistling sound.

[MudMutt]

I just popped a small nail as JeffF suggested and it works pretty well ( easy install and removal) ... I really was not having an issue but these exhaust systems are restricted enough as is. I believe motors should be able to breathe some. Took it for a spin and it does sound somewhat louder. As far as the drone in 4V it's not too bad ... Gone to cruise it for a week or so to see if I leave it open.

[bdbake01]

Seems to be an appropriate thread for this. Looking for ideas. I'm 99% of the way there for my "perfect" exhaust note. One lingering issue is what I'm calling the "flapper slap".

 

Go ahead...make fun. Or come up with a better name.

 

Basically I have the tone & volume that I want, but when I cold start or rev it, the flapper slaps open, then closed, and maybe open again a few times and I get a metallic, clanky noise when it hits full open/closed. I need to dampen this just a bit to take the edge off. I like the adaptive nature of the valve, it does good things to the tone at the right times IMHO, but I need to get rid of the slap.

 

Open to ideas. To be honest, I haven't tried much. Thinking of tack welding on some artificial stops lined w/ high temp/durometer rubber.

[Jaybridge88]

Im new to the site and see this is an old thread. Since I've got my Silverado I have been researching things and find my google searches bring me to this forum quite a bit. Figured I would try to add to the great info I have found here.

 

Ever since I hit about 2k miles I noticed a faint squeak noise when it shifted from V4 to V8 mode. Happens pretty much every time. I took it in for its first oil change and told the dealer about it. They put about 20 miles on the truck doing tests. They diagnosed it to be a faulty adaptive valve in the exhaust and are ordering me a complete new exhaust cat back. I tried to work with them to some how get a credit towards aftermarket but that was a slim chance. Glad they are fixing it though.

Edited January 7, 2015 by Jaybridge88