New exhaust, no drone, no chopper, flapper relocate

[Justin Nachazel]

Hey guys I did a lot of research to try and find the right exhaust for my truck. Finally found a shop that would let me try out a few of them. Tired a Carven and it didn't sound very good in my opinion. So I went with a Magnaflow #14225. It sounds great! I did a resonator delete and relocated the flapper valve to just before the muffler. I don't know much about exhaust systems but figured there was no harm in trying it to see if I could get around the drone. Good news! No drone and no chopper sound! Let me know what you think.

 

 

[Txjose]

Little too quiet for my taste.

 

Not sure about no drone as it is pretty much impossible to achieve that. Maybe its very subtle....

 

The flapper is just a restriction from what i saw when i removed my stock exhaust. Like its activated by the amount of pressure that the exhaust has. So it made no sence to me to leave it in.

 

 

 

 

 

Sent from my Note 4 on Tapashit

[Justin Nachazel]

Little too quiet for my taste.

 

Not sure about no drone as it is pretty much impossible to achieve that. Maybe its very subtle....

 

The flapper is just a restriction from what i saw when i removed my stock exhaust. Like its activated by the amount of pressure that the exhaust has. So it made no sence to me to leave it in.

 

 

 

 

 

Sent from my Note 4 on Tapashit

 

Its not super loud but I didn't want it to be loud anyways lol And no it doesn't have drone hah

[beetle]

_{That sound is just about perfect, I never considered the idea of relocating the flapper before the muffler. How about an interior sound clip? A nice long one.}

[Justin Nachazel]

_{That sound is just about perfect, I never considered the idea of relocating the flapper before the muffler. How about an interior sound clip? A nice long one.}

 

Im going to be borrowing my buddies GoPro so Ill do some actual footage. Wish I could get iMovie working too lol

[Justin Nachazel]

Ok update on this:

Im going to have the exhaust checked out tomorrow. It seems to have a "wet" sound to it and a rattle when it first starts, I haven't gotten under it but I'm guessing a weld broke? I absolutely love the sound of the exhaust though.

[TJay74]

Dude get rid of the flapper valve, it is nothing more than a huge airflow restriction in the system. I have the 6.2 so I am running the Magnaflow 12909 muffler, no flapper and no resonator and have absolutely no drone. I get a very faint chopper sound under V4, but you have to really listen for it to hear it.

[Marticus]

Praise sweet baby jesus. I have been asking this exact question in the main exhaust thread with no answer. TXJose and TJay74 the reason for the valve is simple. When the truck shifts to V4 mode the exhaust on the vehicle is then too large. If it is not restricted then you lose all backpressure in the system. Since you can't have two different exhaust systems on one vehicle the engineers achieved the necessary effects with the valve.

 

Leave the valve on

 

Thanks for the post jnach truck sounds great!

[TxTruckMan]

Yes, the flapper valve will affect performance when you're at peak HP/WOT, but how often do you race your truck? Leave the flapper if you don't want the drone/chopper sound.

[Justin Nachazel]

Ok so this is where Im at so far with it:

1) Swapped the muffler out for a 3" in 3" out

2) sound is louder but the chopper is louder now

3) I don't have any drone what so ever in fact I can't even hear it when I drive really so the chopper isn't that big of a deal

4) I have a sort of "wet blowing bubbles into a water glad sound on slow low acceleration" Is this normal to magna flow? It was there on both mufflers

5) Will be clamping flapper to see if any difference is made between anything.

 

Side note the exhaust sounds great though. I wish mine rolled off the lot sounding like this.

[TJay74]

Praise sweet baby jesus. I have been asking this exact question in the main exhaust thread with no answer. TXJose and TJay74 the reason for the valve is simple. When the truck shifts to V4 mode the exhaust on the vehicle is then too large. If it is not restricted then you lose all backpressure in the system. Since you can't have two different exhaust systems on one vehicle the engineers achieved the necessary effects with the valve.

 

Leave the valve on

 

Thanks for the post jnach truck sounds great!

 

 

If you want to tell yourself this, then go ahead. The flapper valve is for noise abatement only for the V4 mode. I had a nice conversation with a GM engineer on this subject back in 2014. So tell yourself what you want, the truck does not need backpressure for anything in regards to V8 or V4 operation. If it was so crucial to it then GM would not of had released TSB directions to clamp the valve open on the new (2010) Camaro when they came out and had the defective valve and GM didn't have the parts on hand to replace them.

 

My 2014 had the valve removed at less than 500 miles and went to 5k miles before it was tuned and the AFM turned off, the 2016 truck I have now had the valve removed at 300 miles and has 1k miles now and once the tuning software is fixed to be able to adjust all of the parameters in the TCM then I will turn off the AFM once again.

[Justin Nachazel]

 

 

If you want to tell yourself this, then go ahead. The flapper valve is for noise abatement only for the V4 mode. I had a nice conversation with a GM engineer on this subject back in 2014. So tell yourself what you want, the truck does not need backpressure for anything in regards to V8 or V4 operation. If it was so crucial to it then GM would not of had released TSB directions to clamp the valve open on the new (2010) Camaro when they came out and had the defective valve and GM didn't have the parts on hand to replace them.

 

My 2014 had the valve removed at less than 500 miles and went to 5k miles before it was tuned and the AFM turned off, the 2016 truck I have now had the valve removed at 300 miles and has 1k miles now and once the tuning software is fixed to be able to adjust all of the parameters in the TCM then I will turn off the AFM once again.

 

This is correct.

Here is why we have an adaptive valve. During normal operation in v8 mode the vehicle has the correct size piping for the resulting exhaust. When the truck switches into v4, there is a different amount of air moving through pipes that are too big. A good example is to look at a v4 vehicle exhaust system vs a v8, the pipes are smaller to accommodate the appropriate movement of air. The purpose of the adaptive valve is to essentially compensate for this. When in v8 mode there is enough air to push the valve open and allow full pipe. When the pressure drops, the valve closes slightly simulating a smaller pipe. I thought by moving the valve It would compensate till while allowing for the muffler to give me more sound. ProModMike and I will be trying a work around by simulating the Borla system completely but I will be using a Magnaflow instead. In theory it should work. I attempted it with this but it didn't work. ProModMike (Exhaust Genius) thinks the issue is that there is still too much pressure resulting in sound. Basically because of the size of our stock muffler and attached resonator, it dampens the v4 drone and chopper sound. It exists in the exhaust system, you just can't hear it because of the dampening. Borla doesn't have a resonator attached but what they DO have is a J pipe that bypasses the adaptive valve which allows more air to move through the pipe. This might compensate for the pressure differences and reduce the chopper and drone sound while maintaining muffler sound.

 

More to come in the next few weeks! ProMod knows what he is doing so I'm going to let him give it a shot first then if all goes well ill add one to mine since I have a different magna flow. It would be nice to have an option that allowed us to keep our AFM, get a loud ass muffler, and spend $250 instead of $1100 for a kickass exhaust.

[AZ_SS]

I am very interested in the results of this. I guess i will hold off on buying anything for a couple of weeks.

[07Softail]

 

 

If you want to tell yourself this, then go ahead. The flapper valve is for noise abatement only for the V4 mode. I had a nice conversation with a GM engineer on this subject back in 2014. So tell yourself what you want, the truck does not need backpressure for anything in regards to V8 or V4 operation. If it was so crucial to it then GM would not of had released TSB directions to clamp the valve open on the new (2010) Camaro when they came out and had the defective valve and GM didn't have the parts on hand to replace them.

 

My 2014 had the valve removed at less than 500 miles and went to 5k miles before it was tuned and the AFM turned off, the 2016 truck I have now had the valve removed at 300 miles and has 1k miles now and once the tuning software is fixed to be able to adjust all of the parameters in the TCM then I will turn off the AFM once again.

Amen Brother.... all the damn non-sense about back pressure makes me laugh.

[drparker7]

_{opinion on stainless works exhaust?}