Resonators gone new mesh screens replace them

[Black02Silverado]

1 minute ago, Jstnelson said:

I’ve thought about trying some temporary hack like that. I’m curious if there is anything inside the pipe as well though. If there is some kind of obstruction within the piping, I’d just get the pipes replaced. But if it’s just hollow pipes with mesh cutouts, I’ll seal them up. 

I'm no engineer but to me just having the open mesh would allow the exhaust pulse to change with the sound waves traveling through the pipe since it is open to the side making it quieter out the back of the pipe. 

 

I'm sure in time someone will remove and cut open to see inside. Then we will know.

[Jstnelson]

5 minutes ago, Black02Silverado said:

I'm no engineer but to me just having the open mesh would allow the exhaust pulse to change with the sound waves traveling through the pipe since it is open to the side making it quieter out the back of the pipe. 

 

I'm sure in time someone will remove and cut open to see inside. Then we will know.

I agree that’s probably the case. If I do find out there’s something cased within the piping, I’ll report back. 

[Edward Nygma]

Just for your information:

it’s an empty pipe, which has holes to break the pipe resonances (standing acoustic waves within the pipe). The patches are for reducing the generation of further noise sources along the tail pipe. This design replaces a resonator.

 

The best way to test is covering the patches as mentioned (clamps, pieces of metal), no need to remove or cut. The result can be a booming noise at the pipe resonance frequencies. It might rather be noticed in the car than outside.

 

If you replace the muffler, you have to pay attention about the positioning of the patches. The position is related to the tailpipe’s total length, which is calculated from within the muffler (after the last perforation field) related to the standing acoustic waves within the pipe. Positions therefore are 50% and as far as I remember 75% plus one in between of the total tailpipe length (including the section inside the muffler).

 

 

Edited April 5, 2019 by Edward Nygma

[Jstnelson]

4 hours ago, Edward Nygma said:

Just for your information:

it’s an empty pipe, which has holes to break the pipe resonances (standing acoustic waves within the pipe). The patches are for reducing the generation of further noise sources along the tail pipe. This design replaces a resonator.

 

The best way to test is covering the patches as mentioned (clamps, pieces of metal), no need to remove or cut. The result can be a booming noise at the pipe resonance frequencies. It might rather be noticed in the car than outside.

 

If you replace the muffler, you have to pay attention about the positioning of the patches. The position is related to the tailpipe’s total length, which is calculated from within the muffler (after the last perforation field) related to the standing acoustic waves within the pipe. Positions therefore are 50% and as far as I remember 75% plus one in between of the total tailpipe length (including the section inside the muffler).

 

 

Haha, I just found that video and came back here to post it.

 

I’m going to order some exhaust sleeve clamps from Amazon. I figure I can clamp them all closed and test it out. If there’s unwanted changes I can remove some or all of them. I’ll report back. 

 

The clamps are $10 a piece so I can’t decide if I want to order 2 and make sure it works well or order all 6 lol

[Black02Silverado]

1 hour ago, Jstnelson said:

Haha, I just found that video and came back here to post it.

 

I’m going to order some exhaust sleeve clamps from Amazon. I figure I can clamp them all closed and test it out. If there’s unwanted changes I can remove some or all of them. I’ll report back. 

 

The clamps are $10 a piece so I can’t decide if I want to order 2 and make sure it works well or order all 6 lol

$60 to see if it makes a difference?  I think I would do the aluminum can and hose clamp thing first.

[Jstnelson]

4 minutes ago, Black02Silverado said:

$60 to see if it makes a difference?  I think I would do the aluminum can and hose clamp thing first.

Well, If the $60 clamps work, they’re my permanent solution and a simple install; rather than buying hose clamps and cutting up cans just to test it lol. 

 

I ordered 6 of them from Amazon. So I’ll let everyone know how it goes. 

[Edward Nygma]

Quote

I’m going to order some exhaust sleeve clamps from Amazon. I figure I can clamp them all closed and test it out. If there’s unwanted changes I can remove some or all of them. I’ll report back. 

I'd be interested in the Outcome... 
It could make a difference which holes you cover (or don't cover). Do the flute 

Edited April 7, 2019 by Edward Nygma
Wrong quote

[Edward Nygma]

For those not afraid of patent lingo: https://patents.google.com/patent/WO2014126548A1/en

[Jstnelson]

54 minutes ago, Edward Nygma said:

I'd be interested in the Outcome... 
It could make a difference which holes you cover (or don't cover). Do the flute 

Yea, my thoughts exactly. I’m going to cover them all then, if there’s unwanted drone, I’ll take 2 off and experiment covering 4 in different locations. 

 

I received the clamps yesterday and they sent me the wrong size (2.25” instead of 2.75”) so I’m expecting them Tuesday now

[Jstnelson]

4 hours ago, Edward Nygma said:

For those not afraid of patent lingo: https://patents.google.com/patent/WO2014126548A1/en

Nice. It looks like they do decrease sound dB quite a bit. 

[Limelight]

So today I performed a purely scientific experiment in a scientifically sound environment (my front yard) using nothing but industrial strength Duct Tape, from Harbor Freight no less....  Haha!  The duct tape fits over the mesh perfectly so why not?  I covered all 4 of my mesh holes...did I just type that?

 

Anyway,  the results were very surprising!  I mentioned in another thread that my Magnaflow muffler was actually quieter at idle than stock and the exhaust could really only be heard during fairly heavy acceleration.    Duct Tape fixed everything just like always.  Definitely crisper at idle with the deep tone back and I can hear the exhaust all the time now- not much louder, but it's definitely there now.  I haven't driven more than a few blocks so not sure about the highway noise- it'll probably burn the tape off before I can get to the highway anyway, lol.

 

Curious if this makes a big difference to the stock exhaust as well.  I'll be covering these up with something (ahem) better I think.  Go Science.

 

 

[Jstnelson]

5 hours ago, Limelight said:

So today I performed a purely scientific experiment in a scientifically sound environment (my front yard) using nothing but industrial strength Duct Tape, from Harbor Freight no less....  Haha!  The duct tape fits over the mesh perfectly so why not?  I covered all 4 of my mesh holes...did I just type that?

 

Anyway,  the results were very surprising!  I mentioned in another thread that my Magnaflow muffler was actually quieter at idle than stock and the exhaust could really only be heard during fairly heavy acceleration.    Duct Tape fixed everything just like always.  Definitely crisper at idle with the deep tone back and I can hear the exhaust all the time now- not much louder, but it's definitely there now.  I haven't driven more than a few blocks so not sure about the highway noise- it'll probably burn the tape off before I can get to the highway anyway, lol.

 

Curious if this makes a big difference to the stock exhaust as well.  I'll be covering these up with something (ahem) better I think.  Go Science.

 

 

Haha, nice. I contemplated doing something similar first. My clamps were delayed and arrive tomorrow but i’ll be putting them on ASAP. 

[Limelight]

10 hours ago, Jstnelson said:

Haha, nice. I contemplated doing something similar first. My clamps were delayed and arrive tomorrow but i’ll be putting them on ASAP. 

Drove it to work this morning and it is definitely a big difference.  And the tape is still there, ha!

[Jstnelson]

On 4/10/2019 at 8:24 AM, Limelight said:

Drove it to work this morning and it is definitely a big difference.  And the tape is still there, ha!

I installed my sleeve clamps last night and drove it to work this morning. It’s definitely a little louder. I can hear a little tone at idle from inside the truck now. It used to be almost silent at warm idle. I like it. Took it from about a 4 to a 5 on the loud scale. And still absolutely no cabin drone. 

 

2.75” clamps are too big for stock exhaust though. I’m going to get some exhaust patch tape and place that over the mesh and tighten the clamps back over that to get a tight fit. 

Edited April 11, 2019 by Jstnelson

[Jstnelson]

On 4/11/2019 at 8:43 AM, Jstnelson said:

I installed my sleeve clamps last night and drove it to work this morning. It’s definitely a little louder. I can hear a little tone at idle from inside the truck now. It used to be almost silent at warm idle. I like it. Took it from about a 4 to a 5 on the loud scale. And still absolutely no cabin drone. 

 

2.75” clamps are too big for stock exhaust though. I’m going to get some exhaust patch tape and place that over the mesh and tighten the clamps back over that to get a tight fit. 

Just an update after driving a few hundred miles; clamping the resonance free pipe is a definite sound improvement. I highly recommend a Flowmaster super 40 and clamped mesh inserts. It gives a great tone outside the truck and, while driving, you can clearly hear a good V8 exhaust tone with no drone at all and still pretty silent on the highway. There are a couple speeds that you can steadily hear an exhaust tone while cruising but it never drones/resonates within the cab. 

 

Revving the truck with stock exhaust sounded like a vacuum cleaner. 

 

Revving with Flowmaster Super 40 and stock axle-back had a good tone but sounded like someone was holding a pillow over the tips. You could convince me it was a stock exhaust if I didn’t hear a cold start. 

 

Revving with Flowmaster Super 40 with closed off mesh resonators sounds loud and mean. Definitely sounds aftermarket.