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J pipe it
Don't suppose you know a site or article on how to calculate the diameter, length and position for a J pipe for varying engine and exhaust makeups? lol
 

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Cool man, thanks. Think I should straight up replace the Magna or try to shoehorn in the Vibrant and run two resonators?
You might be able to fit both. The Vibrant is quite small, but don't let that fool you, it does it's job better than longer Magnas.

20160127_162838.jpg
 

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You might be able to fit both. The Vibrant is quite small, but don't let that fool you, it does it's job better than longer Magnas.

View attachment 70730
Magnaflow resonators don't do much at all honestly IMO. Especially if loudness is of any concern
 

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this is what science has to say
And from my perspective
THEY ARE RIGHT

from previously posted link
quote

There is, however, and exact science to eliminating drone: calculate the drone wavelength and cancel it with a resonator tube. You can also use the sound frequency to buy the correct sound suppression material since the better ones have different material for different frequencies.

Here's the formula to get the tube length:
((343)/(RPM * 4 * (1/60))) / 4

Just replace RPM with the RPM where drone is at its worst.
E.g. ((343)/(2500 * 4 * (1/60))) / 4 = 0.5145 meters



Tip: if you just want the frequency for buying the correct sound suppression, use this part:
2500 * 4 * (1/60) = 166.67 Hz (replace 2500 with your drone RPM)



For drone at 2500 RPM you need to weld a capped exhaust pipe 0.5145 meters in length before your muffler, as perpendicular to your existing pipe as possible (it should look like a T). It's as simple as that. Although it's often called a j tube, it's actually better if it's straight, as the more it bends the more sound bounces back before reaching the full length. The j shape comes from having to fit it in small spaces. If you can't weld, with this number you can tell any exhaust shop what to do.

For those who are curious, here's the formula breakdown:
343m/s is the speed of sound
4 is the number of pulses per rev the engine makes (a V6 would be 6, but some engines fire two at once, so a V8 would still be 4).
1/60 to convert from minutes to seconds.
/4 divides the wavelength by 4 to get the length of tube that will cancel out the frequency.
 

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Discussion Starter #28
Update.
I had the Vibrant resonator installed Saturday. The rasp is gone! Woo!
SRS header from Mark ---> magnaflow metallic spun high flow cat ---> magnaflow resonator ---> vibrant resonator ---> Flowmaster super 50 series.
Sounds deep, like really deep. Idle is very mellow and not too much above stock.
Wide open throttle sounds wonderful. Aggressive and tuned, dare I say euro-ish.
Normal 4k shifting in traffic sounds nice. Not overly obnoxious or droning.
I still would like it more quiet though. Just a little bit more. Maybe switch to a regular honeycomb cat down the road. Or go with a borla muffler or something non-chambered.
Overall, I'm happy with the sound. Thanks for all the advice fellas!
Hopefully she'll live to see another 160k miles.
 

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Im running a DNA Racing header and DNA Racing full exhaust it didnt have any resonators and the rasp was god awful so I bought a 24inch long thrush resonator and welded it in and it got rid of all the rasp and the car sounds amazing not too loud and not too quite
 
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