Exhaust J-Pipes

[Merlintwist]

I know drone plays a huge factor on the 3.0T with an exhaust, so I've been wondering has anyone tried J-Pipes (or 1/4 wave resonators as they're also known) to cancel out those resonant frequencies?

If so, what was the outcome?

I know Polo Performance used adjustable J-pipes on their system to help cancel out some drone and it seemed to get decent results if set up correctly.


For those curious on the subject of J-Pipes and need the formula for calculating the length, here you go:

1100 feet/second (roughly the speed of sound) divided by the target frequency you're trying to eliminate (in cycles/second) gives a full wavelength in feet per cycle. Divide this number by 4 to get a quarter wavelength (a much more convenient length to work with). Finally, multiply this wavelength by 12 to get the chamber length in inches.

Example 110hz:
( 1100 / 110hz ) / 4 ) x 12 = 30 inches



EDIT: After more digging i finally found JACKAL's thread on expermienting with exhausts which includes 1/4 wave resonators on the downpipes.
https://www.audizine.com/forum/showt...tors-a-j-pipes

[theweebabyseamus]

No disrespect, but search a bit. I know its been done a bit, iirc JACKAL has done something similar.

[JACKAL]

No disrespect, but search a bit. I know its been done a bit, iirc JACKAL has done something similar.

You recall correctly sir. I do have branch resonators on my setup. Mine were approximately 32 inches long, calculated using the same formula noted above but slightly longer because I used a slightly higher speed of sound due to increased air temperature. There were more effective when I still had cats. After going catless, I gave up and had to go back to my stock mufflers to completely eliminate drone.

Photo Jun 18, 11 43 06 AM.jpg

[Merlintwist]

You recall correctly sir. I do have branch resonators on my setup. Mine were approximately 32 inches long, calculated using the same formula noted above but slightly longer because I used a slightly higher speed of sound due to increased air temperature. There were more effective when I still had cats. After going catless, I gave up and had to go back to my stock mufflers to completely eliminate drone.

Photo Jun 18, 11 43 06 AM.jpg

Cats will be staying on my car for a while yet.
Interesting placement for the pipes too! Did they successfully combat the drone you were chasing down when you still had cats in place?

[JACKAL]

Cats will be staying on my car for a while yet.
Interesting placement for the pipes too! Did they successfully combat the drone you were chasing down when you still had cats in place?

They helped a bit. They weren't 100% effective but they cut it by perhaps 50%.

[Fresh.S4]

If you want j pipes,buy a polo exhaust. Seriously everyone's chasing this "idea" yet no one had been able to replicate what polo can do. Save the grief
Save the time
Save the bs thinking you know what your doing lol.
It's financially cheaper just buy the damn system and be done with it. No one has ever complained that polo doesnt work.
No one has ever said "drone" or "rasp" when referring to polo.

[chilort]

If you want j pipes,buy a polo exhaust. Seriously everyone's chasing this "idea" yet no one had been able to replicate what polo can do. Save the grief
Save the time
Save the bs thinking you know what your doing lol.
It's financially cheaper just buy the damn system and be done with it. No one has ever complained that polo doesnt work.
No one has ever said "drone" or "rasp" when referring to polo.

I'm quite happy with my setup (though I would never recommend replicating all that I did). I still need to get some updated videos now that the system has had time settle.

https://www.audizine.com/forum/showt...-exhaust-setup

The Polo likely does a great job if you don't mind a restrictive turbo style muffler in the system. But I'm glad I didn't go that route.

[Fresh.S4]

how do you figure turbo restrictive muffler?
its literally a x pipe muffler (just like the magnaflow everyone swears by) and a traditional x pipe (that ecs runs on theirs/ as well as AWE). the difference being right after all of this, which is literally a straight pipe/ j pipe out?

[Asteven1]

how do you figure turbo restrictive muffler?
its literally a x pipe muffler (just like the magnaflow everyone swears by) and a traditional x pipe (that ecs runs on theirs/ as well as AWE). the difference being right after all of this, which is literally a straight pipe/ j pipe out?

So why pay 2 grand for it then lol?? So many people do this for 500$. I don’t think anyone’s going to buy a used polo with the metal quality , but it does sound great