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Will changing Resonator fix drone?

10K views 10 replies 9 participants last post by  Doc 
#1 ·
Hi!

So I have a manual crosstrek which runs at 3000-3500 rpm on the highway. I had an LP Aventure straight pipe on it and it sounded so good ( https://youtu.be/alAxgiBHE_Q?t=4m37s ) but after two months of doing a lot of highway driving I had enough of how loud it was in the car so took it off and put the stock muffler back on. Unfortunately, I miss the subaru rumble!!! :(

I was talking to a subaru mod shop owner earlier today and he said that, "Drone is actually resonance, its the reverberation of the exhaust pulses that are trapped in the exhaust system. with a freer flowing system, a high quality resonator and muffler, drone is no longer an issue. it really has very little to do with the engine itself, or the rpm range at highway speed. its more to do with the correct combination of exhaust system components." Can anyone validate that this is true?

If this is true would I be able to get a higher quality resonator in conjunction with the LP aventure straight pipe to keep the same amazing sound from the video but cancel out drone on highway speeds to make me a happy camper? :)
 
#2 · (Edited)
Traditional old Subaru rumble comes from unequal length headers/exhaust manifold. All new Subaru engines now have equal length headers with the EJ257 as the sole exception. Although resonators are intended to alter the sound characteristics, I doubt it is enough to get the old-fashioned Subaru sound.

Best you can do is get aftermarket custom unequal-length headers, but they will bring your vehicle out of U.S. federal emissions compliance.


equal-length headers vs unequal-length headers sound difference:


custom unequal-length headers made for Subaru FB20 engine:
 
#3 ·
Appreciate your response, but to clarify im not necessarily looking for the unequal length header sound. I like the sound that the crosstrek had with the lp aventure axelback exhaust.(like the video) I am just looking at how to keep that sound but lower how loud it is on the highway if possible in a manual transmission.(if that has anything to do with it)
 
#7 ·
Ask your muffler shop if they can make a Hemholtz resonator for it. ;)

Basically, it is a dead-end pipe added to your exhaust that is cut to the right length to reflect back the sound waves, which cancel out the drone.
 
#9 ·
I have a muffler delete on mine using the $15 Napa adapter. It doesn't drone at all. I had to slightly cut the very bottom (out of sight) of the rear bumper cover for it but the exhaust opening exits beyond the cover rather than under the car. If your exhaust is exiting under the car, even a little bit, it's going to have that reverb.
 
#10 ·
If I were you, I'd just put in a small 8-12" bottle resonator on the muffler delete. If you want to protect that shiny pipe... you can replace the stock resonator with a longer bottle style resonator. I run no resonator with a nameless 5" and it's quieter and deeper compared to the muffler delete I had with the stock resonator.
 
#11 ·
I replaced my stock muffler with a cherry bomb on my 2016 CrossTrek after mistakenly having the resonator removed. Sounds great, but is a little too loud. If I have the stock resonator re-installed, will it tone it down a little. I like the sound but it's somewhat nerve-wracking at times.................tnx......Doc
 
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