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04-07-2014, 03:38 PM | #1 |
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Is the resonator/muffler the source of the drone?
I've driven straight piped cars before. None of them drone as terribly as my Z4M w/ muffler delete, replaced with resonators. I have heard that the RPI exhaust (I think?) drones a lot too. My drone seems to be more vibration based, in that even if I put earplugs in, the volume isn't decreased all that much. It's a really deep drone.
So, I'm wondering... do you think that the exhaust gases flowing through the resonators are attenuating the sound heard from the outside, but transferring that energy in the form of vibrations throughout the rest of the car? Maybe the only thing I can do to test is remove the resonators completely and drive around the block just dumping the exhaust after the axle. Do straight piped Z4Ms drone a lot? Physics isn't my strong suit, so please forgive me if everything I just wrote is crap. Last edited by intoflatlines; 04-08-2014 at 07:17 PM.. |
04-19-2014, 12:33 AM | #3 |
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So I tested by removing the resonators/mufflers and it still had drone. It was reduced a little bit. Exterior noise was noticeably louder. It was very raspy under WOT. Not worth it for the minor reduction in drone.
You're saying to get an aftermarket X-pipe? And different mufflers? Any custom options for standalone mufflers or are people just buying the pre-made setups? |
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04-20-2014, 11:30 AM | #4 |
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The s54 is a noisy motor you need resonators closer to the headers to kill rasp and most drone...but it will always drone
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2007 //M Coupe. BSM. Fabspeed headers. Catless. BMS x-pipe. Strömung cans. evolve tune. Turner CSL airbox. Airrex air suspension with autopilot v2 management.
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04-22-2014, 11:04 AM | #5 |
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04-22-2014, 12:43 PM | #6 |
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There is a thread out there of creating a horseshoe or U shaped pipe at specific length to remove drone. Decent amount of science behind it but is proven to work. If you're already custom exhaust all the way through you might want to give this a try with a muffler shop or someone who has welding capabilities. I'll see if I can find the thread.
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04-22-2014, 12:55 PM | #7 |
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Skiddish has it right, there's a way to cancel drone.
Here is the thread re: U Pipe. And reference material. |
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04-22-2014, 01:30 PM | #8 | |
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Quote:
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04-26-2014, 01:18 AM | #9 |
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