Exhaust Drone Explained?
08-15-2005, 12:39 PM
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Exhaust Drone Explained?
What exactly is exhaust drone, where is it heard from the most(what section of exhaust) and well that's pretty much my question. I've tried searching but no luck and lately the search function is really really slow while all else isn't. Please if you're going to explain or contribute to this thread be detailed or logic don't post "exhaust drone is noise from exhaust". I removed my resonator from my car and after about 1500 miles of driving i began to hear a deep exhaust noise at higher rpm's. This noise comes from behind the headers to about where the catalytic is. Thanks in advance for any help.
08-15-2005, 12:43 PM
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Resonance frequency. When you change out parts of the exhaust, it changes this frequency in the pipes, which causes the exhaust to drone/buzz at certain RPM. Also, resonators were created to muffle these frequencies and cut down on the noise, once it's removed, you get that "boomy" sound in your exhaust.
08-15-2005, 02:02 PM
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Thanks for the help, i replaced my resonator with a straight pipe at the moment the exhaust change was barely noticeable but as time passed the exhaust tone got deeper and a bit louder, now im hearing sound coming from the midsection of the exhaust sounding like if i had a hole in the exhaust. Already checked but no hole and the exhaust looks ok.
08-15-2005, 02:07 PM
#4
the change is probably best explained by the car breaking in, i.e.: mufflers packing in, engine breaking in, etc. I think the stock resonator (helmholtz type i think) is just designed as a baffle, with no sound deadening insulation.
08-15-2005, 04:12 PM
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I'm pretty sure the pipe that sticks out of your stock exhaust at a 90 deg angle (short 8-10" thing with a cap on the end) is designed to kill that drone. Drone is a natural feature of the exhaust harmonics. None of the aftermarket exhausts have this little pipe thing and as a result they all drone. The HKS has a separate resonation chamber located between the mufflers which probably explains why it doesn't drone and also explains why it's so damn heavy.
08-16-2005, 01:25 PM
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i dont know maybe im being skeptical but this noise doesn't sound normal. I had my car in service for the second gear poping out. So in order to remove the tranny i know they removed the driveshaft and some other stuff but do you think the idiots removed some exhaust components and damaged them? when i'm driving the noise comes from where the cat is. I checked today and one of the bolts holding the heatshield to the headers was lost. I don't think they removed the headers but maybe the cat and then mounted it wrong.
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08-16-2005, 02:03 PM
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removing the transmission means removing the header and by extension the exhaust. Maybe it's not put together right. Wouldn't surprise me if it wasn't. There is no way for us to answer this question so I can only suggest you take it back, complain loudly and let them break something else.
08-16-2005, 04:25 PM
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Damn, i hate taking the car to the dealer, besides being far they can't ever do anything the same day everything has to take a couple of days. They'll probably try to blame it on me removing the resonator. Thanks for your help guys
08-16-2005, 07:10 PM
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They could be right too. I don't really know why you would remove the resonator unless you wanted resonance. If anything you should have removed the mufflers and the 40+ lbs they contain. Like I said, who knows.