| Re: [GMCnet] And another muffler question / discussion [message #315599] |
Fri, 07 April 2017 10:59  |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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Nearly all exhaust systems will "drone" or make more detectable to the
human ear, sounds that occur at specific frequencies. Fix? Shorten or
lengthen any pipes in the system. Change diameter of any or all pipes in
the system. Replace mufflers with ones that have different internal
baffling. Add resonator(s). Change pipe hangers to less rigid designs.
Change final drive gearing so you can run at different loads and rpm's.
Turn up the stereo. (Grin) Look for places in the exhaust system where
metal to metal contact is made with the frame of the coach. Safely support
the coach off the ground and crawl under it. Bump the exhaust pipe with
your hand to see and hear if anything is loose or in intimate contact with
frame components. JWIWD.
Jim Hupy
Salem, Or
78 GMC ROYALE 403
On Apr 7, 2017 8:42 AM, "Carl Stouffer" wrote:
SteveW wrote on Fri, 07 April 2017 07:39
> A recent discussion about mufflers and crossovers reminded me that I also
have a muffler question to pose...
>
> 1973 23 footer. Stock exhaust configuration - two mufflers into one long
pipe to the rear. Well... stock except for headers.
>
> The issue is an irritating drone at 1400 - 1600 rpm.
>
> Anyone have any trickery to eliminate it ??
>
> Thanks,
>
> Steve W
> Southern California
Maybe add a small resonator somewhere in the system? I don't know enough
about exhaust system design to recommend placement.
--
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive,
Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American
Eagles,
Solar battery charging
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| Re: [GMCnet] And another muffler question / discussion [message #315606 is a reply to message #315599] |
Fri, 07 April 2017 15:06  |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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All of what James has stated. You don't say how old your mufflers are, or if stock type replacements or something like a Flowmaster that may be louder. If stock, they can look nice from the outside, but inside be totally broken down from moisture and acids. The perforated tubes are usually first to break down, then baffels can become dislodged.
John Lebetski
Woodstock, IL
77 Eleganza II
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