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Re: Exhaust drone.... [Re: Clair_Davis] #67761
07/05/08 12:49 PM
07/05/08 12:49 PM
Joined: Jan 2005
Posts: 279
Pacific Northwest
W
Weldtech Offline OP
enthusiast
Weldtech  Offline OP
enthusiast
W

Joined: Jan 2005
Posts: 279
Pacific Northwest
Quote:

If we try hard enough, I bet we can spend all his money...

Clair






Thanks for the laugh!

Well I tried stuffing the seat with insulation just for the heck of it, no change....

Then I took a buddy on a car show/cruise and we listened very carefully, it appears that the drone is coming from the back of the car, way back as in the trunk/tip area, amost like it is behind the car???? In a hardtop I would bet there would be no problem.

I also want to thank everybody for their input, as for moving the muffs/resonators there is very little room for movement and no room to run more mufflers.

Before I yank the damn engine and put a slant 6 in I am going to try using some quiet round mufflers in the stock location.....


www.weldtechstainless.com Where NOTHING is made in China! 70 Challenger drop top 440 4 speed R/T clone (Re-creation, Tribute, Fake, whatever...)
Re: Exhaust drone.... [Re: Weldtech] #67762
07/05/08 02:54 PM
07/05/08 02:54 PM
Joined: Jan 2003
Posts: 1,180
Willoughby Hills, Ohio
gd9704 Offline
super gas
gd9704  Offline
super gas

Joined: Jan 2003
Posts: 1,180
Willoughby Hills, Ohio
I had 3 chamber flowmasters on my Demon and they droned like crazy.

I replaced them with Accurate Hemi repros and I have been very happy ever since!

(TTI 2.5" system)

Re: Exhaust drone.... [Re: Weldtech] #67763
07/07/08 08:13 AM
07/07/08 08:13 AM
Joined: Jan 2006
Posts: 8,162
USA
3
360view Offline
Moparts resident spammer
360view  Offline
Moparts resident spammer
3

Joined: Jan 2006
Posts: 8,162
USA
a cheap way to prove to yourself
that the 'science' of an exhaust system
is like the 'science' of a pipe organ or flute
is to buy about a 4 foot long piece of tailpipe expanded on one end,
and clamp it onto your existing pipe tip.

Drive around with this extension
notice the drone and at what rpm it appears,
then cut off six inches
and repeat

In a similar way
if you want to use 'resonators'
and don't know where to place them
to cancel a particular drone/rpm
buy four stainless steel pipe clamps

http://www.jegs.com/p/JEGS/753274/10002/-1/11527

two lengths of exhaust pipe
and a resonator
...then cut and fit the resonator into the exhaust pipe section from main muffler end to exhaust pipe tip. Start with the resonator about 2 feet from the muffler end, and go about 6 inches at a time outward

it is easier to just put a stainless steel, round six inch diameter, 16 inch long DynoMax UltraFlo muffler on as a tip....this will cure most drone

are you good with math
or have a child/friend/wife who is?

{don't laugh about the wife part...it made all the difference for Albert Einstein}

The basics of the exhaust noise math is here,
in GM's home study course for engineering:

http://www.gmi.edu/~drussell/GMI-Acoustics/Filters.html

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