reccomendations for mufflers

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reccomendations for mufflers

Postby jethro » Thu Sep 10, 2015 12:01 am

got my stainless 3 inch downpipe finished- ready to consider a muffler.
My engine didn't really seem loud to me even on the test stand with a 3 inch cardboard shipping tube as an exhaust pipe.
(to get the fumes out the door--)
I am thinking of something like a tractor muffler- which seem to be pretty open when I have looked down them.
Would a cherry bomb be too open to do much ?
Want good gas mileage so I don't want to choke it down too much..... using the stock H1C turbo (for now anyway)
which I have read seems to be a pretty minimal performance turbo- so I don't want to lug it down any more with
the muffler.......
Any suggestions ? Noise volume not the first priority- but I wouldn't mind a good deep gutsy sound !

Tim
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Re: reccomendations for mufflers

Postby CumminsPower59 » Thu Sep 10, 2015 5:01 am

None :mrgreen:

These things really aren't that loud, but if you want some sort of sound control, I would go with a resonator off a commercial application. They are basically a compact muffler of sorts, but qualify as a legal way of sound control in most areas. Otherwise, a commercial application of a straight through muffler will work. BC runs/ran a 5" commercial muffler on his 93.

My 91 currently has a 4" system, no muffler. Cruising down the road, all I hear is the engine...not the exhaust.
Ike

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Re: reccomendations for mufflers

Postby ellis93 » Thu Sep 10, 2015 5:01 am

Muffler? What's that? :lol:
93 D250 ,5 speed,4.11s,k&n autometer tach pyro trans boost guages,GDS 60mm h1c 14cm,honed 5x10,hplp/reg,1/8 timing,M+H M2 fuel pin, tims cooler tubz
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Re: reccomendations for mufflers

Postby BC847 » Thu Sep 10, 2015 2:04 pm

From one of my threads over at the DTR:

When I recently Bombed my heap, I planned to include means of keeping things quiet. I didn't want any low rumble at all. A sleeper's sound if you will. ;)

With the hot-rod turbo, manifold, injectors, 4" pipes, etc, I didn't want to restrict things.

So I did a little homework:

[QUOTE=BC847]
Code: Select all
CFM  =  [u]Engine Displ (cu in)  x  Full Load RPM  x  Eff  x  (Exh Temp F + 460)[/u]
                                  C  x  941760

CFM = exhaust flow rate in cubic feet per minute
Efficiency  =  .85 for naturally aspirated engines
Efficiency  =  1.4 for turbo-charged engines
Efficiency  =  1.2 for engines with scavenging blower
C  =  1 for two-cycle engine    C  =  2 for four-cycle engine

If exhaust temperature is not available, use:
T  =  1200F for gasoline engine
T  =  900F for diesel engine


With the above, we're moving right at 1332 CFM through the exhaust system at 3000rpm.

In a perfect world, we'd be able to move all that through the plumbing with no restriction. The closest to that is the straight-pipe system.

As far as noise control goes, (note, I have no first hand experience with any of the brand-name systems), straight-through/glass-pack type mufflers (resonators) attenuate high frequency noise. They let the low rumble through. The baffled type mufflers attenuate the low frequency noise. While they do mute the high frequencies some, they also tend to contribute some with the baffles (it's weird science, do a Google). That's why you see both devices on the really quiet vehicles.


OK. ;)



I've found that (outside of the brand-name packaged deals), many kits offer something like this; Muffler 4" In/Out 8.5" Diameter X 34" Body Length (Link).
Code: Select all
Rated Flow LR (CFM):  1800
Rated Flow MR (CFM):  2546
Rated Flow HR (CFM):  3119
Back Press LR (In Hg):  1
Back Press MR (In Hg):  2
Back Press HR (In Hg):  3
Attenuation (dBA):  8-12


Note: The rated flow shown, Low, Medium, and High, is at a given back-pressure (resistance to flow). That back-pressure is presented in Inches of Mercury (In Hg). 1 In HG = 0.4911541 psi, or just shy of 1/2 pound pressure.


In the Donaldson product line, that muffler is one of the highest flowing in a four inch pipe system. But it's also one of the loudest at only 8 to 12 db attenuation.



OK



Using the Attribute Search (Link) feature of the Donaldson website, I found one muffler to be the quietest while still maintaining a high flow with the least back-pressure.

This one: M110189 (Link). I call it the BHM (Big Honk'in Muffler)

The specs are:
Code: Select all
A - Inlet Diameter (Inches):  4
B - Body Diameter (Inches):  11
D - Overall Length (Inches):  41.25
E - Outlet Diameter (Inches):  4
Rated Flow LR (CFM):  1050
Rated Flow MR (CFM):  1485
Rated Flow HR (CFM):  1819
Back Press LR (In Hg):  1
Back Press MR (In Hg):  2
Back Press HR (In Hg):  3
Attenuation (dBA):  19-25
Product Type Description:  Muffler, Round, Style 2
Primary Application:  FORD MEDIUM DUTY TRUCK

Gross Weight in Pounds    35.5
Gross Length in Inches    45.5
Gross Width in Inches    11.8
Gross Height in Inches    11.8
Country of Origin    US


As you can see, it flows the required volume with under 1 pound pack-pressure. AND, it attenuates the low frequency noise 19 to 25 db. A BIG drop in noise.

Now, it IS a Big Honk'in Muffler! :o

With a gross length of 45.5", and a diameter of just under 12", it's gonna be a close fit under my 1st gen (250 CC long-bed / Your mileage may vary). It's also a Round, Style 2 muffler, meaning it's inlet and outlet are not centered. With that, you'll most likely have to move your pipes a bit to get them to plug in.



Anyhoot, after installing THIS (Link) exhaust pipe kit, I installed that boy. I'm using resilient rubber mounts that I attach to the stove-pipe with regular U-bolt/clevice clamps. The stove pipe's connected with the band clamp deals.:

Image


There's another mount right behind the muffler. Some custom cut 90's allow tight turns to get over the axle:

Image


You can see the rear mount here:

Image


There's just enough room to clear a full sized spare, and dump three inches behind the tire:

Image


There's about an inch clearance between the top of the muffler and the bed frame rails. The bottom of the muffler sits higher than the transfer cases frame.

Image

The system is VERY quiet at the exhaust outlet save subtle high frequency turbo sounds (see above homework) be it idle or WOT. The strongly predominant sound from the truck originates under the hood. In the cab, all you heard is the engine up front.

. . . . . . . NICE! :cool:[/quote]
David

1993 12mm VE Fueled W250 CC, Green
12.67 @ 103.35
Your basic farm truck ;)
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Re: reccomendations for mufflers

Postby jethro » Fri Sep 11, 2015 8:42 pm

I JUST remembered that the guy who sold me the engine included a 4 inch muffler like that which he said that the muffler and pipes was some kind of Banks brand kit. I havnt looks at it really close yet to see how much rust it has. BBBBut its HUGE.
It is at least 12 inches across and maybe 4 feet long. He never mentioned what it was off of. The motor had an Allison attached too- (plus a spare) so it sould have been a bread truck part maybe (?)
If I used that I would have to step up from 3 ot 4 after the headpipe. (which should be easy enough)

My motor isn't even loud (seemingly) even with a 2 foot pipe on it.

Will investigate the Donaldson ! Thanks
Tim
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Re: reccomendations for mufflers

Postby PToombs » Sat Sep 12, 2015 4:09 pm

It may not be loud to you, but stand behind it as it drives away and you may change your opinion! ;) I deleted the muffler from mine early on and ran a 3" straight pipe out the back, it wasn't real loud, just louder when you got on it than normal.
pete

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