# Dual Port Mufflers, A Comparison



## MasterMech (Feb 7, 2013)

For all those wondering how far off a dual-port muffler for a MS440/460 (or the 044/046) is from the standard US muffler.  Check it out.  (Dual-Port muffler is standard equip. on the Austrailian MS460 Magnum)






The USA OEM muffler vs. the Oz Dual-Port.  This is a Stihl OEM part, not the NWP aftermarket unit.





The difference in the side ports alone is massive.





While the USA muffler isn't very restrictive inside, the Oz muffler is even less so with no deflector at all.


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## StihlHead (Feb 7, 2013)

You can also just get the Canadian 460 DP cover and leave the stock muffler base or a lot less money. My 044 had an empty muffler base in it and the DP CDN 460 cover bolts right on with no modification needed (except tuning the carb, as it will be bad ass and need to be a lot richer). My CDN DP 460 cover looks exactly like that one.


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## MasterMech (Feb 7, 2013)

The covers very well may be the same however you'll notice that the size of the side exhaust port is very different. The Oz muffler's port is roughly the size of a nickel while the USA muffler has the much smaller (3/8" or so?) hole and a narrow slot.  Does your muffler can look like my original?

The Oz muffler cost me about $45.


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## Boog (Feb 7, 2013)

Thanks for the info guys, I'm going to go one of these two routes with my 440 and 460.  Also looking to rig one up for my modified 036 "Pro".  I've also been watching all the cylinder porting videos on Youtube too.  There are a lot of them up there with a lot of good info and tips.  It definitly looks like something I'm going to try myself, probably on one of the old 031AV first as practice.  Just do more of a "good cleanup" versus an all out maximum porting job.


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## HittinSteel (Feb 7, 2013)

Good post MM. Looks like a pretty easy conversion from U.S. to the OZ with a dremel.


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## MasterMech (Feb 7, 2013)

HittinSteel said:


> Good post MM. Looks like a pretty easy conversion from U.S. to the OZ with a dremel.


 
The angle is a bit funky but yeah, punching another hole in the side of the US muffler or enlarging the existing one and using the ported front cover would certainly make for a decent can indeed.  Could even cut or rip out the internal deflector.


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## Couderay80 (Feb 7, 2013)

Where does one get this Oz part from. Is the above Stihl number ( 1128-140-0616) for this dual port? I would like to use a Stihl part if possible. Thanks


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## StihlHead (Feb 7, 2013)

MasterMech said:


> The covers very well may be the same however you'll notice that the size of the side exhaust port is very different. The Oz muffler's port is roughly the size of a nickel while the USA muffler has the much smaller (3/8" or so?) hole and a narrow slot. Does your muffler can look like my original?
> 
> The Oz muffler cost me about $45.


 
My muffler base is the factory 044 one which is different than the base of the 046/460. the IPL shows different numbers. The original flat muffler cover is the same though.


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## StihlHead (Feb 7, 2013)

Couderay80 said:


> Where does one get this Oz part from. Is the above Stihl number ( 1128-140-0616) for this dual port? I would like to use a Stihl part if possible. Thanks


 
Yes, that is the Stihl PN in his part in the photo, and it matches the Stihl 046 IPL for a CDN/AUS complete muffler. If you just want the DP cover that I have on my 044 it is Stihl PN: 1128 140 0801

$45 is cheap for a full muffler. I think I paid $30 just for the DP cover.


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## MasterMech (Feb 7, 2013)

Couderay80 said:


> Where does one get this Oz part from. Is the above Stihl number ( 1128-140-0616) for this dual port? I would like to use a Stihl part if possible. Thanks


 
You should be able to order it from any dealer or comb eBay for one.




StihlHead said:


> $45 is cheap for a full muffler.


 
Yessir. Indeed it is.


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## DexterDay (Feb 7, 2013)

There is a hole on the front of the cover too? No. That's the Dual (2nd) port?

My DP has the factory port and a second port on the opposite side of factory port, with deflector.


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## MasterMech (Feb 7, 2013)

DexterDay said:


> There is a hole on the front of the cover too? No. That's the Dual (2nd) port?​


 
Yup.  There are aftermarket mufflers with the same configuration and I've also seen the ones like yours.


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## StihlHead (Feb 8, 2013)

DexterDay said:


> There is a hole on the front of the cover too? No. That's the Dual (2nd) port?


 
There is a vertical slot on the muffler cover, yes. It is the dual port on the Canadian/Aussy Magnum saws. That is the easiest power upgrade to an 044/440 & 046/460 that there is. No modification needed, just bolt it on, re-tune the carb and you are done.


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## DexterDay (Feb 8, 2013)

StihlHead said:


> There is a vertical slot on the muffler cover, yes. It is the dual port on the Canadian/Aussy Magnum saws. That is the easiest power upgrade to an 044/440 & 046/460 that there is. No modification needed, just bolt it on, re-tune the carb and you are done.



The one I bought has another hole, opposite factory with deflector and arrestor. Also, there is no deflection plate on the inside of the muffler.


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## MasterMech (Feb 8, 2013)

DexterDay said:


> The one I bought has another hole, opposite factory with deflector and arrestor. Also, there is no deflection plate on the inside of the muffler.
> 
> 
> 
> ...


With an OEM cover plate?  Swap that out for the dual-port cover and you'll be running a triple-port muffler.   (don't do that, prob too much port area for the saw.)


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## DexterDay (Feb 8, 2013)

MasterMech said:


> With an OEM cover plate?  Swap that out for the dual-port cover and you'll be running a triple-port muffler.   (don't do that, prob too much port area for the saw.)



After further investigation. The DP I have, Has the Large Hole like the Cdn/Aus Muff and the Opposite hole, is the same size. 

Looks to be about 5/8"-3/4" hole, compared to the 1/4"-5/16" hole from the factory (fac muff also has a small slit in front of small hole) 

I thought I might start looking for the Cdn/Aus Muffler. But what I have now prob flows just as good, if not better. I could Definitely tell a difference after I install it. Snappy, Loud, and gained another Nad 

Terrible phone pic


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## HittinSteel (Feb 9, 2013)

the throttle response is the real noticeable part after a muffler mod


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