# 550XP Muffler Mod Thread



## procarbine2k1 (Nov 7, 2012)

I have seen some 550XP muffler pictures and ideas floating around here a bit, thought we could condense and have a thread for your modification/ how to/ results.
I will try and get a couple pics up of mine this week sometime. I finished mine last night, took some pictures with my cell, but need to purchase another phone card to transfer them to my pc (I dont have a text or email plan).

I cut my deflector off of the muffler, (like opening a soup can) and drilled a 3/8 hole next to the stock outlet. Cleaned this additional port up, welded the deflector back in place and added a flap to extend the deflector. Performance gain is far beyond I have seen with any other muffler modification on other saws I have seen or done. Im into stock appearing, I fought with my welder a little last night, so ended up with a grinder in my hand as well. I really need to get my table up to this shop, its a real treat not having the work area to weld in. Looking forward to gathering up some pictures and or ideas. Hope some of you guys chime in.
Feel free to post up times/ gains.


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## Hermann (Nov 7, 2012)

:msp_drool:

opcorn:


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## blsnelling (Nov 7, 2012)

Like I mentioned in another thread, this is one saw that I can't see selling a port job for. Most of the gains are right in the muffler mod. With a burr with a 1/8" shaft, you don't even have to cut and weld the baffle.


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## mweba (Nov 7, 2012)

blsnelling said:


> Like I mentioned in another thread, this is one saw that I can't see selling a port job for. Most of the gains are right in the muffler mod. With a burr with a 1/8" shaft, you don't even have to cut and weld the baffle.



Yup, get in there without cutting the deflector.

They once said gains were not worth the trouble in the 7900.


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## blsnelling (Nov 7, 2012)

mweba said:


> They once said gains were not worth the trouble in the 7900.



This is true


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## Tzed250 (Nov 8, 2012)

blsnelling said:


> Like I mentioned in another thread, this is one saw that I can't see selling a port job for. Most of the gains are right in the muffler mod. With a burr with a 1/8" shaft, you don't even have to cut and weld the baffle.



My 550 was much stronger ported vs. just MMed. Remember when the 441 was junk because it couldn't be modded?

The easiest way to get good gains to the 550 muffler is to cut the two sides of the deflector with snips, peel it back, then port the can. Bend the flap back down and TIG weld the seams. Less than 1/4 inch of filler rod used. Pics from a mod I recently did for a member here:




Untitled by zweitakt250, on Flickr




Untitled by zweitakt250, on Flickr




Untitled by zweitakt250, on Flickr


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## Jet47 (Nov 8, 2012)

I simply added another port on the starting side of the muffler. Saw responded very well.


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## Tzed250 (Nov 8, 2012)

My reason for not adding a port on the left hand side is that I don't want the gasses vented closer to the operator or toward the wood. Plus, some folks like the muffler to retain a stock appearance. The customer in my post desired just that.


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## Jet47 (Nov 8, 2012)

Tzed250 said:


> My reason for not adding a port on the left hand side is that I don't want the gasses vented closer to the operator or toward the wood. Plus, some folks like the muffler to retain a stock appearance. The customer in my post desired just that.



Good points.


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## procarbine2k1 (Nov 13, 2012)

blsnelling said:


> Like I mentioned in another thread, this is one saw that I can't see selling a port job for. Most of the gains are right in the muffler mod. With a burr with a 1/8" shaft, you don't even have to cut and weld the baffle.



I wanted to have a good look inside, and have a little room to work. Turned out nice and clean (I might be a little on the OCD side on muffler appearance), a little on the loud side though... And I definitely agree with you 110%, these saws REALLY respond to a little muffler work. Spent a little time in the woods with it yesterday. Hands down the most impressive saw for the size I think I have had my hands on.


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## rullywowr (Nov 13, 2012)

Totally agree with the above (under the deflector method). Pull muffler, pull screen, pull the hood up a little bit and sneaked in a 3/8" drill bit at an angle under the deflector to the right of the original port. Get all chips out (important!) and replace screen/muffler. Worked really well and a noticeable improvement in performance and overall "attitude." I did catch the drill bit ever so slightly on the deflector and knock off a little black paint on the deflector but this is my firewood workhorse and not a ladies handbag.


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## TermiteBuffet (Nov 20, 2012)

i just did my 550 lifted the deflector and removed everything on the right of the exit hole , with a dremel i'm now wondering if i left power on the table?:msp_mellow: by not gutting the whole thing ,has anyone done the small hole , ran it and then went back and gutted inlet and outlet? If so were gains noticed ? I did my 562 the other night , i took all i could reach with a dremel out inlet and outlet , it's basically a can now :msp_thumbsup:gonna put them both in the wood tommorrow, morning ,Unless ya'll talk me into going back into the 550 muffler then i'll be slightly delayed ? Advice? Questions ? Comments ? Termite


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## Joe Kidd (Nov 20, 2012)

In regards to the 550, I think we've found that a gutting will only make it louder, but some others may input on this.
The 562 will sound like a nitro burner. :msp_thumbsup:


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## Tzed250 (Nov 20, 2012)

What Jeff said. I think I've done five of them now and so far all are happy. The inlet is a fairly open design so I don't think it is a roadblock. If there is more power left in the can I think it would come at the expense of massive noise.


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## TK (Nov 20, 2012)

The MM does a good thing for the 550, more than just noise


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## komatsuvarna (Nov 20, 2012)

I probably didn't gain anything by doing it, But I gutted the hell out of my muffler. Took 90% of the baffle out and took the pipe thinggymajig out too. Opened it up all I could and still keep it under the factory deflector. It's no louder than my other saws and isn't much louder than a stock 550. Also still running the OEM spark screen.

Took awhile to get all that crap out too!


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## blsnelling (Nov 20, 2012)

I opened up the baffle quite a bit and only made the saw louder.


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## Joe Kidd (Nov 20, 2012)

In my personal comparison, I believe the 562 muff has more restriction than the 550 and can benefit from removing inlet and outlet baffle material. Also the fact you've got 10cc more puke to dump!


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## TermiteBuffet (Nov 20, 2012)

What was funny i was making my first grinds/ cuts on the 562 muffler and the bit came out and fell into the muffler dang that was kinda tough getting out now i can drop a marble in it and will roll right out .....And Joe that 562 does sound like a top fuel car We must come to a conclusion here...... the muffler is at ya'lls mercy...... i did fire the 550 this evening [ for the first time ] sounds good got a nice crack/ pop to it. Termite


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## TK (Nov 21, 2012)

I've heard of some sweet gains on a 550 ported as well. The words used may or may not have been "keeper" and "stopwatch." Time will tell. No it's not mine. But mine maybe next....


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## Tzed250 (Nov 21, 2012)

My ported 550 puts a grin on my face every time I run it!


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## Jet47 (Nov 21, 2012)

After my MM, my 550 is the coolest sounding saw I have ever owned.


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## Fire8 (Nov 21, 2012)

What is the best way to get all the metal shaving out


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## Tzed250 (Nov 21, 2012)

Compressed air.


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## Fire8 (Nov 21, 2012)

Tzed250 said:


> Compressed air.



Well if I can find the right size Allen in my tool box its going to happen today


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## Fire8 (Nov 21, 2012)

Tzed250 said:


> Compressed air.



Does the gasket go between the metel and cyl or muffler and metal


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## Joe Kidd (Nov 21, 2012)

Fire8 said:


> Does the gasket go between the metel and cyl or muffler and metal



Between the metal guard and muff. cyl-metal guard-gasket-muff, in that order.


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## KenJax Tree (Nov 21, 2012)

Jet47 said:


> After my MM, my 550 is the coolest sounding saw I have ever owned.



I've never heard a MM 550 but i like the sound of my MM 372's


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## Fire8 (Nov 21, 2012)

Joe Kidd said:


> Between the metal guard and muff. cyl-metal guard-gasket-muff, in that order.



Thanks 550 done turkey done just waiting on my mastermind 365xt also thanks randy

View attachment 263462


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## Jet47 (Nov 21, 2012)

KenJax Tree said:


> I've never heard a MM 550 but i like the sound of my MM 372's



Its soothing in an angry sort of way.


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## TK (Nov 21, 2012)

Thought I had a vid, I don't. Just this pic.


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## Tzed250 (Nov 21, 2012)

For your viewing pleasure:

[video=youtube_share;6vZQcHGODFo]http://youtu.be/6vZQcHGODFo[/video]


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## Fire8 (Nov 21, 2012)

After the mm on the 550 today it was like I 
Got a new saw for cheap


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## Tzed250 (Nov 21, 2012)

Fire8 said:


> After the mm on the 550 today it was like I
> Got a new saw for cheap



Didn't know there was a 60 under the hood, huh?.


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## Fire8 (Nov 21, 2012)

Tzed250 said:


> Didn't know there was a 60 under the hood, huh?.



O I like the way it sounds:msp_biggrin:


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## A.E. Metal Werx (Nov 21, 2012)

I've posted a thread on this muffler mod before but I think it fits well here also. It has been stated numerous times that gutting the whole muffler really makes no difference, I can vouch for that. I ran the saw for a while with just the added port and ran it a lot with style of mod with no power difference and this mod is no louder then one with just another port added. I wanted it be different and this is what I came up with.


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## born to hunt (Jul 21, 2015)

Nice thread. If I do a similar muffler mod, I assume I will need to retune the saw. My 550 xp has auto tune. Will it therefore tune automatically? Does anyone have any experience with this?


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## KenJax Tree (Jul 21, 2015)

It'll retune itself


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## born to hunt (Jul 22, 2015)

Check me on this: I did the MM on the 550xp AT. It sure screams... Maybe too much? Seems to 4 stroke at WOT and as soon as it bites into the wood, it sounds perfect. Runs a bit loud. If this is the way it's supposed to be, I'm thrilled. It seems to have more snort for sure. And the cool factor just went way up!


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## KenJax Tree (Jul 22, 2015)

Thats how its supposed to be. Enjoy!


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## born to hunt (Jul 22, 2015)

Now I'm trying to talk myself out of having someone woods port my 346xp. Not having much luck. 
The thing that's holding me back is parting with the saw for that long...


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## mbrick (Jul 23, 2015)

Can we get a few more pics? Like to understand better where to add a second hole. A lot of old photos seem to be missing 

There have been enough posts that I am guessing it doesn't just sound louder/faster, but actually is?

I like the idea of prying it open, working inside, and TIG welding the deflector seam back closed.

What kind of paint holds up to the heat?


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## born to hunt (Jul 23, 2015)

I don't have a TIG welder, nor the skill to use one. If I get by the saw again I can post a pic. 
IMHO, if this is a working saw, there is no weld time required. I removed the 4 muff bolts, removed the screen from the muff and pryed open the deflector enough to get a drill bit under it. There is only room to the right of the existing port to drill a 3/8" hole. You could use a dremel also with the right grinding burr. I had to use a smaller diameter bit first to center the hole, and drilled it out. Once the hole was drilled, I smoothed out the edges of the new hole, reinstalled the screen, and reinstalled the muffler. I did end up with bend marks on the deflector, but I really don't mind the way the exhaust system looks on any saw. It was not as pretty as some of the gurus on this site like it, but it worked and I got a saw with seemingly more speed and torque. 

I did not tach the saw before and after, nor did I measure torque, but it sure seemed to cut faster and rev a little higher, faster.


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## mbrick (Jul 23, 2015)

Thanks for the explanation and feedback!

If anyone wants theirs TIG welded back up after modding, send it over with prepaid postage and I'll take care of it.


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## born to hunt (Jul 23, 2015)

Forgot to stress: get all of the metal shavings out via compressed air, per the above posts.


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## Big_Wood (Jul 23, 2015)

I welded a larger deflector on mine with the whole area under it cut open. Also removed near all of the baffle with a long shank bur which I shouldn't have. She be real real loud. My 562 is done the same way. Spark screen intact. Hardly ever use the 550 compared to the bigger saws but I still refuse to get rid of it .


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## weedkilla (Jul 24, 2015)

It's not a muffler mod, but I cut a 016" gasket and got the squish down to 020"

Added a nice little extra gain, no 10mm compression gauge so can't say exactly.
Bit faster, and a heap more torque.


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## GitWood (Dec 23, 2015)

I know that there is a ton of info out here on 550xp muffler mods, but I can't seem to find any reports of quantifiable improvements like timed cut comparison before and after the muffler mod. Lots of anecdotal evidence like "really woke up", etc., which sounds good, but doesn't really help me to decide if it is really worth the cost. By cost I mean extra noise, voided warranty, risk of stripped threads, shavings in the cylinder, etc. I know that these risks aren't high, but still a factor. Anyone know of any measured results?


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## mbrick (Dec 29, 2015)

I also did not find anything quantitative. Only qualitative, sadly...

I remember seeing some posts about a chainsaw dyno but I'm not sure what happened to the project.

To comment on your feedback: I can't tell a difference with earmuffs on, the risk of stripped threads is very low unless you overtighten the muffler bolts or cross thread them like a tool, and blow it out well and you should be good on shavings.


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## procarbine2k1 (Dec 29, 2015)

GitWood said:


> I know that there is a ton of info out here on 550xp muffler mods, but I can't seem to find any reports of quantifiable improvements like timed cut comparison before and after the muffler mod. Lots of anecdotal evidence like "really woke up", etc., which sounds good, but doesn't really help me to decide if it is really worth the cost. By cost I mean extra noise, voided warranty, risk of stripped threads, shavings in the cylinder, etc. I know that these risks aren't high, but still a factor. Anyone know of any measured results?



If you're paying someone to do it, I would say it isn't worth it. Adding an additional port to the stock muffler (under the deflector) yielded 10-12%.

I never compared the one I have from Alex, but I would say it gained a little over my last one. Problem with these mufflers, is that they get loud, FAST.

That is what is so impressive about the muffler I got from Alex. I don't know that it is much louder than stock. Cant queens are one thing, but I don't like a loud saw for work- and neither does anybody else around me.


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## gcdible1 (Feb 16, 2016)

Who is Alex? I'd be interested in having him maybe mod mine. Just don't want it crazy loud. My ms290 muffler mod was super loud. 


Sent from my iPhone using Tapatalk


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## procarbine2k1 (Feb 16, 2016)

gcdible1 said:


> Who is Alex? I'd be interested in having him maybe mod mine. Just don't want it crazy loud. My ms290 muffler mod was super loud.
> 
> 
> Sent from my iPhone using Tapatalk




http://www.arboristsite.com/community/members/a-e-metal-werx.26328/

He's top tier, good guy to boot.


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## gcdible1 (Feb 17, 2016)

The link u gave sent me to a thread about a 359 and 340. Didn't see him on there. Is he fairly close to oh?


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## procarbine2k1 (Feb 17, 2016)

gcdible1 said:


> The link u gave sent me to a thread about a 359 and 340. Didn't see him on there. Is he fairly close to oh?
> 
> 
> Sent from my iPhone using Tapatalk



I dont know what you clicked on, try that link again. It worked for me. A.E. Metal Werx is his AS handle, he is somehwhere in the midwest I believe.


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## mbrick (Feb 17, 2016)

Link works for me. Click on the information tab, and then start a conversation...


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