Lakeside53's --361 muffler mod w/photos

[Lakeside53]

If you're talking about the muffler screw plugs: 1135 145 9001

 

[manual]

Yes Sir thank you.
I should have the Sthil Dealer look the parts up himself But I like the way he looks at me when I tell him the part numbers. "It's Priceless"

 

[Lakeside53]

Yes, its great as dealer also - if you give me the wrong number, you're stuck with it :hmm3grin2orange:

 

[JUDGE1162]

First this should be a sticky (the Moderators show take note this is a great post!!!!!!!!!!!!!!!!!!)


Second for us not so handy are there companies or individuals that do this type of work? I am very interested in doing this to my saw but I do not weld, is they a way that does not include welding?

I know I should have paid more attention in shop class:bang: :bang: :bang:

 

[computeruser]

Good post. Definitely a stickey. And when I finally get my Chainsaw FAQ website put together, I'll be asking for permission to borrow some of these pics and write-ups!

 

[JUDGE1162]

I was researching on several web-site and came across this

"The 455 is a new emission compliant stratocharged design and may not respond to the standard muffler mods. The 455 has a horizontally split crankcase. There are two intake ports and an extra transfer port. The second ports draw air only into the combustion chamber to allow a complete burn of that 30 percent you mention.I believe the muffler is also equipped with a cat which limits mods.The carb may also be fixed jet"

Is this true that the 455 Rancher is not modifiable?

 

[computeruser]

I was researching on several web-site and came across this

"The 455 is a new emission compliant stratocharged design and may not respond to the standard muffler mods. The 455 has a horizontally split crankcase. There are two intake ports and an extra transfer port. The second ports draw air only into the combustion chamber to allow a complete burn of that 30 percent you mention.I believe the muffler is also equipped with a cat which limits mods.The carb may also be fixed jet"

Is this true that the 455 Rancher is not modifiable?

Where did you find this info?

Not sure about the carb issue, but cats are regularly removed from the muffler in the course of modifications.

 

[JUDGE1162]

Would hate to cross post forums names, I have checked out quite a few, the one I found it on was a smaller site, which did reffrence this Site as the place to go for some answers.

It seems like people have done mods to 455 ranchers before but no sure if it does more harm than good.

 

[vegaome]

Howdy folks.

I just could not resist drilling some hole in my muffler after reading all this muffler mod info. I have two Echo CS-510 chainsaws. I bought them both used from different people about eight months apart.

Knowing what I know now I probably would of passed on the first one as the plastic near the muffler was burnt some. I did not pull the muffler to look at the cyclinder, piston and rings. I just cut a few logs and and bought it. It is scorched a little after looking but still pulls 148 cold on the compression test. As this is now my back up saw I thought I will fiddle with it.

I pulled the limiter caps and now drilled ten 1/8 inch holes in the muffler. Five on each side of the front. I will try to adjust the carb in the moring and maybe cut some wood. I used it all last year to cut my wood. Not sure if it was good to drill a bunch of little ones verses a big one but we will see.

I have a friend with an oxy-accetaline torch and some coat hangers if I have to reverse it.

Since the saw has been run pretty hot before and there is some scoring do you think it was safe to mod the muffler?


Any thoughts on ten little holes verses a couple of bigs ones?

Since I don't have any screen I thought it would help keep debre from getting in. I remember as a kid an old lawn mower we had with a muffler with many holes in it. Of course they were in a more symetrical pattern than mine. I just used my old stanley turn by hand crank drill (you know a WV cordless drill).

My second saw is in real good shape so I wont experiment with it, for now. Thanks all and have a good evening.

v/r
Mike

 

[Lakeside53]

Where did you find this info?

Not sure about the carb issue, but cats are regularly removed from the muffler in the course of modifications.

Why would they need a CAT if the 455 is a stratocharged design?? Something isn't right... and yes, if it is a true stratocharge, then it won't respond well to the muffer mods of old...

 

[JUDGE1162]

Why would they need a CAT if the 455 is a stratocharged design?? Something isn't right... and yes, if it is a true stratocharge, then it won't respond well to the muffer mods of old...

Please explain to a 2 stroke newbie, why if it is a true stratocharge, then it won't respond well to the muffler mods of old?

From my understanding and please correct me if I am wrong!!!!!!!!

All stratocharged mean is there is an extra "cycle" where air with no gas/oil mix is pushed into the cylinder to push out the exhaust gas to cut down on "blow by" wasted extra fuel/oil being pushed out with the exhaust which happens in a standard 2 cycle motor.

I know it causes lower max rpms as the extra cycle of air with no fuel takes time to happen. But I am not sure why a standard muffler mod would not work.

 

[timberwolf]

Any thoughts on ten little holes verses a couple of bigs ones?

10 small holes of the same area as one big hole will flow less because restrition to flow is highest along the edge of an orfice, more small holes has a longer edge than one big hole of the same area.

However scavenging can be affected by too big of a single direct opening allowing fresh charge to escape the confines of the muffler, so in a way smaller openings cold be incorporated to minimize losses, but it is going to be complicated as how much of the fresh charge gets out into the muffler and how much gets sucked back into the motor depends essentially on the scavenging efficiency and design of the saw, how dilluted the escaping fresh charge becomes after entering the muffler depends on the shape and design of the muffler. Realy need to look at the flow and mixing of charge and exhaust in the muffler. The more the fresh charge dillutes into the exhaust, the less can be recouped. Run a saw with no muffler at all, and it has less power than with a typical muffler as too much charge is being lost to the suroundings and not recovered during scavenging.

The area of 10 small holes will need to have a greater area than one big hole to give the same flow and back pressure.

 

[twoodward15]

So, I've got this McCullock timber bear 55cc saw that I use on my home made CSM. It's under powered for the job but runs good and gets it done. I didn't pay anything for this saw, so it won't be much of a loss if this doesn't work. Should I do it? I need more power. Anyone have a guess as to how much more power I will get if I do this mod? Where do I get this spark arrester screen?

 

[timberwolf]

Older Pre EPA saws pick up less as a rule because the exhaust are big to start with.

A new cat style muffler may gain 25-30% with a stock chain, 40% with a race chain. How much you gain depends on your chain, opened muffler will change the RPM and torque. If your chain is right you will get more bang for your buck.

 

[twoodward15]

since I am new to this and wanting to do the muffler mod, can I simply just drill another hole in my muffler? I read the first post and the OP (thanks for the info by the way, I've been wanting to do this for a while now) says that it is the simplist way to get it done. Do I need to open up my muffler? I've never had the muffler off this saw, so I don't know what it looks like. Where do I get the screen from? Back to the horsepower thing. Are we talking .1 h.p. or .5 h.p. or more? Any guess would be fine, I'm just trying to grasp some reality here for my own estimations. Thanks for the help. I'll keep asking questions I'm sure. I am going to try to get one saw done tomorrow and I also have a homolite like the one in the movie that I am going to do wednesday if all works out.

 

[SRT-Tech]

would it be worthwhile doing a mod on my Husky 61 muffler? Its a 2 piece, with removable baffle plate/screen.

 

[JUDGE1162]

YEAH, that would be an easy mod, you might not get as much gain as on a new saw with all the EPA crap but you should get some improvement with little effort on a two piece carb.

 

[SRT-Tech]

there is (if i rememebr correctly, still a bit foggy) about ten holes in the baffle, with mesh covering them. My plan is to remove the mesh from the ten holes, which will open up the flow a bit , and then make a spark arrestor cover on the exit side of the muffler. sound about right so far? (plus a carb tune..)

 

[timberwolf]

You gain HP in the form of RPM, torque may be about the same or slighly raised, but RPM shifts up 1000 RPM. This + more horse power but also higher chain speed which = faster cutting. Because a good part of the gain is made in RPM some people claim 10% others 25% or more for the same saw, it depends on cutting style and your chain, if you take a muffler modded saw and lug it to the botem of the power band, it will have no more or little more than stock. Try to run a 5 foot bar with a dull chain and gains will be next to nothing. Run a sharp chain and short bar that will work well at high RPM and you will see bigger gains.

 

[twoodward15]

OK, I did the muffler mod on my homolite 33 cc saw today. I haven't cut any wood with it yet, but it definately runns faster and louder. It seems to actually run a bit smoother as well, but who knows. This weekend it'll cut some wood. Hopefully tomorrow I will get to do my McCulloch.