MS361 WC dual port mod

[James Sawyer]

Finished my dual port 361 muffler mod. Installed a West Coast port. I cut and folded in a louver opening facing the front of the muffler, the area opening is ~ .63 in sq. (~the area of 7/16 hole). The open set back off the face of the can is .700" would have prefer to be at 1.0" but with the can seam it was limited. Looking at it now I might have gotten away with .900". I thought I'd start with that, 7/16" area opening its would be easy enough to open it more if needed. I wanted to get the reflection off the front of the can before the exhausted exited. I believe it will help with the noise and keep more of the back pressure and fuel in back of the cylinder. Guess we'll see how this works, I should have ran a test cut prior but didn't, I had the saw tore down for a good cleaning, clutch bearing lube, a full warp handlebar upgrade, felling spikes, bigger chip cover and 28" light weight bar. The muffler mod was one of those last minutes decisions. Adding the deflector in with another WC parts order. The goal is to get a little more heat out of the saw .. maybe a little more power assuming 5%? These WC deflectors require a little body and fender work them to sit flat if you use the threaded rivets. They bend easy enough to shape to the can. I chose the rivet option because I wanted to run the screen. Just to put it out there... I'm not sure how this will work out! I'm not going have any performance data... some muffler mods work some don't. Saw with modified muffler can burn more fuel and less performance. I'll post once I get the saw back together, tuned, I'll do a test cut. This is my main go to saw so I should know if it helped.

 

[StihlsawuserMS361]

Nice work on the MM. I'm on the bubble with mine. I spoke in another post regarding MM's. I know many use WCS on their 550I's. My 500 is quite loud with stock, even with in and over ear protection. How much louder , do you estimate your 361 is now?

I wonder if you'll have any chain oiling issues in going to 28" B&C?

 

[James Sawyer]

I like WCS products but the bark box product i'm still on the fence... haven't bought one.. so no experience none at all. Loud isn't what I was going for. I did mine because of the longer bar and help with the heat some. I was not expecting any huge performance change. This MS361 has OEM cylinder and is still pretty good shape and I could have ported it but it run pretty good as is. Plus I have bigger saws. When you remove your muffler, you'll see the cylinder exhaust port has lot material that can be removed to match the gasket, I was actually quite surprised and thought about it. I have a ported 038 but it uses lot more fuel. The muffler actually helps keep the fresh charge in the back of the cylinder as the exhaust exits and I didn't what to change that much so that why I was glad it wasn't running lean. I wanted the reflection off the front of the muffler is why I louvered off the side and reduce some of extra noise you get with DPM. I still don't know how this going work out until I tune it and do some cuts. I believe the oem oil will be fine with the 28" bar if not I may drill the bar or put in a larger pump MS460R. This saw cuts and oils fine with the 25" bar FC chain and its running about tank of oil with tank of fuel but I do have the oiler adjustment max out. I guess I could remove the pin and get little more oil out of the present pump. I'm not the expert on Muffler mods, I have one saw that ported and its running a modified muffler and it runs way better then stock but use a lot more fuel.

 

[StihlsawuserMS361]

Thanks for the detailed report on the muffler. I didn't realize it also helps keep the fresh charge in the cylinder.
I've always felt that the manufacturers' put the time into R&D before releasing the product. No doubt, they are smarter than I. Obviously they want their saws to last, limited warranty claims, and happy customers to continue buying their products down the road.
As far as porting, I had a sled that had mild porting done prior to my purchase. Really just never seemed to run as good as my buddy's similar. Always needed tuning it seemed. And it really liked fuel.Louder too. Maybe I'm once bitten?
My 361 has just been a great saw. Decent on fuel,oil pump maxed out and reliable.
The 500I is really in a class of it's own. I started bucking logs yesterday with the 361, went to the 500I when they approached 8"-10" and above. Most say it's a thirsty saw, I have to agree. But I also feel that the higher fuel consumption may be due to how fast the saw cuts and finishes up logs quicker.
If either were to be ported or MM, I would think fuel would go up, longevity would go down?
Thanks again for the info, keep it posted on the end result.

 

[HandLogger]

@James Sawyer ..... You might want to check out this thread regarding the MS361 and muffler mods. If your muffler doesn't work out for you, I can PM with information about where I got mine. If I had to estimate the power increase, it would be much more than 5-percent. Please let this thread know how things work out for you.

 

[James Sawyer]

I did buy aftermarket muffler from Amazon prior because I didn't want use the the OEM as others don't. However, the Amazon DP had no screens and thought what am I going to do with the OEM...I'll never go back to it. It's simple enough the way I did it to take off the deflector and change the opening. I should be about right but I need tune to really know. If anyone want the Amazon muffler ( "no" screens) I'll give it to them if they pay shipping.

 

[Wood Doctor]

I recall installing a dual port muff on an 046 five years ago. It was an immediate power improvement, so much so that a "friend" borrowed the saw and then never gave it back to me. He still has it.

I have to look into this muff for my 361, a tried and proven performer that I bought 12 years ago. It never has failed, but I'd like to pull a 25" bar with it on occasion. Maybe with this dual port on board it could do that. Seem reasonable?

 

[HandLogger]

I recall installing a dual port muff on an 046 five years ago. It was an immediate power improvement, so much so that a "friend" borrowed the saw and then never gave it back to me. He still has it.

I have to look into this muff for my 361, a tried and proven performer that I bought 12 years ago. It never has failed, but I'd like to pull a 25" bar with it on occasion. Maybe with this dual port on board it could do that. Seem reasonable?

@Wood Doctor ..... I'm very sorry that I missed this post, sir. The MS361 that we worked on came with -- and still has -- a 20" bar installed. After getting rid of the factory muffler and replacing it with a modified unit, it is clearly my "go to" overall saw! We own more than one brand of saw, so I'm no brand warrior, but, in my opinion, I suspect that a muffler modded MS361 would do a 25" bar justice ... and, by the way, we bought the saw I'm writing about 15+ years ago.