Author Topic: porting Stihl 361 pros and cons (Read 3420 times)

smith2bj · « **on:** March 02, 2009, 04:35:41 pm »

What are the pros and cons of porting the muffiler on a Stihl 361? And does it really give the saw that much more power?

Troutfisher · « **Reply #1 on:** March 02, 2009, 07:23:20 pm »

The pros would be a gain in performance, maybe 10% or so, and it will get rid of some heat. Some Cons would be more noise, it will get louder. you will have to re-tune the carb, and It may use a bit more fuel.

Troutfisher · « **Reply #2 on:** March 02, 2009, 07:34:30 pm »

I have before and after videos of a muffler mod on a MS361 on --Photos MUST be in the Forestry Forum gallery!!!!!--, I would link them, but can't figure out how

smith2bj · « **Reply #3 on:** March 03, 2009, 10:03:01 am »

Does it hurt the longevity of the motor though? I don't want to have to rebuild the motor every 5 to 10 years.

Rocky_J · « **Reply #4 on:** March 03, 2009, 11:40:01 am »

All the EPA regulations requiring saw makers to make the saws run super lean with ultra high exhaust temps will make the saws last forever. Removing those exhaust restrictions and providing the saw with adequate fuel and lubrication will cause the saw to burn up quicker.

chevytaHOE5674 · « **Reply #5 on:** March 03, 2009, 11:44:05 am »

If the carb is retuned it should not hurt the longevity of the motor, in fact the longevity should be increased. The saw is able to breath easier, and run cooler. All of my saws have ported mufflers and I have no problems with longevity.

Quote from: Rocky_J on March 03, 2009, 11:40:01 am

All the EPA regulations requiring saw makers to make the saws run super lean with ultra high exhaust temps will make the saws last forever. Removing those exhaust restrictions and providing the saw with adequate fuel and lubrication will cause the saw to burn up quicker.

Hahaha.

Troutfisher · « **Reply #6 on:** March 03, 2009, 12:12:20 pm »

My opinion is that a muffler mod will increase the life of the saw, it gets rid of a lot of heat.

Preston · « **Reply #7 on:** March 03, 2009, 12:52:17 pm »

I would have to agree al my saws have been ported and I've been doing it for 11 years.

smith2bj · « **Reply #8 on:** March 03, 2009, 04:44:25 pm »

Now is this something that I could do my self, have a friend who is good with motors or send it out to someone who is a professional with this?
What am I looking at for a cost and will I notice that much of a difference?

Troutfisher · « **Reply #9 on:** March 03, 2009, 05:31:23 pm »

It's pretty easy to do, as long as you're OK with a little welding or brazing, and know how to adjust a carb. Do a Google search, there's lots of info out there.

Rocky_J · « **Reply #10 on:** March 03, 2009, 05:41:47 pm »

Welding and brazing are unneccessary IMO. I own a half dozen engine ported saws, all with muffler mods as part of the deal, and only one of them has the stupid little pipe brazed in place. And it's the worst performing of the bunch!

A dremel tool and some thought is usually about all you need. Simply make the existing exhaust opening bigger and remove the internal baffles out of the muffler. A motor is nothing more than an air pump. Unplug the exit so it can pump more air.

chevytaHOE5674 · « **Reply #11 on:** March 03, 2009, 06:14:19 pm »

Quote from: Rocky_J on March 03, 2009, 05:41:47 pm

remove the internal baffles out of the muffler.

The 361 muffler is not two pieces like many others. So to open up the internal baffles you need to uncrimp and recrimp, and IMO braze it back together.

And to get enough port opening area in the 361 muffler it needs another port added.

Cut4fun · « **Reply #12 on:** March 03, 2009, 07:52:22 pm »

I had a 361 once with just 3 holes drilled in the front and the spark arrestor removed. The cage was still intact inside the muffler. Simple redneck mod.
This saw to date has still been the strongest running STOCK 361 I have ran to date.
I have ran several different ones with goofy little pipes with screens sticking out of them etc and it is really not needed IMO, just overkill.
Another easy 361 muffler mod without splitting the muffler (the cage inside the muffler of the 361 seems to flow pretty good with a stock saw), is a dime size hole or tad bigger on the left side (opposite of the other exhaust port) and screw a husky 288 deflector on it. So easy I call it Caveman muffler modding.

chevytaHOE5674 · « **Reply #13 on:** March 03, 2009, 07:59:49 pm »

If your cutting in dry conditions, or on most state and all federal lands you need a spark arrestor.

Rocky_J · « **Reply #14 on:** March 03, 2009, 08:13:48 pm »

Yup. Which means you need to figure out how to put a piece of screen over the hole. Not a big deal unless you get all fancy complicated and try welding a pipe into the muffler can.

Al_Smith · « **Reply #15 on:** March 03, 2009, 08:14:10 pm »

Quote from: Rocky_J on March 03, 2009, 05:41:47 pm

only one of them has the stupid little pipe brazed in place. And it's the worst performing of the bunch!

Some people think they look cool but I suppose those same folks like flame decals also .

Neither one does a thing to make the saw run better .

Strange how many folks get sucked into buying a cobbled up muffler thinking it will turn their stock saw into a screamin meany and all it does it make it loud .

chevytaHOE5674 · « **Reply #16 on:** March 03, 2009, 08:27:23 pm »

Quote from: Al_Smith on March 03, 2009, 08:14:10 pm

Strange how many folks get sucked into buying a cobbled up muffler thinking it will turn their stock saw into a screamin meany and all it does it make it loud .

I have a port on the opposite side of the muffler as the stock port. I used a piece of pipe with a spark screen from a BR400 backpack blower. The port went from ~64 mm^2 to 140 mm^2. Using timed cuts the saw IS faster than stock. Using an infrared heat gun the temps of the muffler and jug were also reduced. It is in no way cobbled together and in fact looks like the stock muffler should have.

Al_Smith · « **Reply #17 on:** March 03, 2009, 08:40:30 pm »

Perhaps and good for you .However numerous people have payed upwards of 90 bucks a pop for a muffler cover with a cute little pipe sticking out of it .

Just ask around about those little pipe things and see what folks say . All along a second port cut in them would have done better .

You want to get serious about a muffler remove everything inside it and just leave the shell .Leave a hole or series of holes equal to about 80-85 percent or so of the exhaust port area .If you want a screen ,make the hole a tad bigger .Richen up the carb until it 4 cycles and get with it .Then tell me how it runs .

chevytaHOE5674 · « **Reply #18 on:** March 03, 2009, 08:46:38 pm »

I cut up 5 or 6 mufflers for the 361 before I settled on just a second port on the side. To much port (and opened front cover) and the saw fell on its face and was annoyingly loud, to little and the gain was negligible. A second port of around 9/16" ID was the best gain (also backed up by members on another forum).

And correction the port area with a 9/16" port added is around 215 mm^2.

And where do people by "muffler cover with a cute little pipe sticking out of it" for a 361 that has a 1 piece muffler?

Al_Smith · « **Reply #19 on:** March 04, 2009, 05:42:13 am »

Quote from: chevytaHOE5674 on March 03, 2009, 08:46:38 pm

And where do people by "muffler cover with a cute little pipe sticking out of it" for a 361 that has a 1 piece muffler?

Correction on that statement .I should have specified mufflers in general not necessarily a 361 .

However I have uncrimped that style,gutted them and recrimped . It's kind of a pain in the behind to do but possible ----and no before you ask I've never done a 361 .

I do have a 2100 Husky to do though which should prove interesting and likely to be rather loud no doubt .

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Author Topic: porting Stihl 361 pros and cons (Read 3420 times)