MS462 vs MS500i

[Moparmyway]

The actual size and locations of the holes actually would need to have a specialist engineer etc analyse and do performance tests. That is why the Stihl DP muffler that came stock on my saw in non USA versions are made the way they are. If I was going DP, I would get the stock OEM muffler. It would be interesting to see the test results of the noise to hole/s with screen combinations that I am sure Stihl engineers conducted are. How big can the hole/s get before noise gets too loud. I guess I could get a box of foam earplugs and hand them out to anyone that complains haha.

This!

Think Egan did all of them “engineering studies” ??

 

[Funky sawman]

Someone on AS or here did a test and after 120% muffler opening u gain nearly nothing

Is that with a usfs screen or not?

 

[ferris]

Is that with a usfs screen or not?

I don’t know

 

[Funky sawman]

On all the 371 and 372oe saws that I have muffler modded, with stock jugs, seem the best with 3 ports. The factory top one, then a reds97 deflector on the side, then a 3/4 by 1 inch hole out the front on the brace. All with screens of course. Without screens you have a hard time keeping the idle mixture set. I should say they are loud AF!!!!!!

 

[StihlMagnum440]

Someone on AS or here did a test and after 120% muffler opening u gain nearly nothing

Are you talking increasing the stock muffler hole 120 from what it is? Or are you talking making a hole 120 bigger than the actual exhaust port hole on cylinder? I thought the rule was like 80-90 % of the actual exhaust port hole on cylinder was max openings on muffler because a very slight restriction is needed for internals on engine to function properly.

 

[StihlMagnum440]

Think Egan did all of them “engineering studies” ??

I still think a very small restriction is needed for internals on 2 cycle to function properly. A straight pipe can be on but it could actually be slightly smaller where it connects on cylinder exhaust port hole. Yes I think most quality chainsaws and chainsaw parts are all engineered.

 

[MustangMike]

Are you talking increasing the stock muffler hole 120 from what it is? Or are you talking making a hole 120 bigger than the actual exhaust port hole on cylinder? I thought the rule was like 80-90 % of the actual exhaust port hole on cylinder was max openings on muffler because a very slight restriction is needed for internals on engine to function properly.

I'm pretty sure you will get different results with different cylinders and cylinder porting. (They are generally talking the % as compared to the exhaust port).

The factory muffler outlet on most saws (including 044/440) has changes significantly over time. (They were generally reduced to be EPA compliant).

A hotter muffler will generally burn the fuel more completely, reducing emissions. You will also lose power, and the saw will run hotter and may fail due to the excessive heat (typically a burned piston on the exhaust side).

The % will also change depending on if it is screened or not.

From my experience, a ported cylinder will generally benefit more from opening the muffler large amounts.

Open it too much on a stock saw and: it may not idle well; it may lack throttle response; it may lose torque in the cut; and it may burn excess fuel w/o adding any power.

That said, moderate increases in the muffler venting will benefit most saws, but sometimes a timing advance is necessary.

 

[Skeans1]

On all the 371 and 372oe saws that I have muffler modded, with stock jugs, seem the best with 3 ports. The factory top one, then a reds97 deflector on the side, then a 3/4 by 1 inch hole out the front on the brace. All with screens of course. Without screens you have a hard time keeping the idle mixture set. I should say they are loud AF!!!!!!

You guys didn’t do the dual side deflectors?


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[Funky sawman]

You guys didn’t do the dual side deflectors?


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This is my current saw on that platform

 

[Funky sawman]

On the other hand, the 357 likes just 2 exhaust ports, one factory, with the pipe cut of the muffler, and the 266 deflector on the cylinder side. I think some saws just like more open mufflers.

 

[Moparmyway]

You're thinking too hard.

I still think a very small restriction is needed for internals on 2 cycle to function properly. A straight pipe can be on but it could actually be slightly smaller where it connects on cylinder exhaust port hole. Yes I think most quality chainsaws and chainsaw parts are all engineered.

You didn’t answer the question, and what @sawmikaze said

You're thinking too hard.

 

[Skeans1]

This is my current saw on that platformView attachment 319390

Years ago we ran the triple ports with the factory one opened up and deflectors on each side of the muffler those always ran good. Some of the guys ran the front one but always were having to watch for starting bark on fire.


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[Funky sawman]

Years ago we ran the triple ports with the factory one opened up and deflectors on each side of the muffler those always ran good. Some of the guys ran the front one but always were having to watch for starting bark on fire.


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Only had issues with front muffler ports on very large timber, mostly because the saw sits in one spot for extended period and heats up the bark. Never an issue with 36 inch and smaller wood with a sharp chain and strong powerhead.

 

[StihlMagnum440]

I'm pretty sure you will get different results with different cylinders and cylinder porting. (They are generally talking the % as compared to the exhaust port).

The factory muffler outlet on most saws (including 044/440) has changes significantly over time. (They were generally reduced to be EPA compliant).

A hotter muffler will generally burn the fuel more completely, reducing emissions. You will also lose power, and the saw will run hotter and may fail due to the excessive heat (typically a burned piston on the exhaust side).

The % will also change depending on if it is screened or not.

From my experience, a ported cylinder will generally benefit more from opening the muffler large amounts.

Open it too much on a stock saw and: it may not idle well; it may lack throttle response; it may lose torque in the cut; and it may burn excess fuel w/o adding any power.

That said, moderate increases in the muffler venting will benefit most saws, but sometimes a timing advance is necessary.

Agreed. The manufacturers like Stihl have taken steps to make saws run cooler to compensate for the heat generating restrictive EPA mufflers..larger fins and a lighter flywheel engineered for higher air flow are two examples of this on my saw. A saw such as my 2007 Stihl 440 seems to be highly constructed for EPA constraints as evidenced by the single pencil hole outlet on the muffler. A saw like that should respond very positively to a well thought out muffler modification. Fortunately for me, Stihl sold the exact 12mm 440 to countries that did not require EPA approval and they came with an OEM dual port muffler! For the minimal cost involved, I think buying one of these Stihl designed and engineered dual port mufflers and trying it on my saw to see how loud it is may be in the future. With the new muffler that would be allowing more cfms (as you know airflow) but it only makes sense to switch the air filter to a less restrictive one although I am not sure that is needed ie the stock one may allow enough airflow. I know they made different Stihl air filters for my saw because when I went to purchase a new prefilter for the air filter on my saw, the counter guy gave me print outs showing the different models. I know I would need to richen up the high jet after eliminating the limiter on it. I would have to be sure there is a retaining spring on the jet after taking out limiter because from what I understand Stihl started removing the spring and the jet with limiter removed is apt to adjust itself. So air filter , jet, muffler changes and vroom vroom. Seeings how I am "tighter than the skin on a hot dog" with $, I would hold off on the air filter which may not need changing anyhow and just do the muffler and jet changes and see if the noise level is acceptable to me.

Next issue. You say the mtronic would adjust for a muffler mod on a Stihl 462. I know on older ECUs (mtronics) that the electronics could only adjust within certain parameters. Some owners have theorized that the mtronic could not adjust for various changes in temperature induced fuel mixture visocity resulting in hard or no starting on their 462. How much will the 462 mtronic allow in muffler mods before the changes cause a situation that is outside the mtronic parameters? Just a technical question but you can not help wonder just how far the mtronics can adjust for in real world use on each of it's sensors.

Thank you for your well thought out and written post sir.

 

[ferris]

@StihlMagnum440 The m-tronic will tune the saw, even full ported or without muffler.

when u are low on money why spend money for a DP cover from Stihl.
Make ur own muff mod it will save u money and the power increase will be the same

 

[StihlMagnum440]

You didn’t answer the question, and what @sawmikaze said

I am thinking about it! Haha

 

[Maintenance Chief]

Just did alittle reading on this thread and concluded that muffler mods are cool.

If there's a cheap alternative for a dual port cover I'll try one of those, and I like the deflector that @Red97 makes. If I have a nicer factory saw I don't mind spending the money for a factory deflector like the 288 on my 394xp ,pricey little fellow!
Honestly though the 088 Stihl outlet is definitive proof they're not doing any "Scientific " research on mufflers!

 

[MustangMike]

A low restriction air filter can make a big difference. I run the steel screen "winter" filter.

A muffler mod, a low restriction air filter (not sure which filter your saw came with), and a timing advance (.020 - .025) off the key will make a big difference in how that saw runs.

My 044 came with a triple layer air filter that was pretty restrictive. (foam, filter and felt cover).

 

[RI Chevy]

Maxflo FTW

 

[MustangMike]

Don't like the looks of em, and too hard to clean.

With the steel screen filter, I just brush it off with a dustpan brush.