Q's on 'proper muffler-modding' (and basic/entry chainsaw mods in-general)

[ArborOdyssey]

I've drilled holes into a couple mufflers and sadly got no increases on anything except noise (well, the tachometer didn't show anything but I guess I can't rule-out some minimal gains when a unit is pushed-to-max)

 

I'm hoping to understand/learn a few things:

 

1 - When doing the muffler-mod itself, I've begun to think that if you don't open-up that center-wall that's in most mufflers, that holes on the outermost wall won't really matter at-all.  Since I'm about to do some mods to another saw I was hoping to get ANY tips for approaching a "proper" muffler-mod because I don't want to risk stuff getting-into my cylinder, don't want it to be ineffective, etc! 

 

2 - The way I see it is a series of 'weak-points' IE opening the muffler alone would probably be of minimal use on its own, and while I open-up the air-intakes on all my 2-strokes (more, *cleaner* air for all my intakes, full filtration even OEM slots like H/L/Idle openings), I've begun to wonder if air intake + muffler is still useless w/o widening/opening the cylinder's inlet&outlet ports....I've got any attachment imaginable for a variety of grinders so thinking to, at-minimum, smooth-out one of my saw's exhaust-outlet(ports) because right where the block's exhaust outlet-port mates up to the muffler there is a 'ridge', honestly it almost looks as-if the manufacturer cast it that way in a manner of "we've put it there, but made it easy for you to remove" lol, I took a pic to show what I mean but this is on a 25cc climb saw:

[edit: I atttached 2 pics of it, seems I can't put them inside a post here?  Can I put pics mid-post if I host them elsewhere and bring the url?  Only see a URL-hyperlink option for this text-box, all photo-media additions seem they have to be alongside the post not actually in-between-sentences like on most forums/boards]

Seems silly it's not a ridge so much as 2 large arching-ridges lol, that whole upside-down V at the end of that exhaust port right where the piston would slide, is that giant over-hanging area -- I look at it and my intuition is "that shouldn't be there"!!

 

  So am hoping to know whether inlet/outlet 'porting/opening', alongside the intake&muffler openings, will be of value!  Further, how would I best test/benchmark things here?  Have a tachometer but part of me suspects it may be something where it's only going to show under-load and I've yet to get competent at using the tach while in-cut (any tips on that greatly appreciated, am close to using JB Weld to just permanently affix the tach to my saw's case's top )  Lastly am hoping to learn 2 things I'm thinking are 'advanced' modding, one is "What mod(s) are next?" and the other is "when does superior fuel become something that you kinda 'need' for a modified saw?"  Doing timing-mods scares me, probably because I've got little understanding how advancing the timing of the flywheel does *anything* (wouldn't it still just be the ignition module firing 1 burst to the spark-plug for every rotation of the flywheel?)  Beyond that I'm uncertain what else should be given real consideration (I know it's not mods but I'm anal about keeping razor-sharp chains / proper tension, keeping my saw's tuned as optimally as I can, etc, although will admit I'm uncertain IF/when a mod/mods will make it so you've gotta adjust the carb, I figure I'll just go-by-ear (and mind the max-RPM's) after doing the mods....)  Re fuel, I've switched from eth-free mixes and just started getting the Husqvarna 95oct pre-mix, my saws seem to love it, but I can't help but wonder if octane boosters, altered petrol//oil ratios, additives or different base-fuels are able to contribute once a saw has been modified enough, am guessing that for my favorite saws (<40cc limbing saws / top-handled's) that the 95oct Husq will be optimal no matter what the mods but figured to ask!

Thanks a TON for any insight into any of this, would be greatly appreciated!!!!

 

PS -- Anyone have any ideas how hot the outer-walls of lil <40cc mufflers get?  On one of the lil climb-saw's mufflers I plan to mod ASAP I was wanting to spray it w/ this can of High Heat Krylon, says it's good for 600F continuous (1200F intermittent although that's useless in my cases I think unless I'm just spending 30sec fighting a 16" through a 15" limb at a poor angle LOL   )

Again thank you VERY much for any insight on *any* part of my confusions/curiosities here   For context/in-anticipation of being asked, the 2 units I'm approaching in this session are 1- "Scheppach CSP2540" 25cc/12" echo bar&chain, and 2- Tanaka TCS33EDTP w/ new, 16" Oregon bar&chain....I know these may get laughed-at but to be fair the former is nearly a year old now and hasn't needed *any* work(not even a tuning!!) and the other was "dead beyond repair", multiple critical/fatal breaks/failures, got it in-lieu of $25 a dead-beat company owner owned me for a climb and kept jerking me around on, I suspected I could revive the thing and did I mean rebuilt ignition module, fully-built/DIY bar-tensioner, thing was a wreck and is now a beast in fact I've hardly touched my 18"/42cc since this 32cc/16" Tanaka has been so great, super high compression & starts better than anyhing I own (w/ the scheppach being a very close-2nd!)

[spudulike]

That exhaust port looks like it hasn't been machined correctly to me!

[Stubby]

40 minutes ago, spudulike said:

That exhaust port looks like it hasn't been machined correctly to me!

Gonna say the same .  Big lump of flash were the core has not shut off .

[MattyF]

Has the tanaka got a cat ?

[CutterSy]

Have you got pics of the muffler mods you have done?
You can get some gains from just opening up the muffler outlet, but usually you need to open up the baffle to get anything worthwhile.
Hole size and placement can effect it too.
The saw will need a re-tune after.

[Stubby]

2 minutes ago, CutterSy said:

Have you got pics of the muffler mods you have done?
You can get some gains from just opening up the muffler outlet, but usually you need to open up the baffle to get anything worthwhile.
Hole size and placement can effect it too.
The saw will need a re-tune after.

here is one of mine

[MattyF]

Straight out in the Field mod with a ms 150 all that was needed was a 9mm drill bit.

 

 

If the tanaka has a cat that may explain why it did fa ..

From my thoughts though some saws don’t respond from being opened up like the 200t that seem to need a bit of back pressure but modern saws are very restricted to meet emission regs.

 

[Joe Newton]

Gains from a muffler mod wouldn't be measured on a tachometer. The benefits are quicker pickup and more torque, not higher rpm.

 

[CutterSy]

Straight out in the Field mod with a ms 150 all that was needed was a 9mm drill bit.
 

 
If the tanaka has a cat that may explain why it did fa ..
From my thoughts though some saws don’t respond from being opened up like the 200t that seem to need a bit of back pressure but modern saws are very restricted to meet emission regs.
 

Please tell me you didn’t just drill a hole in that muffler with it still attached?!

[NFG]

3 hours ago, Stubby said:

here is one of mine

That your 395 Stubby? bet its loud!