The Forestry Forum is sponsored in part by:

iDRY Vacuum Kilns


Forestry Forum
Sponsored by:


TimberKing Sawmills



Toll Free 1-800-582-0470

LogRite Tools



Norwood Industries Inc.




Your source for Portable Sawmills, Edgers, Resaws, Sharpeners, Setters, Bandsaw Blades and Sawmill Parts

EZ Boardwalk Sawmills. More Saw For Less Money!

STIHLDealers.com sponsored by Northeast STIHL


Woodland Sawmills

Peterson Swingmills

 KASCO SharpTech WoodMaxx Blades

Turbosawmill

Sawmill Exchange

Michigan Firewood, your BRUTE FORCE Authorized Dealer

Baker Products

ECHO-Bearcat

iDRY Wood Lumber Vacuum Drying for everyon

Nyle Kiln Dry Systems

Chainsawr, The Worlds Largest Inventory of Chainsaw Parts

Smith Sawmill Service



Author Topic: Porting vs Muffler Mod  (Read 975 times)

0 Members and 1 Guest are viewing this topic.

Offline Guydreads

  • Full Member x2
  • ***
  • Posts: 136
  • Age: 61
  • Location: Spain
  • Gender: Male
  • I'm new!
    • Share Post
Porting vs Muffler Mod
« on: October 29, 2021, 06:10:17 AM »
So, I want faster through wood :D :D! The question is, will a muffler mod really do that much without porting or vice versa? Obviously if I can get away with just the muffler mod, I'd like to. I'm trying to make my 2071 Turbo faster. So, should I port or not, and should I do the muffler mod or not?

Offline Tacotodd

  • Senior Member x2
  • *****
  • Posts: 2085
  • Age: 50
  • Location: Bauxite AR
  • Gender: Male
  • To learn and help
    • Share Post
Re: Porting vs Muffler Mod
« Reply #1 on: October 29, 2021, 06:54:57 AM »
MM first! Because if it can’t get out then it can’t get in. You can always inexpensively MM more of it later to take even more advantage of your ported saw later ;D My MM was easy on my saw, but my muffler wasn’t your standard “come as equipped” muffler to begin with. I acquired a “jungle muffler” for mine & it was EASY to mod. I didn’t do it the “right” way, but it works ;D
Trying harder everyday.

Offline Guydreads

  • Full Member x2
  • ***
  • Posts: 136
  • Age: 61
  • Location: Spain
  • Gender: Male
  • I'm new!
    • Share Post
Re: Porting vs Muffler Mod
« Reply #2 on: October 29, 2021, 08:00:42 AM »
Ok! We shall see if i get to it one of these days. Will post pics

Offline mike_belben

  • Senior Member x2
  • *****
  • Posts: 12637
  • Location: Middle TN
  • Pulp Friction
    • Share Post
Re: Porting vs Muffler Mod
« Reply #3 on: October 29, 2021, 10:12:49 AM »
both,  they go hand in hand. both will be wasted if you dont have the ear to tune.  

you need to be able to train your ear to hear the difference between "2 stroking" and "4 stroking" and tune the high speed so that it 4 strokes under light load and then when you dog into the cut the saw cleans up to a crisp 2 stroking, ease off the dogs and it goes back to 4 stroking.  thats the spot.  braah
Isaiah 63:10

Offline lxskllr

  • Senior Member x2
  • *****
  • Posts: 2129
  • Age: 53
  • Location: MD USA
  • Gender: Male
  • dummy with saw
    • Share Post
Re: Porting vs Muffler Mod
« Reply #4 on: October 29, 2021, 10:18:09 AM »
I'm not good at tuning by ear. I get it eventually, but do it over a long period of time. I tune it fat til I get used to the way it sounds, then slowly back it off over several cutting sessions. My goal is durability/longevity over performance. I'd rather start "safe" and tune it in than go for max performance and burn it up due to my poor ear.

Offline mike_belben

  • Senior Member x2
  • *****
  • Posts: 12637
  • Location: Middle TN
  • Pulp Friction
    • Share Post
Re: Porting vs Muffler Mod
« Reply #5 on: October 29, 2021, 10:27:22 AM »
nothing wrong with that.  2 stroking all the time is a quick death sentence. 
Isaiah 63:10

Offline Real1shepherd

  • Senior Member x2
  • *****
  • Posts: 1069
  • Age: 68
  • Location: Eastern WA
  • Gender: Male
    • Share Post
Re: Porting vs Muffler Mod
« Reply #6 on: October 29, 2021, 12:22:03 PM »
Muffler modding isn't a proven performance mod across the board. Some muffler designs will not benefit at all and others will lend themselves to significant gains. Best to talk with people that have used MM in the field hard and can tout real performance gains.

Owners that have done a MM, run a tank of gas through it, stuck it on a shelf and concluded that it was a 'great' mod, are useless opinions.

Kevin 

Offline Tacotodd

  • Senior Member x2
  • *****
  • Posts: 2085
  • Age: 50
  • Location: Bauxite AR
  • Gender: Male
  • To learn and help
    • Share Post
Re: Porting vs Muffler Mod
« Reply #7 on: October 29, 2021, 02:58:37 PM »
Mine “felt” like it gave me another 1/4hp, but it could have been in my mind. I “do” know that now (if need be) that I can successfully run a 32” b/c and skip chain, but I normally run a 28” & full comp. BTW, 372XT 🤫. I know that I’m happy with it 👍. Otherwise it’s untouched.
Trying harder everyday.

Offline Guydreads

  • Full Member x2
  • ***
  • Posts: 136
  • Age: 61
  • Location: Spain
  • Gender: Male
  • I'm new!
    • Share Post
Re: Porting vs Muffler Mod
« Reply #8 on: October 29, 2021, 04:14:17 PM »
All of this is very interesting. I would say I am decent at tuning chainsaws, but not perfect of course. Maybe I'll even do a video about performance gains/no gains due to muffler mods/tuning. I might also pick up a digital tach to make sure of myself. Also, any good compression testers out there you know of I could get? Christmas is coming! :D :D

Offline mike_belben

  • Senior Member x2
  • *****
  • Posts: 12637
  • Location: Middle TN
  • Pulp Friction
    • Share Post
Re: Porting vs Muffler Mod
« Reply #9 on: October 29, 2021, 05:45:51 PM »
Muffler modding isn't a proven performance mod across the board. Some muffler designs will not benefit at all and others will lend themselves to significant gains. Best to talk with people that have used MM in the field hard and can tout real performance gains.

Owners that have done a MM, run a tank of gas through it, stuck it on a shelf and concluded that it was a 'great' mod, are useless opinions.

Kevin  

put a temp gun on it and i bet every decently done muffler mod lowers the exhaust side temp which to me is the real value. cooler muffler will lower the cylinder temp as the muffler wicks more heat off the jug, and helps put a few more degrees of safety between running great and melting a piston to the bore. 
Isaiah 63:10

Offline Tacotodd

  • Senior Member x2
  • *****
  • Posts: 2085
  • Age: 50
  • Location: Bauxite AR
  • Gender: Male
  • To learn and help
    • Share Post
Re: Porting vs Muffler Mod
« Reply #10 on: October 29, 2021, 06:05:15 PM »
BUT, with that MM you’ll have to remember to richen up the high side “just” a little bit. In fact with ANY muffler mod you’ll have to. Otherwise you’ll still cook the saw.
Trying harder everyday.

Offline Real1shepherd

  • Senior Member x2
  • *****
  • Posts: 1069
  • Age: 68
  • Location: Eastern WA
  • Gender: Male
    • Share Post
Re: Porting vs Muffler Mod
« Reply #11 on: October 30, 2021, 04:03:41 PM »
put a temp gun on it and i bet every decently done muffler mod lowers the exhaust side temp which to me is the real value. cooler muffler will lower the cylinder temp as the muffler wicks more heat off the jug, and helps put a few more degrees of safety between running great and melting a piston to the bore.
Yeah, I wouldn't argue with that.....and that's a 'gain' in my book if you could make it run cooler/last longer.

Kevin

Offline teakwood

  • Senior Member x2
  • *****
  • Posts: 1755
  • Age: 40
  • Location: Costa Rica
  • Gender: Male
  • Switzerland
    • Share Post
Re: Porting vs Muffler Mod
« Reply #12 on: November 09, 2021, 12:04:47 PM »
I have 2 MS361, one is my falling saw and the other is for the help, mostly limbing and topping. Mine is MM and there is a big diference in them, i would even say more than 15%. The stock saw is a total turd compared to mine
National Stihl Timbersports Champion Costa Rica 2018

Offline Stephen1

  • Senior Member x2
  • *****
  • Posts: 2706
  • Age: 65
  • Location: Kilworthy ON> Canada
  • Gender: Male
  • Where there is a will, there is a way!
    • Share Post
    • muskoka Sawmill
Re: Porting vs Muffler Mod
« Reply #13 on: November 09, 2021, 07:42:42 PM »
Since the word tune and ear have been brought up. I am having trouble with my 361 not running nice at the high end. Is it my spark arrestor or do I need to adjust my high end screw. For All the years of owning saws,  the only time I have had troubles it seems is when I played with the adjustmnt screws. 
Any tips on clening the screen? And or adjusting the high end?
IDRY Vacum Kiln, LT40HDWide, BMS250 sharpener/setter 742b Bobcat, TCM forklift, Sthil 026,038, 461. 1952 TEA Fergusan Tractor

Offline lxskllr

  • Senior Member x2
  • *****
  • Posts: 2129
  • Age: 53
  • Location: MD USA
  • Gender: Male
  • dummy with saw
    • Share Post
Re: Porting vs Muffler Mod
« Reply #14 on: November 09, 2021, 08:14:33 PM »
Is the screen dirty, as in clogged? You should be able to clean it with a torch. A wire brush should work too. I'm not in a position to give advice on tuning, other than it should 4stroke out of wood, and 2stroke when in wood. What they sound like to me is a hotrod getting on the gas a bit going down a residential road(4stroke), it'll then clean up, and turn into a Japanese sport bike in the wood(2stroke). You give it more gas with the highspeed jet to get it to 4stroke, or take gas away by adjusting the jet to get it to 2stroke.

You can lose power going too far either way, so you can't really use that as a test condition to know what you need to do. You should be comfortable doing it yourself. If you don't trust your ear, find someone you trust to help you out, and point out what you should listen for. If you lean it out too much, you can damage the saw.

edit:
You might find this Madsens guide useful...

Saw Carb Tuning

Offline barbender

  • Senior Member x2
  • *****
  • Posts: 9122
  • Age: 46
  • Location: Deer River MN
  • Gender: Male
    • Share Post
Re: Porting vs Muffler Mod
« Reply #15 on: November 10, 2021, 01:08:32 AM »
Have you ever tuned a guitar?😊 A saw is kind of opposite of that. What you want is a slightly rich high speed setting. The leaner you set it, to a point, the more the engine will scream when you hold it wide open. If you make it really lean, it will bog when you open the throttle. You won't hurt anything running too rich, but too lean and you can fry your engine. So err on the side of too rich. When people use the term "4 stroking", what they mean (I think) is the engine will flutter a little and sound like it's not cleaning up all the way. That's what you want because when you are in a cut with a load on the engine, it will be just right and run like a champ.
Too many irons in the fire

Offline weimedog

  • Senior Member x2
  • *****
  • Posts: 1585
  • Location: CNY
  • Gender: Male
  • Better to be a "Has Been" than a "Never Been"!
    • Share Post
Re: Porting vs Muffler Mod
« Reply #16 on: November 10, 2021, 06:58:37 AM »
So, I want faster through wood :D :D! The question is, will a muffler mod really do that much without porting or vice versa? Obviously if I can get away with just the muffler mod, I'd like to. I'm trying to make my 2071 Turbo faster. So, should I port or not, and should I do the muffler mod or not?
Great saws, and there are a lot of simple things not requiring a lathe, mill, or machining services that will perk that series of saws up. To your question the generic answer is it depends...often the muffler is a weak link in that chain of devices moving air/fuel thru the system that is your chainsaw's motor so changing the muffler can sometimes help along with "tweaks" to help with the efficiency of combustion. If you want to change the RPM place where your saw makes power, then in conjunction with the right muffler mods, porting needs to happen. The current set of tweaks builders do essentially have been common place since two strokes were designed. Add compression to a point of diminishing returns to increase the efficiency of combustion. It's a math thing really, thermodynamics exercise. Shape the squish band to get as much of the available gas/air mix in a place it will burn as well. More of the available mix burning=more efficiency=more power as well. Change port size, shape, and timing to both flow more as well as get more RPM's and if the systems to flow mix can feed those RPM's properly, that additional mix being burned means more available energy to convert into useful power. All the "sub systems" ( filter, intake parts, carb, muffler, ports, crank case "pump" etc.) have points in system in the desired RPM range where the "pulsed" flow ( series of positive & negative pressure waves ) move the fluids best, when all are in "tune" more mix flows. And when they are both in tune and optimized to move mix at the RPM you choose to run, that's a good running saw, those fore mentioned things to make the combustion more efficient make it run even better :) AND the 800 lbs. gorilla in the room for a work saw, IF the cooling system & basic saw structure (bearings/cases etc.) can keep up with all that extra heat & energy, you also have a reliable saw. So its pick you budget or add to your tools and skill set :)
Husqvarna 365sp/372xpw Blend, Jonsered 2171 51.4mm XPW build,562xp HTSS, 560 HTSS, 272XP, 61/272XP, 555, 257, 242, 238, Homelite S-XL 925, XP-1020A, Super XL (Dad's saw); Jonsered 2094, Three 920's, CS-2172, Solo 603; 3 Huztl MS660's (2 54mm and 1 56mm)

Offline mike_belben

  • Senior Member x2
  • *****
  • Posts: 12637
  • Location: Middle TN
  • Pulp Friction
    • Share Post
Re: Porting vs Muffler Mod
« Reply #17 on: November 11, 2021, 08:09:02 AM »
Go to madsens saw shop site and read their tuning page its very thorough.


You want to 4stroke while WOT free revving or light load and have it two stroke when you dog it into the wood.  Itll seem like the handle has a pressure switch when youve got it right.  Pull the handle up and its clear and screamy.. Ease off the handle tug but still lightly cutting and itll shift to a raspy cackle like ignition breaking up.. Just a rougher note.  Thats "4stroking"

This is all in the high speed screw.  Turn it in until its screamy free revving.  Turn it out until its raspy.  Then 1/16th turns and hit a big block to test where the switch point is.  You gotta be sawing to tune.
Isaiah 63:10

Offline weimedog

  • Senior Member x2
  • *****
  • Posts: 1585
  • Location: CNY
  • Gender: Male
  • Better to be a "Has Been" than a "Never Been"!
    • Share Post
Re: Porting vs Muffler Mod
« Reply #18 on: November 11, 2021, 09:32:03 AM »
So, I want faster through wood :D :D! The question is, will a muffler mod really do that much without porting or vice versa? Obviously if I can get away with just the muffler mod, I'd like to. I'm trying to make my 2071 Turbo faster. So, should I port or not, and should I do the muffler mod or not?
To the OP's question this was a discussion I did on a 48mm version ( 2065 ) but everything applies to the 2071/2171 as well. Again for the guy with elbow grease to spend more than money to send a saw to a pro mod type. 
Husqvarna 365sp/372xpw Blend, Jonsered 2171 51.4mm XPW build,562xp HTSS, 560 HTSS, 272XP, 61/272XP, 555, 257, 242, 238, Homelite S-XL 925, XP-1020A, Super XL (Dad's saw); Jonsered 2094, Three 920's, CS-2172, Solo 603; 3 Huztl MS660's (2 54mm and 1 56mm)


Share via delicious Share via digg Share via facebook Share via linkedin Share via pinterest Share via reddit Share via stumble Share via tumblr Share via twitter

xx
porting and muffler add ons?

Started by symamania on Chainsaws

6 Replies
1830 Views
Last post June 21, 2015, 11:20:02 AM
by HolmenTree
xx
Does porting the muffler put excess wear on the saw?

Started by George Zarifis on Chainsaws

8 Replies
3951 Views
Last post July 16, 2015, 05:53:35 AM
by skipster
grin
McCulloch model 99 muffler and or a 7-55 muffler

Started by Driestgnat on Chainsaws

1 Replies
674 Views
Last post November 06, 2018, 06:12:21 AM
by thecfarm
xx
porting

Started by oakwood productions on Chainsaws

22 Replies
6309 Views
Last post May 30, 2009, 11:53:05 AM
by Cut4fun
 


Powered by EzPortal