Muffler Testing on a ported 660 - need opinions!

[junkman]

well they all seemed pretty "optimally tuned" to me ...but with out one of you masters here to give my tune your blessing then we'll just never know for sure will we.

for the record - I had Treemonkey check my tune on the saw and he said I tuned it good.

I am done testing mufflers.



you keep saying this but where are the numbers???

Just what I have experienced milling,I messed with mufflers more to reduce sound than was looking for power, I had to retune between stock, stock with dual port cover and gutted dual port. When doing this milling I can feel the pull in the cut difference, the top rpms drop also when start restricting over the gutted muffler tune, I never recorded times I am just posting what I experienced, another saw doing different work may get different results. I also did try a baffled muffler in my 461 I lost roughly 3 seconds roughly in a 30 second cut over the gutted one cutting a 30 inch dough fir cookie

 

[Deets066]

I would like to take a minute and thank red bull for the time, energy and money that he puts into these tests. Members like him are making the online chainsaw forum community a better place.

It's easy to get online a spout things that may or may not be true. But @Redbull661 and others like Chris-pa (who has gone so far as to develop some very cool software) and Snelling (who tirelessly documents his exploits with pics and vids) really make this community like no others.

Thansk-you.

Thanking Chris PA over here won't get ya very far

 

[Redbull661]

update: did another comparison.

1st cut time is due to wood drying out on the outter edge. Usually I'll cut a slice off before I start but it was only a day or so...but just proves I need to do it every time. Anyway so then if you look at the 2nd cuts. tri is 3 sec's faster.

So looks like my theory on the solid/non ported front cover is all wet.

I still don't understand why the modified baffle tri port is equal to...if not faster than the no baffle tri port.


36" .404 stihl rs new chains. mastermind660

tri port - 361F 32.7 35.7

bi-port - 369F 36.3 38.5

attached my 3 separate tests below...

 

[RI Chevy]

Cool comparison.
Thanks for taking your time to do this for all of us!

 

[Moparmyway]

update: did another comparison.

Still don't understand why the modified baffle tri port is equal to...if not faster than the no baffle tri port.

Tune
Its in the tune Julian

 

[Mastermind]

Barometric pressure. Yeah.......that's it.

 

[RI Chevy]

Gotta talk nice to it! It'll treat you better.

 

[Mastermind]

Barometric pressure. Yeah.......that's it.

And relative humility......yeah........humility. Gotta be humble.

 

[Mastermind]

If you are like me Julian, the more testing you do, the less you'll really be able to prove. Some saws just respond different to different things.

Why? I have no idea.

 

[junkman]

When i go from the gutted dual port muffler to the stock muffler without retuning it is super rich and lose a lot of rpm's ,have to lean it out when choke it down with stock cover to get the rpms back .

 

[jmssaws]

Figured out how big a hole needs knocked in the muffler yet?

 

[junkman]

i would like to try a tube going into a stock port a ways to see if knocks the sound down ,sort of like car mufflers so like a flowmaster or such by baffling with pipe ,when mill for 3-4 hours your head hurts bad and ears ring with modded mufflers .

 

[Keith Gandy]

Barometric pressure. Yeah.......that's it.

And relative humility......yeah........humility. Gotta be humble.

Ya that New York altitude chokin that saw to death!!

 

[mdavlee]

i would like to try a tube going into a stock port a ways to see if knocks the sound down ,sort of like car mufflers so like a flowmaster or such by baffling with pipe ,when mill for 3-4 hours your head hurts bad and ears ring with modded mufflers .

It does. I made an angled pipe outlet for a 390 that the guy was going to mill with. The one end was open and was right in front of the exhaust port so it caught a lot of the gas as soon as it leaves the exhaust port. Quieter than a dual port and directed it down more so it didn't bounce off the mill.

 

[Simondo]

In my lesser experience than most of you fellers, I have followed a basic rule of thumb that allows for the differences in the eventual exhaust port size after mods. Rightly or wrongly.
Enlarging any baffle holes or removing obstructions "directly" in front of the cylinder exhaust port, covers most internal work i do.
I calculate 70% of the aria of the exhaust outlet and make a tube to this size . The tube is then let into the side at a forward facing angle on the chain side if posable on most saws iv tackled unless a 550/560 or a Dolmar and then i just make the hole the calculated size under the shield. I leave a short stub of tube inside the muffler with a angle to match the muffler wall. I Have never gone with a output directly out the front or multiple holes or tubes , ,preferring to keep to 1 tube or hole site that is not in the direct line of fire of the cylinder exhaust port. Sound/gasses and heat go 1 way for me doing this plus its overall less work.
Apologies if this is covered ground or a bit mundane.

 

[Mastermind]

In my lesser experience than most of you fellers, I have followed a basic rule of thumb that allows for the differences in the eventual exhaust port size after mods. Rightly or wrongly.
Enlarging any baffle holes or removing obstructions "directly" in front of the cylinder exhaust port, covers most internal work i do.
I calculate 70% of the aria of the exhaust outlet and make a tube to this size . The tube is then let into the side at a forward facing angle on the chain side if posable on most saws iv tackled unless a 550/560 or a Dolmar and then i just make the hole the calculated size under the shield. I leave a short stub of tube inside the muffler with a angle to match the muffler wall. I Have never gone with a output directly out the front or multiple holes or tubes , ,preferring to keep to 1 tube or hole site that is not in the direct line of fire of the cylinder exhaust port. Sound/gasses and heat go 1 way for me doing this plus its overall less work.
Apologies if this is covered ground or a bit mundane.

More ways to skin cats than there are cats to be skinned.

Always share........never hold back. Posts like yours are what helps me learn. If I ever get to the point where I'm not trying new stuff, I'll be looking for a different line of work.

 

[mdavlee]

In my lesser experience than most of you fellers, I have followed a basic rule of thumb that allows for the differences in the eventual exhaust port size after mods. Rightly or wrongly.
Enlarging any baffle holes or removing obstructions "directly" in front of the cylinder exhaust port, covers most internal work i do.
I calculate 70% of the aria of the exhaust outlet and make a tube to this size . The tube is then let into the side at a forward facing angle on the chain side if posable on most saws iv tackled unless a 550/560 or a Dolmar and then i just make the hole the calculated size under the shield. I leave a short stub of tube inside the muffler with a angle to match the muffler wall. I Have never gone with a output directly out the front or multiple holes or tubes , ,preferring to keep to 1 tube or hole site that is not in the direct line of fire of the cylinder exhaust port. Sound/gasses and heat go 1 way for me doing this plus its overall less work.
Apologies if this is covered ground or a bit mundane.

This way is probably quieter for the operator.

 

[Simondo]

This way is probably quieter for the operator.

They still end up louder by a margin but liveable with in public ... but most of my work with mods is about getting heat away from the front end of the saw for a client . I dont end up doing the full on XXX versions of port work so the extra i get from a little generosity in the cylinder port size and gasket matching along with the muffler mod is a nice little bonus for the customer.

 

[Simondo]

With the auto tune/M tron saws you would get what the saw want as regard to fuel after a mod. Wonder if this same muffler mod situation would come out with the same conclusion as there could be no "Fat or Lean" i suppose ?

 

[mdavlee]

Some of the saws run too rich and the others too lean on the Autotune. The 661 is on the 5th coil now.