two_bit_score
Super Star Member
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- John Deere 110 TLB, Diamond C 19LPX GN trailer
A few pictures then?
Just another junk chainsaw
- Thread starter xyz123
- Start date
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Of what?
2 with muffler mod I took on trade 490 and 372. 2 with pipes in them were local trade ins. I dont do pipes on mine myself. So many different ways and so many different muffler sthls with their own problems.
290-390 sees the most from a 30min muffler mod I have timed before.
Just open under stock deflectors or add a deflector or gil them. Called caveman muffler mod that is free.
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cqaigy2
Super Member
I did muffler mod and carb adjustment on my stihl. To be honest i think the carb adjustment was the biggest difference, but my saw is pretty old. The muffler mod was seemed slightly louder and maybe a bit quicker rev and slightly higher rpm, but i did it many years ago and might not remember exactly.
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- Feb 21, 2003
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Unless the saw has an expansion chamber, the easiest method to gain power is to let the exhaust be free flowing.
gstrom99
Veteran Member
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I've really never seen the need to mod my saws. They've always seemed strong/fast enough for what I was cutting. Keeping a sharp chain has always been my priority.
WranglerX
Super Member
Ditto's on sharp chain....
Snobdds
Elite Member
2 strokes need moderate backpressure.
Do an experiment...
Sneeze into two cups. One cup has the entire bottom cut out. The other has a 1"x1" square cut in the end.
Which one has the higher exit velocity?
LD1
Epic Contributor
I disagree
Snobdds
Elite Member
Two-stroke exhaust is part science and part art, as far as I can tell. A properly set up system not only scavenges the burnt charge from the combustion chamber, it directs a "reverse" pressure pulse to keep the incoming charge in place.
I have read that a 2cycle has a "secondary" compression ratio, that of the fuel air mixture in the crankcase. When backpressure is too low the mixture can exit the cylinder w/o burning called short circuiting or "4 cycling". An expansion chamber takes advantage of sound waves which travel through the exhaust pipe faster than the spent gases and both pull the gases out and when they return back toward the exhaust port help hold the next fresh charge in the cylinder.
I have read that a 2cycle has a "secondary" compression ratio, that of the fuel air mixture in the crankcase. When backpressure is too low the mixture can exit the cylinder w/o burning called short circuiting or "4 cycling". An expansion chamber takes advantage of sound waves which travel through the exhaust pipe faster than the spent gases and both pull the gases out and when they return back toward the exhaust port help hold the next fresh charge in the cylinder.