Just for fun :
Dolmar advice needed.
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calamari
ArboristSite Operative
From the EA6100 owners manual.
Kickback:
Kickback occurs when the upper quadrant of the bar nose contacts a solid object in the wood or is pinched. The reaction of the cutting force of the chain causes a rotational force of the chain saw in the direction opposite to the chain movement, mainly in the plane of the bar. This may fling the bar in an uncontrolled arc towards the operator.
EA6100 saw from owners manual. It seems to have lost 0.1 hp someplace as it's now 4.5 and not 4.6hp
Max. power at speed hp / rpm 4.5 / 10.000
Max. torque at speed Nm / rpm 3,7 / 7.000
DCE6400 data
Max. power at speed ...........hp / rpm 4.7 / 9,000
Max. torque at speed........... Nm / rpm 4.2 / 6,500
The 6400 has 12% more torque but only 4.3% more hp. You should be cutting at 1,000 higher RPM than the 6400 with the 6100 to take advantage of its power curve.
Kickback doesn't seem to have anything to do with porting and is strictly a function of where the force of the engine is applied in the tip's top quadrant. I've been careless and had a 35cc saw try to eat my face when I cut wrong.
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If going with the Oregon chains listed, get an EXL instead of LGX.
I have cut a fair amount with LGX but EXL is supposed to be new and improved.
I have cut a fair amount with LGX but EXL is supposed to be new and improved.
calamari
ArboristSite Operative
Thanks. I bought the saw new in Nov 2017 for $550. I haven't kept up with any changes in chains and such. The LGX cuts fine so the EXL should be even better.
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Same, I still have new LGX in stock... Looking forward to switching to EXL down the road to compare.
calamari
ArboristSite Operative
You got me thinking about just what chain I had. I bought a new one this summer to cut up a large (28"+DBH) dead, dry oak tree I got for free. I ordered it from Amazon for ease of purchase with the Oregon # below. Is that the new style, old style or something in between? EXJ instead of EXL and I'm too lazy to look it up myself so I thought I'd just ask those who know.
Oregon 72EXJ093G PowerCut 3/8" Skiptooth Saw Chain.050 Gauge, 28"
calamari
ArboristSite Operative
I tried looking it all up and got confused. I thought the "93" number was the number of drive links but I found an Oregon chain with the same gauge and pitch as mine with "91" as the last number that was supposed to fit a 28" bar. I never found out what the "G" stood for. I gave up.
@calamari For every force, there is an equal and opposite force. I can't find the dyno sheet, but my 6100 being ported means it could be running at 11,500 in the cut at 7hp. That's a lot more kick or push back.
Re: EXL/LGX, if you compare them (see thread "how I exactly sharpen chains" by @Huskybill ) you will see the geometry indicates LGX will be grabbier and cut faster (more of a softwood grind) and EXL less aggressive and hold sharp a little longer (more or a hardwood grind)
Re: EXL/LGX, if you compare them (see thread "how I exactly sharpen chains" by @Huskybill ) you will see the geometry indicates LGX will be grabbier and cut faster (more of a softwood grind) and EXL less aggressive and hold sharp a little longer (more or a hardwood grind)
I vote we keep chain discussion in the chain thread...
https://www.arboristsite.com/threads/how-i-exactly-sharpen-chains.355828/
https://www.arboristsite.com/threads/how-i-exactly-sharpen-chains.355828/
calamari
ArboristSite Operative
Please try to find the dyno sheet. I'd like to have a 7 hp saw too. Maybe details on the porting if you're willing?
46% increase on stock!
calamari
ArboristSite Operative
Interesting! Thanks for digging it out. Can you explain some of what it shows? What happened that caused it to drop so precipitously at 13,000 RPM but continue to increase the saws RPM for about 100 RPM at zero horsepower? Do they have the "before" graph for the saw so you can see where the increase takes place? The torque max looks about what the stock saw has.
Thanks again.
That was the old data system all done by hand. New system reads about 7% lower.
I'll be getting some more dolmars on the dyno soon.
The 13k "drop" isn't really a drop, it is the climb.
Pulls are made from high rpm to low. Just like cutting. 13k ish is where the saw tune was and I started applying load to slow the saw down.
I'll be getting some more dolmars on the dyno soon.
The 13k "drop" isn't really a drop, it is the climb.
Pulls are made from high rpm to low. Just like cutting. 13k ish is where the saw tune was and I started applying load to slow the saw down.
calamari
ArboristSite Operative
Thanks.
So it really starts on the right and goes to the left as far as how the test is run. So when you ended the pull at 5K rpm that was with full throttle with the rpm brought down with load application.
Do you have a hp/tq curve for the stock saw before the work was done?
Thanks again.
calamari
ArboristSite Operative
The EA6100 I mean as far as the stock curves.
calamari
ArboristSite Operative
Since you've been good enough to share a lot of information and since I'm in the habit of asking for stuff I have no reason to think I should have, here's a suggestion that may take more time than you want to spend. You may already have it which if so would be nice to see.
Since you're modifying two of the engine's systems, the intake and exhaust, the info I, and maybe only me, would find interesting would be a stock motor pull, one with just the muffler mod, one with the porting and a stock muffler, and one with both modifications. This would isolate the improvements with each modifications and also show that both in combination result in more than just the sum of their parts if that is true.
I've looked at several sites for saw modifications and all either don't address any increase in heat that the modifications produce perhaps because they use a flash test like you do or else they say it will run cooler w/o any basis to say so. Air cooled 2 cycle engines are always on the ragged edge of overheating and depend on the fins and fan to remove the excess heat from the outside of the engine and the air fuel/oil mix to keep the internal parts within survivable limits.
Davidwyby, more than me but me too, live in a very hot summer environments when at least I have to do my cutting. When the ambient temperature is 30-40 degrees the engine has more of a cushion than when I'm running mine when it's 100-105 degrees. that 60 to 75 increase in the engines temp before it's even started is a big deal in an air cooled 2 cycle. Having a graph showing a stock and modified saw's temp curve from start up to 15 minutes of heavy pulling would be very interesting. I know that at times I'm pushing the edge of survivability of my saws on hot days. I seized the small Redmax on a hot day just by having it be on the lean side of the clean running H/S screw mixture adjustment instead of running it on the rich side.
