KG441c
Keith
I use stihl 20" rshlk semi on my ported 362c and sharpen the square steep at about 30° and rakers set at .025. That 362 loves that setup. Fast and smooth
Dyno tested...... Mastermind Ported 660 vs Stock 660 vs Dual port 660
- Thread starter chadihman
- Start date
Help Support Arborist Forum:
I've never been such a believer in a ported saw till I got some on my dyno. Amazing!!!!
For all of the clowns that brag that that your saw holds 11000 or 12000 RPM in the cut look at this chart, power starts falling off fast after 9500 RPM even on the ported saw an torque falls off even faster. Steve
I don't think I've ever heard anyone saying they made max HP at that RPM, but that the saw will hold those RPMs in the cut with a light load, demonstrating the upper end of the powerband. Even in the example you showed above, the ported saw is making more HP at 12,ooo RPMs than a stock saw is at peak.
Chris-PA
Where the Wild Things Are
I have saws I have ported that will hold around 12k in the cut, and I've posted the videos of them doing just that. Not in a racing can't or with special racing chain, but cutting actual hardwood with boring (but sharp) working chain on bars longer than most would use. Further, I've shown how you or anyone else can measure the rpm the saw is pulling in that video, and I welcome anyone to verify that. So what do you make of that? Am I being dishonest, or just a clown?
We've had our disagreements on some things, and agreements on others, and I think both of us have tried to focus on the positive. It's a shame, but here you are name calling for no reason while showing that you don't understand the graph you used as an example. If you look at that plot again you'll see the ported saw is still making about 80% of it's peak hp at 12krpm - do you really think it can't cut wood there?
Once you exceed peak power, your just making noise.
It's a representation of the powerband. You can't graph or demonstrate that which you do no test. Again, no one said above peak HP was ideal.
Ive heard plenty making of claims their saws hold 11000 to 12000 in the cut which is pure bs, , even the ported one makes the most hp at 9500 to 9600 rpm and thats the most rpm they should be run at for the best cutting speed Steve
Chris-PA
Where the Wild Things Are
That's a nice saying that may make sense in terms of racing, and things like shift points etc, but it really holds no water in this context. With a gearbox you can efficiently change rpm, so you can keep the engine at it's peak hp rpm while using that power at the rpm where you need it. With a chainsaw you have one gear so you cannot shift, and even initial gearing is possible only to a limited extent.
Horsepower is the rate of energy transfer, or the rate of work being done, and I can assure you that the saw in that plot is still capable of doing a lot of work at 12krpm - and the faster the chain moves the faster it cuts through the log. You'd be better off if you could use that engine at 10krpm and gear it up 20%, but you can't.
Your full of bs. any saw is going to cut the fastest where it makes the most hp plain and simple' Steve
The faster a chain spins on a piece of wood the more cutters pass over that piece of wood in a given piece of time, making it cut faster.
2 strokes make power within a power band, not just at a given rpm.
Anybody ever ride a banshee and feel the power band kick in? It's certainly there, and over a range of rpm.
2 strokes make power within a power band, not just at a given rpm.
Anybody ever ride a banshee and feel the power band kick in? It's certainly there, and over a range of rpm.
The above is pure bs . yes at a higher rpm the take more SHALLOER chips which make for a slower cutting speed' Steve
Chris-PA
Where the Wild Things Are
Well, thanks for that excellent analysis.
That's absurd, there isn't going to be any significant chip size different between 10k and 12krpm, it's only 20% faster.
Within reason cut time will be proportional to both the downward force on the chain and the linear speed of the chain.
Compared to 10krpm the ported 660 in that plot at 12krpm is down 20% in power and moving the chain 20% faster - it'll cut about the same speed through the log anywhere between the two rpms.
By 13k it's down 43% in power but going only 30% faster so it's lost ground at that point.
When does your saw cut faster, when you lean on it or let it self feed with a good chain through the wood? 2 identical saws, one ported, one not. One is making more power at a higher rpm, therefore it will feed through the wood at a faster rate.
Nobody is trying to sling bs, and I don't have a dog in this fight, I just don't understand how this is not the case.
I do miss Chads threads though. They were great!
SquareFile
ArboristSite Guru
I think they left. OP built a heck of a dyno! Think it showed true colors of el builders.
Obviously, you didn't read what I wrote.
I've watched quite a few of your vids where you let the saw turn high rpm's in the first cut , 2nd cut loaded the motor more getting it into the peak hp RPM, 3rd cut lugged it a lot. The 2nd cut was the fastest every time when the saw was at the peak hp RPM. Any saw will hold 12000 RPM in the cut not cutting very fast. Steve
I agree. I've said nothing to the contrary.
Brad
I sure wasn't talking about you running saws too fast and your vids that show how a saw cuts at high to low rpm are the best. I just irks me when these clowns get on here bragging their saw holds 12000 in the cut. Steve
I sure wasn't talking about you running saws too fast and your vids that show how a saw cuts at high to low rpm are the best. I just irks me when these clowns get on here bragging their saw holds 12000 in the cut. Steve
