::: Power vs Torque :::
- Thread starter Jonsered2095
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wigglesworth
Booned
Bump
windthrown
361 Junkie
Stirring the shyte?
Power = torque x revs.
Power = torque x revs.
TEZZA
ArboristSite Operative
Without torque there is no Horsepower.
The more torque the less revs needed to do the work.
Therefore the less torque the more revs needed to get the work done in a given time.
The more torque the less revs needed to do the work.
Therefore the less torque the more revs needed to get the work done in a given time.
wigglesworth
Booned
Thats a great post!
Hey, I drive a Cummins powered Dodge Ram and I ride a Harley.....So in my mind Torque RULES!!! That said, I am an engineer and so my true answer is that it really depends on the application and conditions. I can probably cut faster with high RPMs but I just don't like to rev my saws that high all the time. Much prefer to do work with low end torque and razor sharp full chisel chains!
windthrown
361 Junkie
What I posted here back in '07 has not changed.
Its power that drives a chainsaw chain to cut through wood. Torque is just one factor in the calculation of power, and without rotational speed (RPMs) there is no cutting with a chain. So torque is only half of the equation, rotation speed is the other half, and from that you get POWER.
Power = Torque x Rotational Speed
and why chainsaws are rated by horsepower, and not torque.
W/o torque there is no power. Also w/o revs there is no power. Got it nimrods?
Its power that drives a chainsaw chain to cut through wood. Torque is just one factor in the calculation of power, and without rotational speed (RPMs) there is no cutting with a chain. So torque is only half of the equation, rotation speed is the other half, and from that you get POWER.
Power = Torque x Rotational Speed
and why chainsaws are rated by horsepower, and not torque.
W/o torque there is no power. Also w/o revs there is no power. Got it nimrods?
TEZZA
ArboristSite Operative
Nimrod?
windthrown
361 Junkie
Yah, nimrods... old term here in the states for boneheads. I think an equivalent term down under is a donk?
TEZZA
ArboristSite Operative
I know who Nimrod was.
Just wondering who you are calling Nimrods.
Just wondering who you are calling Nimrods.
The way I see it, he posted the Nimrod comment just after my post.....so I must be the head Nimrod. If windthrown would read my post again, he would notice that I stated I am an engineer. So, YES, I am perfectly aware of the formula for power. This discussion is a comparison of how we like our power produced. Most folks refer to low-speed, high torque power as "torque" and high-speed, low torque power as "power" or "horse-power". I simply believe that the low-speed, high torque version of "power" is more useful in most situations. My Cummins powered Dodge produces more power in the useful operating range of 1400-2100 rpm than any gas-engine powered truck. My Harley is the same! I have an Echo 550 that produces more torque than my MS260, but does not produce as much power due to a lower speed range in its torque curve. I find it much more pleasing to run this saw as it does not "scream" to make useful power. Just my own opinion.....which is what this post is all about. No name-calling needed!
Chris-PA
Where the Wild Things Are
Before the other thread was ruined by BS, there were a few comments about the shape of the HP curve. A vehicle must accelerate from a low rpm under load and pull that load continuously to a high rpm. A chainsaw is not expected to pull a load from idle, but it is not really a fixed rpm engine either. So what HP profile is best for a chainsaw?
That's more or less what the OP was asking in the other thread, though specifically he was asking what most people preferred, not necessarily 'what's best' which is subjective depending on endless factors.
I don't think there's any way to frame that question so everyone understands the intent... and I don't think he got the answers he was looking for...
Mastermind
Work Saw Specialist
Who cares?
Seriously......
Go cut some wood and quit playing with your peters.
Seriously......
Go cut some wood and quit playing with your peters.
Chris-PA
Where the Wild Things Are
This topic seems to bother you for some reason? I expect I probably agree with you in terms of desire power profile, but I see no harm in a bunch of saw nerds talking about it.Who cares?
Seriously......
Go cut some wood and quit playing with your peters.
It's the end of January heading down to 8deg. Probably cut some tomorrow but wtf else should we talk about - oil?
Who cares?
Seriously......
Go cut some wood and quit playing with your peters.
I care.... seriously.
Sorting through all the crap is just an inevitable part of the process, still worth it for me at this point, I don't port 5 or even 1 saw a day so I'm not so jaded... yet...
I'm pretty comfortable with 4 strokes but still early on the learning curve with 2 smoke saws so I absorb everything I can.
I've struggled with all the compromises of 'where to put the power' in most every performance motor I've ever built, 'more grunt' or 'more peak', or...
That dyno graph I put up in the other thread was a bike motor I was building specifically for a big fat midrange, massive drive to slingshot out of the corners on twisty roads.
I don't like peaky power for that, it bogs and then spins the rear tire up when the power hits. Different than saws, I know...
Obviously you try the get the most power overall out of a particular motor but it seems ultimately the compromises push toward either a lower peak power in a broader range or higher peak in a narrower range. With a 4 stroke that's due to lots of things, among them the relationship between cam lift, duration and overlap.
Then you can also move the power band around some without affecting it's peak or width quite so much by things like cam timing, intake tract lengths and fuel/advance curves. I'm sure much of this could be paralleled to 2 stroke port timing and transfer parameters but I just don't quite get the big picture... yet.
So here I am...
I also was really interested in the other thread because ms460 port timing numbers were involved in the first post and I just did one that I'm not quite happy with and am not sure what direction to take it from here. Did leave myself some wiggle room.
Was pretty disappointed when the thread almost immediately went to hell...
And my firewood season just ended abruptly with 3 feet of snow the other day... and my shop is freezing...
Mastermind
Work Saw Specialist
Well I should have said that when you guys can't even agree on how HP numbers are derived, this sort of discussion is a complete waste of time.
Better?
Better?
TEZZA
ArboristSite Operative
AS far as I know:
Brake dynos measure torque.
Inertia dynos measure horsepower.
Most dynos seem to be brake type and the horsepower figures are calculated.
Even if everyone doesn't agree on a matter being discussed, it's still good to discuss and learn without copping insults.
It's probably the most piss off thing about this forum.
Peak Hp@Xrpm is a very limited spec but it gives some indication of possible performance, same with Tq.
Brake dynos measure torque.
Inertia dynos measure horsepower.
Most dynos seem to be brake type and the horsepower figures are calculated.
Even if everyone doesn't agree on a matter being discussed, it's still good to discuss and learn without copping insults.
It's probably the most piss off thing about this forum.
Peak Hp@Xrpm is a very limited spec but it gives some indication of possible performance, same with Tq.
Chris-PA
Where the Wild Things Are
Well I know it was a hot topic here, but really it was settled 100 years ago.
