::: Power vs Torque :::

[ericjeeper]

definition of torque

Torque is the amount of pressure required to push down morning wood, without knocking your feet out from under you.. sorry I could not help myself..Only torque joke I know..

 

[GASoline71]

I'll take a big torque monster saw any day over. Especially in big wood. That's why gear drives were used back in the day.

They used the same power... put it through a gear reduction and wham... tons more torque.

Or... like the Stihl 090 and 090G... the 090 is 137cc's where the 090G is something like 106cc's... but run through a gear reduction. I be that the G has more torque than the non-G model.

Gary

 

[peter399]

...
diesel engines are a good example of torque. not a quick sprint on the 1/4 mile, but put that 6000bhp top fuel drag car against a 3000bhp diesel, load em up with 600 tonne of weight, and see who gets to the finish first!
....

Sorry Steve, but with proper gear selection the 6000bhp top fuel drag car will reach the finish first.

Power = Work / time -> Time = Work / Power

Work = Drag the 600 tonnes to the finish line.
Power = Hp

Torque is nothing physical, it is something you need to create power. (Power = Torque * ang. velocity)

 

[oneoldbanjo]

Well...HP is a measure of work.....and the 6000 HP top fuel engine could probably beat the 3000 HP diesel to the finish line if it had proper gearing and didn't fry the tops of the pistons before it got to the finish line.

If you are racing your chainsaw....get as much HP as you can to make those three cuts through the wood as fast as possible. When you are using a saw and cutting wood all day - I believe a nice balance between HP and torque is necessary. You need enough HP to get through the log in a timely manner with good chain speed - and enough torque to pull the chain when the saw blade is buried in the large logs.

 

[stonykill]

if the question is, would I prefer a saw with a lot of torque but a lower rpm for peak hp vs a lot of peak hp at high rpm but lower torque (thats just how it works), I'll choose the torque monster every day.

 

[stevethekiwi]

Sorry Steve, but with proper gear selection the 6000bhp top fuel drag car will reach the finish first.

Power = Work / time -> Time = Work / Power

Work = Drag the 600 tonnes to the finish line.
Power = Hp

Torque is nothing physical, it is something you need to create power. (Power = Torque * ang. velocity)

true if you are comparing a 6000bhp petrol vs 3000bhp petrol, but i wasnt...

i encourage you to surf the web and compare specs on cars / utilitys / stationary engines / gensets that offer diesel / petrol options.

Take my nissan utes for example (I use the diesel)

Petrol - 200kw power 4L v6 385nm torque
Diesel - 100kw power 2.5L 4cyl 403nm torque

I can tell you that when i put the Rayco 1672 on the back (google that too if you wish) the diesel beats the petrol hands down, dont even need to change down when going up hill. however, unloaded, the diesel gets left behind in a cloud of dust.

so yes, 600 tonne being towed by a 3000hp diesel would beat a 6000hp petrol. rate of work means nothing if you cant get the thing moving!

 

[Outlaw5.0]

Without torque you do not have hp plain and simple. The amount of hp you have depends on WHERE in the rpm band the torque is. The formula is horsepower = rpm x torque / 5252.

 

[windthrown]

In a chainsaw engine:

power = torque x revs

You are comparing apples to oranges here when you compare torque to power. I do not see the difficulty in understanding this. Yes, w/o torque there is no power from a chainsaw and no work gets done. Simple physics:

power = 0 torque x high RPM = zero

But the same goes for chain speed. With gobs of torque and no chain speed, your saw just sits there not cutting. Again, simple physics:

power = high torque x 0 RPM = zero.

Same result either way, zero power if torque or revs goes to zero.

The real debate here should be between the factors that make up chainsaw power. Torque... and revs. Now, in that debate, is it better to have a high revving saw with less torque, or a low revving saw with more torque? Horsepower being equal.

 

[RiverRat2]

..and it starts..

O.K. CHOWDOZER, whip out and dust off your prior arguments.

Just try to move that chain with out any Torque!!!!!!!

Torque and Power, Torque and Power, Goes together like dirt and flowers,,,,

Can't have one without the other!!!!!!

2095,,,,, did you do this on purpose??????

It seems to me almost everyone quotes Hp as the only relevant measure of a saws engine [or cutting] performance.

So, whats your preference?



Its a fairly black or white poll, but I am interested to know the general consensus: please vote and/or state your preference and why. :chainsawguy:

 

[1953greg]

Without torque you do not have hp plain and simple. The amount of hp you have depends on WHERE in the rpm band the torque is. The formula is horsepower = rpm x torque / 5252.

therefore: torque = 5252 x hp / rpm

just get a bigger saw and have them both!!!!!!!!!!!!!:hmm3grin2orange: :hmm3grin2orange: :hmm3grin2orange:

 

[Outlaw5.0]

There is a reason why I have the MS460.

 

[Jacob J.]

IMO there is no substitution for displacement.

That's why all those old-time saws are monsters.

 

[husky hustler]

It doesn't matter how much torque you have when you are using a centrifugal clutch! By the time your clutch engages your precious torque is curving off the charts. That is where horsepower kicks in! If a chainsaw had a torque converter instead of the centrifugal deal, then you would have a chance in the matter! It takes no toque to turn a centrifugal clutch, just lots of rpm's and power!

 

[stevethekiwi]

It doesn't matter how much torque you have when you are using a centrifugal clutch! By the time your clutch engages your precious torque is curving off the charts. That is where horsepower kicks in! If a chainsaw had a torque converter instead of the centrifugal deal, then you would have a chance in the matter! It takes no toque to turn a centrifugal clutch, just lots of rpm's and power!

er...no

a centriugal clutch needs rpm to engage. doesnt matter if its torque or power.

a torque converter still uses centrifugal force, but as an example of hydro-dynamics. I have one around here somewhere if you want a peek inside, its been cut open with a gas torch.

 

[stevethekiwi]

i think everyone is still missing the point that both torque and power are relative.................



which saw should i buy?

 

[spacemule]

It takes no toque to turn a centrifugal clutch, just lots of rpm's and power!

Power is a function of torque. Therefore, your statement is completely invalid.

 

[spacemule]

I think a fact that seems to be overlooked is that torque is a force, whereas power includes a movement. You can have a great amount of torque but no movement. Think about tightening a bolt. Once tightened, you can continue applying torque with no movement.

You can never have power with no movement. Torque applied to a static bolt that stays static will result in zero horsepower.

 

[stevethekiwi]

I think a fact that seems to be overlooked is that torque is a force, whereas power includes a movement. You can have a great amount of torque but no movement. Think about tightening a bolt. Once tightened, you can continue applying torque with no movement.

You can never have power with no movement. Torque applied to a static bolt that stays static will result in zero horsepower.

Agreed!

 

[husky hustler]

True that you cant have hp with out torque. In the application of a chainsaw torque is nothing more than the heat generated when your sprocket is turning at a fraction as your crankshaft. Do you honestly think torque is an issue at 13,000 rpm? Look at any dyno. It is below the chart at that point! That is why Stihl reports brake horse power. HP under load.

 

[Tree Sling'r]

Build a saw that has both.