Cc or hp

[Tom Hall]

I have been asking various people who i consider to be my superiors this question and i am struggling to get a sensible answer!

 

I am not a mechanically minded person so this sort of thing is out of my comfort zone.

 

when buying a saw and you have 2 competitors so closely matched one has a slightly higher cc but the other has slightly higher horsepower, what are the advantages to both. I suppose what i am asking is what is hp and what is cc at the end of the day, please don't laugh at my ignorance

[swinny]

cc is engine size

 

hp is the power out put

 

with the bigger cc machines comes more weight, then you start to think about power to weight ratio. Bigger cc generally better for running bigger bars

 

so its a heavy bugger with x amount of power, then another model lighter with the same power or more would have a better power to weight ratio

 

the bigger the cc the more hp 'usually'

 

to help with answers, what models of saws are you looking at?

[Richard 1234]

I would probably go with slightly higher cc as the smaller one will be working harder to produce the extra horsepower.(ready to be shot down by people who know better:thumbup:)

QUOTE=Tom Hall;1231662]I have been asking various people who i consider to be my superiors this question and i am struggling to get a sensible answer!

 

I am not a mechanically minded person so this sort of thing is out of my comfort zone.

 

when buying a saw and you have 2 competitors so closely matched one has a slightly higher cc but the other has slightly higher horsepower, what are the advantages to both. I suppose what i am asking is what is hp and what is cc at the end of the day, please don't laugh at my ignorance

[computeruser]

HP measures power, which is what gets work done. CC measures, quite literally, cylinder displacement, which in and of itself does not translate into getting work done.

 

Increased displacement may correlate with increased torque, or a lower operating RPM.

 

When talking about saws and other two-stroke engines, you get into an additional consideration: porting. Much as you can get different power profiles out of 4-stroke engines of the same displacement by changing the camshaft lobe profile (lift, separation, duration, overlap, etc.), the differences in porting (timing, volume, duration, etc.) as well as the velocity of the fuel/air mix coming through, will influence how much power you will get out of a saw of X displacement.

 

The best (to my mind) example of the dynamics of CC versus HP is the Husqvarna 357xp versus 359. Same chassis, and you can swap pistons/cylinders between them. The 357xp is lower displacement, but produces higher power in stock form. It uses stuffers on the crankshaft to reduce the effective volume of the crankcase, unlike the stufferless 359. The stock porting of the 357's cylinder is more "enthusiastic." And the result is a more powerful saw in stock form

 

The elephant in the room: the primary reason that the porting is not optimized for power from the factory is our friends, the eco-police. Emissions requirements result in reduced power/performance from what is conceivably possible. For a time in the US, a "net emissions" model was being used - saw makers could continue to sell higher performance, higher-polluting models in their professional saw lines if they sold lots of lower-performance, lower-polluting (e.g. choked-down exhaust, non-adjustable carbs, etc.) "homeowner" saws. Luckily, technology has come along way and they can now get high performance and lower emissions, albeit at the expense of higher price points. for its pro saws.

Edited January 4, 2015 by computeruser

[Ukulian]

CC is the Cubic Centimetre capacity, or size of the engine, normally a single cylinder. The hp is Horse Power, sometimes measured in Kw (Kilowatts) and tells you the actual working power of that engine.

As explained above, not every X cc engine has X hp(Kw) which is where the confusion arises.

HIH

[GardenKit]

And Torque is more crucial to performance than either HP or CC.

But at this time of night I cannot explain why!

[Eddy_t]

Torque pulls the longer bar, at the expense of rpm

Power is how strong the saw is, but without seeing a power-curve, this is useless if the peak is at a point where it's unattainable.

Displacement (cc) is the engine size, the larger the saw, generally the higher the torque.

Most never cut on a torque band, most never cut at peak power.

Porting shifts the power and torque bands.

[Mull]

Torque pulls the longer bar, at the expense of rpm

Power is how strong the saw is, but without seeing a power-curve, this is useless if the peak is at a point where it's unattainable.

Displacement (cc) is the engine size, the larger the saw, generally the higher the torque.

Most never cut on a torque band, most never cut at peak power.

Porting shifts the power and torque bands.

 

 

How do you see a power curve eddy?

[GardenKit]

The point is this. There could be two different saws with exactly the same cc and hp. But the one with the greater torque delivery will be the best.

The max torque will come in beneath max revs, but it is at the point where the revs are held onto best.

Torque is what gets work done.

High speed equals low torque, and vice versa. Peak torque is where the max power is generated.

[Mull]

The point is this. There could be two different saws with exactly the same cc and hp. But the one with the greater torque delivery will be the best.

 

The max torque will come in beneath max revs, but it is at the point where the revs are held onto best.

 

Torque is what gets work done.

 

High speed equals low torque, and vice versa. Peak torque is where the max power is generated.

 

 

If the chain is blunt, torque struggles, there is many variables in this argument. Infact, too any to Come up with a sensible answer.