How to explain Torque ?

Last night i was having a bike talk with my brother , he thinks i made a bad choice of bike , and his point was that a FZ6 or a hornet has almost 100hp , but my SV only has 70hp and cost almost the same that a hornet/FZ6, they have something like 30%/40% more HP but only cost 7% more !

So i told him that the SV is lighter and has more torque than any other 600cc Naked , And tried to explain him what is torque ! Only to realise that i cant explain what is torque , or HP
Actually i think i dont know what torque and HP are, fancy numbers but what else ?

I can see that there is a relation between HP and top speed !Top speed is a good , and easy to understand , but torque is kind of hard to explain !

I told him that HP = top speed , and torque = acceleration , and on a naked bike acceleration is fun , top speed not so fun, but im no sure if this is correct !


How would you guys explain the advantages of torque over HP ?

[jambo]

Torque is the turning force of the engine. HP is an artificially created figure calculated from Torque & RPM. If 2 engines produce the same torque but 1 does it at 3,000 RPM higher it will have more power at that point

To look at it the other way: for the same power, the motor turning the slowest has the most torque.

That said it is a useful figure for showing what the engine is doing as Torque curves and power curves tend to tell a good story between them

From google:

Torque - The force which tends to cause rotation. [Basically, accelleration]

Horsepower - Horsepower is a unit of engine power equal to 0,746 kilowatt (kW). Originally developed by James Watt to compare the power of steam engines to the work done by a horse. [Again, I take that to be 'maximum pull', therefore, top speed - I can just imagine Mr Watt now... "This steam engine has power equal to that of 43 horses"]

So the torque numbers ,just mean how easy it is for an engine to gain more RPM ?


And that explains , the drop of accel on the SV after 8000/9000 rpm's , that's when the torque curve start to drop !

Sid Squid and Embee will doubtless be along to give chapter and verse, and to um, twist your thoughts accordingly .


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I wouldn't get bogged down in BHP/Torque figures.
The performance of a bike is dependant on so many other things.

Ok the SV is 20 odd bhp down on the Hornet, but you'll find the top speed and accelleration figures are fairly similar.

[Stu]

I'm confused too.
How can Horse power refer to top speed as surely a carriage with 12 horses isn't going to go any faster than a carriage light enough to be pulled by 4 horses?
Jambo - what is the relationship between HP torque & RPM?

Contrary to popular (forum) belief, the best thing you should do with torque is forget you ever heard of it! Torque is static turning force - and engines aren't much fun when they are not actually moving! If anything, it is the torque that is the calculated figure as engine/rear wheel dynos measure HP. It is HP at a particular RPM that translates directly into acceleration (assuming weight and aerodynamics are the same).

The only thing that matters is the shape of the power curve when comparing two engines. When folk mention torque they are really meaning good power lower down the rev range. Low down power usually means better manners, easier more controllable fast starts, and good acceleration over a broader range of rpm. In theory you could just slip the clutch on the more powerful bike to get it right up in the power band, but in practice this will cause either wheelspin, or wheelies or both...

Two points of reference for those with a thirst for knowledge:

http://en.wikipedia.org/wiki/Torque

http://vettenet.org/torquehp.html


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Originally Posted by sdusk

Contrary to popular (forum) belief, the best thing you should do with torque is forget you ever heard of it! Torque is static turning force - and engines aren't much fun when they are not actually moving! If anything, it is the torque that is the calculated figure as engine/rear wheel dynos measure HP. It is HP at a particular RPM that translates directly into acceleration (assuming weight and aerodynamics are the same).

The only thing that matters is the shape of the power curve when comparing two engines. When folk mention torque they are really meaning good power lower down the rev range. Low down power usually means better manners, easier more controllable fast starts, and good acceleration over a broader range of rpm. In theory you could just slip the clutch on the more powerful bike to get it right up in the power band, but in practice this will cause either wheelspin, or wheelies or both...

That's completely wrong.