How do you explain this?

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Baracade
Relationships! The only time you get to sleep with the enemy!
1972 US Export Moke in Bundaberg QLD

tell that to the rotory drag racing guys running mid 6's at over 210mph with massive hp but not much torque

It all comes down to the weight of the car, the suspension setup, driver, tyres etc just because you have torque dosnt mean your going to win anything, unless its a tractor pull event.

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1974 Moke - 998cc
76 Clubman B16a2 Vtec AWD Turbo 12.9@105mph
https://www.youtube.com/watch?v=V9PW49e1hYs

a good way to explain is:

power (hp) is how hard you punch some1

torque is how fast you punch sum1

oodles of both and ur fine

HP is a calculated number based on Torque x RPM, a race car that has huge torque that is only available at very high RPM will have to be driven at very high RPM all the time to make decent power and go as fast as possible.... a motor that has a lot of torque available through a wide rev range (3000 - 7500 is great for an A series) will be easy to drive fast

those rotary drag cars would use gigantic RPM to make lots of HP with low torque

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did I tell you that I won a trophy?

It's a bit of a play on words Dean but what someone is trying to imply is the sooner you can produce torque the better.

Whilst you can 'improve' the output of torque of a 1.3litre motor they are designed to rev. Refer Simon's calculation about Torque * RPM.

Torque equals leverage equals acceleration.

Power equals ability to push air out of the way equals top speed.

Thus a Harley Davidson (acres of torque) can accelerate hard, but no power for top speed. Hondas (CBR900RR) have to rev really high to acclerate but have very high top speeds.

Performance cars require torque to accelerate their weight, and power for top speed. A surfeit of either will help for drag racing, but top speed can be achieved regardless of torque but you would need a long time to get there. For example, if you slipped the clutch long enough (on a flat road) you could take off in fourth.

Torque vs High end power is a trade off.

So for the same capactity you can have a motor that is torquey down low in the rev range, but no much good at high revs. Or a motor that has no pulling power down low but makes good torque at high revs.

What it then comes down to is driver/rider skill. With a torquey motor it isn't as critical to have the machine in the right gear all the time. You can point and shoot. With a more highly strung motor, you have to keep the motor within a smaller rev range to be fast. But if a motor has very little torque down low in the rev range, then it will be hard to get it to rev up into the range where it does make power.

e.g. Early 500cc Grand Prix bikes were real pigs. Back when Mick Doohan started racing, you had about a 1000 rpm power band where the motor made its power. Drop below that range, or rev harder and the power output really dropped off. High HP but very difficult to ride fast. For the average rider/driver, torque means drivability.

Why do people go for rev happy motors then? Because although the drivability is less, the peak power is higher. In the right hands & on the right track they will be faster for the same capacity.

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"Life is not like a box of chocolates... it's more like a jar of jalapenos. Whatever you do today, may burn your arse tomorrow."

It does relate in a mini world, in that short stroke motors (998) can rev harder (to their mechanical limits) than long stroke motors (1100), but a long stroke motor will in general make more torque.

Road cars generally require more flexibility (torque) than all out power, as this makes them more drivable. Some guys prefer motors that come on in a rush as they feel faster even if they're not. IMO, a motor should produce progressive power, unlike my brother's scooby doo turbo which has a rush of power as the revs rise and the pressure builds, which you can never take advantage of on the road. My CBR600, in a low gear and hgh revs, feels like an electric motor - zinnnnnggggg!!!

I know what you're trying to say here but i think you wrote it backwards...
power is how fast you punch someone and torque is how hard you punch someone. That is the only way you analogy would be correct.

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- Simon -

Or the horse analogy , horsepower is the racehorse that get's there quickly but can carry the lesser load , whereas Torque is the drafthorse with the slower but more constant , stronger force that carry's the heavier load without slowing . It doesn't matter how you try , it's still something that's difficult to explain without a lot of formulae and will still sound confusing ....

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Its pretty simple really HP=torqueXrpm/5240 (I think that's the constant - if not its pretty close). So, at 5240 rpm any engine produces exactly the same amount of torque (in ftlbs) as it does HP.

Is that helpful...probably not..

Cheers, Ian

5252 rpm

I don't want to labour this thread, but that formula is for rotating objects and not objects moving in a straight line. For objects moving in a straight line, a more accurate formula would be force x velocity (more specifically force in pounds and velocity in feet per second, all divided by a constant of 33000).

But it's all relative and is much better exhibited watching motor racing and comparing the differences between say a cosworth and a turbo ferrari, or Wayne Rainey vs Kevin Swantz in the German GP of 1993. I guess it also relates to Minis, in the argument of single HS4 (torque) vs twin HS2 (power)

I think the saying goes....

Torque wins races
Horsepower sells engines.

use metric and you don't need to remember all those stupid constants

torque is the "turning force"
force is measured in newtons N
distance is measured in meters m
torque is the multiplication of the force and distance from the pivot point it rotates about, so the units are newton meters Nm

simple

power is the "rate of doing work" and is mesaured in watts W
and as said above power is the torque multplied by the rpm (speed) Nm/s = W

aah gotta love the SI units

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