purchasing a new ute can someone please explain the above for me in laymans terms that i will understand.
tamarillo,
Aug 23, 6:23am
Torque is twist, or for a ute it's pulling power, torque gives you acceleration. If you've got a tight bolt to undue you use leverage yeh? You find as long a handle as you can get and apply force to its very end. If you had a crappy socket extension it might well twist and stuff itself.
Put another way, A power driver geared at high speed won't undo that nut. Now change its gearing so it's only just turning and it might. Speed won't shift it, torque will. In ute that's the force twisting the drive chain and the wheels, hence it pulls weight including accelerating its own bulk.
Horsepower (or kilowatts) is the torque x the speed it's turning. So whilst it reflects torque it adds in rpm of engine and torque at those rpm. So in low revving diesel a high torque figure is paramount. On a high revving vtec Honda S2000 engine HP is most important as its happy to be revved and there is less weight to haul around. You could get 100hp from a 125cc bike racer engine, but it probably wouldn't get your ute to move. Lots of power, but no twist. But you could stick a 30hp industrial diesel in there and it would move it as it has torque. It's torque that accelerates. There's been great comparative tests of two competing cars, one with latest low pressure turbo and small engine, say 1.4, against a competitors modern 2 litres. On paper they have similar torque and HP and weight. But the little ecoboost gives torque at far less revs so in real world driving feels much quicker.
For a diesel ute, torque pulls stumps, and the weight of the thing. High torque at low revs works.
God I hope that's right.
clark20,
Aug 23, 6:24am
Kilowatts is power, i.e work done, torque is the turning force. Torque makes power, but depends on at what speed to how much power is made. Turbo diesels make low power but high torque relative to a petrol motor of the same specs. I did a quick calculation and found that high torque diesels performed or accelerated like they have 20% more power ie a 100kw turbo diesel accelerated to 100km/hr about the same as a 120kw petrol version (this is a generalisation, and based on Audis etc selling both petrol and diesel motors in the same car)
tintop,
Aug 23, 12:32pm
kW is the measure of power.
Power is the rate of doing work, not the amount of work done.
Yeah (joules per second so energy over time) and my dad can beat your dad up LOL. I don't think we need to get too technical with the answer.
r.g.nixon,
Aug 23, 1:25pm
The mistake most people make when engaging in this debate is considering horsepower and torque independently. Almost everyone argues as if they are separate, unrelated values. They aren??
tweake,
Aug 23, 1:28pm
you have to remember that advertised power and torque figures don't give you a complete picture. what the power/torque curve is like on a graph is a better indication on how the engine performs.
then the gear ratios will make or break the engines performance.
what really matters is power to the ground. eg big grunty engine is no good if its so highly geared you struggle to get off the line and accelerate extremely poorly. theres a few reasonable decent powered utes around that are so highly geared they are gutless off the line and struggle to get up to speed. but once you get the revs up away you go. until you drop the revs to low. put a big load on it and they are a nitemare to drive. eg have to get into low range to get going.
so low gearing is really good for loads, but its poor for high speed cruising. the trouble with ute is often they are restricted to 5 speed manuals. some of the 6 speeds are not any wider spread of gears than the 5 speeds lol.
diesels have such narrow power band that you really need to have a well matched gearbox and diff ratios.
tintop,
Aug 23, 1:49pm
Well - it is a technical question , and the relationships between power, work, energy, acceleration, mass, momentum, force, torque etc are not understood by many and is the reason behind the op's question. Fudging units just adds to the general confusion and indicates a lack of understanding.
tintop,
Aug 23, 2:05pm
Oh - there are so many derived units :)
tamarillo,
Aug 23, 2:38pm
Laymans terms!
melonhead1,
Aug 23, 2:58pm
I really like that saying about "Horsepower is how hard you can hit a wall, torque is how far you take the wall with you.".
kecal,
Aug 23, 3:33pm
well thats clarified things , a little thanks.
woodypc,
Aug 23, 5:36pm
This. It really comes down to at what rpms it make the power/torque at, and what suits the gear ratio.
bwg11,
Aug 23, 7:15pm
Torque is rather irrelevant, it is horsepower (or kilowatts) that pulls heavy loads up steep hills quickly. I know, I've towed big boats with several common rail utes with 450 plus N.m torque, but none of them can touch a 200 kW petrol with only around 385 N.m of torque.
delerium1,
Aug 23, 7:26pm
Actually you're wrong. The percentage difference in torque is tiny compared to the difference in power. That's why the difference. There is a reason big rigs are diesel with gobs of torque
bwg11,
Aug 23, 7:29pm
I repeat, power is work done, i.e. how fast a load is moved up a hill. The reason big rigs are diesel is fuel efficiency, which also has nothing to do with torque or power.
tintop,
Aug 23, 7:33pm
Yup - Power is the only thing. It's the stuff that does the work, and the more of it you have got the faster you can you can do that work - whether it is towing stuff up hills, or overcoming wind and rolling resistance, or dragging off at the lights. Power is the stuff that lets you do these things.
Torque largely is irrelevant as The final drive ratio and the intermediate gear ratios 'should' be correctly chosen by the designer/manufacturer to match the characteristics of the engine and the duty the vehicle is expected to perform.
tintop,
Aug 23, 7:37pm
Power is the RATE of doing work. ie - the more power you have the faster the load can be moved up the hill. In shifting a load from the bottom of a hill to the top, the same amount of 'work' is done regardless of the speed the load is shifted. But shifting it faster is doing the same amount of 'work' in a shorter time, this will require more 'power'
So for a 100kW motor towing a load up a hill an 10 minutes does the same amount of work as a 200kW engine going up the same hill with the same load in 5 minutes, but more power enables the job to be done faster.
bwg11,
Aug 23, 7:55pm
tintop - Thank you putting it so succinctly. I usually give up on these torque/power discussions.
tintop,
Aug 23, 8:01pm
Cheers bwg11. I usually give up too - but TV is crap tonight, and listening to the request session is soooooo relaxing.
So I gave the brain a bit of a kick start.
mrcat1,
Aug 23, 9:58pm
Trucks are rated exactly the same as utes, except they use ftlb's rather than Nm and horsepower than Kw.
tintop,
Aug 24, 6:03am
Yes, considering the fact that the US as a major supplye of engines, transmissions, and fully built trucks are still in the 'dark ages' regarding the use of measurement units units - feet, pounds, horse power etc are still in common use.
mrcat1,
Aug 24, 6:57am
OP, just understand, the more of both the better the ute will go, end of story.
tweake,
Aug 24, 8:31am
not that simple, as explained before.
its only max figures they quote which doesn't really tell you how it performs. then gear selection makes a big impact on how it actually drives. end of the day its how it drives on the road that counts.
its not uncommon to have lower powered vehicles out perform more powerful vehicles due to more usage power range and better matched gearing.
mrcat1,
Aug 24, 9:35am
I think you will find the higher of both units the better a ute will go, and I think from the OP's point of view simple is best, so the greater the numbers the better it will go. As most utes are moving towards 6 speed manuals or 7 speed autos gearing wont come into to much. And none of the manufacturers of utes really give any performance figure's.
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