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torque v power

I

Icey101

Jun 22, 2011
492
10
Australia Victoria
#1
so is the quality of ride or drive better with a motor that has more torque but less power then a vehicle that has more power but less torque?

what do i mean by that...

well my mate has a harley and my other mates have MIJ bikes...

of course the MIJ bikes have twice the power in HP, MIJ bikes get this by increasing the revs of their motors and higher and higher powerbands, in other words you have to be containtly speeding and reving the guts out of the bike to enjoy the power of your bike. The harley has max torque at alot lower revs so as you roll around the streets your contantly using full torque to pull yourself away from the corner

same with v8s v ricer turbo 4s

the 6 litre donk pulls smoothly with low end torque while the WRX will hammer staight past you off the start pushing revs around 7 grand. I'm talking standard cars here

so i ask is the quality of drive better with more torque or more power?
 
#2
Torque is Lb x ft., HP is (Lb x ft.)/time. If we put this in minute we also get: HP= (T x RPM x 2pi)/33000 or HP=(T x RPM)/ 5252 if you prefer.

Basically this little bit of math tells you Torque matters more under 5252rpm and HP more over it. Both are of course in relation as you can see.

I'm not really a car buff or anything, I may be wrong but this is my understanding of it.
 
#3
It depends on what you consider a "quality drive". But I think I know what you are saying. High torque will give you pull off the line, the ability to go up hills without having to change down, easy towing etc. It feels more refined than having to plant your foot and wring the guts out the engine.
 
#4
The fact that you're asking the question means that you're aware of your ignorance and are willing to learn and this is an admirable attitude. Truly, this subject has been beaten to death since engine building became a topic and gigantic piles of information are now available with the click of a mouse.

The short answer is about the lws of physics and applied engineering. Torque is the twisting force that makes your vehicle accellerate and how torque is mechanically applied to the ground from the engine by maximizing this force through the rpm range determines how fast you will accellerate. In theory, this is asimple principle of maximizing the area under the curve, but in practice, the details become an excessively complicated puzzle that rewards those who are best at solving it with racing victories.

Horsepower is mathematically related to torque but is not a direct measure of the ability to accellerate, the way torque is. The only real use it has is to help marketers advertise how awesome their engines are on paper.
 
#5
Icey101 said:
so i ask is the quality of drive better with more torque or more power?
Click to expand...
The driving experience is different, as you have already observed. Which is better is just a question of what you like. Remember that even if two engines produce the same maximum HP and torque, they can feel very different depending on where in the RPM range the maximum occurs and how steeply it rises and falls before and after the peak.

Also remember that 1 horsepower = 745.7 watts = 250 tube watts.
:hiding:
 
#7
Generalising massively, a high-revving engine that is big on power and low on torque will be great fun to drive fast. And a high torque engine will be preferably for most people in day-to-day driving. And Harley's will always be slow until they stop using 1950's technology. And, even then, they'll never go around corners like a sports bike because that's not what they're designed for.
 
#10
Jim Nazium said:
The driving experience is different, as you have already observed. Which is better is just a question of what you like. Remember that even if two engines produce the same maximum HP and torque, they can feel very different depending on where in the RPM range the maximum occurs and how steeply it rises and falls before and after the peak.

Also remember that 1 horsepower = 745.7 watts = 250 tube watts.
:hiding:
Click to expand...

And 1HP=33000 BTU, if anyone cares.
 
#12
It's funny how this can seem and I said seem like tube watts vs. SS watts.

A Porsche 911 say makes it RPMs up high in a light car it's thrilling. Get in a real muscle car say a 454 Chevelle and stomp the gas and it feels like a building just hit you from behind while caving in your chest from the front. That's torque, down low.

In amps those big transformers seem to give a different perception of Boom.

Back to cars. Some of the Ford Formula 1 engines were 1800 HP out of a tiny 4 cylinder engine. Did all that racing with high RPMs and were rebuilt after every race. Its all good. Depends where you want your power band.
 
#13
It's personal preference, and also about where the vehicle needs the power. My regular vehicle is a 98 Jeep Wrangler with a 4.0 liter Inline Six. Plenty of torque off the line, but I rarely take it above 3k RPM because there is no need to - all the power is below that. That's where it's needed when crawling hills in 4 Low or pulling a Hummer out of a mud hole.

In contrast, my other ride is 2006 Yamaha FZ6 sportbike. It revs up to 14k RPM and the power doesn't start until 3k and it really wakes up at 8k. But it's a light sportbike made to go fast, so the powerband is a lot higher and broader where it can be used more efficiently for speed in corners. But it would be horrible for climbing slippery hills or pulling friends out of mudholes.

In regards to the driving experience, I find it much more satisfying to drive to the vehicle's strengths. My Jeep it's best to drop the top, take the doors off, and enjoy some nice countryside driving. On the bike, find an open twisty road and HOLD ON!! :)

Peace,
Greg
 
#14
Hi.

Mike N said:
Horsepower sells cars, torque wins races.
Click to expand...

^This.

Even though it sounds like a clishé, that's the way it is in the real world.

BTW, comparing two geometrically different engine constructions is pointless, and unless You have a stroker, the classic HD engine is shy on torque as well as power.
Compared with anythig.

THANK GOD for the fact that power and torque aren't the only deciding factors when choosing our rides though :).

Regards
Sam
 
#16
Harley's are always a terrible analogy as they have nothing going for them except the "image". They're slow, unreliable, expensive, and have an aversion to turning corners. There's lots of good bikes that perform well without having to rev the hell out of them - good Japanese or European V-Twins that have good power and torque, and know their way around a corner.

The same is true of cars. I drive a 3.8L V6 Commodore which is fairly standard (except for the Stereo). Not the fastest car in the world, but good for towing, and a nice highway car. It's relaxed at high speeds, has good torque for overtaking and handles pretty well. I won't win many drag races, but they're probably one of the most reliable engines ever made, so I'm confident driving it anywhere (and have done). It really just depends on what you need them for.

Now if you want serious torque, my little 15hp Kubota 4wd tractor could probably tow your house away (no kidding!). I had a really bad day once, and used it to tow Wednesday back to Tuesday.
 
#18
I rode a Sporster, and Vrod, briefly EDIT (very briefly, a few minutes apiece)- didn't care for them. Sure the torque starts early, but it's over as quick as it started. My CBR600f2 just keeps making more power. 5k starting to pull, 6k pulling, 8-10k woot! 11-13k OMG! How do you like it? MORE, MORE, MORE! The RPM range where the engine is making good power is more than twice as wide as on an HD.

Not that I'm against more torque. I'm just not willing to give up HP, light weight or cornering to get it. I'd buy I Triumph 675 triple, if I were minted.
 
#19
Its all about the weight of the vehicle, and having enough torque to move it.

Then depending on how fast you wanna go, its more about gear ratio. Gear ratio depends again on the weight of the car, and top speed then relates to RPM of the motor.

So yes as mentioned torque is gonna win the race. Getting out of the start gate faster or out of the hole faster. You need torque to do that and then RPM to hold that speed.

just think of riding a bike when you really have to stand and push on the pedal to get moving, that is torque. How long you can continue to do that over a time period is horsepower.
how fast you can pedal is rpm

horsepower is really a worthless number if your not strong enough to get the bike moving in the first place.
and if your not strong enough to get it moving then it goes back to gear ratio. then within that gear ratio your top speed
depends on how fast you can pedal.
 

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