Torque

[Suprash]

Right I hope I got the right area for this question then, although I nearly stuck it under General Discussion , see what you guys have done to me, Im a reck.

 

Anyway on with question. Now I know BHP and torque go together, and I understand what BHP is all about, but what I dont really understand is the torque side of things. Why is torque so important and why is measured/used

 

/Pupil waits quietly for teachers answer !!!!

 

[Supra_Al]

Ok Ashley, are you sitting patiently, legs crossed, i'll explain......

 

Read this, and all will be clear!! Al.

 

http://www.car-videos.com/articles/horsepower_torque.asp

[Suprash]

Originally posted by Supra_Al

legs crossed[/url]

 

Bar, you got the wrong person mate, GGRRHHHH wheres Mark !!!!

 

Sorry, Im taking this too far now, reading link......

[Suprash]

Right I read that, I do hate when they start dividing and multiplying words, MMMmmmmmm........

 

My conclusion:

 

HP and torque are not different, the're the same, its just basically a different way of working out or display power figures.

 

So why is it better to have a high torque engine, is it just because you will have an overal better BHP figure ????

[Mark Ayling]

Even though you made insinuations as to my sexuality again, I'll help you out here

 

This site is pretty good for basic/non-technical descriptions of stuff, I've learnt a lot from it - this article starts right from the beginning, but may be of use....

 

http://science.howstuffworks.com/fpte.htm

 

EDIT: the third page is about torque...

[Suprash]

Hey mud sticks, what can I say, I didnt start, I just carried on

[eyefi]

basically, torque is a measurement of the force yr engine can turn with. its torque that pins u in yr seat. torque is a real measurement, if u like, and bhp is just a calculation from the torque produced. bhp is the "work" an engine does over time.

 

does that help any?

[B3any]

I understood that Torque is what gets you through the gears (e.g acceleration) and BHP is tied in with your topspeed.

[MONKEYmark]

too much TORQUE in this thread, just get out and enjoy it while you can.

 

its nice and wet now for some arse out action.

 

better rephrase that, i mean get the back end of your car out. torque from what i understand is what throws you back into the seat. i would like a good torque numbers, on supras they seem round about the same levels on dyno graphs. other cars have high bhp and lowish torque numbers.

 

is it possible to tune your car for more torque,

[Darren]

Yes engines can be tuned for more torque......

[eyefi]

the aim of any tuning is to increase torque and thus increase bhp. its all a question of where u put the torque in the rev range, or the area that is under yr torque curve (for the street).

[Mark Ayling]

Originally posted by Ashley Willis

Hey mud sticks

 

I wouldn't know, I'm not a mud valve mechanic

 

[Adam W]

Imagine a big beam welded to your front crank pulley, ten feet long. On the end of it you put a one pound weight. If you engine can turn and lift the weight it has 10 feet/pounds of torque. It's a measurement of turning force. BHP is a measure of "work done", sorta like how much energy the engine emits in a set time. Therefore, rpm is a factor in calculating bhp as the engine fires more times per minute, and therefore emits more energy, does more work in a given time, at high rpm. Torque is measured directly, then multiplied by rpm and a constant factor to give you your bhp number.

[Keith C]

I've always thought "Torque is what you can do, power is how quickly you can do it"

[Supra_Al]

Originally posted by Adam W

Imagine a big beam welded to your front crank pulley, ten feet long. On the end of it you put a one pound weight. If you engine can turn and lift the weight it has 10 feet/pounds of torque. It's a measurement of turning force. BHP is a measure of "work done", sorta like how much energy the engine emits in a set time. Therefore, rpm is a factor in calculating bhp as the engine fires more times per minute, and therefore emits more energy, does more work in a given time, at high rpm. Torque is measured directly, then multiplied by rpm and a constant factor to give you your bhp number.

 

Adam, great explanation on Torque, Al.

[Suprash]

So if you have a torque figure of 315ft.-lb of torque, which is the listed Supra figure, that means a crank would have to be able to lift a 1lb weight on a 315ft beam, going on the basis if what Adam said.

 

So a torque figure is higher the more work it has to do, hence the extra work involved in lifting a 1lb weight on a 315ft beam as opposed to a 1lb on a 10ft beam.

 

Am I getting this.....Although I dont see what the length of the beam has to do with it, I would have thought that the beam would be a set length and the weight on it would differ, but I see the measurement is always worked out to "whatever"ft per 1lb.

[Adam W]

You could have 31.5lb on a 10ft beam, 315lb on a one foot beam, and the load on the engine would be the same. Pounds of weight multiplied by distance in feet from the centre of rotation gives you the ft lb figure. Or lb ft or however you write it

[Suprash]

Adam your a star, thats what I was wondering, some people write it ft.-lb, and then others do it the other way. But as far as the maths go for equalling the same, you have just confirmed a lot in my head !!!!!

[Suprash]

Ok, one more question, why do some torque figures say "whatever"ft.-lb or torque at 4,200rpm, and others will quote "whatever"ft.-lb at 7,000rpm, is this the first point in the RPM range that would be giving maximum torque, or am I dribbling. How do you determin the @rmp figure.

[THOR Racing]

why do some torque figures say "whatever"ft.-lb or torque at 4,200rpm, and others will quote "whatever"ft.-lb at 7,000rpm

 

The reason is an engine produces different torque levels at different engine RPMs. Usually the figure quoted is the maximum/peak torque point and nothing more.

You get torque at any speed, just how much changes.

 

Same as when they say you get 320BHP at 5400rpm or whatever. Its a peak.

 

It's torque and rotational speed that upsets dynos and rolling roads, not BHP. I've seen some guys actually left foot breaking a car during a dyno run just to limit the peak torque to below the maximum the rolling road can handle and then release when the engine speed has gone past the danger point.

 

Reagrds

Pete

[Rich J]

Forget about the previous descriptions, here's the links you are really looking for:-

 

Power versus Torque - Part 1

http://www.autospeed.com/A_0744/cms/article.html

 

Power versus Torque - Part 2

http://www.autospeed.com/A_0755/cms/article.html

 

Also explains how gearing comes into the whole thing, with nice tables and graphs.

[Wolf]

Also explains how gearing comes into the whole thing, with nice tables and graphs

 

And talking of gears sort of - where your engine finds peak torque is theoretically where you should change gear for maximum acceleration - has anyone tried this? Bit hard with an autobox...

[Rich J]

Originally posted by Wolf

Also explains how gearing comes into the whole thing, with nice tables and graphs

 

And talking of gears sort of - where your engine finds peak torque is theoretically where you should change gear for maximum acceleration - has anyone tried this? Bit hard with an autobox...

 

No this is definately not the case, in fact in most cars shifting should be done beyond peak POWER, the reason being that the longer you are in a lower gear the better, because of torque multiplication through gearing, even though at the higher revs you may have less torque at the flywheel, because you are in a lower gear the torque at the wheels will be more than if you shift up and are at high flywheel torque and the gear will give less torque multiplication. There is a point where you have to change because the drop in torque at the flywheel (beyond peak TORQUE) means you are better off going up a gear but in most cars that is beyond peak POWER not at peak TORQUE.

 

This is part of the reason that cars like the Integra Type R are faster than they seem they should be with the small amount of torque they have, the lack in torque is compensated by the gearing, because there are a lot of revs the gearing is shorter that other cars in it's class (that have similar peak power but higher torque, i.e. lower revving turbo motors of around 200hp), making more torque at the wheels through torque multiplication.