Torque

[Seven11]

Vaguely remember torque is more useful indicator than bhp in measuring the power of the car as torque is effective in measuring the pick up. Am I correct or am I miles away from the truth?

 

Also, is torque measured by RPM X BHP?

 

Appreciate comments....

[Seansene]

Ok firstly, power = torque x engine speed (where torque is the twisting ability of the engine, calculated just like a moment - for those who remember that stuff - force x distance).

 

If we assume an ideal flat torque curve, say from 2000rpm to 5500rpm, the power will increase linearly within this spread. This is why you will find that peak torque is achieved before peak power (the Fabia's at 2500 and 5000rpm respectively, for example). In a more realistic situation of a gently parabolic torque curve, the power curve gets steeper as engine speed increases, with the upshot that more revving is required, just like the VTEC response.

 

Essentially this is what it all boils down to: at low revs, because of the equation (P = T x Sp), the total power is completely dependant on torque. This applies at pickup, as well as sudden overtaking manoeuvres. Once engine speed increases, then it's a play between these two factors to achieve a high power figure. Some engines just stick with huge torque at lazy speeds (Bentley, trucks) while others rely on high revs (Honda of course, motorbikes).

 

Remember to look not only at the max torque or power figures, but at what engines speed these figures are reached. Because you should choose something that matches your driving style - if you want a car for mostly city driving, then a VTEC (that achieves max power only past 6000rpm) is useless; conversely if you like to rev the engine, then no point getting a car that runs out of puff at 4500rpm.

Edited January 14, 2002 by Seansene

[Fabiaman]

Well said Sean, very well described.

[Lanzer]

so how do u increase torque for a car without changing its engine?

[Seansene]

I used to be confused for a very long time as well - power and torque are rather abstract concepts, unlike velocity, acceleration or even force. I mean, we all understand that it's easier to open a door at the handle rather than close to the hinge, but how to conceptualise that the resulting moment, or torque (force x distance) is exactly the same? That the door opening at a particular angular speed correlates to power? Or that the door represents the crankshaft of a car engine, while we sit in the passenger compartment hoping to get some linear acceleration from all this?????? (Is there an icon for pulling out hair?)

 

I realised it was better to skip the intermediate steps and just relate cause and effect. Easier on my brain...

[Sky8807]

To me torque is more important. The max torque should be as low as possible in the rpm range. Good strong torque give good pulling power. Of course the big engine all got big number where torque is concern.

 

But for small car, having high torque value and attainable at low rpm is definately advantages rather than high hp and low torque at high rpm.

 

If your torque is low and at high rpm, then, your car will be buzzing most of the time to have the same drivability. Not many ppl drive their car to attain max hp, but most almost all will be maximising their torque during their everyday drive.

 

Torque & power, which is more important. You decide.

[Barakian]

I believe going by way of forced induction is the answer....

[Turbobrick]

Donno about opening doors but to me torque plays an important role when I choose a car as it's more relavant to our daily drives. Imagine dragging a high horsepower car in crawling traffic but lack the torque to create the "off the line" momentum?

 

High horsepower is essential in racing/autobahn as rpms are kept high whereas in Sunny Singapore (or malaysia for that matter) the highways are not really an invitation to unlease the high horsepower.

 

Also torque is the key to "overtaking power" especially from midrange rpms. Thus a flat torque curve hovering around mid rpms (2500-5000?) is best for overtaking sprints.

 

Just my $0.02

[PointyEwe]

Vaguely remember torque is more useful indicator than bhp in measuring the power of the car as torque is effective in measuring the pick up. Am I correct or am I miles away from the truth?

 

Also, is torque measured by RPM X BHP?

 

Appreciate comments....

 

A good site to start knowing more of the above...http://www.howstuffworks.com/horsepower.htm

[Pentagon99]

wat lau,u guys tok very chim...can use simple terms??? hee.. :P

[Turbobrick]

Ok here's a simplified version, torque x rpm = horsepower. Torque will reach peak before horsepower as rpm climbs

[Blue850r]

There is the popular saying from the Americans : That's no subsitute for engine capacity. So the only way to go, get bigger engines.

 

Many motorist thought they could save some money and buys a low capacity car. Later spend a fortune at those mechanic shop ( who tries to beat the engineers in factory which holds PH.D in automotive engineering and physics).

 

Buy a car that suits your drving habit and not just the wallet.

[Ghostrider]

Buy a car that suits your drving habit and not just the wallet.

 

But the heart & head says a inline 8 5.0L but the wallet says....inline 4 1.6L only.....what to do ??? Money No Problem....Problem No Money !!

[Madarmour]

Heard that the smallest petrol engine for the new E200 in Europe is 2.6L. In SG, it's 2.0L!

[Barakian]

That's why they had to slap on the Kompressor on the 2-lite engine to bring it up from a paltry 136bhp to a more credible 163bhp. Imagine trying to move off from the lights with the older engine in the E-class.....think the ah pek on his trishaw would beat the E-class hands down! But, all said and done, the E-class is a supreme high-speed cruiser! [angelic]

[Turbobrick]

Aiyah like my brick is 2.3 in Europe, US and Thailand!!! But I only get the 2.0 with 25bhp less Cannot wheelspin somemore!

 

Now the S60T5 has 2.3......damn it!

[Blue850r]

Less budget for car is O.K. If you like power and ease of driving, choose a car with lighter weight and manual transmission. Drving a lively car makes your mood better also.

 

Can't have best of both worlds, Big car, Auto, good consumption, etc...

 

Never think of mods for NA cars. Turbo cars are much cost effective to mod.

[Myfocus]

Sigh. Shouldn't be surprised - taxation etc. Many more examples abound around us :-(

 

Heard that the smallest petrol engine for the new E200 in Europe is 2.6L. In SG, it's 2.0L!