Horsepower vs Torque

[kinyo]

torque sa akin ... aanhin ko ang hp sa city driving?

accdg to my OBD2 scanner, my diesel suv use only 25 hp while cruising 100 kph ... it doesn't really take much hp to keep a car in motion, but having more torque will make moving the car easier

[niky]

There is no difference between torque and horsepower.

Well, there is a difference. You can have a million foot pounds of torque and have a car that's as slow as molasses. But if you have a million horsepower, as long as your gearing fits the motor, you will be very, very quick.

This is because torque is twist, but without a time component, you don't know if that twist is applied in one second or one minute. Only adding a time component will tell you how much work that torque will do within a given timeframe.

And what do you call torque applied over time? Horsepower.

In other words, a Santa Fe 2.2 is not incredibly fast because it makes 436 Nm of torque at 2,500 rpm. It's incredibly fast because it makes 153 horsepower at just 2,500 rpm, and averages between 150-190 hp from 2,500 rpm to 3,800 rpm.

Peak torque and peak horsepower figures are misleading and mostly meaningless. To gain a better idea of how quick a car can be, you need to know what the average horsepower and gearing are.

And while peak acceleration in each gear occurs at torque peak, peak horsepower still matters, because that's where peak acceleration occurs when you're choosing between different gears, like so:

[170kphlang]

The high-revving nature of the Hondas don't necessarily mean malakas sa gas.

The R18A on the Civic actually has decent mileage. Also, even without having to use the upper rpms, kaya namang magovertake. I rarely found myself needing to go past 3000 rpm with an FD. Sa bagal magdrive ng mga tao, di naman kailangang flat out para makaovertake.




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yup gaya ng namention ng isang post dito, yung mga civics ng 90's-early 2000 ang nagsusuffer sa low end power but yung mga fd ay di na gaano

[roycruz]

Read this explanation somewhere: hp is like a sprinter--it gets you there faster but slows down with more load. More torque means it can move at the same speed with heavier load but it's not necessarily fast.

My interpretation: You need more hp if you like driving fast with less load, and more torque if your car is usually at full load but you don't need to drive fast. More hp = mas mabilis. More torque = mas malakas ang hatak.


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[brainmafia_310]

Mga sir makikisawsaw na din po.

Para mas simple ibukod natin ung engine alone hanggang sa flywheel wag natin sama iba component engine muna.

Hp and torque are directly proportional to each other. Parang magkakambal po oyang dalawa na yan.

Nagvavary lang kasi different engine perform differently.

For example honda 6000rpm max power out put ibig sabihin yan ang max torque at hp niya.

Nagiging complikado pagnasalpakan na ng transmission dahil sa gear ratio.

So technically bigger engine can produce bigger hp and relatively higher torque.

Nagkakatalo lang sa configuration ng gears sa transmission and/or gear box.

Hope this helps.

By the way on a mathematical standpoint hp is determined by the torque multiplied by the rpm - i hope i recall it correctly from my thermodynamics class.

About gear ratio, mas maliit po ang gear mas mababa po ang torque. Kaya ung iba feeling nila mahina humatak ang vtec (stock lang ha walang iba confi) kasi maliit gear eatio niya at mas makakaproduce ito ng speed.

Parang bisekleta lang sir at constant rpm bigger sprocket and main plate combi is lighter on your feet because it has bigger torque but speed will suffer kahit tulinan mo padyak mo hanggang dun na lang iyun. Pagniliitan mo naman ung sprocket tutulin ka pero mabibigatan ka kasi maliit ung torque na napoporduce ng sprocket naniyun kaya yo u need to exert more effort.

Hope this helps mga sir.

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[Retz]

Hindi ba comparable sa gasoline and diesel engine? If you need more Hp then sa gasoline ka but if you need torque sa diesel engine naman.


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[brainmafia_310]

Hindi ba comparable sa gasoline and diesel engine? If you need more Hp then sa gasoline ka but if you need torque sa diesel engine naman.


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Mas maganda po paliwanag ni sir niky kaysa sa akin, inelaborate ko lang in my own words.

Diesel engine at same size produces more hp and of course torque kaya mo ramdam ang torque is that of the diesel having higher hp can pull up a load faster on a smaller gear ratio.

Imho ang limitation ng diesel vis a vis gas engine is the rpm. Kasi diesel engine are compression ignition while gasoline is spark ignition. Kaya mas mataas rpm range ng gaso sa diesel dahil sa flwxibility nito in controlling intake exhaust and spark timing.

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[godwhacker]

Mga sir makikisawsaw na din po.



Hp and torque are directly proportional to each other. Parang magkakambal po oyang dalawa na yan.


By the way on a mathematical standpoint hp is determined by the torque multiplied by the rpm - i hope i recall it correctly from my thermodynamics class.

Hope this helps mga sir.

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this is the equation most tuners used to predict wHP during dyno runs...

HP = T x 4000
-----------
7120

Where:

HP - horsepower
T - torque, Nm (engine torque mapped in the ECU)
4000 - RPM
7120 - constant

HP to be multiplied with 10-12% (FWD) and 15-20% (RWD) for loses in the drive train.

[niky]

5252 if you're talking foot pounds.

And more precisely, 7121 for Nm.

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Drivetrain losses are nothing more than ballpark, nowadays. With some cars using ultra low-friction drivetrains, you can't assume anything. The Nissan GT-R boasts some 10-15% losses only versus something like 20-25% losses for STIs and Evos.

And then you get to the problem of dynos calibrated to different standards, SAE (over)correction and etcetera.

[Helios]

used to be a big deal back then, but engine tech has matured since and microchips and control systems have increased performance and fuel economy. our road going cars benefitted much from f1 and other track cars.

now going full electric...