Torque, HP, Speed

kakx · 17th April 2004, 20:01

I read a lot about these 3 things on How stuff works, now i want to just clear some of my doubts, Guys plz hlp me understand the fundas clearly

You can use the HP either to Create more speed or Tourqe right, Tourqe is reqd to do Heavy duty work, if so why is emphasis given on tourqe when discussions abt cars are going on. I am royally confused plz explain.

Shan2nu · 17th April 2004, 20:40

Like you said, Torque is basically the pulling power of the engine. BHP is usually gained higher up the rev band.

If you were to relate torque and power to humans, i'd say torque is like strenght and power is like stamina.

A body builder (torque) can lift twice the weight, that an athlete can, but the athlete (power - bhp) can run twice as fast and maintain those speeds for a longer time. *

Power and torque are not directly related to engine capacity.

Whether you pull 550 pounds - across 1 ft - per sec or pull 1 pound - across 550 ft - per sec, you're still producing "1" bhp.

Race cars rely more on power than on torque. The F1 car for example produces around 400-500nm of torque which is less than most "supercars" but at the same time produces close to 1000bhp which no present supercar can match.

From what i've noticed, torque of a petrol engine is directly related to the displacement of the engine. A 1.6 ltr petrol engine will usually produce less than 160nm of torque, 3ltr engine produces less than 300nm. Note that i'm reffering to "naturally aspirated" engines here.

The Vtec which has more power can accelrate faster through the rev band and will reach a higher top speed but the Accent CRDi which has loads of torque can do more heavy duty work and will accelerate in 4th and 5th gears faster than the Vtec from lower rpm.

""why is emphasis given on tourqe when discussions abt cars are going on" this is becoz most drivers like to cruise at lower rpm in a higher gear and would preffer a car that car pull away without having to downshift, this is where torque makes all the difference.

Regards...
Shan2nu

Shan2nu · 29th April 2004, 00:43

Hey guys,
I found this very informative site on Power and Torque. There are some more interesting topics.
http://www.dur.ac.uk/r.g.bower/PoM/pom/node7.html

Regards..
Shan2nu

Pferdestärke · 29th April 2004, 05:06

Nicely explained Shan2nu, but ..
Why dont people talk about power to weight, as much? When it comes to talking performance.
Infact I dont see any MAGs publish Power to Weight Ratios of the cars they test.
I feel thats also very crucial.

GTO · 29th April 2004, 12:01

Quote:

Originally Posted by [b

Quote[/b] ]Why dont people talk about power to weight, as much? When it comes to talking performance.
Infact I dont see any MAGs publish Power to Weight Ratios of the cars they test.

Power to weight is one of the most important influences on the performance of a car. Autocarindia and Overdrive, both publish these figures in their road-tests.

GTO

Sheruken · 29th April 2004, 19:24

hey gto.. how do you calculate power to weight ratio?

Shan2nu · 29th April 2004, 19:33

Power to weight ratio is maybe the easiest and cheapest way to make your car go faster.

Infact, instead of adding, all you have to do is reduce the weight of the car buy removing unwanted things.

Regards...
Shan2nu

Shan2nu · 29th April 2004, 19:49

1000*power of your car / by the weight of your car.

For example for the vtec.

1000*106 / 985 = 107.61 bhp/ton

Regards...
Shan2nu

GTO · 29th April 2004, 19:52

Quote:

Originally Posted by [b

Quote[/b] ]hey gto.. how do you calculate power to weight ratio?

Formula - BHP/Weight multiplied by 1000.

Forf e.g. if you want to calculate the power to weight for a Tata Safari (hehehe, my favorite joke) the weight is 2040 kg and the power output is 90bhp.

Thus 90/2040 x 1000 = 44.12 bhp to the ton.

GTO

GTO · 29th April 2004, 20:16

Oops, looks like we were typing on the dot Shantanu.

But same difference, nevertheless.

GTO

hot_rod · 28th May 2005, 18:32

Bravo well explained dude!
keep ip the good work!

karthik247 · 18th June 2005, 20:10

guys while doing wheelspins, does torqur or BHP count more??

skidrock · 20th June 2005, 11:47

I think it's torque. Am I right guys ?

kooldude · 20th June 2005, 17:34

The Vtec which has more power can accelrate faster through the rev band and will reach a higher top speed but the Accent CRDi which has loads of torque can do more heavy duty work and will accelerate in 4th and 5th gears faster than the Vtec from lower rpm.
[quote]
""why is emphasis given on tourqe when discussions abt cars are going on" this is becoz most drivers like to cruise at lower rpm in a higher gear and would preffer a car that car pull away without having to downshift, this is where torque makes all the difference.
[quote]
hey shantanu can u explain both of these things a little better

17th April 2004, 20:01	#1
kakx BHPian Join Date: Apr 2004 Location: Mumbai Posts: 41 Thanked: 0 Times	I read a lot about these 3 things on How stuff works, now i want to just clear some of my doubts, Guys plz hlp me understand the fundas clearly You can use the HP either to Create more speed or Tourqe right, Tourqe is reqd to do Heavy duty work, if so why is emphasis given on tourqe when discussions abt cars are going on. I am royally confused plz explain.
	() Thanks

17th April 2004, 20:40	#2
Shan2nu Senior - BHPian Join Date: Feb 2004 Location: Hubli - Karnata Posts: 5,533 Thanked: 125 Times View My Garage	Like you said, Torque is basically the pulling power of the engine. BHP is usually gained higher up the rev band. If you were to relate torque and power to humans, i'd say torque is like strenght and power is like stamina. A body builder (torque) can lift twice the weight, that an athlete can, but the athlete (power - bhp) can run twice as fast and maintain those speeds for a longer time. * Power and torque are not directly related to engine capacity. Whether you pull 550 pounds - across 1 ft - per sec or pull 1 pound - across 550 ft - per sec, you're still producing "1" bhp. Race cars rely more on power than on torque. The F1 car for example produces around 400-500nm of torque which is less than most "supercars" but at the same time produces close to 1000bhp which no present supercar can match. From what i've noticed, torque of a petrol engine is directly related to the displacement of the engine. A 1.6 ltr petrol engine will usually produce less than 160nm of torque, 3ltr engine produces less than 300nm. Note that i'm reffering to "naturally aspirated" engines here. The Vtec which has more power can accelrate faster through the rev band and will reach a higher top speed but the Accent CRDi which has loads of torque can do more heavy duty work and will accelerate in 4th and 5th gears faster than the Vtec from lower rpm. ""why is emphasis given on tourqe when discussions abt cars are going on" this is becoz most drivers like to cruise at lower rpm in a higher gear and would preffer a car that car pull away without having to downshift, this is where torque makes all the difference. Regards... Shan2nu
	(1) Thanks

29th April 2004, 00:43	#3
Shan2nu Senior - BHPian Join Date: Feb 2004 Location: Hubli - Karnata Posts: 5,533 Thanked: 125 Times View My Garage	Hey guys, I found this very informative site on Power and Torque. There are some more interesting topics. http://www.dur.ac.uk/r.g.bower/PoM/pom/node7.html Regards.. Shan2nu
	() Thanks

29th April 2004, 05:06	#4
Pferdestärke BHPian Join Date: Mar 2004 Location: Mumbai Posts: 311 Thanked: 18 Times	Nicely explained Shan2nu, but .. Why dont people talk about power to weight, as much? When it comes to talking performance. Infact I dont see any MAGs publish Power to Weight Ratios of the cars they test. I feel thats also very crucial.
	() Thanks

29th April 2004, 19:24	#6
Sheruken BHPian Join Date: Mar 2004 Location: Mumbai Posts: 24 Thanked: 0 Times	hey gto.. how do you calculate power to weight ratio?
	() Thanks

29th April 2004, 19:33	#7
Shan2nu Senior - BHPian Join Date: Feb 2004 Location: Hubli - Karnata Posts: 5,533 Thanked: 125 Times View My Garage	Power to weight ratio is maybe the easiest and cheapest way to make your car go faster. Infact, instead of adding, all you have to do is reduce the weight of the car buy removing unwanted things. Regards... Shan2nu
	() Thanks

29th April 2004, 19:49	#8
Shan2nu Senior - BHPian Join Date: Feb 2004 Location: Hubli - Karnata Posts: 5,533 Thanked: 125 Times View My Garage	1000power of your car / by the weight of your car. For example for the vtec. 1000106 / 985 = 107.61 bhp/ton Regards... Shan2nu
	() Thanks

29th April 2004, 20:16	#10
GTO Team-BHP Support Join Date: Feb 2004 Location: Bombay Posts: 70,497 Thanked: 300,308 Times View My Garage	Oops, looks like we were typing on the dot Shantanu. But same difference, nevertheless. GTO
	() Thanks

28th May 2005, 18:32	#11
hot_rod BHPian Join Date: Mar 2005 Location: mumbai Posts: 166 Thanked: 2 Times View My Garage	Bravo well explained dude! keep ip the good work!
	() Thanks

18th June 2005, 20:10	#12
karthik247 Senior - BHPian Join Date: Feb 2005 Location: BLR, HYD Posts: 2,710 Thanked: 30 Times	guys while doing wheelspins, does torqur or BHP count more??
	() Thanks

20th June 2005, 11:47	#13
skidrock BHPian Join Date: Aug 2004 Location: Hyderabad Posts: 42 Thanked: 0 Times	I think it's torque. Am I right guys ?
	() Thanks

20th June 2005, 17:34	#14
kooldude BHPian Join Date: Oct 2004 Location: Charlotte,North Carolina Posts: 283 Thanked: 0 Times	The Vtec which has more power can accelrate faster through the rev band and will reach a higher top speed but the Accent CRDi which has loads of torque can do more heavy duty work and will accelerate in 4th and 5th gears faster than the Vtec from lower rpm. [quote] ""why is emphasis given on tourqe when discussions abt cars are going on" this is becoz most drivers like to cruise at lower rpm in a higher gear and would preffer a car that car pull away without having to downshift, this is where torque makes all the difference. [quote] hey shantanu can u explain both of these things a little better Last edited by kooldude : 20th June 2005 at 17:35.
	() Thanks