HP vs. Torque Question
Burning Brakes
Joined: Jan 2007
Posts: 1,057
Likes: 4
From: Concord Calif
Just wow! about all the different opinion's here. Torque is the power of an engine Horse power is only a calculation of torque and rpm. And nether of these numbers will tell you what the acceleration rate of the engine is either. Yea in an above post one showed a 600hp gas engine at 6000rpm and a 600hp diesel engine at 2000rpm as being 600hp is 600hp and a huge difference in torque. As all knows I hope the power of these two engines is not even close, in even comparison you would need to use the same rpm's in you calculations to get the same so called hp. How much hp do you think that gas engine has at 2000 rpm!!! One will be way ahead if you forget the hp numbers and use and shoot for torque numbers in the range you intend to use the engine. Meaning, look for max torque to be about your shift point, as well as max torque at your launch also assuming you have the traction to hold it.
Race Director
Joined: Mar 2003
Posts: 11,608
Likes: 780
From: Eustis ( Area 51 Bat Cave ) Fl
Hum...In my own terms, lol
I had a 383 and it didn't "come on" until well over 2500-3000 no rpm and nothing,
Hp wise hum...300/350 plus torque?
Now I have a mild 454 hp perhaps 200 plus
Torque well up there 450 plus, and right off the line so with my gears in the 3's it will melt the tires, 10" 50's if you dont let off you will ruin the tires,
so for stop light to stop light its a terror, when I get the 4 speed auto in there it will do ok after 70 but it's what I wanted the low end off the line dig.....I'm not kid racer.
I had a 383 and it didn't "come on" until well over 2500-3000 no rpm and nothing,
Hp wise hum...300/350 plus torque?
Now I have a mild 454 hp perhaps 200 plus
Torque well up there 450 plus, and right off the line so with my gears in the 3's it will melt the tires, 10" 50's if you dont let off you will ruin the tires,
so for stop light to stop light its a terror, when I get the 4 speed auto in there it will do ok after 70 but it's what I wanted the low end off the line dig.....I'm not kid racer.
Last edited by The13Bats; Nov 21, 2013 at 03:00 PM.
Drifting
Joined: Jan 2012
Posts: 1,908
Likes: 129
From: Fredericksburg Virginia
I'd like to offer a couple different perspectives:
A 3.0L V8 Formula 1 engine produces a peak of approximately 260 lb-ft of torque. Not very much. It produces that torque at about 16,000 RPM whereby it is making over 790 hp. That puts the specific output of the engine at well over 250 hp per liter with no turbo or supercharger...stratospheric isn't the word. That's downright crazy.
The car is light, so torque is not required to fulfill its duties.
My 2012 F-250 produces 800 lb-ft of torque and redlines at 3,000 RPM. That truck DOES NOT CARE what it is anchored to the ground with. I carried 3,500# of pavers over 200 miles and got 19 MPG doing so. I regularly pull my 6,000# travel trailer around and I accelerate almost as well as without it.
But that's just the thing...not that my truck is slow, but it is almost as fast WITH a 6k# load as WITHOUT. And spin the wheels in 2nd gear no matter what is in or connected to the truck. No faster, no slower. No matter the load. That is TORQUE, not HORSEPOWER.
If you GEAR a 'torque monster' engine properly, you could probably get pretty good times out of it. There were numerous Cummins entries into the Indy 500. But that 'torque monster' engine weighs a TREMENDOUS amount more than its gasoline counterpart.
In my Corvette, I like having torque available (versus a "short on torque" Honda S2000 or Mazda RX7 or RX8), but horsepower is more desireable.
A 3.0L V8 Formula 1 engine produces a peak of approximately 260 lb-ft of torque. Not very much. It produces that torque at about 16,000 RPM whereby it is making over 790 hp. That puts the specific output of the engine at well over 250 hp per liter with no turbo or supercharger...stratospheric isn't the word. That's downright crazy.
The car is light, so torque is not required to fulfill its duties.
My 2012 F-250 produces 800 lb-ft of torque and redlines at 3,000 RPM. That truck DOES NOT CARE what it is anchored to the ground with. I carried 3,500# of pavers over 200 miles and got 19 MPG doing so. I regularly pull my 6,000# travel trailer around and I accelerate almost as well as without it.
But that's just the thing...not that my truck is slow, but it is almost as fast WITH a 6k# load as WITHOUT. And spin the wheels in 2nd gear no matter what is in or connected to the truck. No faster, no slower. No matter the load. That is TORQUE, not HORSEPOWER.
If you GEAR a 'torque monster' engine properly, you could probably get pretty good times out of it. There were numerous Cummins entries into the Indy 500. But that 'torque monster' engine weighs a TREMENDOUS amount more than its gasoline counterpart.
In my Corvette, I like having torque available (versus a "short on torque" Honda S2000 or Mazda RX7 or RX8), but horsepower is more desireable.
Drifting
Joined: Aug 2009
Posts: 1,635
Likes: 8
From: Enid Oklahoma
Torque and horsepower are very missunderstood even by some of the magazine writers. I've seen so much misinformation out there it drives me crazy. Being performance has been my career for almost all of my 60 years here on earth, I want to set this straight.
Torque and horsepower go hand in hand. You can't have horsepower without torque. Torque is a static rotational force. Test this by clamping the socket end of a torque wrench in a vise and pull it up to 100 lb/ft of torque. How fast is the vise going? It's not moving is it? Now if you could get it to rotate to 5252 RPM and maintain the 100 lb/ft of torque, you would have 100 horsepower. The formula for horsepower is torque X RPM/5252. This is why torque and horsepower are always equal at 5252 and the lines cross there on graphs.
The simple deffinition of horsepower is the work being done. Moving a vehical is the work being done. So to move the vehical from a stop to any speed and any acceleration rate you need horsepower just as you need it to reach top speed.
Now here is how torque should be discussed. Where in the RPM do you want your peak torque and where in the RPM range do you want your torque to come in. More torque at any RPM point means more horsepower to move your vehical. Idealy you want to make good torque at a low RPM and maintain it through a wide rpm range for the street. What people should say instead of "I want torque!" is "I want strong bottom end power", as this is what people really mean.
Now the discussion about which is quicker on the street, an engine with strong bottom end torque or high RPM torque and horsepower. This is just as missunderstood.
Torque and horsepower go hand in hand. You can't have horsepower without torque. Torque is a static rotational force. Test this by clamping the socket end of a torque wrench in a vise and pull it up to 100 lb/ft of torque. How fast is the vise going? It's not moving is it? Now if you could get it to rotate to 5252 RPM and maintain the 100 lb/ft of torque, you would have 100 horsepower. The formula for horsepower is torque X RPM/5252. This is why torque and horsepower are always equal at 5252 and the lines cross there on graphs.
The simple deffinition of horsepower is the work being done. Moving a vehical is the work being done. So to move the vehical from a stop to any speed and any acceleration rate you need horsepower just as you need it to reach top speed.
Now here is how torque should be discussed. Where in the RPM do you want your peak torque and where in the RPM range do you want your torque to come in. More torque at any RPM point means more horsepower to move your vehical. Idealy you want to make good torque at a low RPM and maintain it through a wide rpm range for the street. What people should say instead of "I want torque!" is "I want strong bottom end power", as this is what people really mean.
Now the discussion about which is quicker on the street, an engine with strong bottom end torque or high RPM torque and horsepower. This is just as missunderstood.
