Sorry, the point I was trying to make is that both HP and torque are measurements of WORK, however HP is a measurement of WORK over TIME, whereas Torque is just a raw measurment.

200 FT LBS may sound good, but it's a heck of a lot better to have an engine make it at 10,000 RPM than at 2000 RPM. The reason has to do with TIME. Yes, the concept of spinning a beta motor to 15000 is beyond any of our budgets. In order to modify the engine to handle those stresses, it would hardly be a beta motor any longer.

Turbulence, your anology of the Drag engines and their superchargers is not accurate. Their blowers do not take 400 HP to make them turn, they take 400 Ft. Lbs to make them turn. They take FORCE to make them turn (Torque), not FORCE over TIME(work a.k.a. HP).

I highly suggest you read these 2 articles.

http://www.autospeed.com/A_0744/page1.html
http://www.autospeed.com/A_0755/page1.html

 

Up there somewhere, turbulence, you metioned NHRA drag racing and the type of engines they use. and it reminded me I wanted to mention something about basic engine building/design principles. Anyway, here goes:

The effective maximum cylinder bore for normal gasoline engines is 4". The fuel doesn't burn fast enough across the face of the piston in a 4 stroke motor to get more power out of the "power" stoke. If you understand what I mean. Change the type of fuel you use, you can have larger cylinders.

Longer stroke = higher torque rating. If you think about it, this makes sense. The stoke in the distance the piston is moved by the crank during 180 degrees of motion from highest to lowest point. The longer the stroke the farther the piston rod attaching point must be from rotational center of the crank. This means that it is farther away at the 90 degree point during the power phase as well. Farther distance with the same applied force creates more torque.

BUT longer stoke means more rotating mass. Its harder to accelerate and there is a real-world RPM limit at which the engine will operate safely. This is why large high torque engine (like diesels) have a redline at 4500 RPM. (or sometimes lower)

The opposite is true, but an engine with a short stroke developes power differently. It relies on its ability to achieve high RPMs to do work for us. (This is the area under the curve mentioned above).
Since a short stroke motor developes less torque, to achieve the same HP rating (do the same amount of work), it must be operating at higher RPM. This allows for much more area under the curve as well, as Random explained. So, I can gear my Ferrari to operate thru a 6000 RPM range.

Where I gear my truck to operate thru a 1500 RPM range. This is partly why 18-wheelers (or specifically the tractor) have 15 or 18 gear transmissions.

Am I still making sense?

 

[QUOTE]Originally posted by Random:
Sorry, the point I was trying to make is that both HP and torque are measurements of WORK, however HP is a measurement of WORK over TIME, whereas Torque is just a raw measurment.

200 FT LBS may sound good, but it's a heck of a lot better to have an engine make it at 10,000 RPM than at 2000 RPM. [quote]

I kindof reiterated the articles in my post. I was typing its as random was posting. Sorry. sad.gif

Random, understanding we are talking about performance engines, I agree with the above. But I wouldn't want that engine in my 4Runner, where I need the 200 lb/ft or torque at 2800 rpm to tow a trailer (or more fun) climb a hill off-road. wink

[ January 03, 2003, 06:35 AM: Message edited by: blue2000 ]

 

Change the gearing in your 4 Runner, and it will be just as applicable. With the current gearset in your 4 runner, no, it wouldn't be much fun. tongue.gif

 

I know you guys are trying to prove your points by using examples of power-plants you'd find in a 'big rig' or a Ferrari. That's all find and dandy, but isn't the real issue here, how do we increase Torque and/or Horsepower values in the cars that WE own?
The Beta in my 2002 Elantra redlines at 6500 RPM. Would I be better off concentrating on increasing the torque or horsepower of the engine? From what I understand so far from this conversation is that; in an engines powerband there must be a level where the torque value and the horsepower value increase at the same percentage - relative to their original value, when you apply modifications to the engine, whether is be FI or NA. I'm a incorrect? Since I plan on doing simple NA mods for now, what will these changes most likely effect the most? Torque or horsepower?

 

elantravision, you are way off. this is a discussion on which is a more valuable measurement (which we have learned neither is), and what they both exactly are. the reason we're using big-rigs and ferraris as examples is that they are two vehicles with entirely different engines, perfect for explicating our points. i understand now. torque is what the engine produces, like i initially said. and i had the right idea about hp, i just didn't fully understand it. yeah, it's better to have 200 pounds of tq at 10,000 rpms, because there is that multiple of rpms, so there is the same amount of torque as in my beta example, except that the engine is doing it 10,000 times/minute, rather than 6,750 times. got it. thanks for all of the support and posts, guys!!! smile.gif

edit::

i would also like to add that the application is also very important. if i'm not mistaken, 3rd and 4th gears in our tibs (and just about every other car) are the best gears to do dyno runs because they give the most accurate measurements of torque, whereas 1st and 2nd are too short, and create a sort of torque-multiplying effect. that's why a dodge 3500 cummins turbo diesel redlines at like 3500, but could rip my house off of the foundation.

[ January 03, 2003, 08:52 AM: Message edited by: turbulence ]

 

* * VOTED MOST INFORMATIVE POST * *
-by Fast.Shark

 

I came up using metric and this is what I know about HP and TQ.

Power is the rate at which work is done. Energy or Work (J)/Time(s). 1 J/s = 1 Watt

Torque is the product of a force (N) and it's perpendicular distance (m) to the fulcrum/pivot. As people say a "twisting force" as in revolution of a crankshaft.

If you don't know the rate (time) the torque is being exerted then it's not that helpful, hence the use of power. They are related though as torque gives you the energy being produced. Don't quote me on this but this is what I roughly know on the matter. Check out this link it can give you more insight....

http://www.howstuffworks.com/horsepower1.htm

 

short version:

torque is good for low end speed, hp is good for high end speed

is that right?

once u start moving, it goes from depending more on torque to more on hp?

 

Well, I think is would be HP because.

torque is a rating of raw power for 1 rpm.
(i think)

So if your torque peak is at 3000rpms and you make 100 torque then.

But you make 70 torque at 6000rpms

At a given moment, how torque is made in combination?

100x3000 = 300,000 torque in a min

60x6000 = 420,000 torque in a min

You would still be putting down more power(torque) at 6000 rpms within a given minute.

mmmmm, something does not side right so I could be far off, or this could be crude thinking.