92RS3.1L

Me and one of my friends are having an arguement, and hopefully some of you can help us out. What do YOU think is more important in racing? Horsepower or torque?

PETE

iTrader: (1)

Depends on the racing and the automobile. Circle track/ top speed runs, you want high hp/high rpm. In drag racing it varies little. The weight of a car comes into play here. Assuming a 2000lb. car has 300hp and a 4000lb. car has 400 hp who do you think would win.

SmokinZ28

Well, since HP is just a calculation off torque.... Here's a very good site that explains it

www.vettenet.org/torquehp.html

92RS3.1L

hey man, thanks, that website cleared a lot of things up! I guess the arguement with my friend was a stalemate!

83 Crossfire TA

iTrader: (2)

They are 2 sides of the same thing. Torque is how much turning force is available at any instant, hp is the amount of power available at any point.

Hp determines how fast you can ultimately accelerate the car and in the end, this is what we’re talking about when we’re talking about racing, but that doesn’t mean that it’s more important, it’s just an easier way of saying that you need both torque and rpm to move a car.

In a way, you’re asking the wrong question. Assuming that the chassis is setup correctly, with gearing/stall that matches the power band of the engine, it doesn’t make a difference if you make the power at 2000rpm or 10000rpm. If you’re not willing to make significant changes to the chassis then you need to make sure that you have as strong an engine as you can have in the rpm band that the chassis works in. By all this I mean that the question that you are probably really arguing about is an engine that makes power in a lower or higher power band better for racing, and the answer is that neither is as long as you’re willing to change the chassis to work with the powerband.

Another way of looking at it is that HP is how much work the engine can do at any rpm, and torque is how efficient that engine is at any rpm (torque is proportionate to VE, if you know one you can find the other).

PETE

iTrader: (1)

Just to chime in. An easier descriptive definition of HP and Tourqe is: The amount of turning force or simply work performed, HP is how fast that work can get done!

Where the automakers started focusing on HP is beyond me. Is it that it sounds better than tourqe, but the general public when looking to buy a vehicle tend to look at the HP numbers(if power oriented) instead of tourqe. HP is a derivitive of tourqe multiplied by rpm.

Another thing to consider is given two equal cars with the same curb weight and cubic inches making the same power(say400hp/425lb/ft). Engine number 1 makes it's hp at 5800 and peak tourqe at 2800, engine 2 makes it's hp at 6700 and peak tourqe at 4700. That would be a better question to debate over.

92RS3.1L

yeah, all the commercials emphasize horsepower, and I didnt know what was more important, thanks for straightening it all out!

Jester

yeah, they are just two ways of looking at the same thing, but in any pratical application like we here are interested HP is the only side that matters. Torque is of significant concern if you're building say, a truck motor where you're dealing wth heavy traily loads and/or rolling 40"+ of tire up a cliff. In the go fast world, it's of little importance. The best performing motors in pretty much every class of drag, road, and roundy round racing all make way more hp than tq, and you should take a leson from that. To us, Tq is good for breaking parts and killing tires, maybe the first 60' of a 1320' race, but thats it.

PETE

iTrader: (1)

Interesting theory however turbo Buicks have been proving that theory wrong for years(mine would too if I ever get it running right).

There are a couple people running 400hp and an ungodly 600+ lb/ft. I know it's a V6 and turbocharged, but I didn't know If you were speaking of a certain combination or not. Doesn't matter which way you produce your power in a drag race(within reason). If you have 600+ lb/ft and the other guy has 370 across the same range, but his makes a higher hp number. If you can put that tourqe to the ground and jump out ahead it would be tough for the other driver to catch you. Now on a highway, it may be a different story.

83 Crossfire TA

iTrader: (2)

No, torque is simply the turning force exerted. HP is the force * rpm, or HOW MUCH WORK something can do, originally defined as lifting 550# 1’ in 1second.

To figure out how much work a power source can do you need to know what torque at what rpm, or just the HP.

because it’s a more easily tangible measurement of how much work can be done. If you’re given just a torque number you have no way of knowing how much work/what you can move/how fast you can accelerate… If you’re given a HP number you know exactly what can be done, assuming that you gear it to a speed that is useful to do the work.

If they really wanted to give you a useful number they’d give you an HP/weight ratio (amount of work the engine can perform and some idea of how much work it will have to do to get things moving), and then you could make a pretty good estimate how fast it will accelerate knowing how good a driver you are.

If they both have the same max HP, and assuming that the drivetrain is geared so that you see the rpm where that peak happens when you’re trying to use the power, both will be able to do the same work AND both will be putting the same torque to the ground after gearing…. Since we don’t live in a perfect world where we can have constantly variable gearing to keep the engine at the power peak, but instead one where we have gear ratios and RPM drops… then the faster car will be the one that can stay at a higher average HP number through the rpm band dictated by the gear box, that one will get more average torque to the ground.

Again, like I said earlier, you’re arguing the wrong question. The real question here is if power made at a high rpm or low rpm is better, or is it better to make power using a small displacement and a lot of rpm or a large displacement and lower rpm.

The expression ‘torque rules the streets’ is a load of crap. Torque doesn’t rule the streets, making HP in an rpm range that matches the rest of the drivetrain and that the driver has the ***** to use rules the street (ex, a Honda S2000 can be driven fast, but most drivers don’t have the guts to let go of the clutch at 7krpm and spin it to over 9K to get the power out of it, so someone like me can come along that’s willing to beat the **** out of his 210hp/5-6000lb/4500rpm redline truck and beat them at a stop light).

ctandc

I love that statement about HP....we don't need torque except in the first 60 ft


As stated, HP is a PRODUCT of torque.

Think of it this way...

Torque is that grunt off the line that pushes the car to get it going....HP is the "pull" that keeps it going higher up in the rev range.


And peak HP is a MOOT point. I've seen / driven 550 HP small blocks that were absolute dogs. And I've seen 300 HP small blocks ( with a FLAT torque / power curve ) that ran easy 12's....

TORQUE is the reason that everyone wants more cubic inches. If you were building an engine JUST for the MAX peak HP, you would sometimes want a smaller cubic inch engine to let you take advantage of the HP at a higher RPM.


And higher HP is usually harder on drivetrain parts than compatible torque levels. Example... your engine makes 450 HP at 6500 RPM. That means it makes it's power up high. So to take advantage of that HP, you'd need to leave the line at alot higher RPM to get the motor into it's powerband.



Just my 2 cents

onebadwagon

torque is just as neccessary as HP, it is a mathmatical calculation that makes horsepower, from torque.

a high horsepower low torque motor, say something like a chevy 302, that makes its power up high, is going to be a pain to drive on the street, in some peoples books, but it should et well, given proper gearing.

say you take a 383, with similar components, and put it in a similar chassis, you are more than likely going to et a .1 or .2 better, however you may not mph as much.

the simple fact is, torque is quite useful on a car that has to be driven around everyday, as you dont have to go with some crazy stall, or some steep gears, you can keep the setup relatively tame.

area under the curve wins races, if you can make 400hp/400lbft for 3k rpm, when the other guy makes 450hp, but due to the components he has, he can only stay in power for 1500 rpm, unless he can stay in that power band, you will most likely win.

all this, torque is only good for a 60', thats bull****, torque helps your engine pull the entire way down the track. the more torque you can make, at a higher rpm, the faster you will go.


why do you think turbo cars are all the rage? because you can make 600lb ft from idle to 5k-6k rpm with well chosen components.

crossfire t/a is correct, i just thought i would throw my opinion in on this one.


adam

Ian_F

I heard two sayings that deal with this. The first being, Horsepower sells cars, but Torque wins races. The other was, Horespower is how fast you hit the wall and Torque is how hard you hit the wall.

onebadwagon

okay, to further this discussion it was brought up which would be faster.


an engine that made 400lb feet of torque at 2500rpm, and 300 horsepower.

or an engine that makes 400lb feet of torque at 4500 rpm, and 300 hp

the simple fact is, that unless something is wrong with one of the vehicles, this cant happen.

so that should end some of the comparisons there.


adam