Now don't get ME wrong, the 330i's inline six is a marvel.(It's a Bimmer!!!) I have driven an Acura with the 3.0 liter VTEC and was impressed. However, I can completely understand what Road & Track meant when they said the VQ "Revs like no other engine this side of a V8 Ferrari.." I mean, after a fast drive home this evening, I can completely agree. The VQ is absolutely a jewel, it revs so freely and quickly, with absolutely NO vibration or drivetrain harshness whatsoever. It is simply extraordinary. Now before I had my Maxima I was like "Whatever, it only has 190 HP..." But now, I absolutely LOVE the engine in my car. The fact that Nissan can turn a modest 190HP into sub seven second 0-60 times absolutely amazes me. It is absolutely and positively SPECTACULAR!!!!!

 

So what's the meaning of torque?

 

Guess what? You just described HP.

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Another proof that HP is the main determining factor for acceleration. A test using the CarTest program:

Test #1 - Acura GS-R 1994, stock engine. 170 HP @7600 rpm, 128 lbft @6200: 0-60 in 7.1s, 1/4mi in 15.6s @91.6 mph

Test #2 - Same car, same torque but reduced-HP. 110 HP @5500 rpm, 128 lbft @3000 rpm: 0-60 in 10.0s, 1/4mi in 17.4s @78.9 mph

Launces were optimized for each test.

Huh? According to Brubenstein, peak torque was supposed to dictate acceleration? The second test should have yielded the same acceleration times. Oh wait, he just recently stated that the rpm that the peak torque occurs is also important...just describing HP. The closed integral for torque over the entire operating range is what's important...total area under the torque curve, not the peak torque figure. Peak HP is the one single value that best indicates increased or decreased area under that torque curve.

Brubenstein, why don't you for once give us all a good example that supports your point? Since I obviously don't know what I'm talking about and must have just totally spaced out during my 5 years of mechanical engineering education, please enlighten me. What's your main point(s), anyway? Please state it in a couple concise sentences if you don't mind.

 

O.K.

Try this one on for size

(The average torque of the engine across its full operation range) X (the peak operating RPM of the engine) X (gear multiplication which is torque multiplication)

Everything else being equal, the above three factors all put together make the difference --


So average torque to the wheels and peak HP to the wheels are important --

 

Ok, I don't know if this will help, but I read somewhere once that you never feel HP, only torque.

 

The accord 6 would prob be sub 7 or close if it was manual!
Thats teh main difference!

 

If you spent 5 years in an engineering program, and don't know:

f=ma

torque is a force and HP isn't

You either missed something, or deserve a refund.

 

Austin why don't you tell them about your torque experience in the 750!!!!!!!
oh and I could not agree with you more on the past posts you have made, f#ck some honda

 

Wow, I actually feel dumber now then before I read this thread. Lets just say that more of both is better and call it a day.

 

I think he was asking for an example. I would be interested too. The VTEC gsr vs non-VTEC Integra was a nice example.

 

An example of what? Torque and HP have formal, technical definitions. There is nothing to be proved. To understand the terms requires nothing more than a dictionary. How the behavior of a car is determined by these two things is more complicated. For a senseable explanation, though, one has to adhere to the definitions of the terms. Within this context, by definition:
Horsepower is the work required to move a car, at a given speed, through air and overcome mechanical losses and friction.
Torque is the force needed to change its velocity with respect to time (acceleration).

Any valid explanation of a car's performance has to be able to be worked through forwards, and backwards (fundemental principles to performance numbers) without violating the laws and definitions of physics.

 

Well then please elaborate on the two Integra examples please.

Integas w/ the same torque but different hp values have different acceleration rates for 0-60 time. By your defination(torque is the important factor), why does the non-VTEC'ed Integra slower to the 0-60 or 1/4 mark?

Or why can a relatively low torqued S2000 still achieve a really low 0-60 time w/ only about 160ftlbs(guess) torque? It's not that much different in weight than say a Miata right? What's the biggest determining factor that is accounting for these big 0-60, 1/4 time differences? Gearing, weight, torque or hp?

Side bar: And if this is true, then it would seem that Honda has wasted a great sum of money developing high hp(relative to their torque values) engines. ie.. NSK, GSR, SI, S2000 etc.. Honda basicly has bet the bank on high rpm/high hp engines. Yet this is 100% contradictory to your theory.

I'm trying to understand your side, but just saying you can't defy physics is not very clear to me.

 

Jeez, are you you being so difficult?

The ONLY point I am trying to make is that if you have to pick one engine output parameter that best indicates what the acceleration times of the vehicle will be, it is HP and NOT peak torque. I KNOW that the acceleration of the vehicle is ultimately dictated by the torque at the wheels, but acceleration G's at an instant in time does NOT provide you with enough information to find 0-60/0-100/etc times. You need more information...how long that torque can be sustained...and the one value that describes that is HP.

 

Because you are WRONG. You can't simplify things by violating definitions. You need a force to accelerate, not work. I could stand on the end of a torque wrench all day long, which would provide sustainded, constant torque, and no work (HP) would be generated.
Where HP comes into all this is that for any given speed that the car is already moving, you have to know how much work is being done (HP) to maintain that speed. Whatever torque (force) that can be generated at the driving wheel, in excess of maintaining its present speed, is the force that generates continued acceleration.
Even if a constant torque could be maintained at the driven wheel through the entire trip through the 1/4 miles, the rate of acceleration drops off at (about) the rate that drag increases (V^2). (A rocket powered car (with constant thrust) would be a good example of this.)

 

So what one parameter best indicates a car's potential to accelerate from 0-60/0-100/etc? Please enlighten me.

 

If you're a real engineer, why would you settle for a "one size doesn't fit much of anything" parameter, when you could do a proper calculation based on mass, torque curve, gear ratios, Cd and frontal area.
There just isn't some single figure of merit parameter that is going to tell you much. Even for initial acceleration, from a stop, you have to know the mass and drive wheel torque.

 

Not to flame but if we took your approach below, we would not get anything answered here on this forum. Technical repairs and discussions regarding performance would get nowhere because it would get bogged in forumulas and specific case senarios. In order to discuss anything, you must be able to make at least SOME assumptions or the dicussion gets nowhere(like this one) So in order to make a point, Keven and I both used real life cases that best explain our points. I don't see why can't you work off of these examples? You guys could go around in circles all day.

The best example that I can see is the Integra(s) example. If you could comment on that, maybe this discussion would get somewhere. Same car, about as close as you can in weight, assume the same gear ratios and final drive ratio, same tire sizes. The only real differences is the engine type. Vtec and none-Vtec. They even have torque values that are real similar. So for the sake of this discussion, please use this one.

 

Look, the title of the thread is "Meaning of Torque", and not "Pull a Number Out of Your ***". You don't need examples out of some car rag; you just need a dictionary. Newton set the rules. The first thing you have to do is learn what they are. Then you learn how to use them. Cars, and their performance is technical. Do you think designers sit around doodling and saying things like, "Yea, Dude, that looks like a cool size for a piston!"?
This discussion is going nowhere, because some people are trying to deny that the first principles of the laws of motion, and their terms exist.

 

If you can't explain the example, just say so! hehe.

I didn't pull anything out of a mag. It was a simple question. It doesn't require a fancy answer.

I don't think designers say stuff like that. Do you? I'd hate to be sitting around discussing car stuff w/ you becuase it would be a seriously dry conversation. Spouting formulas is not really my idea of a good time. The title was meaning of torque but the example he used was a real life situation, get it? It wasn't "What is the meaning of torque" period. He could have just as easily looked in the dictionary for that. It was meaning of torque as it applies to a specific example.

Of course the discussion is going nowhere, you don't want to apply what your saying to any real life situations.