[Fundguy1]

Originally Posted by trey100

The OP did not ask that. He asked why it couldn't have a higher HP than torque.

The short answer is - it could.

My response was to the part I quoted. Just correcting it. That quote said cars with a peak torque below 5252 will have a HP number lower than the torque. I was clarifying that as long as there wasn't a steep drop off the HP could still be numerically higher with a peak torque below 5252.

I agree with you and this is exactly what I was saying. Its the other guys I'm disagreeing with who continue to say they are not related and not defining their basis for this or trying to argue sae is different from nm, which wasn't the question. I actually used your post as an example of the correct answer and how they weren't answering the OP question.

[GuidoK]

They are just as much related as say time is related to power
Or for example as antych said litres and meters. You can make a perfect formula to link those physical quantities.
What makes it silly is wanting to have more meters than litres...

[antych]

Originally Posted by Fundguy1

I agree with you and this is exactly what I was saying. Its the other guys I'm disagreeing with who continue to say they are not related and not defining their basis for this or trying to argue sae is different from nm, which wasn't the question. I actually used your post as an example of the correct answer and how they weren't answering the OP question.

lol, we have one guy who doesn't understand basic math, and another who doesn't understand basic English. The OP never asked what you're implying he did. Stop digging yourself into a bigger hole.

[3GFX]

Originally Posted by Stubbie Blue

It's just the way the equation works out:

hp = torque (lb-ft) x rpm / 5252

If an engine produces peak torque below 5252 rpm, the peak hp will be lower than the torque in lb-ft. e.g. most diesels.

If it produces peak torque at or around 5252 rpm, the peak hp will be close to the torque number. Most engines are like this.

If it produces peak torque above 5252 rpm, the peak hp will be higher than the torque number. Usually high-revving, small displacement NA sports cars are like this.

As previously stated....this!




Each motor has a different objective. For example, a transport truck motor isn't able to rotate at high speeds, thus not allowing the equation of horsepower to truly demonstrate how strong it actually is. They make monstrous torque. The job of those motors is to pull so it makes sense.

Performance automotive motors have different objectives as well, and with lower reving turbo motors becoming more mainstream we're seing a bias to higher torque figures.

"The perfect engine produces ample torque at low rpm and sustains that output to the redline. The amount of torque produced is directly proportional to the air flowing through the engine." - Car and Driver

http://blog.caranddriver.com/horsepo...he-difference/


"Remember, you cannot have horsepower without torque, but you can have torque without horsepower!" - Hot Rod

http://www.hotrod.com/articles/hrdp-...sepower-guide/

[merakulous]

Originally Posted by antych

lol, we have one guy who doesn't understand basic math, and another who doesn't understand basic English. The OP never asked what you're implying he did. Stop digging yourself into a bigger hole.

So tell us what the OP DID ask and grace us with your wisdom by answering his question - sound reasonable?

[davesz4mc]

You always measure TQ and calculate HP. You build an engine to make peak TQ where you need it for your task. Peak TQ is the max power output of an engine, The longer you can maintain TQ the higher your HP because RPM's usually climb faster than TQ falls off.
If you have two equal cars with equal weight and drive ratios operating at their peak TQ values they would run exactly the same speed and times even though the engines are working differently...
Example:
300HP Civic at 8k RPM peak TQ of 197
VS
300hp Charger at 4k RPM with a peak TQ of 394
They are making the exact same power level by differing means.
No replacement for displacement as low RPM TQ gets you moving and does not fall off drastically allowing you to continue to make decent power past peak TQ.
Large displacement limited in peak RPM due to mass of engine components.
Small displacement tuned to run peak TQ at higher RPM's can make less peak TQ but have an equal power output.
Forced induction can significantly increase TQ output in both applications and move that value earlier or later into the power band depending on turbo size and efficiency. Smaller sooner, larger later.

Diesel’s make so much power because of the high CR and fuel source which also requires much beefier components and the heavier components severely limit peak RPM. Diesel’s also do not have a carburetor/throttle body they increase/decrease RPM by adding or removing fuel not controlling airflow.

[davesz4mc]

My question in the title, let’s say a Porsche 911 turbo has 580 HP/ 780 Torque why can’t it have 750HP/ and 580 torque?


580HP / 780TQ puts peak power at 4,008 RPM
750HP / 580TQ puts peak power at 6,791 RPM


I would believe the second to be truer for that vehicle and engine configuration, so it can and often does…

[trey100]

Originally Posted by davesz4mc

My question in the title, let’s say a Porsche 911 turbo has 580 HP/ 780 Torque why can’t it have 750HP/ and 580 torque?


580HP / 780TQ puts peak power at 4,008 RPM
750HP / 580TQ puts peak power at 6,791 RPM


I would believe the second to be truer for that vehicle and engine configuration, so it can and often does…

This is not necessarily true. Each peak can and usually does occur at a different rpm. Your math above assumes the HP and Torque numbers are peak values occurring at the same rpm.

So 750 HP peak may occur at 8,000 rpm where torque has dropped off to 492 lb ft.

While peak torque can occur somewhere lower than 8,000 rpm.

[3GFX]

Originally Posted by davesz4mc

My question in the title, let’s say a Porsche 911 turbo has 580 HP/ 780 Torque why can’t it have 750HP/ and 580 torque?

I think that question is answered more based on the engine and its intended usage.

For example, square bore and stroke versus longer stroke or larger bore, how many valves, flow of the heads, is it force inducted or not, size of motor, variable valve timing etc. These differences will result in the different style of power output. These differences in the Porsche motor are probably more down to the limitation of the rev range, versus the forced induction and compression ratio.

[Zippster]

Originally Posted by antych

lol, we have one guy who doesn't understand basic math, and another who doesn't understand basic English. The OP never asked what you're implying he did. Stop digging yourself into a bigger hole.

Hang on mate. Typically an internal combustion engine will have two output values HP and Torque. Yes they are different values, However, for most naturally aspirated engines the HP value will be larger than the torque. In supercharged engines I think it changes to higher torque than HP. I think that is what OP was asking here. Further, engine design such as piston diameter vs stroke have an effect on HP vs Torque values as well. Having a large diameter piston and relatively short stroke will yield larger torque numbers I think, it's called an over square engine like Harley Davidson, they make a lot of torque vs HP. Then again, I might have missed something here.

[antych]

Originally Posted by merakulous

So tell us what the OP DID ask and grace us with your wisdom by answering his question - sound reasonable?

I already did, just read my replies. It's a simple misunderstanding by the OP, taking torque measured in Nm, comparing it to power measured in hp, and thinking that the difference in numbers means anything. The original question cannot be answered because it's illogical.

Just to show how stupid this is, let's take 911 turbo s numbers:
580hp and 750 Nm - and convert torque to imperial units
580hp and 550 lb ft - solved, more power than torque like the OP wanted, but wait, you can express power in kW like they do in some countries
427kW 550 lb ft - now it's less power than torque again, magic!

You can't do maths and physics like that. It's idiotic. And there's no unit called "torque" either. To compare two measurements they need to be of the same kind, like power, length, volume, temperature, etc. You can compare miles to inches, but you can't compare miles to gallons. Having more torque than power is like having more miles than gallons.

I don't know if I can be any clearer. It's like explaining physics to a child.

[antych]

Originally Posted by Zippster

Hang on mate. Typically an internal combustion engine will have two output values HP and Torque. Yes they are different values, However, for most naturally aspirated engines the HP value will be larger than the torque...

No, for most naturally aspirated engines, the power will be higher, than power on a turbocharged engine, producing the same amount of torque. So you're comparing power vs power on different engines, not power vs torque on the same engine.

The reason people are confused, is because those numbers look similar, being roughly in the same range. That is only because scientists and engineers picked units that are easy to work with.

If you express torque as "ounce force inch" instead of pounds, 550 becomes 105600, or 0.75 in kNm.

I don't think anyone would ever ask this question if they knew that porsche turbo s produces 0.75 "torque".

[Fundguy1]

Originally Posted by antych

No, for most naturally aspirated engines, the power will be higher, than power on a turbocharged engine, producing the same amount of torque. So you're comparing power vs power on different engines, not power vs torque on the same engine.

The reason people are confused, is because those numbers look similar, being roughly in the same range. That is only because scientists and engineers picked units that are easy to work with.

If you express torque as "ounce force inch" instead of pounds, 550 becomes 105600, or 0.75 in kNm.

I don't think anyone would ever ask this question if they knew that porsche turbo s produces 0.75 "torque".

What the frig are you rambling about?

[Fundguy1]

Originally Posted by antych

I already did, just read my replies. It's a simple misunderstanding by the OP, taking torque measured in Nm, comparing it to power measured in hp, and thinking that the difference in numbers means anything. The original question cannot be answered because it's illogical.

Just to show how stupid this is, let's take 911 turbo s numbers:
580hp and 750 Nm - and convert torque to imperial units
580hp and 550 lb ft - solved, more power than torque like the OP wanted, but wait, you can express power in kW like they do in some countries
427kW 550 lb ft - now it's less power than torque again, magic!

You can't do maths and physics like that. It's idiotic. And there's no unit called "torque" either. To compare two measurements they need to be of the same kind, like power, length, volume, temperature, etc. You can compare miles to inches, but you can't compare miles to gallons. Having more torque than power is like having more miles than gallons.

I don't know if I can be any clearer. It's like explaining physics to a child.

He didn't ask that. This is why you are the only person on this thread who everyone is asking wtf are you talking about. You are answering a question and arguing about something that wasn't asked.

He didn't ask why do cars rated in nm hp have lower numbers than sae. He asked why does one nm car have higher torque numbers vs another nm car that has higher hp numbers. What variable causes thst to happen.

[Fundguy1]

The original poster wanted to know how a car could have higher or lower hp numbers vs torque. Pure and simple. Since hp uses torque to be calculated, the answer is a car could have higher torque vs hp if peak torque is at low rpm. The car could have lower torque vs hp if peak torque is at a higher rpm. Simple easy. No other explanation is needed. READ THE ORIGINAL POST AGAIN. It doesn't matter which system is used to measure hp, sae or nm, the answer is the same. He was asking the relationship between the two, not the calculated values, etc.

[Fundguy1]

Post title
Why do cars have higher torque outputs than horsepower?
Op
My question in the title, lets say a porsche 911 turbo it has 580 HP/ 780 Torque why cant it have 750HP/ and 580 torque?

Nowhere is what you're offering asked for.

The answer is if it made max torque high rpm it would.
And if he wants more specific it would require jigher rpm still if he wants nm hp and not sae hp.

Move along folks. Next.

[stooker]

[antych]

I give up. I could explain this to a child, but not someone this stupid.

[Fundguy1]

Originally Posted by antych

You can debate the torque curve etc. but you can't compare those numbers with each other. The apparent difference is accidental and depends on units used. If that 780 was in Nm, then converted to lbf⋅ft it becomes 575, so it's less than 580 now, which could also be metric or imperial hp, or kW. It would get higher or lower depending which country's measurement system you pick.

This is where you are incorrect. Sure if you use different units, nm vs sae for example, the hp numbers will vary. But that still doesn't mean that a motor with lower hp in nm vs torque is automatically going to be higher hp number in sae than torque or equal. Diesels for example, low reving v8s, supercharged cars can all have lower hp numbers than torque no matter what hp unit is used. Conversely, high reving engines like 4 cylinder cars, race bikes, etc can all have higher hp numbers than torque again regardless of the unit used. If you use nm instead of SAE, the hp number will be lower on an absolute basis, but not necessarily lower than the torque. I don't know why you don't understand his question.

[GuidoK]

Originally Posted by antych

The reason people are confused, is because those numbers look similar, being roughly in the same range. That is only because scientists and engineers picked units that are easy to work with.

This sums up every misunderstanding in this thread. Everyone who's bickering about x is higher than y and such doesnt undertand this sentence.

I can make my torque or power 0.0000001 or 100.000.000 or 593.678.456.787.876.112 and they're exactly the same. Just change the way the unit of measurement is expressed. The unit of measurement sets a scale.

[Fundguy1]

Originally Posted by GuidoK

This sums up every misunderstanding in this thread. Everyone who's bickering about x is higher than y and such doesnt undertand this sentence.

I can make my torque or power 0.0000001 or 100.000.000 or 593.678.456.787.876.112 and they're exactly the same. Just change the way the unit of measurement is expressed. The unit of measurement sets a scale.

Correct. That is what others are arguing but for no reason. The op was asking given the engineers used identical ratings for hp and torque, how come one car would have higher hp than torque, and another the opposite. The scales, ratings, etc are meaningless as they are identical in both instances. The only variable is the torque bands of the two cars are different. This explains how two different cars, say a 1969 gto and a 2012 m3, that the first can have higher torque and lower hp, and the m3 can have lower torque and higher hp. I'm not arguing anything contrary to the other posters except that their answers weren't relevant to the op question, and that hp is totally unrelated to torque, because it is. Torque is used in any formula with rpm to determine hp, but different adopted standards vary the calculation.

[Fundguy1]

Why some other people are arguing about different rating systems is irrelevant.
Yes, there are different standards used by different countries
Yes, they were developed by engineers as a way to quantify power
Yes there are formulas to compare the numbers of each standard to each other
Yes, the power numbers as a result will look different depending on what standard is used.

All irrelevant.

The question was how can torque of one car be higher than that car's hp and torque of a different car, entirely different make, model, etc, be lower than the other cars hp?
The answer is how the engine develops its power over the span of rpms it covers. This is the torque curve. Max torque can be achieved early on or later in the curve. Early shows a lower hp figure. Later a higher one. Simple, easy, straight forward. No comparing standards, conversions, etc.