Torque vs. Horsepower, who gets it?

[HT32BSX115]

Re: Torque vs. Horsepower, who gets it?

We are in sync

BTW, doesn't the steam locomotive kinda always do a kinda burnout as soon as the steam piston pushes down once? Isn't that then rotational and we have ourselves some ponies? I get your point, but still even at 1 RPM the massive torque just made horsepower . . .

Well yeah sometimes in the movies.....( but only by accident in practice) ........... they went to great lengths to prevent that because it caused severe damage to the drivers and the rails any time there was "slippage" .......... "Train Drivers" were trained to increase the steam pressure up to but just before the point where the drivers would slip. (I hesitate to call them "Engineers" mainly because of how long it took me to get my "Engineering degree!!)

The HP started out at zero and rose (directly) in relation to the actual RPM of the drivers. (torque with a steam engine is highest at zero RPM.........sort of like an electric motor)

The HP is just a mathematical representation torque at a particular (specific) RPM. Since most people think of HP in terms of automotive, marine, aircraft, truck, etc engines that turn in similar ranges of RPM, HP is a great way to compare them..........(and sell them)

Even gas turbines are described in terms of SHAFT HP (instead of actual engine HP) because the actual "main" N1 or N2 engine shaft is turning more than 8000-10000 and higher RPM but the output shaft might be turning only 2000 RPM or less..... so we talk about SHAFT HP (SHP, Kw or Mw)

Engines that don't turn shafts aren't described in terms of HP (or even torque), Like a Jet engine. They're rated in terms of lbs (thrust) but you can easily convert mathematically.....which brings us back to HP!!

 

[HT32BSX115]

Re: Torque vs. Horsepower, who gets it?

Well I can settle this once and for all. MORE IS BETTER!!!

AND I WANT MORE!!!

 

[parrisw]

Re: Torque vs. Horsepower, who gets it?

No I saw it, you said "horsepower sells, and torque wins races". Maybe at the drag strip. Not on the water it doesn't. . . .

The way these threads always go. I either shut my mouth and let the inaccuracies (semantics only some of it for sure) continue. Orrrr, I actually try and persevere on what I promise is factual. To say that Horsepower is just marketing is flippin' ludicrous. I will concede one inaccuracy on my part, when I was speaking to Rick, and that is the thrust and torque comparison.

In some simple ways, everyone is correct here. Yes torque is all that matters if you add maintained at any RPM. The only problem with that, again, is that when you add RPM, what you get is horsepower. So either James Watt was a fool, or we're just not communicating.

Reguardless, I still said Horsepower sells, and that's exactly what you said. I agree with what your saying, just not how your saying it sometimes.

 

[stackz]

Re: Torque vs. Horsepower, who gets it?

If you guys keep this up, as punishment I'm not going to post photos and videos of my new engine.

well now thats just mean

 

[Frank Acampora]

Re: Torque vs. Horsepower, who gets it?

NONE of you people "get" it! Normally I don't get into these long discussions but today I will and give a real world example.

My avatar boat has used two different engines: a 3 cylinder 90 HP Chrysler and a 4 cylinder 90 HP Chrysler. The torque curves are different, but at 5000 RPM with the same prop and same lower unit gearing, both engines drive the hull at 45 MPH. The difference is that the 4 cylinder engine develops more torque at lower RPM and gets the hull to 45 faster. BOTH engines top out at 5000 so obviously, the torque at that point is the same value. But at less than 5000 RPM the increased torque of the 4 cylinder translates into more horsepower so the hull accelerates faster. However: 90 horsepower will drive this boat at 45 MPH. Period!
In a short race, the 4 cylinder at the same horsepower will win because AVERAGE horsepower developed over that time is greater. THUS: Drag racers seek to maximise torque delivered by their engines over the RPM range.
Now, If I could increase the torque at 5000 RPM on either engine, the boat would go faster. Not because of the increased torque, but because I would have increased the horsepower (Torque X RPM) the increased horsepower would allow the engine to turn faster than 5000 RPM to the point where the power absorbed by the prop equaled the new higher horsepower.

In essence, I would be raising the torque curve and generating more horsepower at a higher RPM, but not necessarily increasing average delivered horsepower.
Thus Torque and horsepower AT ALL RPM is what wins the race.
It is NOT Either-Or: Like a man and woman married, you can not consider one curve without the other.

 

[southkogs]

Re: Torque vs. Horsepower, who gets it?

I think I'm going to have to switch to sailing ...

It's been a very entertaining thread to read guys.

 

[joewithaboat]

Re: Torque vs. Horsepower, who gets it?

So.. you guys that "get this" think that drag racers should concentrate on building and operating in areas of peak torque in order to go faster,quicker.

Negative comments about folks with more "car" experience than "boat" and how that makes them less able to understand boats, puzzles me.

 

[QC]

Re: Torque vs. Horsepower, who gets it?

My avatar boat has used two different engines: a 3 cylinder 90 HP Chrysler and a 4 cylinder 90 HP Chrysler. The torque curves are different, but at 5000 RPM with the same prop and same lower unit gearing, both engines drive the hull at 45 MPH. The difference is that the 4 cylinder engine develops more torque at lower RPM and gets the hull to 45 faster. BOTH engines top out at 5000 so obviously, the torque at that point is the same value. But at less than 5000 RPM the increased torque of the 4 cylinder translates into more horsepower so the hull accelerates faster. However: 90 horsepower will drive this boat at 45 MPH. Period!

That is 100% percent consistent with everything I have ever said on this topic, Frank.

So.. you guys that "get this" think that drag racers should concentrate on building and operating in areas of peak torque in order to go faster,quicker.

Negative comments about folks with more "car" experience than "boat" and how that makes them less able to understand boats, puzzles me.

I assume you are speaking to me specifically. It is not about understanding boats, but the horsepower curves required in either application is actually different. Many here will say that marine requires more torque than an automotive application, maybe so if getting on plane is the issue, but in Bert's case the goal was higher top speed and some were screaming for more torque as an argument against the small block gas engine. The fact is he needed more hp, and voila, this monstrosity . . . My point has always been, like Frank's, that those who believe that a high(er) peak torque value will somehow translate into higher top speed are missing it. Yes, a higher peak torque value may result in lower ET's on a drag strip, and better hole shot, but it will not increase top speed unless you also increase torque or RPM or both at WOT.

The other point I have been trying to make is that increased low end torque will not even be utilized in many marine applications if you do not require better hole shot. One way to remind yourself of the value of peak torque is that you are only there with the throttle at 100%. So if peak torque is developed at say 3200 RPM, if you never operate there with the throttle mashed, then you don't even use peak torque.

Thus Torque and horsepower AT ALL RPM is what wins the race.
It is NOT Either-Or: Like a man and woman married, you can not consider one curve without the other.

I have also preached that we shouldn't try and separate them. The fact is , higher peak torque gives you more horsepower at lower RPM. This is best utilized by wheeled vehicles for lugs and decreasing downshifts. In marine it only assists with acceleration. But again, that's because there is more horsepower available if you have more torque, at ANY RPM. The trick is matching the application to the power band, or visa versa.

 

[g1sammons]

Re: Torque vs. Horsepower, who gets it?

But but but
If we get back to the basics of this topics
You can't make a engine make more horse power
You have to make it make more torque
Because thats what it does

Simplest to understand is torque is a force
Simlar to how much weight you could lift horse power is measure of how fast you cand run while lifting that that weight

I know what you thing qc
But it's not right
This is why
If you look at the peak torque values of his 6.2 you'll see he was dam near right on top of it
So thus the forces holding is boat back were equal to what he was making in order for him to go faster he has to make more torque not more horse power
I understand they are tied together but my understanding and maybie I'm wrong but I don't think so
I believe that with anything boat car train when you have reached max speed the only thing you can do to go faster is to ad torque assuming that your in your peak torque range
Now if you had a given torque value that stayed the same and you could add horse power to that without adding anymore torque you could get to your max speed faster

 

[g1sammons]

Re: Torque vs. Horsepower, who gets it?

Oppps said something wrong you could make a engine with the same torque but have a higher hp rating by making it higher in the rpm range


By the way one of the biggest factor for all this is the useable rpm range which makes the gasser have a huge advantage over the diesel
And yes. The torque in a higher rpm range translates into higher horsepower which translates to higher torque if. If. If you have a multiple gear transmission
For what we are talking about it does not and this is why what your saying about him needing more hp to go faster is wrong

 

[Luhrs28]

Re: Torque vs. Horsepower, who gets it?

Hey which is better, synthetic or conventional motor oil?

I'M KIDDING! PLEASE NOBODY ANSWER THIS.

I used to belong to an automotive forum where asking that would literally get you thrown off the site.

Bert

 

[QC]

Re: Torque vs. Horsepower, who gets it?

You can't make a engine make more horse power
You have to make it make more torque
Because thats what it does

Frankly, you are so close it makes me crazy. The fact is all "reciprocating engines" make both. There are two ways to make more horsepower: 1) make more torque at the same RPM or 2) spin the same torque faster

Simplest to understand is torque is a force
Simlar to how much weight you could lift horse power is measure of how fast you cand run while lifting that that weight

This is correct.

I know what you thing qc
But it's not right

This is false

If you look at the peak torque values of his 6.2 you'll see he was dam near right on top of it

I actually agree, but what needed to happen was lower pitch selection, so that it would spin faster and get to rated horsepower. This is a naturally aspirated diesel. Peak torque is weak. There are turbocharged diesels that make so much torque at their peak that they actually have more horsepower than at "advertised" or "rated" RPM. This is not one of them. Even if it was, propping that way would usually be a bad idea. Not always

I understand they are tied together but my understanding and maybie I'm wrong but I don't think so
I believe that with anything boat car train when you have reached max speed the only thing you can do to go faster is to ad torque assuming that your in your peak torque range
Now if you had a given torque value that stayed the same and you could add horse power to that without adding anymore torque you could get to your max speed faster

This is kind of a mess . . . they are tied together, but you can't really "add horsepower". In fact, this is where previous comments of yours are correct, to "add more horsepower" you actually have to add more torque IF we are talking a fixed RPM point. This is a fact. However, with the written word we have to be precise, so there are probably only a few simple changes to the wording and more of your posts become correct. It is the small mistakes that make them false

 

[g1sammons]

Re: Torque vs. Horsepower, who gets it?

Now for the dragstrip stuff it's much different because you have defined a distance that you have to go and it's all about hoe fast you can go in that distance not how fast you can go overall
Theres a huge difference between speed and quickness

 

[QC]

Re: Torque vs. Horsepower, who gets it?

Yes.

 

[QC]

Re: Torque vs. Horsepower, who gets it?

The torque in a higher rpm range translates into higher horsepower which translates to higher torque if. If. If you have a multiple gear transmission
For what we are talking about it does not and this is why what your saying about him needing more hp to go faster is wrong

True that a lower gear (higher numeric) ratio in creases torque at the output shaft. The latter parts is utterly false. More speed always requires more horsepower. Always. If it is not reaching RPM and you lower pitch, it spins faster and you now have more horsepower at the propshaft. Goes faster.

 

[g1sammons]

Re: Torque vs. Horsepower, who gets it?

Let me say this wrong one time
But i this it will be understood better
If torque was work than hp would be how quick you could get that work done
I understand thar this is not correct but I think it's because most folks don't think of work in the correct terms

 

[g1sammons]

Re: Torque vs. Horsepower, who gets it?

Qc that's wrong
When force acts opon an object it accelerates until restance meaning opsite force is equal to the force that set that object into motion in the first place when both forces are equal we hold a constant speed
This is what the boat is doing

 

[g1sammons]

Re: Torque vs. Horsepower, who gets it?

When you lower the pitch it's just like down shifting in a car which raises the torque not the horse power
You can push harder with a lower pitch prop

And some times it can make you go faster
But getting into this would only make it more confusing

 

[g1sammons]

Re: Torque vs. Horsepower, who gets it?

Do a search on the word force and read newtons laws think there is only a few
Force is the same as torque
It's not the same as horse power

 

[g1sammons]

Re: Torque vs. Horsepower, who gets it?

If you do a search on horse power you find that is a measure of force for a period of time
Thus 550ft-lbs for 1 second
33000 ft-lbs in a minute
This is meaning that you moved 550 lbs 1 ft in on second
The force is 550 lbs