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Old 07-09-2011, 04:58 PM
PMR = JUNK

 

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Horsepower vs Torque - What really matters

There seems to be a large misconception about the importance of torque and horsepower out there, especially in the diesel world. I've taken the conversations from the ORG chat about it and put them into one thread so hopefully people will learn, and to also have further discussion on it since J-Rod kept whining about it in "his" thread.

Some of it may be hard to follow but bare with me, it took like 2 days to get this quoted and put together to try and make it make sense.

Quote:
Originally Posted by Buffalo444 View Post
lets say I have a lot (this is gonna be a project anyway)... whats the MOST I could get out of it, and how much would it cost me?



You cant get 1000 ft lbs out of a stock block cummins?
Quote:
Originally Posted by chvyrkr81 View Post
What he said, a DT360 is IH's version of a full built Cummins.



Sky is the limit, or your checkin account anyway.

And no, you can't 1000 HP out of a stock block cummins. Not for long anyway.
Quote:
Originally Posted by Goose350 View Post
You can make thousands of horsepower and it will cost you tens of thousands of doll hairs.

Yes, you can make 1000 ft/lbs on a stock Cummins.

I didnt realize people set their goals based on torque This is a HP world.
Quote:
Originally Posted by Buffalo444 View Post
thousands? was that intentional? you can make over 2000 hp on a dt360 bottom end?

Lol and yeah I set goals based on torque. I dont go fast much but I do pull lots of heavy things just for s's and g's
Quote:
Originally Posted by chvyrkr81 View Post
I dunno about 2000 HP, but 1000 HP is a simple enough task for a 360.

And you should forget about torque. I can make 1000 ft lbs of torque with a 5 foot cheater bar and my 200 lb butt, but I can't snatch a sled down a dirt track.

HP is what's gettin it done.
Quote:
Originally Posted by Buffalo444 View Post
ok, so what would it take to get a thousand hp out of it? and why forget about torque? didnt dodge just bump the 6.7l torque 150 but the hp stayed at 350? isnt it supposed to be relative? i.e. x ft/lbs at y rpms = z hp? and whats the point of your big displacement engines at like 450 hp but 2000 ft/lbs of torque?
Quote:
Originally Posted by Goose350 View Post
Turbo, injectors, modded P-pump would be the main thing. Just need money.

Torque is irrelevant for people like us that wanna go fast or pull a sled, but yes... the more HP the more torque. Dodge bumping their torque rating is strictly a defense move. Had to do something to make themselves look better.
Quote:
Originally Posted by chvyrkr81 View Post
Fair question. TQ is a measurement of a single moment of the rotation of the engine. Once you take that measurement, and the RPM you got it at, you get HP. HP tells you how much work that engine can do, and how fast.

The RPM range they make that HP at is the biggest part of this story. Like the large displacement high TQ low HP engine you asked about. They're makin that TQ instantaneously, which translates to a powerband that jumps up right off idle and lasts all the way to redline.

Now throw a 10 speed trans and a strong drivetrain at it, and the powerband in that machine can put a constant 450 HP to the ground at just about any speed.

When you do the math for 450 HP through all that gearing, it calculates out to an incredible amount of TQ on the end of the axles. In the end those calculations show us that we put more TQ on the end of the axles at our HP peak than we do at our TQ peak.

Quote:
Originally Posted by Zytek_Fan View Post
I like HP, but I pay more attention to torque when it comes to diesels...
Quote:
Originally Posted by Buffalo444 View Post
Ah I see, so when you use the multipliers through out the drivetrain, you get both HP AND torque multiplication. So torque is just the movement the engine is putting on the drivetrain, and horsepower is the force thats making it go. I.e. you're getting 50 hp at idle or 600ish rpm, but have a 5:1 1st gear and 4:1 axle, so you're getting 20:1 HP at the wheels or 1000 actual (not dyno adjusted) hp (and saying the drivetrain loss is 0). but at 1800 rpm you peak at 450 hp, and your OD is .72:1 and your axle is still 4:1, you're putting 1296 to the ground. Right? So by using large engine component and long strokes like in your large displacement engines, you get better low end "torque", but that also equates to better low end horsepower, which is actually doing the work. right? So does that mean the longer stroked engines of similar displacement will have a better low end pull (because of horsepower) than the same displacement with a short stroke? So whats the point of boreing engines? is it just for a smooth plane on a rebuild? Is it the stroke kit that is actually giving you the power? And whats with the fall off at high RPM's? Is it just lack of consumables (air and fuel) at the high end that makes it drop off? So if thats right, thats why your chips and stuff increase the HP peak, because the allow adequate fuel to be delivered at higher rpm's, therefore increasing power produced? If this is true I have seen the light! If not I wandering around in the darkness...


Somebody opened up a can of worms....
Quote:
Originally Posted by Zytek_Fan View Post
I like HP, but I pay more attention to torque when it comes to diesels...
Quote:
Originally Posted by Jake View Post
You are sort of on the right track but not exactly, i think . I can't come up with the right words right now to describe it better.

And as far as boring and stroking, you increase the displacement of the engine. More displacement means you can get more air in the cylinder, more air means more fuel can be added efficiently, therefore, more power. Boring is usually done on rebuilds so there is a good, undamaged surface, so you are right on that, but boring can also increase HP and TQ. Stroking technically would increase torque more, due to the longer throws on the crank, this can however lower peak RPM, which can lower actual HP. Confused yet?



Torque really means nothing. All it does is give you an idea of how low in the RPM range power comes on. Lets for example take a diesel pickup and a honda civic that both make 500 horse. Clearly the diesel pickup has more torque. Lets make them both have the same gross weight of lets say 15,000 lbs (i know, unrealistic for a honda but for sake of example) and run them both up a 10% grade. The honda and the truck will run side by side. There are other factors involved but assuming they have the same usable range of RPM where they are making peak HP, they will be side by side. So if you wanna know how well a truck will pull a trailer, look at the HP, not the TQ.

The way the new cummins are, now with 800 ft lbs, look at the HP, it remains unchanged. The only way they could do that is to increase fueling in the lower RPM range. While I'm sure it can handle it just fine, that is actually harder on an engine.
Quote:
Originally Posted by chvyrkr81 View Post
A diesel that makes 500/1000 and a gasser that makes 700/500.

Gear 'em so the diesel is at it's TQ peak, and the gasser is at it's HP peak.

Put 'em head to head on the hill with the trailer that Jake mentioned, roll WOT and watch the gasser eat the diesel for lunch.

Now, if that's a very long hill the gasser will most likely kill itself before reaching the top, and even if it survives. Gasser's don't live long at that power level.

This is why diesel's are the kings of heavy hauling. In addition to their incredible ability to take abuse for mile after mile, they have excellent powerband ratio's that allow a driver to make use of his engines potential at a wide RPM range. I.E. powerband ratio.

Now, powerband ratio is quite literally that. Today, we'll talk about the 90% ratio of a couple engines making similar power. The 90% ratio is simply the ratio of RPM's that it makes at or above 90% of peak HP.

First, we have my old PMR motor's dyno sheet. 361/770. Not that impressive, right? But, lets take a look at the 90% powerband ratio. Max HP is 361, so 325 would be 90%. 325 HP begins at 2200 RPM's, and the pull ends at 3800+ with it still making 325 HP. So, the 90% powerband ratio we'll use for this motor is 3800 (rpm's) divided by 2200 (rpm's) = 1.72 ratio.



Now, we have a lightning motor. I pulled this off google, so I have no idea the history or application or mods. Just that it makes about the same max HP. We'll use the same 325 HP from my old motor, even though this gasser is making just a touch more. 325 HP begins at 4000 RPM's, and is still there at the end of the run at 5400 RPM's. So, once again, divide the upper end of the powerband by the lower end, and 5400 / 4000 = 1.35



Let's translate the difference there...

Put both motor's in the same truck, with a 3:73 rear end and a ZF6 trans. Run 'em down the road and go WOT at 50 MPH. Just so the gasser has a sporting chance, we'll put the diesel in direct drive, 5th @ 1900 RPM's, and the gasser in 4th @ 2500 RPM's.

Roll wide open.

At 57.9 MPH the diesel gets into it's 90% (2200 RPM's) and begins to pull away, it'll continue to pull in that powerband until it reaches 100 MPH. Incidentally, the upper MPH divided by the lower MPH is 1.72, ring any bells?

Lets get back to the gasser... In 4th at 50 MPH he goes WOT, but doesn't get to his 90% until 80.3 MPH, which lasts until he hits 5400 RPM's at 108.5 MPH. And, you guessed it, 108.5 / 80.3 = 1.35.

So, while he's luggin it up the hill hoping to get to 80 MPH so he can use his powerband to make a decent time of it in the gasser, you've been comfortably floating along right there in the powerband, lettin off the throttle for corners, and rollin right back into it on your way up that mountain.

Now, he could downshift to 3rd gear, and he'd be right at 4000 RPM's and the bottom of his powerband at 50 MPH. In which case he'd jump out on you while you got up to 57 and came into yours. But, at 67 MPH he'd be at his redline, and he'd have to shift to 4th, which would drop him back under his powerband to 3350 RPM's. And you'd come walking right on by him in fifth gear as he struggled to get his speed back.

Anybody remember Grandpa or Dad luggin his truck up a mountain? He'd lug out a gear, and downshift. The downshift would speed the truck up, and he'd shift again, only to repeat the process each time he fell out of his powerband.

Well, if Gramps had the powerband modern diesels do, he'd have never had to downshift.

So, hopefully I've done a fair job illustrating why diesels pull better.

It's not the torque, it's the powerband. Power = Horsepower.

Took a very long time to beat it into my head, and the above was the illustration that finally got it done.

On EDIT: If we started up that hill at 50 MPH in 4th on the diesel, we'd have been around 2500 RPM's. In our powerband. When we got to redline at 76 MPH and shifted, guess what? Yup, still in the powerband in 5th, at about 2900 RPM's.

Just a little icing on the cake there.
That is the end of the first conversation. Just a few days ago we got into it again.

Quote:
Originally Posted by e99f2506sp View Post
All manuals have more torque from the factory too if I remember right. I don't remember anything in more hp, but I though the autos were 525ft lbs and the manuals are 550 or something like that.

Either way...manuals are clearly better
Quote:
Originally Posted by Jake View Post
Correct. The injectors are the same.



I don't really wanna do this, but having more torque with no extra horsepower isn't really beneficial, except for maybe a slightly larger power band. My flame suit is on, because i know i'll need it, but i will say this, torque does not matter. I believe this smiley may now be appropriate.
Quote:
Originally Posted by Zytek_Fan View Post
Torque gets you moving off the line and from a slow speed, while HP keeps you moving and gets you going faster.
Quote:
Originally Posted by Buffalo444 View Post
Torque is a measure of force on an object, horsepower is a measure of work over time. So horsepower is what moves you. Having high torque allows you to produce horsepower at a lower rpm, thus giving you that "off the line" feel.
Quote:
Originally Posted by e99f2506sp View Post
Hmm. I disagree about the increase in hp and torque being a non issue, but whatever makes yall happy in your happy places. I'll just sit over here content in the knowledge I do indeed have 25 hp and 25 ft lb of torque more than the autos (plus the chip, they will program more power into a truck with a manual than they will a stock 4r100)

If it wasn't a big issue, the big 3 wouldn't spend millions to have a number that is 5 over the competition.

As far as loosing power during shifts, if you know where to shift and how to drive it, its also not an issue. Like was said, an auto is designed to slip, once you let the clutch out, a manual is set in that gear for the entire power band.

Anyway, carry on.
Quote:
Originally Posted by e99f2506sp View Post
Horsepower is how fast you hit a wall
Torque is how far you move it.
Quote:
Originally Posted by chvyrkr81 View Post
Horsepower is how fast your going, powerband is how far you move it.

Even though that analogy never made sense to me. I garuntee I can move the wall further hitting it at 50 in a 200 HP gasser dually than a 1000 fl lb regular cab at 50.
Quote:
Originally Posted by Buffalo444 View Post
dont you need the other half of the equation to make that statement true? i.e. you can move it farther with a 200 hp/ 300 ftlb gasser than a 100 hp/ 1000 ftlb diesel? i mean cuz the gasser dually could be a reg cab and the reg cab could be a gasser dually.... hell they could be the same truck.
Quote:
Originally Posted by Jake View Post
Increase in HP makes a difference, torque, not so much, like i said, only a possible larger power band. And they will not purposefully tune an auto less than a manual.

Get me at a time when i'm not half drunk still and not about to go to bed and i will educate all of you on horsepower and torque. Many of you will say i am full of chit, however, if you actually did some reasearch in physics, you would realize that i am right and all the other people that think that higher torque means its easier to pull a trailer and horsepower doesn't really matter are wrong. Horsepower is the essentially the ONLY thing that matters pulling a trailer.
Quote:
Originally Posted by Buffalo444 View Post
I'm pretty sure you, Tom, and I had this discussion a while back. Idr what thread (I know I said I wanted a 3000 ft/lb dt 360 or 466) but anyway we went through the whole schpeal, I didnt get it at first, but once the 90% powerband and peak torque example was used, it clicked, and I got it.

I'm going to look for it.

I'll be back.
Quote:
Originally Posted by Buffalo444 View Post
Yup, cant find it.

Key points are:

-It was a lightning versus a modded 7.3 (366 peak rwhp vs 360 rwhp)
-peak horsepower and the 90% powerband
-shifting and staying in the powerband
-the 90% powerband rpm ratio's
-operational efficiency at peak hp of each truck
-how a 700 hp/ 500 ft lb truck can out pull (in every way, but thats it) a 500 hp/ 1000 ft lb truck

That should definately ring some bells to some of yall. Heck one of ya even posted a graph (dyno chart) of each truck.

but off to bed for me...
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  #2  
Old 07-09-2011, 05:00 PM
PMR = JUNK

 

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Quote:
Originally Posted by e99f2506sp View Post
Nevermind, I just remembered I don't care....

No need to start anything about it. You've got your views and I got mine. We've already talked way too much about it and obviously disagree. If we get the chance to talk about it over a beer someday, great, that will be a lot more fun and not get anyone butthurt. If not, we'll just agree to disagree
Quote:
Originally Posted by Jake View Post
Its not about "views." It's about physics, and what is actually true. Any engine makes torque. Torque is rotational force. Horsepower is a measurement of torque over time. Without the time part of the equation, it means nothing. You can take a 10 foot bar and a socket and put 100 pounds of force on it, equaling 1000 foot pounds. However if whatever you are applying that torque to doesn't move, you have done nothing. Now if you apply that torque at say 100 RPMs, you have now made 19.04 horsepower.

And i'm not butthurt. Just trying to stop the spread of false information.
Quote:
Originally Posted by e99f2506sp
Ok, I get what you are saying, and it certainly sounds good, but by your logic you are still making torque by adding 100 rpms to the equation. I'd like to see the torque numbers you are producing when you are making 19.04 hp or whatever, clearly it will be more than the 1000 ft lbs you would be making by putting 100 lbs on a 10 foot bar...

The torque in my example stays at 1000 ft lb. At 100 RPM, in order to make 19.04 HP, you must apply 1000 ft lbs. In order to make 19.04 horse at 1000 RPM, it only requires 100 ft lbs. Now if you took that same 1000 ft lbs and bumped it up to 1000 rpm, you are now making 190.4 horsepower.

You also said that torque is nothing in pulling trailers...I just don't see how that is true when big trucks have say 1500ft lbs of torque and only 480 hp. Clearly torque plays a roll. Horsepower moves any set amount of mass in a straight line with no other variables other than wind.

It really isn't anything. An engine that has higher torque will have more horsepower at a lower RPM than an engine that creates less torque, so it will feel as though its more powerful, but it is still horsepower that determines how well it gets it moving. A 480 horse honda will pull the same weight at the same speed and accelerate the same, given that the honda could hold that much weight, and that the honda was in its power band. The difference is that the semi makes 480 horse at a lower rpm, whereas the honda makes it at higher rpm, so you'd just have to slip the living hell out of the clutch to have the honda start that load moving while still in its power band. However if they were both already moving up a hill at 50 MPH and both were already in their power band, they would pull the same.

If that mass comes across a hill, or is taking off from a stop light and needs to accelerate for any reason, torque is way more important that hp.

Explained above.

I am just trying to play this out and get information out there, lets not play the "trying to stop the spread of false information" card just yet, nothing bugs the hell out of me more than someone who isn't open to opposing views whether they be right, wrong, or otherwise hilarious. (coughliberalscough)
My responses in red.

I'm not playing any card. This is solid scientific stuff i'm telling you. There is no correct opposing view, this is how it is. Many will not believe it. I didn't at first either. I used to think torque is what really mattered too. Then i started listening to people saying the same things i am now and researching. Its just hard to wrap your mind around this concept when your whole life you have been told by people that were ignorant to what is really fact.

Other scientific facts that are undeniable; the planet is round, and it orbits the sun. Those can not be argued, though at a time they were. Just the same as the HP/torque thing. It can not be argued, it is what it is.

Quote:
Originally Posted by Buffalo444 View Post
bravo Jake. i was afraid i was going to have to correct him and use my entire lunch doin it on the phone. lol.

if you look at it, the reason the torque on the dyno changes is only because more fuel and air are consumed. if you take an electric motor (instant torque because its all in the current) the horsepower is purely limited by rpms. because it is an equation. a 1000 ft lb electric motor spinning at 500 rpms is only going to pull half as hard as a 1000 ft lb electric motor spinning at 1000 rpms. right? so its simple. torque is only as useful as the amount of work it can do over time. which hey, guess what, thats horsepower!
Originally Posted by Buffalo444
it is an equation. a 1000 ft lb electric motor spinning at 500 rpms is only going to pull half as hard as a 1000 ft lb electric motor spinning at 1000 rpms. right? so its simple. torque is only as useful as the amount of work it can do over time. which hey, guess what, thats horsepower!
That is dead on.

Quote:
Originally Posted by e99f2506sp
Please keep the type of talk in bold to a minimum, nothing good can come of it and it certainly is not helping anyone look good. I'm not the smartest kindergardener on the playground, but I still have yet to grasp your views even after some light researching and chatting with you.

Ignorance was not meant as an insult. Ignorance is not stupidity. Ignorance is defined as a lack of knowledge, or simply, unknowing. So the word fits perfectly with what i was saying. I'm not calling you stupid at all, just ignorant. Huge difference.

What your saying works if you keep the torque static at 1000 lb ft. It will not however work in a range, like a dyno. Clearly torque plays a bigger roll in your example that hp though because your still operating at 1000 lb ft with only 19.04 hp. If you add 1000 rpm, you only have 190 hp but you still have 1000ft lb.

It works when the torque is not static as well. If you can apply more torque at a higher RPM, you make more horsepower. Torque is work, or the rotational force an engine makes in this example. Engines don't truly make horsepower. Horsepower is a measurement of the amount of work (torque) done over time (RPM). Therefore if an engine can do more work in a shorter amount of time, it will accelerate faster/pull more weight. Take the semi engine that makes 1500 ft lb at 1500 rpm. At that point it is making 428.4 horsepower. Now if you could spin that engine to 3000 rpm and 1000 ft lbs of torque, it is now making 571.2 horse. Less torque, but more work is being done.

What you are also saying about the honda vs the big truck plays into my views perfectly. The reason the truck makes its power at a lower rpm is because it makes its torque at a lower rpm. This is correct. Why do you think they have so many gears...to keep it in its torque curve while accelerating. Also correct, there are other reasons for this though, such as a narrower usable RPM range and it will accelerate faster (assuming shifts are done quick enough) if there is a smaller gap between gear ratios. If it was to keep it in its hp curve, they would shift at higher rpms than 12-1400 out of 3000. It is to keep it in its HP curve, they make their HP at low RPMs. Once it hits its cruising speed, it makes no difference anymore other than good mpg and to keep itself moving against wind speed so thats when its relatively low hp numbers kick in. If they hit a hill, they drop a gear and get back into the torque curve and take off. They drop a gear to get it to where it makes more HP. It wont cruise down the highway at 150mph like the honda will though because thats where the hondas hp curve is, up high in the rpms. Not true, that is all in the gearing. There are semis that run over 120 mph across the desert. Bore and stroke come into play here to change the hp vs torque curve. Big trucks...big bore and long stroke...lots of torque and low rmp. hondas...smaller bore and short stroke....lots of hp and higher rpm. People bore out engines and add heads to increase bore and stroke to increase torque numbers, its really the only way to do it. Horsepower can be added by adding fuel (injectors, etc)

Yes, big bore and big stroke will equal more low end torque, which means it makes more horsepower in the low RPM range. Horsepower is also increased when you bore and stroke an engine, and both are added by more fuel.

The reason you have to slip the clutch in the honda really depends on where the torque curve is...i gotta find a 480hp honda to figure that one out.

This is correct. The powerband in a honda motor may not come in til over 4000 RPM, whereas the semi has it dang near off idle.

My dads track car with only 280hp will blow the doors off of a mustang with 300 hp because my dads car has 340 lb ft of torque and the mustang only has 320. Sure the mustang will probably get it in a top speed race, but its not geared for that its geared to get him down the quarter or around the road course faster than everyone else. Granted power to weight ratio comes into play with this example as with any, but keeping all other variables the same other than hp an torque numbers, it would operate as Ive stated.


My responses again in red. Give both cars the same gross weight and same gearing and i promise you the mustang will beat the track car. Which you actually just admitted yourself, you just don't know it. Look at what you said. The track car has lower gearing, and is lighter. Of course it will beat the mustang. Same reason a 200 horse honda would put a whoopin on my truck that puts down around 300-325.

Quote:
Originally Posted by e99f2506sp
Please, no one feel the need to "correct me" we all have better things to do. I still think yalls point works when you keep a certain number static, but it makes no since when it comes to a range....which all engines endure.

It works whether a number stays static or varies. The formula is the same.

Electric motors have huge torque numbers, and very low hp numbers.

look at a motor from tesla for example. the peak torque is at 400 rpm, right down low while your accelerating, and its peak hp is at 6000rpm up there where its needed to keep itself speeding along at 125mph


Why do you think it need the HP at 125 to keep it moving? I'll answer that for you. Wind drag. When your speed doubles, the wind resistance quadruples. According to the "torque is what is more important" theory, you would want torque up there to help push it through that wind resistance, which in a sense is just simulated weight.

Just for S&G's... Tesla dyno chart.



Quote:
Originally Posted by e99f2506sp
Sorry, but it sounds like you just said that an engine creates hp due to torque....so is torque necessary then, or should we just get rid of it? Your arguing against yourself with every post...You yourself said it takes a certian amount of torque to create hp.

An engine makes torque, so yes it is important, but what i'm getting at is more torque alone will not get a trailer moving easier. I never said we didn't need torque. I am not arguing with myself at all. My wording may not be perfect because I'm tired, but the point is definitely there, you just don't want to see it because you think I'm full of chit.

"Take the semi engine that makes 1500 ft lb at 1500 rpm. At that point it is making 428.4 horsepower. Now if you could spin that engine to 3000 rpm and 1000 ft lbs of torque, it is now making 571.2 horse. Less torque, but more work is being done."

Your driving my point home exactly with every post! It takes torque to get a mass moving, and hp to keep it moving, your quote from above makes perfect since!

The sentence in blue is totally false. Horsepower gets it moving and keeps it moving. Torque alone does not determine an engine's power or it's ability to move heavy objects. You need a measurement of time to go along with that. And that, ladies and gentlemen, is what horsepower is. Work done over time. Take a 500 horse semi and a 500 horse gasser. Make all variables equal, weight, final drive ratio, wind resistance, etc. Get them both in their power band and run them both side by side up a 10% grade. I promise, they will pull side by side.

If narrower rpm range is an issue...why not go ahead and make a semi engine that revs to 8, 10, 16k? even if it would hold together in that long stroke, big bore engine, thats not where torque happens in that kind of an engine.

They don't rev that high because they would scatter. They have rev limiters for a reason. There are 2 approaches to making horsepower. One way is like a semi engine. High torque, or high RPM.

And actually what i said was... "keeping all other variables the same other than hp an torque numbers, it would operate as Ive stated." There are thousands of variables that would give each car an advantage...suspension, brakes, tires, etc, but as far as the track car beating the mustang around a track if both cars weighed, say 2400lbs, my dads car would beat the mustang all day long...it has more torque.
If you made all variables the same other than the engines, the mustang with a few more horse but less torque WILL beat the track car. I guaran-fing-tee it. I would even go as far as betting the title's of our trucks on it. Run the mustang in a quarter mile, then pull the track car motor out and put it in the mustang, and run the quarter again. Your mind will be blown.


Quote:
Originally Posted by e99f2506sp View Post
Ohh, and I just read your part about the tesla...

I never said "torque is most important" overall. It is most important down low in the rmps, to get a mass moving. Hp is most important once the mass is moving to keep it moving...hence the high torque numbers low in the rmp range and high hp numbers high in the rpm range. I've said all along that it takes hp to keep it moving in wind drag.

Your arguing my point as much as your own... its you and me against yourself it seems...

I'm making a case for hp just as much as torque really, just fighting more for torque cause that seems to be the part you don't want to believe exists.
Quote:
Originally Posted by Jake View Post
I'm gonna bow out for the night. Perhaps by the time i get back someone that is a little better at wording things than myself will have chimed in and explain exactly what i have already said only using different words that might explain it better. I'm hoping Tom comes in on this. I can tell you right now he will say that what i have said is dead accurate and true, and possibly elaborate on it a bit more than my currently tired brain can do right now.
Quote:
Originally Posted by e99f2506sp View Post
It will win in the quarter mile yes, it has more horsepower, but my dad will beat him in the 1/8th cause hes got torque to get him off the line

Its another reason it will win on a road course over a mustang with all other variables the same...because it has torque to pull itself through a corner and accelerate out the other side. otherwise a ford edge would beat my dads car assuming all other variables were the same, it has 285 hp. However, it only has 250 lb ft of torque...so there is no way it would keep up.

And as far as thinkin your full of ****, I don't I wouldn't have spent the last few hours away trying to research your point of view and talking to you about it if I thought you were.
Quote:
Originally Posted by e99f2506sp View Post
I gotta hit the hay too bud, Good chattin with ya. There aren't any winners or loosers here, just more educated people.

If Tom chimes in, I'm out for good. Theres no fightin that brick wall with the crayons and safety scissors I got just kidding Tom.

I'll continue to do research on it, clearly you think your on to something so I am more than open to reading opposing views, and have. I just have found reasons not to believe them in every case so far...
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Old 07-09-2011, 05:02 PM
PMR = JUNK

 

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Quote:
Originally Posted by e99f2506sp View Post
Sorry, was laying in bed thinking about this, and came up with the simplest solution I could...

Say you have a bolt that you need to loosen. You put the breaker bar on there and pull, that is torque against the bolt just as an engine put torque against the ground starting from a stop. The bolt breaks loose and you spin the breaker bar, that spinning at a steady speed is horsepower just as driving your vehicle at a steady speed is. You spin the bar faster, feeling the torque against your hand, just like pressing on the accelerator, putting more torque against the ground to speed up a vehicle.

If speed is constant at any speed, no accelerating is happening, then horsepower is working...maintaining the vehicle at a speed with no other forces against it but wind...

If speed is changing up or down, torque is working, whether it be from the engine through the tires to the ground to speed you up, or friction agains the brakes to slow you down.

By what you are saying, I could just as easily run down and get a ford edge (sorry, grandparents just bought one so I know all its specs) because it does have 10 more horsepower than my truck (without tunes) and just as easily tow the focus in my sig, or my trailers around daily for work assuming I could get the frame to handle the weight? The fact that my truck has 275 more lb ft of torque is irrelevant and unnecessary?

I know for a fact we could both haul the same load at 50mph across flat terrain perfectly fine, hell with 10 more horsepower the edge may do it more efficiently, but put 10k behind both of them and take off from a stop and which one would win?
Quote:
Originally Posted by Buffalo444 View Post
Ok, first off use a torque wrench to break that bolt loose. What happens to the ft lbs once its un-seized? They drop off. So there is not torque and no horsepower, because it isnt doing work.


Here is the GLARING HOLE I find in Jake's arguement, which is probably why you are not seeing why its horsepower doing the work. First off, remember we are talking PEAK HP numbers, which do not show a powerband. We need a dyno sheet for that.

Lets take your 285 hp ford edge vs your 275 hp truck. This is why you would be faster, Because your 90% hp powerband is MASSIVE compared to the edge. For the most part, gassers tend to peak horsepower right around redline, due to the fact most of them are indirect injected and require air flow and engine speed to build power and inject fuel, two things powerstrokes do directly via forced induction (turbo charging) and direct injection (our heui system). So lets say you are just cruising along, around 2k rpms in each vehicle. The powerstroke is well within its powerband (90% peak horsepower), and the edge is probably about 1k under its powerband. You are probably geting 2 times the horsepower to the ground just cruising around.

Now here is where I have to say something else, every time you say something will be quicker at doing something you are AUTOMATICALLY TALKING HORSEPOWER. Torque is load on an object, it can be statically defined. Horsepower is work done over time. The reason the higher torque vehicles have that "off the line" feel is because of one thing, they produce more HORSEPOWER, earlier. That's it.

And the reason those massive semi engines dont run at those high of rpm's is one thing, supply. What happens when you have a 4x4x4' empty hole and go to fill it with water. Using as big of hose as you need, you can only fill it so fast. That's physics. Now take a 16x16x16' hole and try doing the same thing. Again it can only fill so fast, and it CAN NOT be filled as fast as the smaller hole, due to physics. SO fueling is the limiting factor, as well as delays in the mechanics of it all (take our heui system for example, we are really limited where we can effectively use our fuel as far as rpms go)

Now here is why two trucks, with the same curb weight, same horsepower, and same gearing can race and have a clear winner every time. Say we take some stock big block gasser that produces around 300 rwhp at 5k rpms, and makes about 450 ft lbs of torque. Then we take a mildly modded 7.3, that makes about 300 rwhp and 600 fl lbs of torque. Set em up in two 4x4 trucks, autos, same rear ends, torque converters with the same stall speed (say 2.3k rpms). Make em weight exactly the same. now here they go:

Both trucks are lined up, both get to brake boost to load up the trans and be ready to start the race. The gasser is maxed at 2300 rpms, its barely making 50% of its max horsepower. So its about to launch with 150 hp. The 7.3 is sitting at about 275 hp, a little over 90% of it peak hp. Its going to launch in its power band.

Both trucks launch; the 7.3 making way more horsepower and doing way more work than the big block, so its pulling ahead. The gasser is winding up trying to get to its peak hp, which is near redline. It can't keep up.

The trucks both go to shift. The 7.3 shifts and drops down to 2300 rpm, and stays well within its powerband. The big block shifts and drops to 2300 rpms, and falls right out of its powerband. The 7.3 keeps pulling ahead and the gasser keeps falling behind.

The trucks reach their speed limiters. The 7.3 long before the big block. Because the 7.3 stayed in its powerband the whole time, it did more work in a shorter period of time, got out ahead, and now in o/d will maintain the lead. The big block fell in and out of its powerband, fell behind, and now even when in o/d its out of its powerband.

So now you see ( I hope ) HORSEPOWER is what moves you, and POWERBAND is what determines how efficiently you move.
Quote:
Originally Posted by chvyrkr81 View Post
Powerband ratio...

That's what isn't being explained that should turn the light on.

I can make 2300 ft lbs of TQ with a ten foot bar, but if I can't do that quickly (RPM) then I won't get any loads moving.

Now, add some RPM to that and we can start moving some weight with it. But, TQ at RPM is called power, or horsepower.

Back to powerband, the ability of those OTR tractors to produce 480 HP at 1200 - redline is what gets the load moving. When you're making max power right off idle, and have the gearing to multiply that power, you end up with a machine that can move anything you hook to it. Or destroy the drivetrain trying.

But you can't do any of that without RPM, and TQ at RPM is HP.
Quote:
Originally Posted by e99f2506sp View Post
I read through your posts Tom, and if I understand what you are saying correctly, Torque times rpms equals horsepower?

Example...

T = Torque
R = RPM
H = HP

So, T x R = H correct?

I think the confusion happened back when Jake said something about more torque is unnecessary to move a load, when according to the math equation that I understand from your explination, the more torque you have, gives you more horsepower at lower rpms?

So according to the T x R = H math equation, there can be any amount of infinite numbers for T and R and that will always give you a different number after the equal sign. However, that can't and won't work in any other way... ex H x R ≠ T and H x T ≠ R.

That being said, it sounds like we are discussing the same point, torque is indeed important? Whether it is Horsepower that gets a load moving off the line or not, torque is definitely needed because without T the equation is R = H and that can't work...

Please explain, I am very interested in this now. Again, no hard feelings to you Jake, I'm glad you brought this up.
Quote:
Originally Posted by Buffalo444 View Post
Well torque is important, but it is not that important. You can have a 3000 ft/lb engine, but if the torque takes a steep drop to 0 at 600 rpms, the most horsepower you made there was about 350. Its all about the Powerband, which involves the torque curve that determines the horsepower curve that determines the powerband. The important part is the work that can be done and where you can do it, right?
Quote:
Originally Posted by e99f2506sp View Post
If torque takes a steep drop to 0 at 600 rpm, then that means 0 horsepower is being made if I understand their equation right. If all was made was 350 hp, there was still 3000 lb ft of torque being produced to make the horsepower.

The part in bold falls into the T x R = H equation I said earlier. It can be graphed for sure.

If I understand them correctly, put torque on the x axis and rpms on the y axis. The line that comes out of them both creates the horsepower that they are talking about. Go up to 1000 lb ft, and across to 1000 rpm, whatever the math equation is there, mark the spot on the graph...Then run up to 1500 lb ft and 1500 rpm, the amount of hp made will have gone up until you hit the peak of the engine.
Quote:
Originally Posted by chvyrkr81 View Post
Jared, 24 is the number we're worried about.

24 is HP.

We can multiply various numbers to reach 24, like 3, 4, 6, 8, 12.

In the end, none of those numbers matter except 24.

We can talk all day long about what the number 8 means to us, and how much better we feel about having the mods to push us to 12. But, that number is still only telling part of 24's story.

TQ is a piece of the puzzle, not an indicator of anything until it's matched to RPM. But, as soon as we match it to RPM it's not called TQ anymore, it's power.

But since the TQ number is usually higher, and the word alone does more to conjure up images of barrel chested red blood Americans gettin stuff done, manufacturers have gotten really stuck on advertising it, especially in the diesel pickup world.

OTR tractors, farm tractors, etc, are all rated in HP for a reason. HP is a measurement of power, power gets stuff done. Torque is only part of the formula.
Quote:
Originally Posted by e99f2506sp View Post
You lost me on the 24 stuff, but it looks like we all agree on the fact that torque is key to producing horsepower. Without it, you don't have horsepower.

Like my equation above, T x R = H, if you take T out of the equation you can't get H.

Sounds to me like Torque is a vital part of producing power? I'll agree that horsepower is what moves a vehicle, but it looks like torque has to be there.

Example...

Big truck: high T x low R = H low in the rpm range (big trucks produce it at about half of its rpm range)
Honda, low T x high R = H high in the rpm range (hondas produce it up high near redline of its rpm range)

Either way, H is still being produced, just at a higher RPM for the honda because any number times a bigger number = a higher number. Or in the case of the big truck, a big number times a small number = a higher number. This falls right in line with what Jake and I were talking about last night comparing a 480hp honda to a 480 hp semi. If gearing and all was the same, you'd have to still slip the clutch in the honda to get into its power band vs the truck where its immediate.

Torque is only part of the equation, but a vital part of the equation because without it, horsepower is not being produced according to yalls point. All vehicles advertise HP because like you said, thats the number everyone has been engrained to want to listen to.
Quote:
Originally Posted by chvyrkr81 View Post
No...

HP is the number that moves stuff.

I can make 2300 ft lbs of TQ with a ten foot bar, but there's not a chance I can move even a light truck at highway speeds like that.

I need lots of RPM.

But once the TQ x RPM formula is introduced, it's power.

TQ alone is meaningless. Absolutely and completely.

TQ and RPM does mean something. But it's not called TQ anymore once it's plugged into that formula.

TQ alone is only part of the math equation. Thus the 24 example.

Telling you the torque number alone when trying to communicate the capabilities of an engine is like giving dirrections to my house without street names, only telling you left and right. It's only part of the information needed to paint the whole picture.
Quote:
Originally Posted by chvyrkr81 View Post
A 230 HP Honda can keep up with any 230 HP diesel out there, as long as it holds together.

Keep them both in the powerband and there will be no advantage had by either engine until the honda lubricates the undercarriage.

Power is the word I keep using here.

Power as in power across the RPM's, powerband.

HP is a measurement of power. So is watts, but let's keep it simple lol. I'm not tryin to get into my old textbooks here.
Quote:
Originally Posted by e99f2506sp View Post
I'm pretty sure we are saying pretty close to the same thing here. I'm not sure what your "No...." was referring to. Whether everything I said was wrong, or some part of it.

Im saying Horsepower is not possible without torque, we are both saying horsepower is what moves a vehicle.

I have said that I will agree that horsepower is what moves a vehicle, but torque has to be there in order for horsepower to be made. Without torque there is no equation to make horsepower.

We are both using the T x R = H equation, but it seems to me your more set on the R and H part of the equation and I am just making a case for the T part of the equation.

I say Horsepower by itself is meaningless and not possible without Torque. Torque is possible without RPM as you've said, and if you add RPM you are only then creating HP which will move a vehicle down a road.

How does my example of the big rig producing high T at low R and creating H and the honda creating low T at high R creating H not come true. It falls right in line with the dyno graphs you have shown me. It also falls right in line with an electric motor that we were talking about last night, High T at low R and as the R goes up, the H goes up. As the vehicle speeds up T falls off as R goes up producing H.

Yore saying torque isnt called torque plugged into the equation T x R = H....well then what is it then called. I know the final outcome is called horsepower, but again, there has to be an equation to get horsepower. Thats like saying 2 x 3 is 6 but once you plug both 2 and 3 into the equation, the are no longer 2 and 3. However, without 2 and 3, there is no 6.
Quote:
Originally Posted by chvyrkr81 View Post
No as in, TQ alone is worthless, HP alone is not.

Having established that TQ alone can't do anything for us, why do we talk about it?

HP is a measurement of power.

Power tells us what an engine is capable of, all by itself.

Lay the powerband in there and we know at what speeds the engine has those capabilities.

But that doesn't change the capability itself.
Quote:
Originally Posted by e99f2506sp View Post
Like I've stated before, I know a 230 hp car and a 230 hp truck will tow the same amount of weight at a set 50 mph speed if you can get the car to handle the weight

The difference comes in acceleration because of torque. Like I said before, the truck produces high torque at low rpm, and therefor produces power low in the rpm range and will accelerate with no problem hauling the load. The honda creates low torque but high rpm, therefore like was said before, you would have to rev the engine high up and slip the clutch or lug the car bad assuming all gearing was the same to get the same load moving, because the power is higher in the rpm range.
Quote:
Originally Posted by e99f2506sp View Post
How is torque alone useless? I can torque on a bolt and break it loose not have any horsepower involved whatsoever. Its only after you add rpm to the mix that you even begin to create horsepower. You yourself have said this.
Quote:
Originally Posted by chvyrkr81 View Post
And if you let an OTR tractor fall out it's powerband it would be just as dead in the water as a Honda out of it's powerband.

I'm keeping the discussion away from those area's as the discussion is about power vs TQ.

Although, most diesels peak TQ is made outside the powerband. So the difference you feel in vehicle response should be enough to prove this arguement without a single post.
Quote:
Originally Posted by chvyrkr81 View Post
Because without knowing what speed you can break bolts loose or TQ them down, I have no idea how much work you're capable of performing.

And, once I know the speed at which you can TQ, I call you power.

Like I've also said, I can create 2300 ft lbs by hangin on a 10 foot bar. Does that really tell you how much work I'm capable of performing?

I'd be better off to come in and tell you I can do that very thing 30 times per minute. Then, you'd know my capability. My power.

So I can tell you power, and you know what I'm capable of.

Or I can tell you TQ, and you know what I can do for one second, and absolutely nothing else.
Quote:
Originally Posted by e99f2506sp View Post
The reason the truck would fall out if you run it out of its power band is because thats not where the torque is. Your then multiplying a small torque number by a comparatively low (comparing to the hi revving honda) rpm number. Low torque x low rpm = low hp...again I refer to a dyno graph.

How is a diesels peak torque made out of the power band? Take that same semi engine. It will produce all 1500 lb ft at 12-1500 rpm, right smack dab in the middle of its power rpm range. The power band you speak of is only as big as its torque and therefor hp curve. Without them, there is no power band.
Quote:
Originally Posted by e99f2506sp View Post
Yes, it tells me you are capable of producing 2300 lb ft of torque without any rpm. Therefore you have produced 2300 lb ft of torque, but to hp because there is no rpm. You don't even have to be sucessful at breaking a bolt loose to produce torque. Its only once there is rpm added to the equation that horsepower can even exist.

They make guages to read torque without rpm, therefor torque exists without horsepower.
Quote:
Originally Posted by chvyrkr81 View Post
Ok sorry...

A high TQ number usually, stress usually, indicates a high powerband ratio.

But it doesn't change the fact that neither engine accomplishes anything notable outside of it's powerband.
Quote:
Originally Posted by chvyrkr81 View Post
You've completely missed the point.
Quote:
Originally Posted by e99f2506sp View Post
Agree 100%. I don't think that is what we are discussing, but I do agree with you.

Goes back to the high torque x low rpm vs low torque x high rpm and where the power band is created depends on those equations
Quote:
Originally Posted by e99f2506sp View Post
I think I have missed your point yes, because I just can't logically make it work. Torque CAN exist without horsepower. horsepower CAN NOT exist without torque.
Quote:
Originally Posted by chvyrkr81 View Post
You are correct, on both counts.

What you seem to be clinging to though, is that the above somehow makes the TQ number worth something when it stands by itself.
Quote:
Originally Posted by e99f2506sp View Post
And what you seem to be clinging to is that horsepower is everything, when in fact it can not exist without torque...or rpm even

Torque can exist without horsepower. Whether it is worth anything by itself or not is irrelevant to this conversation, just the fact that it exists by itself is enough to prove my point home.

Horsepower can not exist without torque just as much as it can not exist without rpm. I could be arguing the case for rpm just as much as I am arguing for torque, and from what I gather, you'd still be saying horsepower is everything.

I have not problem admitting the fact that horsepower is what accelerates and moves a vehicle if thats what it takes, but you have to admit that torque has to exist in order for horsepower to exist, and I've only come to believe this from your own information given to me.
Quote:
Originally Posted by chvyrkr81 View Post
Your stubbornness is admirable.

Tell me what knowing TQ does for me.
. .
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  #4  
Old 07-09-2011, 05:03 PM
PMR = JUNK

 

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Quote:
Originally Posted by chvyrkr81 View Post
Ok, after rereading a few of your posts I see you've got the big picture.

I'm still not sure why you think it's important to note one of the variables that forms that picture though. Torque.
Quote:
Originally Posted by e99f2506sp View Post
I'm not being stubborn, just standing up for what I know is right.

Not saying what you know isn't right, it sounds like we are on the same page even, but from what I gather, you seem to be stuck on whats after the = and I'm saying its not possible without whats on front of it.

I could just as easily call you stubborn, but as I said last night, I would prefer to keep personal issues out of the discussion and keep it strictly professional so no feelings get hurt. You and I have been down that road before and I think we've made it past it.
Quote:
Originally Posted by chvyrkr81 View Post
My point is, that you can tell me the HP of an engine, and I know all I need to know.

I put that engine on a dyno and note the RPM's at which it's in it's powerband, and gear accordingly.

If it's a short powerband high in the RPM range, then I know I need a low rear end, so I can use gearing to make it through the RPM gap below the powerband. If it's wide, I can go higher.

I never need to know TQ to select an engine for a task. To select, I need power.

To gear the vehicle carrying it, I need to know the powerband.

So telling me TQ does nothing for me.

Telling me TQ and HP together is a little better, as it gives me an idea of the powerband ratio I should expect, but I still need a dyno to see the powerband.

In the end though, I never need to see TQ.
Quote:
Originally Posted by e99f2506sp View Post
You may never need to see it, thats up to you. I like to see it cause I don't have a dyno in my garage. Setting up track cars really depends on those numbers and a dyno is nice to dial it in, but you can generally get close on your gearing and whatnot without one.

Anyway, who torque numbers are important to is not really the point of the last 2 days of discussions. The comment was made that torque is not necessary to move a load. If he had said "I don't need to see torque in order to move a load" this would have gone a whole different route.

I think we both agree that torque is indeed necessary to move a heavy load. You either gotta have high torque at low rpm, or high rpm to make up for the lack of torque. both create horsepower though.
Quote:
Originally Posted by chvyrkr81 View Post
TQ may be necessary, but whether that number is high or low has no direct impact on the efficiency with which that load is moved.

Just so that point at least is understood.


Quote:
Originally Posted by e99f2506sp View Post
hmm...

So a big rig could just as easily have say...500 lb ft of torque and only 3000 rpm of useable range and still be able to accelerate the same weight with no problem as a truck with 1500 lb ft of torque? The HP ratings of both would stay the same either way?

or

a honda could have 1500 lb ft of torque and still rev to 8000 rpm, but still only have 160 hp?

You have to look back to our equations from earlier because those examples and what you said doesn't make since.
Quote:
Originally Posted by chvyrkr81 View Post
If the tractor with the Honda engine was geared to stay in the powerband, it would pull the load just as efficiently as the diesel, until it blew up.

I'm sure I've said nothing thus far that will contradict that point.

The reason now, that the diesel is used, is a powerband ratio over double that off the Honda, requiring less gears to tow efficiently, and the ability to run hard in it's powerband day in and day out.

High low end TQ, is a product of the wide powerband. Not the other way around, and as such, high low end TQ should not be taken as a definite indicator of a wide powerband.
Quote:
Originally Posted by e99f2506sp View Post
Back to the power band stuff again?....ok back to our equations from earlier.

Power band still goes back to the T x R = H

high torque times low rpm = horsepower at lower rpm. The reason the power band is relatively wide is because the engine can only rev to 3k max as it is built for torque and would otherwise spin itself to pieces...for reasons unrelated to what we are talking about now (larger bore, stroke, pistons, connecting rods, etc. Therefor the power band is wide across the rpm range

low torque times high rpm = horsepower at higher rpm. This means the power band is smaller and is up high in the rpm because thats where the numbers are. a honda producing 110 lb ft of torque at 2000 rpm is not producing hardly any horsepower compared to the big rig that is producing 1500 lb ft at 2000 rpm. However. Take the same honda and mulitiply it by a higher rpm and youll see the hp number jump considerably because its up in the power band.

Its why 4 cylinder cars are always geared at 4.10 and what not, to make them jumpy off the line and keep you up in the power band in all gears including top gear.

Bigger trucks if you could manage to use the exact same transmission gearing and tire size, would run out of their power band waaay too quick with 4.10 rears.
Quote:
Originally Posted by chvyrkr81 View Post
There is litterally nothing else I can say to explain why the TQ number of the engine does not matter once continous motion is introduced.
Quote:
Originally Posted by e99f2506sp View Post
I'm running out of words myself. I can only repeat myself so many times. I have agreed that torque numbers fall off higher in the power band because thats where rpms are and therefore horsepower takes over. The only reason this conversation started is, again, someone said that torque is not needed to haul a heavy load.

I guess I could say, without torque there is no power band. You talk about "both vehicles being able to tow the same amount of weight if you keep them in the power band"

To this I agree 100% like I have said. The difference torque numbers.

The power band is created with low rpm on a big rig because it has high torque.

The power band is created with high rpm on a honda because it has low torque.
Quote:
Originally Posted by Buffalo444 View Post
Torque IS important. but horsepower is what moves you. Because in order to move, you need to have time and something making it move. So what determines how fast you can do it? Horsepower. What determines horsepower? Torque and rpms. But who cares about what creates the horsepower, its all about what the horsepower does.
Quote:
Originally Posted by e99f2506sp View Post
Sigh...

Well at least I got yall sayin that torque is indeed important and we all understand the various ways hp is made by various torque vs rpm equations.

I can only go back to my simple 2 x 3 = 6 equation. You guys are set on that number 6, I am saying without 2 and 3, there would be no 6 at all.

Like I said earlier, I could just as easily argue the same point for rpm that I have been for torque.
Quote:
Originally Posted by Buffalo444 View Post
Because 6 is what does work. You can have 6 without 2 and 3, you could have 1 and 6 to get 6. Just like you can have 4 and 5 or 2 and 10 to get 20.
Quote:
Originally Posted by e99f2506sp View Post
Sure, there are several ways to get 6, just like there are several ways to get horsepower with various torque and rpm numbers.

but we are back to arguing the point Ive already said... you can't have horsepower, in any number however high or low without torque and rpm so saying torque is unimportant and irrelevant to the equation is false.

Anyway, I can't repeat myself over and over with the 3rd person. We are all saying the same thing and I just say you guys are stuck on the number after the equal sign, and i say you cant have that number without the numbers before the equal sign.

I gotta go to bed.
Originally Posted by e99f2506sp
I think I have missed your point yes, because I just can't logically make it work. Torque CAN exist without horsepower. horsepower CAN NOT exist without torque.


Well, technically horsepower can exist without torque, just not in this situation dealing with engine horsepower.

Quote:
Originally Posted by e99f2506sp
The reason I am standing up so much for torque is because last night it was said torque is not necessary to move a load, and higher torque numbers will not increase anything. Well through our equations, we have proven that to be false.

Maybe he wrote it wrong, or maybe he meant something else.

Like I said, I would stand up just as much for rpm if he had said "rpm has no role in moving a vehicle down the road"

No T and no R = No H


To help clear things up, i did word it bad. I know i said torque is meaningless. What i meant was that torque is meaningless as far as showing an engine's ability to accelerate a load. Clearly torque does play a role, but that role is nothing more than one of the variables in the equation to find horsepower, AKA, the amount of work being done, or, the acceleration of a load.

Originally Posted by e99f2506sp
Sigh...

Well at least I got yall sayin that torque is indeed important and we all understand the various ways hp is made by various torque vs rpm equations.

I can only go back to my simple 2 x 3 = 6 equation. You guys are set on that number 6, I am saying without 2 and 3, there would be no 6 at all.

Like I said earlier, I could just as easily argue the same point for rpm that I have been for torque.


No one ever meant that without 2 and 3 aren't needed, which clearly they are. We just don't care about them when determining what an engine can do. Tom's 24 is a better example, as there are more numbers that can be used to get it. Whether we use 2 and 12, 12 and 2, 6 and 4, 4 and 6, or 24 and 1, the answer is still 24. 24 is the only number we care about. The other 2 are just how we got to 24.

To help understand everything, the actual formula for horsepower would be a good thing. T * RPM / 5252 = HP. Torque, times RPM, divided by 5252 equals horsepower.

Clearly torque means something, but it does not help an engine move loads, big or small, to have just more torque. I can raise torque and lower RPM and end up with less horsepower being made. Which would mean that the engine would have more trouble moving the load. I could also lower torque yet raise RPM and end up with more HP, which means that the load would be accelerated faster.

Quote:
Originally Posted by Dave View Post
I created 600ft lbs of torque just yesterday with my two hands.

can I pull 12k?
Of course you can, just very very slowly.

Quote:
Originally Posted by e99f2506sp
I thought about the tq, rpm, and hp conversation of the last couple days as I was falling asleep last night.

I finally realized that you guys weren't saying torque isn't part of the equation, you're just saying that you don't care what the equation is after the horsepower has been made. I THINK we are all on the same page that torque is important and we've discussed at length the way torque is made with various rpm ranges so I think that is pretty clear among us.

I just was stuck on the fact that it was said that torque is not important to hauling a load, when clearly it is, just as much as rpms are. Jake has since cleared up the confusion so that is no longer an issue. Sure they create power together, but the more torque you have with lower rpms coincides with how quick you can get a heavy load moving compared to lesser torque with higher rpms coincides with keeping a load moving.

The torque number still really isn't important to hauling a load, as long as you have enough RPMs to make the horsepower required to move it. And saying torque gets it moving and horsepower keeps it moving isn't right. Horsepower is what gets it moving and keeps it moving. Horsepower is the "equals" part of the equation, which in the end is all that matters.

Sure they can both move the same load fine as long as they are in their sweet spot, but there is a reason a trucks sweet spot is created with low rpms, to get loads moving, and a cars is created with high rpm, to get good fuel mileage and give you power up high where everyone "needs" it.

Like I said, I think we were all discussing topics on the same page of the exact same text book for most of the last 2 nights, its just that I was more concerned with stating that paragraph 2 could not exist without the explanation from paragraph 1 first

As far as moving a vehicle with torque alone, no its not possible, as soon as the vehicle is moving you've created rpm and therefore horsepower. Once the rpm goes up and the torque drops off, the torques job has been completed and horsepower has taken over...a previous dyno graphs prove this point perfectly.

So no hard feelings toward anyone, Jake and Tom, I'd still sit down and have a brew with you any night of the week
The horsepower's job is from start of movement til it comes to a stop, it doesn't just "come in" when the torque number drops off. Whether that horsepower comes from torque or high RPM's, its still horsepower that we care about. Torque of the engine is what is doing the work, be it at 800 RPM or 8000, since torque (rotational force) is what an engine makes, but horsepower is what tells us how much actual work is being done with the torque the engine creates.

No hard feelings here either. If i thought you were a douche i wouldn't still be explaining this to you and helping you understand it. I'd be down for that beer any day too.


Quote:
Originally Posted by e99f2506sp View Post
Torque is important in relation to rpms as Tom and I were discussing. In order to create hp with low rpms, such as in a truck, you have to have high torque. If you had low torque and low rpms, it would be a 4.5 horse briggs

I did mis-speak when I said horsepower just "comes in" I do apologize. What I meant to say was once you start loosing torque numbers up high in the rpm, you have high rpms to to "multiply" for lack of a better term by the torque numbers being put out, thus giving you horsepower like we've all said.

I think we are all on the same page now

As far as the people who don't like our conversation in the general topics thread...sorry we interrupted your completely random talk about nothing that means anything to anyone. I think we are done with our real factual conversation now so we can go back to whatever issues Jarrod is having again.
Quote:
Originally Posted by chvyrkr81 View Post
Still missing one big point brother...

TQ isn't TQ anymore once you add RPM to the equation. It's power
Quote:
Originally Posted by chvyrkr81 View Post


One other note for those following...

It helps to understand this if you don't think of torque being the contributing element to a wide powerband, and think of it as a side effect of a wide powerband.
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  #5  
Old 07-09-2011, 05:05 PM
Viking Heavy Diesel

 

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What ever is wrong with you Jake is no small thing!
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Old 07-09-2011, 05:20 PM
The Tamed Racing Driver
 

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Thats probably the longest post I've ever seen

I think this thread is gonnna be interesting.

This is what I don't get. Driving along, manual trans, pulling a trailer and you hit a hill. 75 mph/ say 2500 rpm (4.10 gears) and your in O/D. You are making about 500 ft.-lbs. and 300 hp, but its not enough so you down gear. Now you have enough power to pull the hill. But, when you down gear you don't gain any hp at the wheels, just torque. Now your in 5th and still taching 2500 just not moving as fast. Can anybody explain.
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  #7  
Old 07-09-2011, 05:24 PM
MARSOC > Seals



 

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I started to read this.. untill I noticed how much was really there

I give up...


were is the Cliff notes?
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  #8  
Old 07-09-2011, 05:27 PM
PMR = JUNK

 

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O/D as in 6th gear?
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  #9  
Old 07-09-2011, 05:28 PM
The Tamed Racing Driver
 

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I think this should be a class in high school

Edit: And yes, assuming a zf 6 speed.
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Old 07-09-2011, 05:31 PM
Viking Heavy Diesel

 

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The engine is not necessarily making any more power but because you shifted it can now deliver it in a much more manageable ratio. Smaller gears (numerically bigger) are just much easier to spin.
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