Topic: torque vs. HP

[KeithTurk]

Put a 454 in a VW....  If it roll goes over backwards when you pop the clutch that's torque... if it rolls over sideways when you rev it up .. that's HP... ( okay not exactly but cute )...

As for 2 busa motors Vs 1 .... Ack Vs Wheeler Vs Bub....  all those guys have their pluses and minus's...  Sam Wheeler has the UCLA Wind Tunnel and a group of engineering students who spent Massive tunnel time.... Ack Has Brute HP and Money...  Bub or Dennis Manning have tenacity... and some stupid engine sorta kinda built with Ford's help... and each of them have owned the fastest Motorcycle on the Planet

I know all of them fairly well... though Sam and Mike hang out in the same pit area at Bonneville....  These guys and thier riders have Massive passion... something the average person will only read about .... it's truly incredible to hang around them...

Keith

[Bill/BentON Racing]

Mrieck,+1,Sabres7,I agree,we can't have it all,usually sacrifice low end for more midrange and top end POWER,Paulage all that POWER you are making took out 3rd?What a great read ,only had to take my shoes off twice!!Bill

[sabres7th]

thank you for the welcome. I'd just like to say i am glad a site like this exists! I have always like the the cbs cafe'd out since i was a kid, but brought up on harleys so i respect both. i just picked up a cb550k as my next project.
   but to sum up my point. here we go. if you have the same cc engine say 550cc (one all low end torque and one high rev horse power peak) the one that will win will be effected by which area of the power curve your racing in. i.e. stop light to stop light, rolling start, or highway 80+. i think it is safe to say that the manufactures designed the bikes with different ideas in mind. the torque based bike has that usable power that comes on quick whether you want it or not. but was not designed to sit on the red line. but to just have the power there at normal low cruising rpms for that bike. while the higher rev bike has more of its power when you give it the gas at wot @5000+. with all that being said it is just style that makes these bikes different. style of design of where the power is placed in the rpm range. if you like to get thrown back of the get go you'll be on a harley, if you like to ease into it a honda.
     just think of this. when moving the power of your engine to the low end or high end for every action there is a equal or opposite reaction.
     one of the things that used to be done is for these companies was to try and flatten the power curve just to be rider friendly, meaning you seen no difference through the rpm range.( the holy grail of perfect engines the one that does it all)
      me myself i would take the horse power in the high end as that would allow me to control when it is used. because if if i don't want to go balls out i just short shift.

[754]

Keith, I had heard that the Bub bike has wind tunnel time, and scored quite well in that area..

 Not sure why you would call the engine stupid.. .. he built it to try to set a world record, and actually did it.. myself I have a lot of respect for that.

 I do believe it is also a testbed for a street engine he is producing..

[Bill/BentON Racing]

More on that engine?

[754]

Street or racer ?
 Try the Bub Exhaust homepage, should have info.

[KeithTurk]

Here's the reason I called it stupid... and don't mis-understand the statement... it was built by an incredibly intelligent group of people... at a time when there wasn't a busa motor available... and he's stuck with the motor long enough to overcome all the teething problems associated with a One off Motor....  But it is a one off Motor... and with that comes enormous difficulties...    once overcome... the squeeze might be worth the juice but in today's world, HP needn't be complicated... it's a simple matter of How much do you want???  and then how are you going to harness it and get it to the Salt... after that you need a fairly talented rider/driver...  ( Each of these guys have shown some incredible skills in handling some Very destructive situations )

None of these bikes have "Bad" aero numbers... and I think your right in that the BUB bike has had some kind of tunnel time... just not to the extent Sam Wheeler has...   Simply stated Sam's the guy who's doing this on the cheap so to speak...  he's an engineer ( worked for Norton Motorcyles by the way ).... and his answer is to cheap the wind first and apply HP second....  

Hp is a fascinating thing... and to keep this on track...  I've tried several different combinations of HP Vs Torque over the years that I've raced at Bonneville....  We've run the 9300 rpm 302" small blocks and the 5800 rpm 572 big blocks...  each with thier own drivablity issues....  Ultimately it's always a compromise and the key is to not be Over exhuberent in your selection of cam's and compression...  Being honest with yourself in the first place about "HOW" your going to actually use the HP is the key to building something that has Value beyond the "looking Cool " concept of twin turbo's on Nitrous

[paulages]

i came up with a refinement for my analogy:

torque is one dude that can lift 500lbs in one brief grunt. say you have 5 guys that can each only lift 100lbs. each of these guys has less individual strength (= torque in this analogy) than the first guy, but with 5 of them you can do the same amount of work (=more PRMs). in other words, the small guys have less "torque," but they still have equal power ultimately. add a 6th, and they can ultimately lift more, but each guy is still weaker than the strong guy. say they are both lifting with a short bar or in a small closet (short track)- the big guy's gonna win. allow as long a bar as possible to allow more of the small dudes to team up (long track)- they're gonna win.

 

[754]

I prefer bikes as an example..
 you are going up a steep mountain pass at 60 mph, a bagger passes you..
 you give er on your sprotbike, he gives her.. he pulls ahead of you.. then you realize that the only way you are going to catch him ,is to gear down a few gears and get into your powerband..

 then you realize he did that (in top gear) with 2 people aboard, 100 lbs of gear, pulling a 400 lb trailer, with 2 Honda minitrails on a rack ( gotta have pit bikes ).. and find out later that he only has 75 hp...

 That is my explanation of torque..

[mlinder]

I still can't understand why you guys insist it's two different things. It's the same thing, measured differently.
Amount of power available, and frequency of that same power being applied.

[paulages]

I still can't understand why you guys insist it's two different things. It's the same thing, measured differently.
Amount of power available, and frequency of that same power being applied.

while you're right mark, what he's describing makes sense, even if it's based on misunderstanding of the terms. if the sportbike in 754's example has more power, but in a small band, then ultimately it could tow just as much or more up that hill, but would have to be in exactly the right gear the whole time. what he's missing is that the bagger with loads of torque is still making plenty of HP (since it's making all that torque, and more torque automatically equals more HP, as we know), it's just usable in a broader range. but i realize you understand this and are just making a point.

what most people think of the terms we're talking about here is broad low-end torque (twins, singles, long stroke) vs. high-revving top-end HP (multis, short stroke, etc.) engines. it makes sense that people think this way, because they apply their power so differently. even if we aren't all speaking the same language, i'm getting the answer i was looking for anyway, which is what type of power people would rather tune for.

my dyno readout, interestingly enough, begins right around 5252RPM where the two curves cross. according to the guy i got in the argument with, i should shift right around 8200 RPM, right?   the 5 HP past that are meaningless i guess.


to answer my own question: when i build the 718cc engine, i wanted it to have a broad torque band but still have a nice sweet spot up top. going oversquare and higher compression helped achieve this i think. the HP curve still peaks a little sharper, giving me that rocket-like power band at the top, but the torque curve plateaus much earlier. sometimes i wish the powerband was even wider though, which i'd likely accomplish with more compression and a larger bore (more torque).



i still think my strong guy analogy says it well.

[mlinder]

I still can't understand why you guys insist it's two different things. It's the same thing, measured differently.
Amount of power available, and frequency of that same power being applied.

while you're right mark, what he's describing makes sense, even if it's based on misunderstanding of the terms. if the sportbike in 754's example has more power, but in a small band, then ultimately it could tow just as much or more up that hill, but would have to be in exactly the right gear the whole time. what he's missing is that the bagger with loads of torque is still making plenty of HP (since it's making all that torque, and more torque automatically equals more HP, as we know), it's just usable in a broader range. but i realize you understand this and are just making a point.

what most people think of the terms we're talking about here is broad low-end torque (twins, singles, long stroke) vs. high-revving top-end HP (multis, short stroke, etc.) engines. it makes sense that people think this way, because they apply their power so differently. even if we aren't all speaking the same language, i'm getting the answer i was looking for anyway, which is what type of power people would rather tune for.

my dyno readout, interestingly enough, begins right around 5252RPM where the two curves cross. according to the guy i got in the argument with, i should shift right around 8200 RPM, right?   the 5 HP past that are meaningless i guess.


to answer my own question: when i build the 718cc engine, i wanted it to have a broad torque band but still have a nice sweet spot up top. going oversquare and higher compression helped achieve this i think. the HP curve still peaks a little sharper, giving me that rocket-like power band at the top, but the torque curve plateaus much earlier. sometimes i wish the powerband was even wider though, which i'd likely accomplish with more compression and a larger bore (more torque).



i still think my strong guy analogy says it well.

Or an advanced cam

[Joel]

I still can't understand why you guys insist it's two different things. It's the same thing, measured differently.
Amount of power available, and frequency of that same power being applied.

while you're right mark, what he's describing makes sense, even if it's based on misunderstanding of the terms. if the sportbike in 754's example has more power, but in a small band, then ultimately it could tow just as much or more up that hill, but would have to be in exactly the right gear the whole time. what he's missing is that the bagger with loads of torque is still making plenty of HP (since it's making all that torque, and more torque automatically equals more HP, as we know), it's just usable in a broader range. but i realize you understand this and are just making a point.

what most people think of the terms we're talking about here is broad low-end torque (twins, singles, long stroke) vs. high-revving top-end HP (multis, short stroke, etc.) engines. it makes sense that people think this way, because they apply their power so differently. even if we aren't all speaking the same language, i'm getting the answer i was looking for anyway, which is what type of power people would rather tune for.

my dyno readout, interestingly enough, begins right around 5252RPM where the two curves cross. according to the guy i got in the argument with, i should shift right around 8200 RPM, right?   the 5 HP past that are meaningless i guess.
...

to answer my own question: when i build the 718cc engine, i wanted it to have a broad torque band but still have a nice sweet spot up top. going oversquare and higher compression helped achieve this i think. the HP curve still peaks a little sharper, giving me that rocket-like power band at the top, but the torque curve plateaus much earlier. sometimes i wish the powerband was even wider though, which i'd likely accomplish with more compression and a larger bore (more torque).



i still think my strong guy analogy says it well.

Only at a specific RPM.  For example, a 2009 Corvette has 424 lb-ft of torque and 430 hp.  A 2010 BMW M5 has 383 lb-ft of torque and 500 hp.  The Corvette has more torque but less hp.

[mlinder]

I still can't understand why you guys insist it's two different things. It's the same thing, measured differently.
Amount of power available, and frequency of that same power being applied.

while you're right mark, what he's describing makes sense, even if it's based on misunderstanding of the terms. if the sportbike in 754's example has more power, but in a small band, then ultimately it could tow just as much or more up that hill, but would have to be in exactly the right gear the whole time. what he's missing is that the bagger with loads of torque is still making plenty of HP (since it's making all that torque, and more torque automatically equals more HP, as we know), it's just usable in a broader range. but i realize you understand this and are just making a point.

what most people think of the terms we're talking about here is broad low-end torque (twins, singles, long stroke) vs. high-revving top-end HP (multis, short stroke, etc.) engines. it makes sense that people think this way, because they apply their power so differently. even if we aren't all speaking the same language, i'm getting the answer i was looking for anyway, which is what type of power people would rather tune for.

my dyno readout, interestingly enough, begins right around 5252RPM where the two curves cross. according to the guy i got in the argument with, i should shift right around 8200 RPM, right?   the 5 HP past that are meaningless i guess.
...

to answer my own question: when i build the 718cc engine, i wanted it to have a broad torque band but still have a nice sweet spot up top. going oversquare and higher compression helped achieve this i think. the HP curve still peaks a little sharper, giving me that rocket-like power band at the top, but the torque curve plateaus much earlier. sometimes i wish the powerband was even wider though, which i'd likely accomplish with more compression and a larger bore (more torque).



i still think my strong guy analogy says it well.

Only at a specific RPM.  For example, a 2009 Corvette has 424 lb-ft of torque and 430 hp.  A 2010 BMW M5 has 383 lb-ft of torque and 500 hp.  The Corvette has more torque but less hp.

this doesn't matter.

Torque IS horsepower.

Again, torque is the available power available at any given time. Horsepower is how many times per second that torque is applied.


More torque always equals more horsepower, because torque is horsepower.

Again, you are confusing them as separate entities. The reason the BMW makes more horsepower at whatever rpm that is, is because of how much TORQUE it makes at that RPM.
Engines make less torque (per rotation) at higher RPM's due to frictional loss, reciprocating mass, heat, etc, but the engine is APPLYING that lesser torque more often, which is what we call "horsepower".

[paulages]

Joel C: wherever there is more torque, there will automatically by definition be more HP in the same place.

[Joel]

Joel C: wherever there is more torque, there will automatically by definition be more HP in the same place.

That's what I said, at that RPM, more torque does mean more HP.

But torque is not HP.  Torque is a force.  HP is power.  Yes, they are related in an engine.

[mlinder]

Joel C: wherever there is more torque, there will automatically by definition be more HP in the same place.

That's what I said, at that RPM, more torque does mean more HP.

But torque is not HP.  Torque is a force.  HP is power.  Yes, they are related in an engine.

No. Torque IS horsepower. HP = how much force is available, calculated by how many times it happens in a minute.

Even the calculation says this. HP = tq*rpm/5252
HP is merely a number showing how much power is applied by the torque. That is, X amount of torque is being applied Y amount of times per Z amount of time.

The same amount of torque will always make the same amount of horsepower at the same RPM. If the vette made 400lbft of torque at 5252rpm, and the bmw made 400lbf at 5252 rpm, they'd both make 400 hp at 5252 rpm.
If you make more torque, you make more horsepower, and that's at ANY RPM. If you make 300lbft at 3000RPM, you always make 171hp at 3000RPM. Always. Every engine that makes 300lbft at 3000rpm. Period. Because they are the same thing, one is measurement of availabe power in one rotation, the other is a measurement of the application of that power at X times per minute.

More torque will always make more power (the same amount) at EVERY RPM.

[davesprinkle]

Good grief, boys, you should spend less time posting.  More time hogging out your inlet ports.

[Bill/BentON Racing]

If they did that they might make more POWER and get a headache figuring out whether they made more torque or more horsepower or both!! ,been a good read,thanks,Bill

[paulages]

Good grief, boys, you should spend less time posting.  More time hogging out your inlet ports.

for more torque, or a higher peak HP? 

[paulages]

and joel, yes i should have clarified: more torque at a given RPM will by definition make more HP at the same RPM, not necessarily more peak HP.

i still think the main problem here is semantics... the difference between different bikes and how different they can feel is indisputable. the problem is in how people have come to describe them, while using terms that actually have factual definitions that are not exactly as they are commonly used.

colloquially speaking, POWER is what is available when you twist the wrist, whether it's described in terms of HP or torque; where you want it and how efficiently you want to use it is where the different engine characteristics come into play.

[754]

Confuscius say;

 Man with more torque look good in high gear rollon,


 And man shifting down to keep up, look like 2stroke rider...    

[Joksa]

And man shifting down to keep up, look like 2stroke rider...    

There is a such thing as hondamatic if you are somehow challenged in gear changing.

[754]

I dont think you will find the Hondamatic shifting down a 55 mph...

[Joksa]

i.e. if you find changing gears challenging you should consider riding/driving an automatic. Fact is the more HP you got the more torque you can get from the wheel. Top gear roll-on is only used for marketing turbo diesels and others having challenges is power producing department.