Torque vs Horsepower

[91TTZ]

Originally posted by: manowar821

Originally posted by: mariok2006

Originally posted by: manowar821
All I know is that Honda still makes the torqueless wonders, and that's hilarious.

Why exactly is that funny?

Because of the huge ricer crowd who think that civics are the ultimate racing machines. I have nothing against the cars themselves, or people who love them for what they are.

What really gets me are the idiots that think that a car is better if it revs higher. In other words, if they had the option to get an engine that produced 200 hp at 5000 rpm or 190 hp at 9,000 rpm, they'd take the higher revving one. In reality, the one with more power would have more power (obviously), but also be much more streetable.

 

[Demon-Xanth]

Originally posted by: 91TTZ

What really gets me are the idiots that think that a car is better if it revs higher. In other words, if they had the option to get an engine that produced 200 hp at 5000 rpm or 190 hp at 9,000 rpm, they'd take the higher revving one. In reality, the one with more power would have more power (obviously), but also be much more streetable.

IMO, redline and HP/l are both really trivia numbers UNLESS the car is built to rules regulating gearing and displacement (ie: top fuel cars can only be 500CID and mandate a 3.20:1 rear end).

HP/lb==where it's at.

A 5L V10 that makes 503HP and weighs 540LBs isn't as impressive as a 7L V8 that makes 505HP and weighs 450LBs. Regardless of the amount of whizbang tech thrown into it.

 

[Vic]

In the absolute simplest words possible, torque is force. That force spins the crank and it becomes work. Horsepower is the speed at which that work can be done.
Which is why -- all else being equal -- horsepower wins races.

 

[overst33r]

Originally posted by: Vic
In the absolute simplest words possible, torque is force. That force spins the crank and it becomes work. Horsepower is the speed at which that work can be done.
Which is why -- all else being equal -- horsepower wins races.

based on your statement, torque is responsible for spinning the crankshaft. if torque causes the crank to spin fast enough, IT wins the race. hp is merely a function of torque. torque fuels the HP... so how can your last claim be true?

feel free to correct my assumptions

 

[Zenmervolt]

Originally posted by: mariok2006

Originally posted by: Vic
In the absolute simplest words possible, torque is force. That force spins the crank and it becomes work. Horsepower is the speed at which that work can be done.
Which is why -- all else being equal -- horsepower wins races.

based on your statement, torque is responsible for spinning the crankshaft. if torque causes the crank to spin fast enough, IT wins the race. hp is merely a function of torque. torque fuels the HP... so how can your last claim be true?

feel free to correct my assumptions

Because horsepower is torque at high RPM. An engine with a peak torque of 200 ft-lbs at 5,000 RPM will be faster than an engine making a peak torque of 200 ft-lbs at 1,000 RPM because the first engine makes more power with the same amount of torque.

Technically, since HP is simply a function of torque, you're right, but "HP" is generally shorthand for "torque at high RPM".

ZV

 

[Zenmervolt]

Originally posted by: manowar821
I guess I'm just jaded because I've experienced the rx-7 in all it's stock glory.

You complain about "torqueless wonders" and then name the Mazda rotary engine as a counter-example? Please tell me you're joking.

ZV

 

[Vic]

Originally posted by: Zenmervolt

Originally posted by: mariok2006

Originally posted by: Vic
In the absolute simplest words possible, torque is force. That force spins the crank and it becomes work. Horsepower is the speed at which that work can be done.
Which is why -- all else being equal -- horsepower wins races.

based on your statement, torque is responsible for spinning the crankshaft. if torque causes the crank to spin fast enough, IT wins the race. hp is merely a function of torque. torque fuels the HP... so how can your last claim be true?

feel free to correct my assumptions

Because horsepower is torque at high RPM. An engine with a peak torque of 200 ft-lbs at 5,000 RPM will be faster than an engine making a peak torque of 200 ft-lbs at 1,000 RPM because the first engine makes more power with the same amount of torque.

Technically, since HP is simply a function of torque, you're right, but "HP" is generally shorthand for "torque at high RPM".

ZV

Exactly. 2 people do the exact same job with identical tasks, but one does that job faster. Who gets the raise? 2 people of identical size and weight are running in a race, but one moves his legs faster. Who wins the race?
That's horsepower. Force times distance is work. Work over time is power. The engine that -- all else being equal -- can put out the 200 ft-lbs at 5,000 rpm is doing the same work faster.

 

[thomsbrain]

Originally posted by: mariok2006

Originally posted by: Vic
In the absolute simplest words possible, torque is force. That force spins the crank and it becomes work. Horsepower is the speed at which that work can be done.
Which is why -- all else being equal -- horsepower wins races.

based on your statement, torque is responsible for spinning the crankshaft. if torque causes the crank to spin fast enough, IT wins the race. hp is merely a function of torque. torque fuels the HP... so how can your last claim be true?

feel free to correct my assumptions

if you need two pieces of rope to make up 10 feet of rope, does it make a difference what length those two pieces of rope are? if one is 2 feet long and the other 8 feet long, is that better than 3/7? You still have 10 feet of rope, right?

Well, torque is one of those pieces of rope. Having one really long piece of rope (say, torque) helps make the total length (power) longer, but what matters is still the total length (POWER), not the length of one piece. the longer your TOTAL rope, the better. and if the guy next to you has his first piece long and his second short, and mine are the other way around but my total length is longer, then all other things being equal, i win the race.

people have brought up all kind of side issues that come along with the engines that focus on torque or focus on RPM in order to make power. torque-y engines are easier to drive without drama, while smaller engines are lighter and fit in lighter cars. all other things being equal, a light car with high power is faster than a heavier car with the same power, regardless of torque. that's why race cars and ferraris and S2000s and motorcycles and Ariel Atoms are fast as hell even though they have relatively small engines with far more power than torque. The Ferrari F40 had a 2.7 liter engine, but it did 0-60 in under 4 seconds and hit 201 MPH. And yeah, you had to drive it hard to make it go fast, but if we are talking about fast cars, we can assume that DRIVERS like to DRIVE. and therefore, they don't mind making some noise, they don't mind winding out an engine, and they don't mind taking a momentary hit in mileage when they pound the throttle. save the torque-monster for the Benz or the truck, where it is suited for the application, and put the power-above-all-else engine in the sports car, because power is what makes the car go faster.

 

[Pacfanweb]

Originally posted by: Zenmervolt

Originally posted by: manowar821
I guess I'm just jaded because I've experienced the rx-7 in all it's stock glory.

You complain about "torqueless wonders" and then name the Mazda rotary engine as a counter-example? Please tell me you're joking.

ZV[/]
Yeah, that's exactly what I thought when I read that. Hope he was joking.

 

[kevinthenerd]

Originally posted by: Zenmervolt

Originally posted by: mariok2006

Originally posted by: Vic
In the absolute simplest words possible, torque is force. That force spins the crank and it becomes work. Horsepower is the speed at which that work can be done.
Which is why -- all else being equal -- horsepower wins races.

based on your statement, torque is responsible for spinning the crankshaft. if torque causes the crank to spin fast enough, IT wins the race. hp is merely a function of torque. torque fuels the HP... so how can your last claim be true?

feel free to correct my assumptions

Because horsepower is torque at high RPM. An engine with a peak torque of 200 ft-lbs at 5,000 RPM will be faster than an engine making a peak torque of 200 ft-lbs at 1,000 RPM because the first engine makes more power with the same amount of torque.

Technically, since HP is simply a function of torque, you're right, but "HP" is generally shorthand for "torque at high RPM".

ZV

That's the misunderstanding that annoys me. It's not just at high rpm. It's at EVERY rpm.

 

[kevinthenerd]

Originally posted by: Zenmervolt

Originally posted by: manowar821
I guess I'm just jaded because I've experienced the rx-7 in all it's stock glory.

You complain about "torqueless wonders" and then name the Mazda rotary engine as a counter-example? Please tell me you're joking.

ZV

When the rotary was relatively new in Japan it had more torque than anything else you could buy in its range of displacement.

Rotaries develop a lot of power in a very lightweight package.

 

[Demon-Xanth]

Originally posted by: kevinthenerd

Originally posted by: Zenmervolt

Originally posted by: manowar821
I guess I'm just jaded because I've experienced the rx-7 in all it's stock glory.

You complain about "torqueless wonders" and then name the Mazda rotary engine as a counter-example? Please tell me you're joking.

ZV

When the rotary was relatively new in Japan it had more torque than anything else you could buy in its range of displacement.

Rotaries develop a lot of power in a very lightweight package.

The thing about the displacement, is that they only measure one chamber per rotor, while it's actually in three parts of a stroke at once. So the displacement of a rotary is very misleading. Rotaries are very space efficient, but their long, narrow combustion chambers aren't very efficient at burning the fuel when compared to piston engine. Turbines are even more space efficient, but have downsides of burning a lot of fuel, having a hot exhaust, and being slow to rev while being very high revving. In helicopters, they're well suited. In cars, not so well suited. (read one of the many reviews on Jay Leno's motorcycle)

 

[ElFenix]

Originally posted by: marincounty
Power=work per unit of time
It's power that matters, unless you are trying to tow something from 0 mph, then you want low rpm torque. Interestingly electric motors have peak torque at 0 rpm, meaning that a hybrid truck or SUV could be an outstanding tow vehicle.
Power matters, that's why Formula 1 engines, limited to 2.4 liter V-8s, rev to 19,000 rpm, and make over 700 hp with minimal torque.

minimal torque? it's about ~225 ft-lbs from a 2.4 liter engine. but they make that from about 7000 rpm to 19000 rpm. 12,000 rpm without shifting is very nice.

i have to wonder if those transmissions overdrive at all.

 

[Zenmervolt]

Originally posted by: kevinthenerd

Originally posted by: Zenmervolt

Originally posted by: mariok2006

Originally posted by: Vic
In the absolute simplest words possible, torque is force. That force spins the crank and it becomes work. Horsepower is the speed at which that work can be done.
Which is why -- all else being equal -- horsepower wins races.

based on your statement, torque is responsible for spinning the crankshaft. if torque causes the crank to spin fast enough, IT wins the race. hp is merely a function of torque. torque fuels the HP... so how can your last claim be true?

feel free to correct my assumptions

Because horsepower is torque at high RPM. An engine with a peak torque of 200 ft-lbs at 5,000 RPM will be faster than an engine making a peak torque of 200 ft-lbs at 1,000 RPM because the first engine makes more power with the same amount of torque.

Technically, since HP is simply a function of torque, you're right, but "HP" is generally shorthand for "torque at high RPM".

ZV

That's the misunderstanding that annoys me. It's not just at high rpm. It's at EVERY rpm.

*sigh*

Learn to deal in layman's terms, eh?

In the practical world, where torque falls off after the peak, HP is typically gained by maintaining torque at high RPM rather than by having massive torque at low RPM.

Real world. Peaky engines, limited powerbands. In the real world, the tradeoff is almost always low-end torque or high RPM horsepower.

ZV

 

[Zenmervolt]

Originally posted by: kevinthenerd

Originally posted by: Zenmervolt

Originally posted by: manowar821
I guess I'm just jaded because I've experienced the rx-7 in all it's stock glory.

You complain about "torqueless wonders" and then name the Mazda rotary engine as a counter-example? Please tell me you're joking.

ZV

When the rotary was relatively new in Japan it had more torque than anything else you could buy in its range of displacement.

Rotaries develop a lot of power in a very lightweight package.

Look at the power/torque curves. Low torque, high RPM.

Also, torque to displacement isn't relevant. Look at torque per unit of fuel burned. In terms of power developed per unit of fuel burned. The rotary doesn't look so great in that regard.

ZV

 

[Zenmervolt]

Originally posted by: ElFenix
minimal torque? it's about ~225 ft-lbs from a 2.4 liter engine.

So 100cc more displacement and 20 fewer ft-lbs than my Volvo.

(And yes, I'm just playing devil's advocate since the Volvo's turbocharged and the comparison isn't really accurate, though the curve is at least flat from 2,100 RPM through 5,100 RPM.)

ZV

 

[Gillbot]

my dyno graph: http://pics.bbzzdd.com/users/gillbot/jmgdyno3.jpg

Nice power under the curve!

 

[Demon-Xanth]

That's pretty much an ideal curve there. Flat and smooth.

 

[kevinthenerd]

Nice dyno. I'd rather have that than a peaky motor that makes 400hp after spooling up. Your car would probably HAUL if it had good gears and weight reduction.

Yes, this can get confusing and almost sound contradictory at times, and that's why there's so much CRAP going around the car world. You want horsepower, but it's AVERAGE horsepower that matters. Torque is only a mild indicator of a wide power band, but torque itself doesn't matter whatsoever. The wide power band that usually comes with it is what's good about it. (Yes, that's POWER band, not torque band, that matters.)

I'll say I'm impressed... What have you done to this car? 400 hp is a bit much for a naturally aspirated small block without some minor modifications, especially if this is a wheel dyno. While your torque falls off after 5000 rpm, 6000-6500 rpm is a good place to be if you want to go like hell. The gearing makes the difference; the higher rpms allow you to run out a lower gear for more wheel torque.

 

[natto fire]

It always amuses me that this argument continues to rage on, when it is a simple one of math and personal preference, but especially math.

 

[ElFenix]

Originally posted by: kevinthenerd
Yes, this can get confusing and almost sound contradictory at times, and that's why there's so much CRAP going around the car world. You want horsepower, but it's AVERAGE horsepower that matters. Torque is only a mild indicator of a wide power band, but torque itself doesn't matter whatsoever. The wide power band that usually comes with it is what's good about it. (Yes, that's POWER band, not torque band, that matters.)

no, torque matters and more and more people know that. it's why magazines and car companies are quick to point out that there is 90% of peak torque available from 2,000 rpm to 6000 rpm.

 

[Gillbot]

Originally posted by: kevinthenerd
Nice dyno. I'd rather have that than a peaky motor that makes 400hp after spooling up. Your car would probably HAUL if it had good gears and weight reduction.

Yes, this can get confusing and almost sound contradictory at times, and that's why there's so much CRAP going around the car world. You want horsepower, but it's AVERAGE horsepower that matters. Torque is only a mild indicator of a wide power band, but torque itself doesn't matter whatsoever. The wide power band that usually comes with it is what's good about it. (Yes, that's POWER band, not torque band, that matters.)

I'll say I'm impressed... What have you done to this car? 400 hp is a bit much for a naturally aspirated small block without some minor modifications, especially if this is a wheel dyno. While your torque falls off after 5000 rpm, 6000-6500 rpm is a good place to be if you want to go like hell. The gearing makes the difference; the higher rpms allow you to run out a lower gear for more wheel torque.

Who said it doesn't haul now?
EDIT:
http://pics.bbzzdd.com/users/gillbot/DCP_1530.jpg
http://pics.bbzzdd.com/users/gillbot/1185.jpg - Car #15

It does pretty good for what is has done to it and all i've spent though it could use more gear, like a nie set of 4.10's or so.

Thunder Racing TR230/224 Camshaft
Comp 918 Springs/Titanium Retainers
Thunder Racing Hardened Pushrods
STOCK untouched heads (never been off the car)
Custom Tuning
Yank PT4000 Torque Converter
SLP Subframe Connectors
"Stock" Catback with Hooker AeroChamber Muffler
Flowtech Cutout
MAC Headers and Off road Y-pipe
Shaner S3 Throttle Body
Home made smooth bellows
Boyd Coddington Shyster 17x9.5 wheels w/ Yokohama ES100 Tires
Stock 16" Wheels with Mickey Thompson Drag Radials for the Track
Stock LS1 Aluminum Driveshaft
Lakewood Driveshaft Loop
UMI Performance Shock Tower Brace
Slot Car Products Adjustable Lower Control Arms
Trackbird Adjustable Pan Hard Rod
NGK TR55 Plugs
Stock 3.42 gear GM Corporate 10 bolt Rear Axle (from a Manual Transmission Car)
Stock 4L60E Transmission
MTI Clear Airlid

Yes, the heads are STOCK UNTOUCHED!

Since then i've added:
SLP Underdrive Pulley
Full Throttle Speed Upgraded Fuel Pump with Hotwire Kit
and I have a set of PAC Racing 1518 springs to put on in place of the Comp 918 springs which are getting aged.

IMHO, the most impressive part of the list above is the fact that this amount of power was made with "unpopular" MAC Midlength headers instead of the more popular long tubes and this was all run through a PT4000 race converter which is known to be rather inefficient on the dyno.

 

[Zenmervolt]

Originally posted by: kevinthenerd
Nice dyno. I'd rather have that than a peaky motor that makes 400hp after spooling up.

Let's take 2 cars, otherwise identical, with only the powerband difference.

Car 1: 400 ft-lbs of torque from 1,000 RPM through redline (in this example, 5252 RPM to make the calculations simple)

Car 2: Low torque at 1,000 RPM, building slowly then suddenly spiking to 400 ft-lbs at redline (5252 RPM)

Which car is faster? Both engines' peak power is 400 HP at 5252 RPM. Car 2 has the "peaky" engine that you say you'd rather have.

That's all I've been saying. Ideally, you have a big, fat, wide torque curve. That will yield large amounts of HP too. Peak values are irrelevant really. What you want is maximum area under the HP curve.

ZV

 

[Smartazz]

Originally posted by: drpootums

Originally posted by: kevinthenerd
Otherwise, the driver shouldn't really care about how fast the engine is spinning unless they're looking for a particular sound or something else irrational like that.

Not exactly. Wear on your engine (particularly the piston rings) is close to the square of engine speed. The faster your engine spins on average, the faster your rings (and other engine internals) will wear out, and the faster your engine will require a rebuild. If the driver wants his engine to last at all, he should care about how fast it's spinning. Some engines are designed to rev higher on average than others (4 cylinder engines vs. V8 engines), but in the end, higher revs = increased engine wear.

I know this isn't exactly the point of the thread, but I wanted to comment on that.

That's part of the reason why diesel engines on trucks last so long. The first reason is that they are overbuilt and the other is that they are consistently on lower rpms, I also think that this may be the reason why single engine planes have huge displacement for so little horsepower and they rev really low as a result.

 

[kevinthenerd]

Originally posted by: Zenmervolt

Originally posted by: kevinthenerd
Nice dyno. I'd rather have that than a peaky motor that makes 400hp after spooling up.

Let's take 2 cars, otherwise identical, with only the powerband difference.

Car 1: 400 ft-lbs of torque from 1,000 RPM through redline (in this example, 5252 RPM to make the calculations simple)

Car 2: Low torque at 1,000 RPM, building slowly then suddenly spiking to 400 ft-lbs at redline (5252 RPM)

Which car is faster? Both engines' peak power is 400 HP at 5252 RPM. Car 2 has the "peaky" engine that you say you'd rather have.

That's all I've been saying. Ideally, you have a big, fat, wide torque curve. That will yield large amounts of HP too. Peak values are irrelevant really. What you want is maximum area under the HP curve.

ZV

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