Question about horse power

[Yoga Face]

A friend at work has a corvette stingray coup

I asked him what the horsepower is and he said 455 HP WITH A 6.2 L 8 CYLINDER ENGINE


The only part I understood was 8 cylinder

I have 2 questions:

1 What does 6.2 liter refer to??? Is that the amount of liquid you could pour into the cylinders?

2 How can a car have 455 HP and those 18 wheelers hauling 40,000 pounds of freight have only 350 HP ?? as horsepower is the power needed to move 550 pounds one foot in one second


HP is determined by torque because torque is easier to measure which is what a dynamometer determines:

What the dynamometer, is measuring is the torque output of the engine as the wheels apply force to an object. In a vehicle, torque is measured at revolutions per minute (RPM). These two numbers are fed into a formula -- torque times RPM divided by 5,252 -- to arrive at horsepower.

Torque is defined specifically as a rotating force. For example, if you use a one-foot-long wrench to apply 10 pounds of force to a bolt head, you're generating 10-pound-feet of torque.

 

[good to go]

Torque is power and power gets you moving off the line there is very little power needed to keep you moving as momentum aids in this. If there is a upgrade or hill then you require power to overcome those forces. You require torque to move weight.

Displacement is the volume of the cylinders times the number of cylinders. The higher the volume the more power you can generate as that allows you to add more fuel and air to provide combustion.

 

[Titalian]

To long to explain and I'm lazy this morning. But thiis guy esplains it well.

 

[Yoga Face]

Torque is power and power gets you moving off the line there is very little power needed to keep you moving as momentum aids in this. If there is a upgrade or hill then you require power to overcome those forces. You require torque to move weight.

Displacement is the volume of the cylinders times the number of cylinders. The higher the volume the more power you can generate as that allows you to add more fuel and air to provide combustion.

you answered my liter question


the corvette has 460 pound-feet of torque

a Cummings big truck engine at 425 HP has 800 pound-feet

less than twice the pulling (twisting) force of the corvette yet the Corvette cannot pull half the weight of the Cummings which can pull over 100,000 pounds (weight of vehicle and trailer included)


What logic escapes me???


Obviously, it is the size of the engine that makes the difference but I am wondering about why they measure so little difference in the power ratings

This size difference is shown in the size of the cylinders measured in liters

11.9 liter in the Cummings truck engine

6.2 in the corvette engine

 

[good to go]

http://www.tridentsportscars.com/

This sportscar is an engineering marvel it outperforms most of the supercars while giving you over 100 mpg with a pickup truck diesel motor.

 

[IRIS]

you answered my liter question


the corvette has 460 pound-feet of torque

a Cummings big truck engine at 425 HP has 800 pound-feet

less than twice the pulling (twisting) force of the corvette yet the Corvette cannot pull half the weight of the Cummings which can pull over 100,000 pounds (weight of vehicle and trailer included)


What logic escapes me???

Because the Cummings tracks calculated with Draft Horse's power and the Corvette calculated with Thoroughbread Horse's power.

 

[Yoga Face]

Because the Cummings tracks calculated with Draft Horse's power and the Corvette calculated with Thoroughbread Horse's power.

actually, different horsepower was my first thought but it is the same horsepower measurement

 

[abv]

Gearing?

I've driven a vehicle with two 360 cubic inch V8's that had a 6 speed transmission but would only go 12 mph.

 

[Yoga Face]

To long to explain and I'm lazy this morning. But thiis guy esplains it well.

informative

thanks


HP is torque times revs so horse power increases as torque lowers at higher speeds

but it shows a graph of a Mercedes f63 twin turbo V8 with a torque of 611 ft pounds

a Cummings big truck engine at 425 HP has 800 pound-feet (it also has a turbo)

almost the same as the Mercedes ??????? yet it can do waaaaaaaaaaaaayyyy more work than any car because it has a bigger engine so I am still confused as to why this ability to do more work does not show in the HP and torque ratings

 

[Yoga Face]

Gearing?

I've driven a vehicle with two 360 cubic inch V8's that had a 6 speed transmission but would only go 12 mph.

no

certainly the gears of the tranny and differential make a difference but it is the size of the engine that makes the biggest difference by far

Why is this ability to do more work than a car not found in the tractor engine HP and torque ratings ????

 

[KBear]

as horsepower is the power needed to move 550 pounds one foot in one second.

Is the power to LIFT 550 lbs 1 foot in 1 second.

The car engine can produce that power for a short time before burning up, the truck engine can produce that power all day. Something like that.

 

[Yoga Face]

Is the power to LIFT 550 lbs 1 foot in 1 second.

The car engine can produce that power for a short time before burning up, the truck engine can produce that power all day. Something like that.

Actually, I was wondering About HP definition

I read one HP is the ability to MOVE 550 pounds in one second

But at what grade ???? Under what conditions???

Lifting answers these questions


I was thinking the same thing


A car can have the same work ability as a big truck but it will not last as long ??? Could be the answer



Torque measures work ability but not the length of time a engine can do that work

 

[KBear]

Torque measures work ability but not the length of time a engine can do that work

A 1 hp electric motor will produce that power for years. Marine engines are also rated lower, but can produce the power all day. Different engine design to produce different amounts of power depending on the use.

For power, Can think of a water well, with the crank at the top and rope going down to the bucket in the well. Assume it would take 20 lbs of force on the crank to hold the bucket at one point. An old lady might just be able to hold the bucket in place. so P=20 x 0. P = 0. So, you have torque but no power. A young guy might be able to turn the crank at 10 rmp, so P=20x10, P=200. When you know you have P=200 of available power, you could work backward with gears to lift more water at a slower rate, or less water at a faster rate.

 

[Yoga Face]

A 1 hp electric motor will produce that power for years. Marine engines are also rated lower, but can produce the power all day. Different engine design to produce different amounts of power depending on the use.

For power, Can think of a water well, with the crank at the top and rope going down to the bucket in the well. Assume it would take 20 lbs of force on the crank to hold the bucket at one point. An old lady might just be able to hold the bucket in place. so P=20 x 0. P = 0. So, you have torque but no power. A young guy might be able to turn the crank at 10 rmp, so P=20x10, P=200. When you know you have P=200 of available power, you could work backward with gears to lift more water at a slower rate, or less water at a faster rate.

ok

but are you saying the car does not have the same power as a tractor?

I thought we decided it does but it will not last as long and will quickly blow up

How do you measure this power you are describing ??? The young fellow has 200 power of what ?? Watts ?? Horses??? One foot-pounds pulling force per second?

By your definition torque does not measure ability to do work (which could be correct) but I THOUGHT IT DID.

As well, HP can only be measured if you know the torque so I am not exactly sure what the value of knowing what the horse power is as HP is a measurement of torque described in a different term

 

[KBear]

ok

but are you saying the car does not have the same power as a tractor?

I thought we decided it does but it will not last as long and will quickly blow up

Yes, same power. car engine would blow up.

How do you measure this power you are describing ??? The young fellow has 200 power of what ?? Watts ?? Horses??? One foot-pounds pulling force per second?

By your definition torque does not measure ability to do work (which could be correct) but I THOUGHT IT DID.

As well, HP can only be measured if you know the torque so I am not exactly sure what the value of knowing what the horse power is as HP is a measurement of torque described in a different term

I left units out in my example. In the well example, you could hang a weight at the end of the crank handle to hold it in place, you would have the torque, but can't do anything with it, no power. Maybe can think of it as, Power = how much is being lifted x how fast it is being lifted.

 

[Yoga Face]

Yes, same power. car engine would blow up.



I left units out in my example. In the well example, you could hang a weight at the end of the crank handle to hold it in place, you would have the torque, but can't do anything with it, no power. Maybe can think of it as, Power = how much is being lifted x how fast it is being lifted.

ok

we are solving stuff i think


but what do you think measures the power of an engine ???

i say it is torque

how long said engine can do this work is not measured, as far as i can see

 

[KBear]

ok

we are solving stuff i think


but what do you think measures the power of an engine ???

i say it is torque

how long said engine can do this work is not measured, as far as i can see

For power, HP is just a unit of measure like watts. 1 HP = 745 Watts. Same as units or measure for length, 1 inch = 2.54 cm.

Torque is the same as, how much is being lifted. You also need the know how fast it is being lifted which is the same as engine RPM to get power, or HP.

 

[zigma99]

Car manufacturers provide the highest hp output that a car engine can generate
Typically this is at 6000 rpm whereas most cars would normally run between 2000 to 3000 rpm
You would never get that power output during regular driving
Most people dont understand the horsepower hype that car manufacturers trick customers into

 

[Yoga Face]

For power, HP is just a unit of measure like watts. 1 HP = 745 Watts. Same as units or measure for length, 1 inch = 2.54 cm.

Torque is the same as, how much is being lifted. You also need the know how fast it is being lifted which is the same as engine RPM to get power, or HP.

it is conceptual, but it is sinking in

watts is volts times amps or a measure of power being used (although coulombs used is a better measurement, i think)


so the value of knowing HP is that it tells you how fast you can go while torque tells you much your engine can pull (but not how long it can pull it) ?

 

[IM469]

Torque is the same as, how much is being lifted. You also need the know how fast it is being lifted which is the same as engine RPM to get power, or HP.

That is my understanding. The difference in a truck and car of similar horsepower is the transmission. You can get a one horsepower pull a trailer (eg a winch) but it won't be as fast accelerating as a truck.