[GretchenGotGrowl]

Originally Posted by hotlapZL1

Torque is force
HP is the rate the force can be applied.

That's pretty close. Work is the application of a force to a mass to move it (mechanical work). HP is the rate of work and can be expressed as foot-pound-seconds. This is directly related to a drag racing because you move a certain distance (1320 ft), in a car of a given weight (say 3950 lbs) in some number of seconds (say 12.9). If you have more horsepower you can go further for the same weight and time, push more weight for the same distance and time, or get there faster for the same distance and weight.

This is average horsepower and not peak horsepower, and it doesn't matter what type of force is applied (it could be a rocket engine that produces zero torque). You can have a 1000 lb weight dangling over a cliff held by a rope run through a pulley with a radius and 1 ft and produce 1000 ft-lbs of force. If the end of that rope is tied to something immovable, then no work is done and no power is produced. Fat lot of good all that torque is doing you, right?!? Tie the end of that rope to a 100 lb sled and then it will move the sled (work) and pull it all the way to the pulley in some amount of time (power). Make the weight 2000 lbs and you increase the torque AND the power, because:

HP = (RPM * TQ)/5252

And for all those that say the HP is just calculated and TQ is what matters, just a little algebra yields:

TQ = (HP * 5252)/ RPM

Torque can be calculated, too. Both TQ and HP can be measured and the other can be calculated by simply knowing the RPM.

Low end torque only gets the car moving because allows for more power. Assume you launch your car at 3700 RPMs

300 TQ at 3700 RPM = 211 HP
900 TQ at 3700 RPM = 634 HP <-- gets off the line quicker!

[SUKXOST]

Originally Posted by DenverTaco07

Or it could be a really efficient drivetrain 10% loss would give 405 at the wheels, 450 at the crank. I don't know if 10% is realistic or not, if not you are right, or it's a ringer.

wait wait, they are saying 455 HP on the SS...that would be a 89.2% efficiency rating.

Using stock 426hp #'s for my 5th Gen....my drive train loss was 9% before my build (baselined @ 387WHP in GA).

Not calling you wrong and obviously different motors/gearing/cars etc....was just stating.

[SpeedIsLife]

Originally Posted by joemosfet

For comparison, the Scat Pack Challenger dynos at around 430rwhp. Even with its added weight, I'll have to line up my new Camaro with my new Charger Scat Pack and see which one wins, and swap drivers too, to see if its consistent.

Note that my Camaro will be an M6 while the Charger Scat Pack was ordered with an A8. Around corners, there's no question the Camaro will win, but... is that extra 25 horsepower enough to make up for the added weight?

(also, which one will be delivered first? TPW of 10/19 for the Camaro and a production week of 11/9, but it seems that the Charger has quicker delivery times?)

I wouldn't say it's fair to compare the two cars..

However for a 4 door the Charger is quite quick and very aerodynamically slippery.

That being said as long as there are no parts restrictions..the average order to delivery time on Chargers is about 6 weeks.

[hotlap]

Originally Posted by GretchenGotGrowl

That's pretty close. Work is the application of a force to a mass to move it (mechanical work). HP is the rate of work and can be expressed as foot-pound-seconds. This is directly related to a drag racing because you move a certain distance (1320 ft), in a car of a given weight (say 3950 lbs) in some number of seconds (say 12.9). If you have more horsepower you can go further for the same weight and time, push more weight for the same distance and time, or get there faster for the same distance and weight.

This is average horsepower and not peak horsepower, and it doesn't matter what type of force is applied (it could be a rocket engine that produces zero torque). You can have a 1000 lb weight dangling over a cliff held by a rope run through a pulley with a radius and 1 ft and produce 1000 ft-lbs of force. If the end of that rope is tied to something immovable, then no work is done and no power is produced. Fat lot of good all that torque is doing you, right?!? Tie the end of that rope to a 100 lb sled and then it will move the sled (work) and pull it all the way to the pulley in some amount of time (power). Make the weight 2000 lbs and you increase the torque AND the power, because:

HP = (RPM * TQ)/5252

And for all those that say the HP is just calculated and TQ is what matters, just a little algebra yields:

TQ = (HP * 5252)/ RPM

Torque can be calculated, too. Both TQ and HP can be measured and the other can be calculated by simply knowing the RPM.

Low end torque only gets the car moving because allows for more power. Assume you launch your car at 3700 RPMs

300 TQ at 3700 RPM = 211 HP
900 TQ at 3700 RPM = 634 HP <-- gets off the line quicker!

I was trying to express as simply as possible for non engineers that both HP and torque are important. It’s not just HP, HP, HP. A very high rpm, high HP engine that is relying on momentum has disadvantages in the real world. Knock it off its speed and it needs time or gearing to recover. Tesla electric (max torque and zero rpm)

Regarding HP being a physical thing. Torque can be felt. RPM can be observed. HP is a function of those physical quantities

[GretchenGotGrowl]

Originally Posted by hotlapZL1

I was trying to express as simply as possible for non engineers that both HP and torque are important. It’s not just HP, HP, HP. A very high rpm, high HP engine that is relying on momentum has disadvantages in the real world. Knock it off its speed and it needs time or gearing to recover. Tesla electric (max torque and zero rpm)

Regarding HP being a physical thing. Torque can be felt. RPM can be observed. HP is a function of those physical quantities

Oh, I know. I was basically expanding on what you said.

I will add this as well. Most drag racers consider the powerband to be between the the peak torque and peak hp. They use things like torque converters and gearing to keep the engine RPM between those two points all the way down the track. It the general idea is to have the highest average hp all the way down the track. Since you have a limited number of gears, that has typically been the best way to achieve the goal.

[Eric SS]

Originally Posted by Gen_Nick3.8

Most people who buy manual buy it for the fun & connection with the car. I had a BMW DCT & Gen 3.8 8sp. They're extremely fast shifting but after a while it gets very very boring all you do is floor it and go fast. Manuals never gets old, now that we have Rev-Match I feel like manuals are more attractive than ever

I'm still not tired of my 8speed auto and didn't get tired of my DCT before I traded it in but that's probably because I spend a lot of time in traffic now and don't consider my BMWs muscle cars . If I could afford it, I'd buy one of each but I can't justify to myself buying a car that is slower with a manual and for what I'm going to be using it for (Daily driver in traffic). If the manual was faster, I would still consider it the favorite. I will likely rarely track the car. I'll still drive both, but the pendulum has definitely swung in the autos direction for me.

[newb]

I am amazed, yet not surprised, that my underrated joke has completely derailed this thread and made it a scientific discussion of torque and Hp.

[xgnxs]

Originally Posted by Eric SS

I'm still not tired of my 8speed auto and didn't get tired of my DCT before I traded it in but that's probably because I spend a lot of time in traffic now and don't consider my BMWs muscle cars . If I could afford it, I'd buy one of each but I can't justify to myself buying a car that is slower with a manual and for what I'm going to be using it for (Daily driver in traffic). If the manual was faster, I would still consider it the favorite. I will likely rarely track the car. I'll still drive both, but the pendulum has definitely swung in the autos direction for me.

Technically, it's up to you if the manual is slower or faster than the automatic.

[RenegadeXR]

Originally Posted by rayhawk

Horsepower is not a marketing or legacy term, it just happens to be a measure of power based in U.S. units. Watts are no more proper than horsepower, they just happen to be based on the metric system.

Just because it's widely used in the U.S. as a unit of power doesn't mean it isn't a legacy term. I mean, you're comparing your car to a horse. Horses existed before cars. It's a legacy term used to help people sell cars over 100 years ago. I'm not debating that it's a widely use term today, obviously, but you can see where its roots come from. "Legacy" can mean out of date, or still current but in need of replacement. I think the term "HP" needs to go away, but maybe I'm alone on that.

Just think how weird it would say to state "My fancy new LED bulb puts out the brightness of 20 candles." We don't use weird associations like that. We use a standard measurement that stands on its own -- lumens. I think persisting to using the term "horsepower" is honestly equally ridiculous even if common in practice.

Originally Posted by rayhawk

Watts are no more proper than horsepower, they just happen to be based on the metric system.

But what else do you measure in horsepower other than engine power? It's so limited in its application. I think the most proper term should be the one that fits best, universally. If watts was truly no better than horsepower, again going to the lightbulb analogy, people would be rating lightbulbs in horsepower and not watts. Which would be weird for sure.

[GretchenGotGrowl]

Originally Posted by RenegadeXR

Just because it's widely used in the U.S. as a unit of power doesn't mean it isn't a legacy term. I mean, you're comparing your car to a horse. Horses existed before cars. It's a legacy term used to help people sell cars over 100 years ago. I'm not debating that it's a widely use term today, obviously, but you can see where its roots come from. "Legacy" can mean out of date, or still current but in need of replacement. I think the term "HP" needs to go away, but maybe I'm alone on that.

Just think how weird it would say to state "My fancy new LED bulb puts out the brightness of 20 candles." We don't use weird associations like that. We use a standard measurement that stands on its own -- lumens. I think persisting to using the term "horsepower" is honestly equally ridiculous even if common in practice.

That's really not a good analogy. Candlepower is still used for brightness in a particular direction. Lumens is used for total output in all directions.

But what else do you measure in horsepower other than engine power? It's so limited in its application. I think the most proper term should be the one that fits best, universally. If watts was truly no better than horsepower, again going to the lightbulb analogy, people would be rating lightbulbs in horsepower and not watts. Which would be weird for sure.

The reason we don't use horsepower for lights is horsepower is a specific type of power (like thrust is a specific type of force). There is no mechanical movement in a light bulb so no horsepower. There is an equation that will convert between watts and ELECTRICAL horsepower, but no one uses that because watts is a better measure. There is a difference between electrical power and mechanical power.

[FenwickHockey65]

Originally Posted by RenegadeXR

Just because it's widely used in the U.S. as a unit of power doesn't mean it isn't a legacy term. I mean, you're comparing your car to a horse. Horses existed before cars. It's a legacy term used to help people sell cars over 100 years ago. I'm not debating that it's a widely use term today, obviously, but you can see where its roots come from. "Legacy" can mean out of date, or still current but in need of replacement. I think the term "HP" needs to go away, but maybe I'm alone on that.

Just think how weird it would say to state "My fancy new LED bulb puts out the brightness of 20 candles." We don't use weird associations like that. We use a standard measurement that stands on its own -- lumens. I think persisting to using the term "horsepower" is honestly equally ridiculous even if common in practice.



But what else do you measure in horsepower other than engine power? It's so limited in its application. I think the most proper term should be the one that fits best, universally. If watts was truly no better than horsepower, again going to the lightbulb analogy, people would be rating lightbulbs in horsepower and not watts. Which would be weird for sure.

Originally Posted by GretchenGotGrowl

That's really not a good analogy. Candlepower is still used for brightness in a particular direction. Lumens is used for total output in all directions.


The reason we don't use horsepower for lights is horsepower is a specific type of power (like thrust is a specific type of force). There is no mechanical movement in a light bulb so no horsepower. There is an equation that will convert between watts and ELECTRICAL horsepower, but no one uses that because watts is a better measure. There is a difference between electrical power and mechanical power.

Yeah, just saying, footcandles is still the unit of measurement used by the FDA to determine sufficient lighting in milk plants.

[SuperSound]

Originally Posted by RenegadeXR

Just because it's widely used in the U.S. as a unit of power doesn't mean it isn't a legacy term. I mean, you're comparing your car to a horse. Horses existed before cars. It's a legacy term used to help people sell cars over 100 years ago. I'm not debating that it's a widely use term today, obviously, but you can see where its roots come from. "Legacy" can mean out of date, or still current but in need of replacement. I think the term "HP" needs to go away, but maybe I'm alone on that.

Just think how weird it would say to state "My fancy new LED bulb puts out the brightness of 20 candles." We don't use weird associations like that. We use a standard measurement that stands on its own -- lumens. I think persisting to using the term "horsepower" is honestly equally ridiculous even if common in practice.



But what else do you measure in horsepower other than engine power? It's so limited in its application. I think the most proper term should be the one that fits best, universally. If watts was truly no better than horsepower, again going to the lightbulb analogy, people would be rating lightbulbs in horsepower and not watts. Which would be weird for sure.

I understood what you were trying to say. SI is a legacy measurement system. Metric is the accepted scientific system but marketing in the auto industry has kept HP and ft lbs of torque around as what everyone uses.

With cars now featuring electric motors, watts is starting to gain some traction, but will likely be a long time before SI is replaced.

[joemosfet]

Originally Posted by RenegadeXR

But what else do you measure in horsepower other than engine power?

Well, any use of power can be measured in horsepower or watts.
If you are referring to the units that people most often use when measuring power, sure, it's generally devices that output rotational or linear motion. My garbage disposal advertises its power in horsepower units, for instance.

But just because it's not used outside of those types of devices doesn't mean it is an invalid unit of measurement.

Similarly, we measure our furnace in BTUs per hour, which is also a measurement of power and can be directly converted into watts. There is also "metric horsepower" as well.

[Eric SS]

Originally Posted by xgnxs

Technically, it's up to you if the manual is slower or faster than the automatic.

Maybe a dumb question but how is it up to me? No way will the manual be faster than the auto with the same person driving IMHO.