Engine Performance

[semievolved]

sounds like this has been handled well, my 2 cents. i used a 2010 V6 Toyo Taco for towing our Scamp for several years and switched to a Chevy Colorado Diesel in 2017. The 4.0L Toyo has lots more HP but the 2.8L Colo has lots more torque and is far better (and much lower fuel consumption) at towing at any speed. There simply is no comparison.

[dubbreak]

Originally Posted by Civilguy

HP = Torque x RPM ÷ 5252

There, that's settled.

What else have we got on the menu for this morning?

Yep, lock thread done.

What's next? Current doesn't matter it's wattage that counts!

[floyd]

Originally Posted by dubbreak

Yep, lock thread done.

What's next? Current doesn't matter it's wattage that counts!

Yeah, but that really would be for a "motor"... will we have to say "engine" for "What's next"?

[Geronimo John]

Many new members don't have a clear picture of the difference between horsepower and torque. And even if they do, they may not understand how an engine of one type or another may produce more torque or less torque than another type.

So instead of tossing you into the trash heap of the delete key or saying "you can't fix stupid" as one member did, I will refer you to an article that briefly sums up the concept. I hope it clears the subject up a bit for you. If not, please take the time to Google the subject. What you will find is that about 99.99 of all commercial truck drivers prefer torque over HP. The other .01% are new members that don't understand the concept yet.

I cut and pasted the entire article below, complete with it's advertisement.

++++++++++++++++++++++++++++++

You Need Torque or Horsepower for Towing?
Posted at Fri, May 20, 2016 9:00 AM

There has always been a debate on which of the two is more important for a powerful vehicle – Torque or Horsepower? The answer is- both are important but have different functions. But for the specific work of towing, torque is more important.

To put it simply, Torque lets you work but Horsepower makes the work go fast. You know that heavy-duty vehicles and giant trucks run on diesel. It is because of the greater torque generated by diesel engines. The piston moves relatively farther (than in gas engines) resulting in longer strokes and consequently, a greater torque. If you compare a diesel engine with a gasoline one of slightly higher horsepower (but lesser torque), you will see a huge difference in their towing performances. Although they might be able to heft the same load, the diesel engine will not have to take any strain at all.There is no need to rev up the engine; the high torque will complete the task at a significantly low rpm (revolutions per minute). Also, the diesel fuel has higher energy content than gasoline. This means that you will get a better mileage with diesel engines – they can tow for a longer period of time without stopping to refuel.

To sum up, torque plays a greater role in towing than horsepower. This is because of the ‘low-end rpm’ generated by the higher levels of torque, which allows the engine to easily carry heavy loads. A high torque vehicle will be able to tow trailers or other objects with an extremely low value of rpm. Tires, suspensions, wheels, and gears also play an important role in towing.

If you are looking to buy a used truck, check into Tim’s Truck Capital & Auto Sales Inc. today.

[EricJ]

Originally Posted by FRED SMAILES

Please state your knowledge base, where can I read that will confirm what you say?

No where.

[Doctor Harold]

Originally Posted by dubbreak

Yep, lock thread done.

What's next? Current doesn't matter it's wattage that counts!

My 125 watt Hobart N50 5-quart mixer will knead bread all day and never heat up or complain. My 325 watt KitchenAid 5-quart mixer doing the same job will overheat and need to cool down after 20 minutes.

What's next?: Dino oil vs. Synthetic? (Now that's a thread I can really ignore!)

--Harold

[Raspy]

Originally Posted by Doctor Harold

My 125 watt Hobart N50 5-quart mixer will knead bread all day and never heat up or complain. My 325 watt KitchenAid 5-quart mixer doing the same job will overheat and need to cool down after 20 minutes.

These numbers sound like Craftsman Shop Vac horsepower claims. FIVE HORSEPOWER!!!! (Of course it runs on a 15 amp household plug) Or some of the Harbor Freight compressor claims. All can be misleading, as you've pointed out. But you didn't say how fast each one does it's job. The 325 watt mixer might be going three times faster.

I find all of the horsepower vs torque claims kind of funny and missing the point.

Horsepower describes the amount of work that can be done with an engine. Climbing long grades with a truck requires horsepower. In other words, mass raised to a new elevation over time is work.

Horsepower is calculated by multiplying torque times RPM. You can't consider torque as something different than horsepower, any more than you can consider RPM as something different that horsepower. Each is a component of HP.

Torque is a force that describes no movement. RPM is a speed that describes no force.

The reason high torque engines are so good for heavy pulling is that they are steady economical workhorses that last a long time, are easy to couple to the wheels and can run at full throttle while being easily controlled. They are more friendly to deal with than running something at 15,000 RPM but gearing it way down. If you want more torque, you can simply gear the transmission at two to one and double the torque. But you would still have a high speed engine that might not be practical.

The point is, you can adjust the torque with gearing. Horsepower is what accomplishes work. Practical designs take into account the real world use of things. It's not valid to simply say torque does work.

Each engine must be suited to its job. For instance a turbo diesel engine is not suitable as a chainsaw engine because it is too big and heavy. But a bank of two cycle chain saw engines is not practical for over the road trucking, because they would never last long enough and would be hard to control as well as use a lot of fuel. It's not the HP, it's the practicality.

Once you figure out how much horsepower you need in a given machine, you can design the engine to fit that need. Tractors, for instance, need weight to engage the ground and remain stable while working. And they should last a long time with minimal maintenance. Putting a Yamaha R1 bike engine in a tractor would be ridiculous, but it has nearly 200 HP, so it would do the work. For a while.

Helicopters are another good example. They need lots of horsepower and minimal weight. Try a Caterpillar turbo diesel engine in one and find that torque isn't the whole story. Once again, it's horsepower in a practical machine that wins the day. Or put that helicopter engine in a truck. Geared down it would likely have twice the torque of a diesel, but the fuel usage would be off the charts and engine braking would be non-existant.

When lifting a tractor bucket full of gravel, the arms rotates around a pivot point about 8' back from the bucket. A 1000 lb load in the bucket, requires about 8,000 ft lbs of torque to lift. It's not the speed that counts or is even a factor when holding it steady. It's torque. The bucket arms are producing about 8,000 ft lbs of torque to support the bucket.

The slow turning turbo diesel piston engine turns out to be the most practical design for heavy trucks. Not because it produces the highest crankshaft torque, but for all the reasons combined.

HP = torque X RPM, divided by 5252. HP produces work. Climbing long grades is measured in work. (how much weight, raised how far, in how much time).

[Kennet]

In towing diesels work best because the max horsepower arrives at low rpm.

[Doctor Harold]

Originally Posted by Raspy

These numbers sound like Craftsman Shop Vac horsepower claims. FIVE HORSEPOWER!!!! (Of course it runs on a 15 amp household plug) Or some of the Harbor Freight compressor claims. All can be misleading, as you've pointed out. But you didn't say how fast each one does it's job. The 325 watt mixer might be going three times faster.

Actually I am running both mixers on their lowest speed. The difference is that the Hobart is an induction motor (brushless) that runs at constant speed (it's 3 speeds are accomplished with a transmission), while the KitchenAid is an AC commutator series motor that has ten speeds, accomplished electrically.

My point was that, just as the horsepower/torque debate is nonsense, wattage claims are nonsense as well. As you so eloquently explained, without an understanding as to how the power is developed and used, it's all advertising hype.

In Europe automobile engine power is described in watts, which may be a better gauge for comparison, but I would think it's still subject to distortion by sellers.

I notice the OP hasn't re-engaged. Just stirring the pot: hit and run. I used to belong to a British Car Club years ago, and it seemed that in almost every meeting someone wanted to inflame the dino oil vs. synthetic debate. Then it escalated to zinc additives. I finally had enough and quit the group.

Harold

[dubbreak]

Originally Posted by Doctor Harold

My 125 watt Hobart N50 5-quart mixer will knead bread all day and never heat up or complain. My 325 watt KitchenAid 5-quart mixer doing the same job will overheat and need to cool down after 20 minutes.

The implied point was:

P = I*V

I.e. wattage equal current times voltage.

HP is just the amount of torque at a specific rpm. Wattage is just current at a specific voltage.

You can't separate the two and say one is more important. They are tied. It's like saying mpg is more important than gallons per hundred miles. It's two representations of the same thing.

Also, trying to guess behavior or make rules of thumb about peak hp or peak torque figures is absurd when torque curves (and consequently HP curves) are available for most vehicles. A good tow vehicle will have peak torque available early and will have a nice broad torque band. A vehicle with high peak hp might be making that HP at 9000rpm and be totally useless for towing. It could also be good. A look at the torque curve will clarify that. The rpm at which peak torque occurs gives a good clue, but what the torque curve is doing before or beyond that is anyone's guess without a graph.


HP isn't a single number. Peak hp is, peak torque is (and should denote the rpm they occurred at). In reality HP and torque are curves over rpm and one curve can be calculated from the other so one isn't more important than the other.

[Raspy]

Originally Posted by Kennet

In towing diesels work best because the max horsepower arrives at low rpm.

And because they are a more robust and efficient design that uses a safer fuel with more energy per gallon. But the higher initial cost, complicated emissions systems and higher priced fuel are starting to make them not seem better in all cases.

For towing fiberglass trailers, a higher reving engine, while climbing grades, can be more desirable than a higher initial cost and more complicated maintenance.

[Marty Smiltneek]

Originally Posted by Civilguy

HP = Torque x RPM ÷ 5252

There, that's settled.

What else have we got on the menu for this morning?

Ya- hooooo finally a person who can be related to. When I read the opening statement I thought to post the formula.

[Iowa Dave]

Originally Posted by Johnny M

Tell this to the farmers gathered around the feed n seed any Saturday morning and you will be laughed out of the town. Tractors of relatively low hp can pull far more times in weight than much higher horsepower auto tows, albeit the tractor will be relatively slow in comparison it will out pull the auto all day long.

These same farmers often meet in the basement of the Grange Hall to complain about the price of corn and beans. That room is usually called a whine cellar. Might not be going that fast but road gear in a row crop H seems pretty fast on gravel.
Iowa Dave

[Yellowjacket]

Actually the thing that will get you stuck on the side of the road is cooling capacity, or the lack there of. That's why they have extra radiator capacity included in towing packages.

[sokhapkin]

Originally Posted by dubbreak

What's next? Current doesn't matter it's wattage that counts!

Only in America power is measured in Amps...

[Yellowjacket]

Originally Posted by sokhapkin

Only in America power is measured in Amps...

Power is measured in Watts the world over... Specifically 746 (50% Columbus) per horsepower.

Amps is the measure of how many electrons are flowing past a certain point in a circuit. Volts is essentially the pressure they are under to move. Volts X Amps = Watts, unless they've updated it to metric and made it Kilo something or other.

[John in Santa Cruz]

Originally Posted by Yellowjacket

Power is measured in Watts the world over... Specifically 746 (50% Columbus) per horsepower.

Amps is the measure of how many electrons are flowing past a certain point in a circuit. Volts is essentially the pressure they are under to move. Volts X Amps = Watts, unless they've updated it to metric and made it Kilo something or other.

it does get a bit trickier in AC land with inductive loads, where the current lags the voltage due to phase shift, so you have to take 'power factor' into account. with purely resistive loads, or with DC, then yeah, V * A = Watts.

and the 746 Watts per HP only works if the motor is 100% efficient, nothing is perfect, so an actual 1HP motor is probably more like 800-900 watts, where the extra watts are leaking out as heat.

/me takes off his Engineering cap, and goes back to drinking beer.

[Geronimo John]

Well done gentlemen. Now if that pot stirring young member ever shows up and reads this, he will know for sure that.....



He stirred the pot and we fell for it!

:-)

[C&G in FL]

Originally Posted by JPRussell1952

Well done gentlemen. Now if that pot stirring young member ever shows up and reads this, he will know for sure that.....



He stirred the pot and we fell for it!

> He stirred the pot and we fell for it! <

Are you paraphrasing P.T. Barnum (.......”born every minute.”)?

[Geronimo John]

Drats, showing my age again!

Cud-do's to Steve L and RockyBob. They saw it for what it was first!