For those in the know what are your thoughts on Horsepower vs Torque?

Please let me know if my understanding is correct.

I understand that horsepower is the muscle while torque is the sprint.

Here is an analogy I was thinking of for a 270 hp vehicle (RDX) vs a 180 torque (CRV) vehicle:
1. A weightlifter may be able to bench press 270 lbs while another only 180 lbs. This means that if the lifter was doing reps of 70 lbs that the 270 lb person would be able to do it easier and longer than the 180 lb person. This would mean that the 270 hp engine works less when traveling at 70 mph vs the 180 hp engine. This can lead to a longer life with less wear and tear.

2. As for torque the 250 torque vehicle will have a better 0-60 and passing power than the 180 torque vehicle kind of like a sprinter or NFL wide receiver in the 40 yd dash to get that extra step on the defense.

If my thoughts are correct then torque is more important than horsepower since a 230+ hp vehicle should be able to handle 65-75 mph on the highway well but the ability to pass, especially on a hill, is why you need torque. This would be a reason to favor the Ford Escape 2.0 over the Jeep Cherokee (3.2 L) since the Ford has 230 hp and 270 torque while the Jeep is 270 hp and 230 torque. The RDX is around 270 hp and 255 torque.

Please let me know your thoughts and if my understanding is correct.

 

instead of making up your own analogies that doesnt make sense, why not just google the terms.... ?

Torque is a measure of rotational force. It is typically expressed in ft-lb, Dyne-cm, kg-meter or newton-meter. If you put a one foot long wrench on a lug nut and press down on the free end with 50 pounds of force, you are exerting exactly 50 ft-lbs of torque on the nut, whether it is moving or not.
Work is what happens when you exert a force through a distance. You can lean on that lug wrench with 50 pounds of force until you are drenched in sweat, but if the lug nut doesn't turn, by definition you have not done any work. If, on the other hand, you succeed in rotating the nut, you have.
Cute little illustrations should go here some day. Power is the ability to do work over time. Let's say it takes 100 ft-lbs of torque to turn the nut, and that it takes a constant 100 ft-lbs to keep it turning. (Maybe we're rolling the car up a slope.) If you turn the nut through one revolution in 10 seconds, you have done the work in a certain amount of time, so we can express your strength, or the ability to do work over time in terms of Power. Power can be expressed in Watts, Horsepower, calories per hour, ergs per second or many other measures.
Let's say your strength is equal to 1 horsepower. If I can turn the nut the same 360 degrees in 5 seconds, I would have 2 horsepower, because I would have done the same work in half the time. (Hey, I'm writing this - I get to be the strong guy!).
To review, we exerted a force on the wrench, which resulted in a torque on the nut. Because we both turned the nut the same amount, we did the same amount of work. But I have more power than you, because I did the same work in less time.
Now, we're getting somewhere!
Horsepoweris related to torque by RPM. The formula is: Horsepower = (RPM * Torque)/5252. It is RPM (revolutions per minute) that adds the dimensions of work and time to torque in order to reach a horsepower figure. A side-effect of this formula is that when RPM=5252, the horsepower number = the torque number. But concluding, as some do, that this means "horsepower = torque" is foolish - it is like comparing apples and oranges. One is an expression of power and one is an expression of something far simpler - rotational force.
Hopefully you now understand the proper, legal, scientific definitions of torque, work, and power. That's good, because we need them as a common ground to move forward.
Now, we need to look at two more vital concepts before we can truly understand how torque and horsepower affect our car's performance:

 

as stated, your analogies dont make sense and you're over complicating things by over thinking them

 

well the explanation is very detailed but for a non-physics layperson what will I notice in a higher horsepower or higher torque vehicle?

Look at the Escape 2.0 and Cherokee 3.2. With their HP and Torque #s reversed what will the driver experience differently in each? I saw one review that claimed the Escape 2.0 was like a rocket when accelerated from a dead stop.

 

I think there is no fault in trying to grasp the concept of torque and hp thru analogies. It is difficult to understand what and how force of a distance or time correlates to a vehicle's acceleration ability.

As explained above HP is a product of torque, it is a fixed equation for 4-stroke IC engines.
I believe the issue here is when you quote performance figures (e.g. Escape vs Cherokee) those values are peak values only.

Typically turbo engines have max torque low in their RPMs (the ones cited in their spec sheet) and start to lose torque in higher RPMs (the often used term "runs out of breath"). Their HP numbers follow accordingly.

NA engines OTOH, typically have flatter torque curves (esp Honda engines) thus the HP curve continues to rise linearly until the torque curve dives.

The real world result:
Turbo engines feel more powerful off the line and during up shifts as the engine dips into low RPMs where the HP# is RELATIVELY higher than NA engines at the same low RPM #.
NA engines try to compensate for this by using close ratio gearing in their transmissions to keep the engines RPM's high.

OTOH, during highway speeds, engine RPM during downshifts don't dip low in RPM anymore, thus taking away the advantage turbo engines had. At those high RPM #s the NA engine, typically with larger displacement, will produce more HP than a smaller displacement turbo engine.

So all in all, it is still HP vs. HP, not torque vs. HP.
Torque is not better than HP and vice versa. Torque is mathematically converted into HP (and vice versa).

It is just that during low RPMs (which isn't covered in the spec sheet), turbo engines have a clear advantage in HP over competing NA enignes. That HP advantage is lost during high RPM situations like highway passing.

 

Torque will win races.

if you have a higher torque number coming in at an earlier time(RPM), it will be the more powerful car at that certain time(RPM)

in the example you gave, if the Escape's peak TQ comes in early at 2000 RPM, while the Jeep's peak TQ comes in at 3500-4000RPM, the Escape will feel more powerful off the line(just an example, I dont know where the peak torque comes in for either vehicle.)

 

What about gear ratios?

 

that's next years class.

we're still taking baby steps and we're on the subject of horsepower.
but, if you're being serious.....

gearing can make or break a car. you can gear a car for great gas mileage(Tall gears) or make a fast car(shorter gears)
Acura chooses a middle ground.

 

"Torque wins races" is akin to saying "The big guy will win the fight".

Would a vehicle with a turbo V6 making 280hp max & 360lb-ft max torque win against a NA vehicle of same weight making only 260lb-ft? Depends.

Not if the 260lb-ft engine is an F1 engine with 792 hp at 16,000rpm.

 

^wait wait wait, that's too advanced.

we're still in horsepower and torque 101 and not in weight and gearing 101

 

Actually if you have the power available tall gears make the car faster. Short gears make the car quicker.

And to keep it simple, I know not exactly true but torque gets the car moving and horsepower keeps it moving.

 

so if on the highway traveling at 55-60 mph up a slight hill and want to pass a truck or another vehicle what would you look for? Maybe it is one of those highways like the ones between Phoenix and Vegas where it is mostly 1 lane that opens to 2 lanes for passing at certain points where the passing lane ends after about 1 mile. I would think you need to accelerate from 60-75 quickly for the pass before the passing lane ends.

 

you look for torque.
but different engines have different characteristics.
one may display a heave of torque at 2500 RPM and the other might show its true colors up HIGH at 5000 RPM.
also, gearing and weight play a role in this passing situation.
if the vehicle is geared correctly for that 70-75mph jaunt, it will pass the other car with ease.
if it's a LONG gear, which most freeway speeds are, then you'll need to drop down into a lower smaller gear.

 

I've gotta admit, even though I consider myself a car guy, the torque vs. hp thing is always a little puzzling. I guess I understand the definition, but not the application.

Here's an example: On another car forum I frequent, whenever the conversation turns to diesels, the fans talk about "mid-range torque, blah blah blah, mid-range torque."

Now I don't know how you guys feel about the RDX's performance, but whenever I put my foot to the floor, whether from a standstill, or when passing, the thing takes off like a muscle car - faster than the muscle cars I drove as a kid.

Torque? Horsepower? Gearing? I don't know. But I like it. (And I like not having a diesel. )

 

combination of all three in your acura.
again, acura has chosen a compromise or a middle ground of fuel efficiency, power and gearing....Just like other cars in this segment.

your muscle cars probably had the LONGEST gearing ever.

 

This^

 

Haha ... yes weight, gearing, aero forces: so many things that affect a cars acceleration.
But assuming all these equal, torque and HP are hand in hand.


I recall discussion on the Audi A4 regarding the 2.0T vs. the 3.2V6. Many preferred the 2.0T as it has a sufficiently satisfying butt dyno feel (cheaper too).


Think about it; turbo and diesels (typically turbo too) reward you instantly: flooring the gas from a stop and for every upshift which brings the RPMs back into the torque-y zone.


Honda NA engines reward you when you don't shift and let the engine rev pass 6K with a steady increase in pull which to many is less felt as it is a gradual increase. When you do shift, the engine goes back into a power hole (most AT drops out of VTEC) thus feels less rewarding.

 

think of it like riding a bike. torque gets you moving. horsepower determines how fast you can go. you start off in a low gear, and go up hills that way too. you go down hills in a bigger gear.

 

One of the things that you want is a nice F L A T torque curve. Take a look at the J series that was used in the original CL and TL type S. That thing had a seriously flat torque curve and that allowed for a very linear delivery of power. Go back and read the reviews of that motor, people were heaping praises on that engine because it was able to rev like no tomorrow and deliver the power pretty much to the WOT shift points. Anyone with a 4th gen TL know exactly what I am talking about... power comes on early and keeps going...

Another example of a high torque application was the S2000 (original motor) but it was peaky and required you to really get on the throttle to get any performance out of it.

the new RDX has a nice flat torque curve as well and even though it has less torque than the turbo 4, it makes it for a much wider rev range and as a result you get MORE HP out of the engine especially in the upper rpm range and it results in the newer model being noticeably faster than the old one 6.2 vs the old 7.1-2

 

Exactly. ratio of each gear in the transmission, final drive ratio, etc. Just as important, curb weight, also have to take into measure the curb weight of the vehicle. The new generation RDX is actually slightly lighter than the old turbo 4 RDX. More use of high tensile steel. That is why the new MDX, despite it's smaller 3.5 vs old 3.7 V6 and 10 less horsepower is slightly faster than the old model. It is 275 lbs lighter than the old MDX.

 

The new RDX also has 6speed with better gear ratios than then the 5spd auto of the prev RDX in addition to about same curb weight, 50 lbs lighter?

 

absolutely nothing to do with engine output and ability to provide power......

but if you are wondering about the gear ratios

1st: 3.36
2nd: 2.09
3rd: 1.48
4th: 1.07
5th: 0.75
6th: 0.56
Reverse: 2.27
Final Drive: 4.25

vs

1st: 2.70
2nd: 1.61
3rd: 1.07
4th: 0.69
5th: 0.54
Reverse: 1.89
Final Drive: 4.31

 

the old model was a 2.5L turbo 4, not a v6

 

I had a '11 RDX SH-AWD/Tech, my '14 AWD/Tech is faster and way more fun to drive. My right foot wouldn't lie.

 

It's easier to see things in HP instead of torque.

Torque relies on the gear ratio. Torque is a moment which is multiplied by the gear ratio to get the actual torque to the wheels.

HP doesn't change. HP is the amount of work output of the engine, the gear ratio doesn't change the output of work (tho the tranny does cause parasitic loss).

 

The way I see it HP is derived from TQ since it's a mathematical calculated off TQ.

I also believe you absolutely have to consider the particular gearing and curve of the particular car in question. Flat TQ curve will not feel the same as a peaky curve. Also diesel truck gearing will not feel the same as turbo sport car gearing of similar TQ.

 

If you want to learn the difference between horsepower and torque real quick , drive a Ford ecoboost 3.5 in a Flex or Explorer back to back with an RDX....


The Fords weigh close to 1000lb more than the RDX, and will feel significantly faster and more responsive than the Acura.....Due to the substantially higher low end torque.

No comparison in throttle response....The ecoboost 3.5 will feel like a rocket compared to the Acura.

The ecoboost 2.0 in the Escape is a dog , and doesnt feel very responsive....relative to the 3.5 ecoboost in the Flex / Explorer even though on paper, the power to weight ratios are similar.

Either the 2.0 ecoboost horsepower is overated...a lot....or the 3.5 ecoboost is underrated....

 

If you really want low end torque, get a diesel. Or better yet, an electric car, like a Tesla.

 

Okay, to further stir the pot
... and hijack the thread


Why do turbos "run out of breath" at high rpm?
Why doesn't someone make a quad turbo with one spool for each segment of RPM up to 7K RPM?

Thus it simply behaves like an engine twice it's size with no change in character.


We always have turbos that have gobs of tq down low but start wheezing beyond 4K rpm.

 

I have been testing my v6 older SUV (non- Hyundai). It is 219 torque at 3500 RPMs. The engine runs at around 2000 RPMs on normal highway driving. The 3500 RPMS seems really good as 5000 or more would take too long to kick in when passing.

I was on a highway entrance ramp behind a slow poke (happened to be a CRV going like 45-50). I had to get over to pass but another car was coming around 60. I was able to pass the slow poke but it did take a few seconds to reach the torque level to get the sprint needed. I think I would prefer the torque to kick in around 3000 RPMs for this kind of pass.

The 2014 RDX has 251 Torque that kicks in arounf 5000 RPMs. The 2012 RDX has 260 Torque at 4500 RPMs.