HP or TQ Which is faster?

[bah319]

http://www.vettenet.org/torquehp.html
This discusses 2 vettes with different motors. Explains further questions that might arise as well as hitting your original question pretty quickly. i'm surprised theres no video for this kinda question.

[ChronoX720]

What's the point of this thread? Is the OP racing someone?

[twinturbo_z]

no race..i drove a friends STi with supposedly less power and more torque and it felt considerably faster..jdm 2.0 sti

[ruskiyab]

Horsepower determines how fast you hit a wall, torque is how far you will take the wall with you

[Davenow]

It all depends on

Gearing
Weight of car
Rev limit of the engine

Light car+high rev limit+low tq/high hp=fast
Heavier car+normal rev limit+BIG tq and lower HP=fast


More TQ and more HP=faster.

[relliMmoT]

Whenever my neighbor braggs about his mustang he always says "Horsepower sells cars, torque wins races"

But ive got 304whp/289wtq, almost even- so I dont know if he is just saying that to sound witty or just doesnt know too much...

[beanbeanbean]

this is like watching a slow motion car wreck... i just can't look away

[Chi_San]

YouTube - Chinese Car, Truck Crash Testing

YouTube - Chinese Car, Truck Crash Testing

I'd rather have 250 hp and torque at the wheels from 2,000 to 8,500 RPM, with no dips below that level ever.

[UFOpilot]

Yeah, this is why people should forget about HP numbers. It appears that very few actually get it.

*Rant:
Horsepower is a way to sell your ego something to feel good about. Post it up next to your user name broda. Youtube material, that's it. Then again, if we all used torque only, it would become equally meaningless. Thank you to all the stupid folks in the world that have to destroy the very fabric of humanity with their illusions of power.

It's a system of measurement, based off of a system of measurement. If you never equated power with anything but torque, and work toward getting the most torque for the biggest section of RPM possible, you don't need to even worry about how much horsepower it produces. Torque not only wins races, it propels your car out of the driveway, Horsepower is nothing but the short-form answer for how much propulsive force you have at a given rpm, and without knowing the torque in some form you cannot derive a number for HP. Don't confuse yourself with it now.

*End rant.

[fizzin_A]

Originally Posted by ruskiyab

Horsepower determines how fast you hit a wall, torque is how far you will take the wall with you

I like this explanation though not entirely correct!

[luvless2620]

My head hurts from reading this whole thread.

[Audioexcels]

LOLOLOL...

The responses are very good. Just put them all together and you have

300WHP vs. 300WTQ will all depend on the bandwidth the car makes that torque and also how you will be gearing+revving at given RPM's and Speed bursts.

Take the freeway scenario-Car uses 2nd/3rd to burst out and try to make its run, eventually going into 4th, and maybe into 5th if it's at very high speeds. The car with the most torque per HP during these high RPM bursts is going to win. Since we do not know how much torque the 300WHP OR the 300WTQ car is making in the 6-7.5K range, we don't know which car theoretically would win on a freeway race.


Take the winding roads scenario-Car with more torque should theoretically beat the one with less torque, though in "real" winding roads, neither of these cars are even making boost unless they're using an extraordinarily fast spooling turbo which a 300WHP or 300WTQ 2.0L car will not be using unless it's using a twin scroll setup.


In either event, I would worry far more about the trans than which car would be faster.


Just my .02

[REX8]

Originally Posted by Audioexcels

LOLOLOL...

The car with the most torque per HP during these high RPM bursts is going to win. Since we do not know how much torque the 300WHP OR the 300WTQ car is making in the 6-7.5K range, we don't know which car theoretically would win on a freeway race.

TQ per HP?

[REX8]

All make it VERY VERY simple.

At a given RPM, the car making the most horsepower (which means it's also making the most torque) will be accelerating harder.

If you're looking at two different RPMs, then the one with the most HP will be accelerating harder, regardless of which one is making the most torque.

[Chuck H]

Originally Posted by twinturbo_z

300AWHP 250Tq vs 250AWHP 300Tq is one car faster than the next?

Neither one is a very likely scenario, but plug in some numbers.

The first car (300 hp, 250 ft-lb) is still making 250 ft-lb of torque at 6300 RPM to achieve 300 hp. Chances are that it has a nice fat torque curve, since it's highly unlikely that 6300 RPM is peak torque. With all that area under the torque curve, it's going to be pretty fast. Either that or it has a monster turbo that doesn't spool until 5000 RPM, and it's going to be an absolute dog unless you keep it wound out constantly.

The second car (250 hp, 300 ft-lb) sees its torque peak at 4375 RPM and starts dropping off after that. With its narrower torque curve, my money would be on car 1 being faster overall. Car 2 might be able to beat car 1 off the line, but car 1 is going to reel him in pretty quickly as he winds out each gear.

The way to really tell which car is going to be quicker is to plot the torque curves, and then figure out the area under the curve in the RPM range where the car will spend most of its time. A car with a slightly lower, but much wider curve is probably going to be faster than one with a higher peak, but a narrow power band.

[REX8]

Perhaps this will help.

Torque: Think of it as a twisting force. It is this force that drivers the car.

Horsepower: Think of it as a measure of how quickly that torque is being delivered.

Car 1:
To make it simple, lets say every engine revolution puts out 100 lb-ft. of torque. Let's just say that revolution takes 1 second to complete. So, over 1 second, 1 revolution of the engine, we've put down 100 lb-ft to the ground.

Car 2:
Now, if you had an engine that put out the same torque, 100 lb-ft-lbs, but was spinning twice as fast, aka one revolution putting down 100 lb-ft every 1/2 second...

Comparing the two cars:

In one second, car 1 puts down 100 ft-lbs in the fist second of the "race". However, car two has put down 200 ft-lbs in that same first second. Car 2 is making more power, i.e. it is applying the torque it makes more times in a given period of time.

Maybe that helps see the relationship.

[ADAS1223]

should be stickied. dunno why

YouTube - basic understanding of auto torque and horsepower

YouTube - basic understanding of auto torque and horsepower

[REX8]

Originally Posted by ADAS1223

should be stickied. dunno why

YouTube - basic understanding of auto torque and horsepower

He gets stuff wrong right off the bat!


For instance, at 45 seconds he states that as the RPM's rise, the engine starts to lose torque (100% true) then he says, because it's losing torque, it is also losing HP.

That is FALSE. The RPMs are rising, horsepower may VERY WELL still be increasing even though torque is falling off. You'd have to have specific numbers to know what the HP curve is doing there.

Loss of torque does not necessarily equal a loss of HP if your RPMs are increasing.

He does get it right at the 5:00 mark though. Maybe he had a mental lapse early in the vid.

[Chuck H]

This post from a while ago illustrates pretty well the difference between a motor set up for all low-end torque vs. one set up for all high-end horsepower.

http://forums.nasioc.com/forums/show...8&postcount=81

Both are very fast, but achieve that completely differently. The WRC car makes a ton of power at relatively low RPM, while the F1 motor is wound out like a sportbike to make its insane power.

[Beaverboy]

Originally Posted by UFOpilot

Yeah, this is why people should forget about HP numbers. It appears that very few actually get it.

No. Read REX8's posts. He actually knows what he's talking about. You're absolutely right about very few actually getting it.

1/4mi speeds can be calculated fairly accurately using power and weight. Torque and weight won't tell you anything about how fast a car is.

The biggest mistake people make when talking about torque is forgetting that torque is multiplied by the gearing before getting to the wheels. We express wheel torque on a dyno by dividing the true wheel torque by the final drive ratio and by the gear ratio for the specific gear the run was done in. This is why most tuners try to measure cars in the top non-overdrive gear.. as they're usually very close to, or at 1:1.

Here's a rundown of some flywheel torque numbers and what those torque numbers actually mean at the wheels:

Originally Posted by Beaverboy

More on the crazy torque of diesels:

Lets put it into perspective.. 1st gear torque at the wheels for the following cars:

TDI A3: 236lb-ft * 3.46 * 3.04 = 2488lb-ft
Civic SI: 139lb-ft * 3.267 * 4.76 = 2161lb-ft
Golf GTI: 207lb-ft * 3.36 * 3.94 = 2740lb-ft
STI: 290lb-ft * 3.636 * 3.90 = 4112lb-ft

Top gear torque at the wheels for the same cars:

TDI: 546lb-ft
Civic SI: 436lb-ft
GTI: 595lb-ft
STI: 952lb-ft

Just assume for a minute that all of those cars make full boost in 1st gear, even if they don't...

Notice that the diesel engine makes more torque at the flywheel than the GTI.. but the GTI makes more torque at the wheels. Why? Well, the engineers put lower gears in the GTI due to it's wider powerband.. this corresponds with the fact that the GTI is both rated higher for horsepower (200hp GTI vs 140hp TDI) and is the faster car overall.

[REX8]

Great examples.

All of my posts become irrelevant when one brings different gearing into the mix, just trying to keep it simple.

[Jack ffr1846]

Horsepower sells cars
Torque wins races

Carroll Shelby

[REX8]

Originally Posted by Jack ffr1846

Horsepower sells cars
Torque wins races

Carroll Shelby

Fail.

Try: Peak horsepower sells cars, high average horsepower wins races. Se below.

[REX8]

http://www.docstoc.com/docs/10015075...OWER-VS-TORQUE

Read, rinse, repeat.

[mentalcase87]

Holy ****! I thought i understood this a bit before, but after all of you going back and forth and arguing this and that with each other, i am soooooo confused. Can someone not take it to such complexitys and make it very elementry? I don't really care how the math and what not works out in the end... It would make more sense if i could actually make some sense of the basics, I had always thought the 300 hp in my old car was what truly allowed me to knock myself back, yes i understood it was thanks to torque. But never figured oh its got 300 hp because it has high or low torque.

Also if anyone has ever driven a 2010 mazda 3 not the speed, could you tell me why in the world this thing lights tires up like a champ and chirps 2nd and 3rd gear.... My mustang would chirp 2nd but it was only when pushing it. My buddy asked me to see if i could get the same results as him since he is new to stick, and just for fun i figured i would try to launch it and tire's just went to town... I was like you got to be kidding me! This thing has only 167 HP!!!

Every time i would shift in his car if i was pushing into it a little, during the shift it almost seemd like the rpm's would jump by them self. I knew where the rpm should land when i left off the clutch during the push and they would land a lot higher and that would cause a quick bit of tire spin in second and third. Now what is even more confusing is the car isn't fast, I am not saying its slow. But next to mine it's not got nothing, I am fully aware i dont get wheel spin anymore aside from launch and that's very little thanks to my new love AWD, but hell i would of had a iffy time getting my mustang to do the exact same thing, what in the world makes his car do that with such low numbers? Is it just a good amount of low end torque?