Torque vs. HP Revisted

[lovehamr]

Originally Posted by fordracing65

Just try to get 600hp and 600ftpds torque by 6000rpm's and you will be fine...

Yup!

[lovehamr]

Originally Posted by Jaydee

You can multiply torque with gearing, but you can't multiply HP. The higher the gear ratio, the higher the torque.
JD

But that higher torque only matters if it's measured over time, which means its power. No matter how you cut, slice, chop, filet, churn or mix it, if you measure it over time - its power performing work. Changing the gear ratio only changes the apparent rpm/speed in which the work happens.

Nearly everyone here is actually talking about POWER in certain rpm ranges, no matter how it's expressed. Ya know how I know that? The constant reference to rpM. If that "M" is there, then we are talking about power, a measurement over time. You can build your motor to put the power where ever you want it in the rpm band and arguing about whether it's torque or HP is just silly. You know, mathematics being what they are.

[Tommy]

We engineering types can never resist a good HP versus torque thread even after the issue is long resolved. No one in our everyday lives will dare to bring up the topic in our presence for fear of a long winded, jargon laced reply that leaves ordinary people glassy eyed. So when someone on the web happens to bring it up, we dust off that part of our brains that's been dormant for decades and jump in with our favorite explanation. .... I can hardly wait for someone to do it again next year.

[Cobra #3170]

Originally Posted by lovehamr

But that higher torque only matters if it's measured over time, which means its power. No matter how you cut, slice, chop, filet, churn or mix it, if you measure it over time - its power performing work. Changing the gear ratio only changes the apparent rpm/speed in which the work happens.

Nearly everyone here is actually talking about POWER in certain rpm ranges, no matter how it's expressed. Ya know how I know that? The constant reference to rpM. If that "M" is there, then we are talking about power, a measurement over time. You can build your motor to put the power where ever you want it in the rpm band and arguing about whether it's torque or HP is just silly. You know, mathematics being what they are.

Great explanation!

[RET_COP]

Ok Ok I give - I want the POWER [without breaking the bank account]
am I on the right track now.

[AL427SBF]

1/4 Mile
Blue Daytona Coupe: 363 Crate Motor - 426 HP/369 ft-lbs_ET: 11.87 Trap Speed: 117 MPH (weight 2,460 lbs)
Red Mk IV: 5.0L Coyote Engine - 388 RWHP/330 ft-lbs ET: 11.74 Trap Speed: 118 MPH (weight 2,243 lbs)
Silver Mk IV Summit Racing 427w (Carbureted) - 372 HP/461 ft-lbs ET: 11.50 Trap Speed: 115 MPH (weight 2,200 lbs)



Silver Mk IV: Lowest HP and highest Torque of the three - best ET, worst Trap Speed. Sort of like Torque and HP, impress your buds with a fast Trap Speed, get the job done with Torque.



Road Course?
Just a bunch of 1/16th - 1/4 mile blitzes strung together one after another to make a lap





http://www.youtube.com/watch?feature=player_embedded&v=V96-AQ1FghI

[twin turbo]

I'm not quite sure I'm following your point with the above cars. The silver car had the lowest ET because it had the best 60 ft time, which is all about traction at the launch. Are you saying it had the lowest ET because it had 130 lbs more RWTQ but similiar hp?

The few times I've made a passes at a track my ET has varied by up to a full second depending on my 60 ft time, but my mph remained fairly constant.

[scottj]

Yeah... road course is a bunch of 1/16-1/4 mile passes strung together

Where are the results for the '33? 510 HP, worst 60' time, fastest trap speed (123mph), and fastest time on the road course.

[vector1]

doesn't matter what numbers you use, you are still operating under the constraints of time, and the only mathematical formula for time is horsepower. the powerband with the highest average horsepower is going to make the best time. f1 cars don't have squat for torque, but notice how fast they are? if you have to operate your car over the highest portion of the torque band because you don't want to go higher in the rpm range, you are still using the most avg. hp within the constraints of your limitations. torque and horsepower have no other relation than horsepower is formulated in time using torque.

[AL427SBF]

Originally Posted by scottj

Yeah... road course is a bunch of 1/16-1/4 mile passes strung together

Where are the results for the '33? 510 HP, worst 60' time, fastest trap speed (123mph), and fastest time on the road course.

Just mess'in with ya. The '33 coupe was impressive, but quite a different animal than the cobras imo. Just the rubber all around, once hot, would tilt the scales. Even more surpising, the Red Mk IV 5.0 Coyote beat the Blue Daytona Coupe 363, wouldn't have expected it. Too bad the Silver Mk IV Summit Racing 427w (Carbureted) didn't run the road course, that would have been a telling story one way or the other.

[AL427SBF]

Originally Posted by vector1

doesn't matter what numbers you use, you are still operating under the constraints of time, and the only mathematical formula for time is horsepower. the powerband with the highest average horsepower is going to make the best time. f1 cars don't have squat for torque, but notice how fast they are? if you have to operate your car over the highest portion of the torque band because you don't want to go higher in the rpm range, you are still using the most avg. hp within the constraints of your limitations. torque and horsepower have no other relation than horsepower is formulated in time using torque.

vector1, if you have -
... the powerband with the highest average horsepower
... then you also have the powerband with the highest average torque
... because you are stuck with this HP = TORQUE x RPM / 5252

[AL427SBF]

Comparing F1 to this discussion is a little outside the box anyway ...
F1 = 2.4 litre motor able to rev to 19K, we're talking 5-7 litre motors operating between 3-6K lol.

[lovehamr]

Originally Posted by AL427SBF

Comparing F1 to this discussion is a little outside the box anyway ...

They’re only out of your box because they so completely contravene any of the semi/non-mathematical drivel that’s been spewed in this thread by the low brow “we like the word torque” crowd.

Really though, when are you guys going to get it? The instant any movement comes into play then time does as well. In that instant we are talking about power not torque. It doesn't matter if the engine is turning 1900 rpm or 19000 rpm. I swear, loosing the words "torque" and "HP" all together and using "watts" instead would make this discussion so much easier.

[Tommy]

lovehamr,
I suspect we're talking past each other more than disagreeing. For the non-technical crowd, the HP vs. Torque debate usually comes down to whether its better to have a big HP number you can put in your signature block, or to have strong mid-range torque to smoke the tires at will while driving around town. If you want the biggest HP number, you typically end up with an unpleasant street car that requires a lot of time and attention. That is why many here suggest engine builders pay more attention to the torque curve than the peak HP number.

Regarding your technical argument that power matters more than torque, I see your point. For example, you can apply all the engine torque you like to a car with the brakes locked and it won't move. The output of the engine only starts to matter when the car is moving, and power is a better indicator than torque as to how fast it is moving. But, Newton's F=MA says that force (torque in this case) is what causes it to get faster. So, if you want to know how fast your car will go, look to power. If you want to know how quickly it will accelerate, look to torque. As I spend more time accelerating than cruising at maximum speed, I find the engine torque output more informative than the peak HP. ..... Watts are for Europeans and stereo speakers.

[olddog]

For those who do not understand the concept of torque

Suppose you wake up and go to the bathroom. You have a piss hard-on, and are pushing down with all of you might, so you can hit the toilet. Suddenly your feet kick out from under you. Than my friends is torque.

[AL427SBF]

Originally Posted by AL427SBF

... If we agree that torque is what moves you (acceleration), and HP is what keeps you there (speed) then it seems to me Torque is king and all efforts go to giving you the most torque relatively early in the RPM range (say @ 3K) and holding strong (flat or better) for as long as possible past the RPM range of 5252 where HP passes torque in terms of raw numbers. I figure, if you have maximized your torque curve in that way, who cares about peak HP in a practical sense. Not withstanding bragging rights, I see no reason to give a damn about HP if you have nailed the torque curve ...

[Tommy]
yeah, what he said ...

[PLDRIVE]

Lovehamr I remember having deep discussions similar to this years ago. Funny thing we always ended up having the munchies afterwards, thus requiring us to make a run to Taco Bell

[eschaider]

I think the more torque you have and the sooner you have it, both the more exciting the car is to drive and the more responsive to the driver's wishes it becomes.

The following dyno tune was through the side pipes and the power was measured at the rear tire so you need to use a correction factor to get to flywheel power for an apples to apples comparison. Although I have heard of some relatively high drive train losses I believe around 15% is probably fair.

I can assure you that nearly 500 ft/lbs of torque at about 1500/1600 rpm at the tire when measured by your seat of the pants dyno will get your attention. The ability to hold that torque level out to 6000 rpm makes the car a very memorable experience in any gear.

This is what it looks like on a dyno session report.




Ed

[Hotfingrs]

Me, I like torque. My philosophy is build for torque and horsepower will follow. My last dyno session I showed 688 lbs at 2700 rpm before the tires spun on the dyno. Gotta love it.

[Bruce M]

My Cobra has a 560HP big block Chevy with a wide ratio trans and 3.70 rear on Hoosier Q/T tires. It has so much torque that it leaves marks on pavement hitting it from a roll and recovers from RPM drop between gears. Torque is definitely king but getting car to stay together was challenging.