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-   -   HP and torque? (http://www.hotrodders.com/forum/hp-torque-50375.html)

BadAss_Beaver 10-23-2004 01:49 PM

HP and torque?
 
If its the torque that moves your car then what is horse power and why does it matter? and wut are they measureing when they measure hp

arch 10-23-2004 02:39 PM

Simple explantion in 1/4 mile terms.
Torque gets you off the line, HP gets you to the line.

Want a more detailed explanation?
Check out the Knowledge Base or this site or this site or this site or this site or better yet... start here
:) :cool:
edit
Sorry, I forgot about
this site as well.

killerformula 10-23-2004 03:33 PM

they're not two separate phenomena, they're mathematical derivatives of one another.

K

pro70z28 10-23-2004 03:57 PM

An interesting FYI:

James Watt is said to have developed the definition of a horsepower. The
story goes that in the early days of the industrial revolution in England,
horses were used to help raise coal up from the coal mines. Usually a team
of horses were used. James Watt developed his steam engine and tried to
sell it to the coal companies to replace their horses. So, to compare
apples to apples, he measured how fast it would take a horse to lift a
weight a certain distance, and then he compared it to how fast his steam
engine could lift the same weight the same distance. That way, he could say
that his steam engine has the equivalent power to so many horses, or
horsepower.:cool:

And the rest as they say is history.........

troy-curt 10-23-2004 03:58 PM

You should ask Lonestar, he knows all about that kind of stuff, his granpa was a designer or something at gm, he says.

Troy:D

stepside454 10-23-2004 04:12 PM

Horsepower is a bi-product of torque... torque is work...horsepower is work within a certain amount of time...that time is RPM
I kinda compare it to watching birds fly. If you watch a big Hawk, there wings dont move real fast, but there long & forceful, gets that large bird moving & moving fast.
Than look at say a humming bird....there little wings are just screamin fast. Thats my way of comparing.

Max Keith 10-24-2004 10:51 PM

torque vs horsepower
 
Torque is the key engredient of power output for an engine. Horsepower is just a mathmatical formula derived for selling engines. The main reason vehicles are rated in horsepower was way back in the old days when engines only put out maybe 10-15 hp, people could relate to it with their horseless carriages, and it just never changed. For instance, during the heyday of muscle cars, which sounds more impressive? 410 hp @ 6000 RPM or 360 lb ft at 6000 rpm?

Watts formula was 30,000 lbs one ft in one minute + 1 hp.

Food for thought. No matter what the size or state of tune your engine is in, the horsepower and torque numbers will always be identical at 5252 rpm.

Rhansen 10-28-2004 05:25 PM

Like Killer said, horsepower is derived from torque. Dyno's measure torque, then calculate the horsepower. More or less, horsepower is an engines ability to produce torque at high rpm's.

Sleeper319 10-28-2004 06:47 PM

To make it eiser to understand HP maybe this will help, Or complicate the issue......

HP(N) = RPM(N) * TORQUE(N) / 5252

The 5252 is what kieth said, :)


Torque, how i remember it, A torque wrench. Force.
Torque on a motor is calculated by the bore, stroke, and the PSI, force of the explosion pushing down on the piston, turns the crank. Stroke is the length of the arm on the crank, Or the length of the torque wrench. You pushing on the wrench is the PSI of the explosion pushing on the top of the piston.





another formula just for anyone interested since on the topic.


Bore (in.) ?
Stroke (in.) ?
Cylinder Head Volume (in.) ?
Head Gasket Thickness (in.) ?
Piston- Deck Clearance (in.) ?
Piston Dome Volume (c.c.'s) ?
OR Piston Dish Volume (c.c.'s) ?
Piston DOWN Distance ?
Measured Volume (ml)

CYL.VOL = BORE * BORE * STROKE * .7854 * 16.39
GASKET.VOL = GAS.THK * BORE * BORE * .7854 * 16.39
DECK.VOL = DECK.CLR * BORE * BORE * .7854 * 16.39
TDC.VOL = HEAD.VOL + GASKET.VOL + DECK.VOL + DISH.VOL - DOME.VOL
BDC.VOL = TDC.VOL + CYL.VOL
COMP.RAT = BDC.VOL / TDC.VOL
LET EXP.VOL = BORE * BORE * .785 * DOWN * 16.39
LET EFF.VOL = EXP.VOL - ME.VOL

That is just to get the compression ratio.. ill see if i can find all the other info to calculate more.. If anyone is interested.

poncho62 10-28-2004 07:07 PM

Re: torque vs horsepower
 
Quote:

Originally posted by Max Keith

Food for thought. No matter what the size or state of tune your engine is in, the horsepower and torque numbers will always be identical at 5252 rpm.

Didn't know that..................See, you can teach an old dog........................

Sleeper319 10-29-2004 06:56 AM

Look at that.. Someone posted the 5252 answer..... :sweat:
lol OPS
Thanks Poncho and Kieth :)

troy-curt 10-29-2004 07:06 AM

Lonestare has a dyno, he should be able to explain all this?


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