What's the difference between brake HP & dynamometer HP? I'd rather hear it from you gurus.

Also, what the conversion equation for HP as a function of torque?

Go Niners!!!

HP = Torque in Lbs-ft x rpm / 5252.

KW = torque in NM x rpm / 9549

The SAE deleted “brake” from HP nomenclature decades ago.

You might be thinking of the differences between location where torque (and used for calculating power) is measured: flywheel vs rear wheels. They’re different due to frictional losses in transmissions, differentials.

Horsepower is how fast you hit the wall.
Torque is how far you move it.


Chiefs Rule.

Torque is what is measured.

HP is a computation from this measurement adding rotational speed.

It's "smoke and mirrors" from my perspective.

Torque is what you feel when you get pinned into the seat. (think Tygaboy's V8 car)

Torque is what wins races!

HP is what sells cars...

(might be a Carrol Shelby quote!)

Torque is a pork roast hp is a ham salad Mahome is on the bench

Torque is force with no time dimension.
Power is rate of energy, thus with a time dimension.

Copy that. Energy = power X time. I guess power can be consider as a derivative or rate. Cool. Thanks guys.

Close. The definition of power is work per unit time. (Energy and power share the same units in science, physics, engineering.)

https://en.m.wikipedia.org/wiki/Power_(physics)

Nope. Energy has units of watts x time. Power has units of just watts. And... watts = amps X volts. Cheers.

Whenever looking at Product manufacturers advertised HP/ Tq claims on RWHP, FWDHP, or AWDHP, its good practice to read the fine print;
True #s will be certified by the phrase noted on dyno sheet "Corrected Horsepower/ Torque".
Otherwise, uncorrected #s (always higher) will appear and makes mfg claims look better !
Also different make dynos have lower and higher power gains; as the Dynojet 248C is usually 3-5% higher compared to a Mustang (brand) dyno...based on my experiences.

Bhp… is British horsepower… same other than 5250 as the denominator.

Interesting.

Good stuff here!!

HP= how much you will pay for the car
Torque=how you feel driving your new car

Right you are! My bad. I’m embarrassed

no.
brake horse power.
and i come from a british colony.

but maybe british horspower is brake horsepower?
always since i was a mere babe. bhp = brake horsepower.
whatever the f$%^ that actually means scientifically speaking.


as to torque
thats the force you hit the gum tree with via your gum tree magnet installed in the front of your holden or ford when you are 18 years old and ready to die.
or causes your clutch to die a horrible death.
or rips your diff apart.
or shreds your tyres.
something like that.

all i know is my 1.8 has heaps of t,,,,alk that lasts for about 2.6 seconds at a traffic light drop at best. and then its over to hoarse - power and its pretty much wheezing like a 4 packet a day marlboro smoking ex cowboy.

Torque and HP are inversely proportional to your bank account.

"Brake Horse Power": Some dynamometers (how we measure power and torque) work by having the engine work against some kind of brake. The brake applies resistance to the spinning motion imparted by the engine. You may hear of "water brake", that is one type.

Some dynos work by having the engine spin a weight of known mass. The longer it takes to spin the mass up to speed, the less power or torque is being put into it.

Some dynos work using electricity and magnetism to resist the motion imparted by the engine.

In most use, BHP and HP are used interchangeably. Most people don't know the actual difference, and it doesn't really matter to most.


HP versus torque is another question entirely. One that has consumed many pages of writing and lots of air arguing in person.

In reality (unless you're talking about electric motors) you can't have one without the other. As soon as you start spinning something, you are applying torque and power to it. The definition of Horsepower is (Torque * RPM * [scaling factor]). For units of horsepower and foot-lbs, the scaling factor is 1/5250.

Torque is good because it's what pushes the car forward.
Power is good because that's the energy you can add to the car as motion.

They are related, very strongly.

Then there's the discussion of peak HP and TQ numbers without further context. Let's just say they aren't that useful on their own, and it's good to at least know what kind of RPM the peaks appear at--and more useful still to have a graph of each versus RPM so you can look at the area under the curve. And you have to figure gearing into it, because you can use gearing to transform high power at high RPM to high torque at low RPM. And then there's drivetrain losses, and and and and....

Ahh, f**k it. It's easier just to say "My engine makes XXX HP and XXX torque!"

--DD

Another use of peak hp rpm & peak torque rpm …

They are however useful in gleaning a little more info about both curves if the only info available is peak hp @ rpm, and peak power @ rpm.

By definition these “peaks” indicate the rpm at which that curve’s slope = 0. By differentiating the power =f(torque, rpm) equation first by d(power)/d(rpm), then differentiating T=f(power, rpm) by d(T)/d(rpm). The 2 differentiated equations define the slope of the power curve @ peak torque rpm, and slope of the torque curve at peak power rpm.

All great description's with a good mix of humor

Re BHP “Brake” horsepower …

Don’t know what made me think of this, but in addition to bhp, there were also bsfc and bmep commonly used in engine test, development, etc.; brake specific fuel consumption and brake mean effective pressure, respectively. All dropped from use about 1980+/-