Horse power

[CBR97]

found this site http://www.factorypro.com/dyno/true1.html
interesting reading, if you like this sort of stuff

[98tls]

Interesting stuff,did my head in but interesting nonetheless,had a very long day, another tommorow but will get back to it on my days off.

[Monsterbishi]

HP is a number that you just don't need to know, the key is measuring the gains and tuning off one dyno, so you can measure the % increase over baseline, not the actual hp number it spits out.

[warewolf]

Must say I'm a fan of Factory Pro stuff. The Triumph is running their jet kit and emulsion tubes. The emulsion tubes are fantastic for throttle response, particularly off the bottom.

[cowpoos]

HP is a number that you just don't need to know, the key is measuring the gains and tuning off one dyno, so you can measure the % increase over baseline, not the actual hp number it spits out.

depends on what the base line is based on dude...on a inertia dyno changing the rear wheel to a lite weight wheel will yeild increased horse power. as will low weight chains and sprokets...so what is it your tuning off those results??

[Motu]

They need to stop using ''software'' to calculate HP.Hook the bike up to a proper brake dyno (water brake is good) with a chain direct to the dyno - and then with a pad and pencil calculate Horsepower from the torque readings.

HP = T x N
------
5252


Where T = Torque (lbft)
N = Speed (rpm)

[Ocean1]

They need to stop using ''software'' to calculate HP.

I'd be happy if they stopped using HP for internal combustion engines altogether.

It's an entirely contrived unit, of little use in describing useable energy.

Torque, however, is a real unit, and I think it's more indicative of real-world use.

[Pancakes]

How does that work with the systems like Dyno-Dynamics and their "Shootout" mode for the dyno comps? Does that give the true on the day reading or a detailed calculation of all losses form temperature and all the other factors involved?

Why do they calculate drivetrain losses? You lay the power down with the rear wheel, it's RWP that counts and % gain (or loss with some mods or mods without a re-tune) that really count eh?

[Monsterbishi]

depends on what the base line is based on dude...on a inertia dyno changing the rear wheel to a lite weight wheel will yeild increased horse power. as will low weight chains and sprokets...so what is it your tuning off those results??

baseline - ie, the run you do before you change anything.

HP is a composite value, measuring effort over time, making it a higher number than before is, well, good. Using the word tuning with regards to changing to lightweight rotational would be a fair call I reckon, since you just can't put the lightest one possible and expect it to have the exact results you personally desire, some sort of informed choice(ergo tuning) has to be made.

[Fooman]

I'd be happy if they stopped using HP for internal combustion engines altogether.

It's an entirely contrived unit, of little use in describing useable energy.

Torque, however, is a real unit, and I think it's more indicative of real-world use.

Alas, it is not a contrived unit.

Torque is a good way of measuring the efficiency of the IC engine - i.e. how much of the energy in the cylinder after combustion is converted to mechanical rotational force around the crank.

Power is the measurement of how that force efficiency is translated into motion (be it rotational velocity of the crank, or forward motion or whatever)

Power is force times distance per second. That force can be linear or it can rotational (torque). Distance per second can be linear (e.g. m/s) or rotational (radians per second).

Having a high force/torque but applying it slowly is a lot different to having a high force/torque and applying it quickly - the power is higher.

Cheers,
FM

[Ocean1]

Alas, it is not a contrived unit.

Torque is a good way of measuring the efficiency of the IC engine - i.e. how much of the energy in the cylinder after combustion is converted to mechanical rotational force around the crank.

Power is the measurement of how that force efficiency is translated into motion (be it rotational velocity of the crank, or forward motion or whatever)

Power is force times distance per second. That force can be linear or it can rotational (torque). Distance per second can be linear (e.g. m/s) or rotational (radians per second).

Having a high force/torque but applying it slowly is a lot different to having a high force/torque and applying it quickly - the power is higher.

Cheers,
FM

Yes. The theory is immaculate.

Now take your GS125, gear it however you like, arrange perfect traction and compare how much mass it can move in a minute compared to a TE-20 Massey Ferguson.

[sinned]

Torque and Power are both required to move stuff. If torque alone were the answer steam engines would be common - but that is another argument.

[Motu]

Alas, it is not a contrived unit.

Yes,it is a contrived unit - calculated from the torque value as in my formula.....that was how horsepower was measured until the computer came along.There was never a dyno that measured HP,they all measured torque...and HP is contrived from torque and speed - it's a rate of work....how much wood could a woodchuck chuck.By using software the choice of pit pony or clydesdale is up to the programmer.

[cowpoos]

They need to stop using ''software'' to calculate HP.Hook the bike up to a proper brake dyno (water brake is good) with a chain direct to the dyno - and then with a pad and pencil calculate Horsepower from the torque readings.

HP = T x N
------
5252


Where T = Torque (lbft)
N = Speed (rpm)

what does N stand for??? rpm? newton metres x rpm
--------------------
5252


is the calculation I understood to be correct?

[Motu]

Sorry,my computer skills are not too hot...I couldn't get it to post as a proper division calculation,keeps changing.But it does say N = speed (rpm) if you actually read it.

When Mr Watt invented his steam engine....he wanted to sell the thing too.But how to explain to his potential customers what it actually did.So he came up with the formula based on the amount of work one horse could do,pulling a weight up a mine shaft...what his engine was going to do.So one horse could pull a certain weight a certain distance in a certain amount of time - a rate of work.A smaller horse could pull half the weight the same distance in half the time...same result (4cyl 250).The distance and the weight are foot/pounds....what we call torque on a rotating shaft.33,000 ft/lbs of work done in one minute equals one horsepower.Because we are dealing with a rotating shaft we use a constant (derived using pi) of 5252.

If that's not contrived I don't know what is.

So now International Standards use the Watt as the unit of work produced - whether it's light bulb,steam generator,traction engine,fuel dragster.....or a DT230.