View Full Version : Horse power
CBR97
18th December 2007, 19:42
found this site http://www.factorypro.com/dyno/true1.html
interesting reading, if you like this sort of stuff
98tls
18th December 2007, 20:22
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
18th December 2007, 21:00
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
18th December 2007, 21:49
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
18th December 2007, 22:28
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
18th December 2007, 22:44
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
18th December 2007, 23:09
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
18th December 2007, 23:26
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
19th December 2007, 08:35
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
19th December 2007, 10:27
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
19th December 2007, 10:57
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
19th December 2007, 11:11
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
19th December 2007, 18:05
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
19th December 2007, 18:33
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
19th December 2007, 18:56
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.
Ocean1
19th December 2007, 19:20
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.
That's mah Man!
There's even half a dozen flavours of HP, all developed by different industries to suit their own ends, all subtly different.
Kilowatts are harder to abuse, but some manufacturers seem to manage that too.
Fooman
20th December 2007, 09:07
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.
The maximum rate of moving (i.e. speed) of a unit mass against some load (e.g. friction or gravity), assuming perfect traction and 100% efficiency of power transmission would be about 2:1 in favour of the MF, based on the assumption of the bucket making 10 hp.
That assumption is pretty far fetched, as currently the GS125 motor is in bits awaiting removal of a valve from a piston and sleeving of the cam bearings in the new head.
But a 20 hp motor is a 20 hp motor, regardless of the speed at which it makes it power. A 20 hp motor with peak power at 2000 rpm has the same capacity as a 20 hp motor which peaks at 10 000 rpm. How the speed of that power is changed by gearing etc for the final application will change the loading characteristics at the application (be it thrust through a contact patch or powering a conveyor), but it won't change the ultimate capacity of the motors to do the amount of work in a set time. Knowing this is extraordinarily useful in engineering applications!
What you probably mean is that the MF has power available at low speeds. It has, due to to having high torque at low rpm. But to get high power, it would need to run faster. How many tractors have a 10 000 rpm rev limit?
Cheers,
FM
The Stranger
20th December 2007, 09:27
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??
Sure it isn't changing engine HP, however, one assumes that changing to a lighter weight wheel yields a benefit none the less (else why do it). If a lighter weight wheel reduces rotating mass it may well be reducing HP loss in the drive chain. Surely measuring that benefit is potentially of some use i.e. it is handy to be able to quantify a change at times, and just try convincing someone else that your bum dyno is accurate.
Fooman
20th December 2007, 09:29
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.
Yup, "Horsepower" as defined by Watt is a contrived unit - something like 550 lbs lifted in 1 ft in 1 second if I recall correctly.
But power, regardless of the units used to describe it, it not contrived - the rate of energy consumption or production. If there is no rate of production/consumption - there is no power, and no work can be done - which suggests that web-browsing is in-fact a state of no power...
FM,
getting back to work...
DMNTD
20th December 2007, 09:42
Torque, however, is a real unit, and I think it's more indicative of real-world use.
Spoken like the true V Twin owner :niceone:
Pwalo
20th December 2007, 09:45
I don't care what it is I just want more of it. (Well I would, cos I ride a Suzuki).
Ocean1
20th December 2007, 09:52
Spoken like the true V Twin owner :niceone:
I do like my Massey Ferguson. :whistle:
Pancakes
20th December 2007, 11:22
The maximum rate of moving (i.e. speed) of a unit mass against some load (e.g. friction or gravity), assuming perfect traction and 100% efficiency of power transmission would be about 2:1 in favour of the MF, based on the assumption of the bucket making 10 hp.
That assumption is pretty far fetched, as currently the GS125 motor is in bits awaiting removal of a valve from a piston and sleeving of the cam bearings in the new head.
But a 20 hp motor is a 20 hp motor, regardless of the speed at which it makes it power. A 20 hp motor with peak power at 2000 rpm has the same capacity as a 20 hp motor which peaks at 10 000 rpm. How the speed of that power is changed by gearing etc for the final application will change the loading characteristics at the application (be it thrust through a contact patch or powering a conveyor), but it won't change the ultimate capacity of the motors to do the amount of work in a set time. Knowing this is extraordinarily useful in engineering applications!
What you probably mean is that the MF has power available at low speeds. It has, due to to having high torque at low rpm. But to get high power, it would need to run faster. How many tractors have a 10 000 rpm rev limit?
Cheers,
FM
I assume you mean capacity for work/effort not motor size?
and here's the tractor!
PS, Revs are a great way of making power but I personally love the slow rev - fast pickup of a vehicle with more torque that HP! Who let me drive that turbo V8! mmmmmm,
Fooman
20th December 2007, 12:51
I assume you mean capacity for work/effort not motor size?
Er, yup, my bad engrish
FM
Ocean1
20th December 2007, 12:54
Spoken like the true V Twin owner :niceone:
You've changed your avatar, thank fook fer that.
What you probably mean is that...
I's not very articil… artiucill … clever at saying shit.
But this guy’s not bad: http://www.msgroup.org/Tip.aspx?Num=221
And someone recently sent me this: http://www.superbikeplanet.com/2007/Dec/071217b.htm
Which helps explain some of the mechanisms which alter power delivery characteristics. Astonishingly, riders have known this for fekin ages. <_<
Powered by vBulletin® Version 4.2.5 Copyright © 2025 vBulletin Solutions Inc. All rights reserved.