ESE's works engine tuner

[SS90]

so we know how to get torque (known mass, acceleration and time over a measured distance.)

now how do you get horse power (whats the maths)

in my maths book it had a horse lifting a weight. cant remember the figues involved thow ?

just whant to know the maths ???
is it something like Torque /mass over time or there about's ????

From Wikipedia.:-
Only torque and speed can be measured; Power must be calculated from the torque and speed figures according to the formula:

Where K is determined by the units of measure used as can be seen below:
To calculate power in horsepower (hp) use:

where:
Torque is in pound-feet (lbf·ft)
Rotational speed is in revolutions per minute (rpm)
To calculate power in kilowatts use:

HP=TORQUE MULTIPLIED BY R.P.M DIVIDED BY 5252
where:
Torque is in newton-metres (N·m)
Rotational speed is in revolutions per minute (rpm)
(On graphs of torque vs. rpm the numerical values of torque and power are always equal when the rpm value is equal to the constant, K. The numerical values of horsepower and lbf·ft of torque are always equal at 5252 rpm because 5252 rpm in the numerator cancels out the constant, 5252, in the denominator leaving only the torque figure equal to the power figure.)

So, measure the Torque with an (inertia Dyno) then, to find out the horsepower, simply find a point on the graph Axis (Torque times R-P-M, and divide it by the constant 5252), do this for every point on the graph, and you have a horsepower curve, to go with your Torque curve.

Correction factors not withstanding.

[SS90]

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............1/4 mile standing start.


Calculate HP From ET and Weight

HP = (Weight / ((ET/5.825)^3))



Calculate HP From MPH and Weight

HP = (((MPH / 234)^3) * Weight)



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Erm, yes, I can also paint the walls in my house by putting a grenade in a bucket full of paint, and there will be paint on the walls.

But it's not very accurate.

What about the constant variable of the wind acting against the rider. Very important on a bike with a low BMEP (Like yours)
I'm afraid that none of these methods will give you any useable data when it comes to developing an engine.

You can't beat the readability of a dyno curve!

[SS90]

From TZ's post:-
Now we know Walter did not have a dyno, or not in the early years.

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Yes, while not in the early years (it would seem), it would be very unrealistic to assume that someone like Kaadens, a big part of MZ's GP winning succes, did not use a dynometer. While Teezee's equations may well be correct (from a mathmatical perpesctive. Think of this.

Head wind, or tail wind. Or side wind, Or no wind.

Just getting a horsepower figure doesn't mean anything.

You have to graph it.

Dyno's are not a giant "fruit machine"

When you develop an engine, you look for the shape of a curve. You look for when you have maximum torque (what RPM), and how long you make the torque for. Same with peak power....how long are you making peak power for? You measure your exhaust gas temperature, and try to ascertain if you are going the right way with exhaust design. (some exhausts get hotter and hotter, and if you where in a 5 lap race it O.K, but after say 25 laps, you can overheat your engine, just from the wrong pipe design.)

[gav]

Just getting a horsepower figure doesn't mean anything.

You have to graph it.

Nah, you have to ride it mate!

[Buckets4Me]

Horsepower is defined as work done over time. The exact definition of one horsepower is 33,000 lb.ft./minute. Put another way, if you were to lift 33,000 pounds one foot over a period of one minute, you would have been working at the rate of one horsepower. In this case, you'd have expended one horsepower-minute of energy.

http://www.web-cars.com/math/horsepower.html

Even more interesting is how the definition came to be. It was originated by James Watt, (1736-1819) the inventor of the steam engine and the man whose name has been immortalized by the definition of Watt as a unit of power. The next time you complain about the landlord using only 20 watt light bulbs in the hall, you are honoring the same man.

To help sell his steam engines, Watt needed a way of rating their capabilities. The engines were replacing horses, the usual source of industrial power of the day. The typical horse, attached to a mill that grinded corn or cut wood, walked a 24 foot diameter (about 75.4 feet circumference) circle. Watt calculated that the horse pulled with a force of 180 pounds, although how he came up with the figure is not known. Watt observed that a horse typically made 144 trips around the circle in an hour, or about 2.4 per minute. This meant that the horse traveled at a speed of 180.96 feet per minute. Watt rounded off the speed to 181 feet per minute and multiplied that by the 180 pounds of force the horse pulled (181 x 180) and came up with 32,580 ft.-lbs./minute. That was rounded off to 33,000 ft.-lbs./minute, the figure we use today.

[Buckets4Me]

Put into perspective, a healthy human can sustain about 0.1 horsepower.
Most observers familiar with horses and their capabilities estimate that
Watt was a bit optimistic; few horses could maintain that effort for long.


so I add about 0.1 hp to the bike (if I'm fit and well)

[TZ350]

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Just shows you what Kaaden achieved with so little, you have to admire it.

I like SS90's idea for painting the room, a handgrenade in a bucket of paint, now thats a "Real Bloke's" way of doing it.

Bert Munro would have been impressed!

Lots of Bert Vido clips here:- http://video.google.com/videosearch?...um=4&ct=title#

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[saxet]

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Bert Munro would have been impressed!

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Bert Munroe..now there was a guy to admire. Sometimes as mad as a fruit bat but in a clever way!

[SS90]

[QUOTE=TZ350;1999917].

Just shows you what Kaaden achieved with so little, you have to admire it.

One thing in particular that Kaaden and MZ team are credited for is the "clip section" system of chamber sections.

I must say that was (is) a really good way of developing exhausts.

And, as you have pointed out, it would appear "born of necessity"

[Brian d marge]

Yes, I have to agree, some Dyno's really do show some optimistic results, and (to a certain extent, price is not always a guarantee of quality, and accuracy)

I have personally inadvertantly caused strange readings by having the data box too close to the RPM inductive pick up (causing the correction factor to defuault to 80 Deg dyno room temp), making the correction factor read strange. (see attached pic)

Correction factor 1.136, and ambient air temp 80 Deg...... I DON'T THINK SO!

As always, it's important to have a good dyno operator (with good data to reference from.)

I don't mind using Dos based dyno's with no Correction factors, the numbers are somewhat absrtact, but if it is well maintained, they seem to read consistently.... A few years ago I know that a dyno was tested (when it was built) using a particular bike, the bike wasn't used much, and 5 years later, when retested (unchanged) the curve was EXACTLY the same, right down to the H.P

Good for developing in my book!

That said, with technology now, and a clever programme writer (and experienced operator), all "bugs" seem to be a able to be over come.

Me mate Dan ( Royal Enfield , no1 Ama plate ...bought a dyno ....lets just say it was a steep learning curve before he could use it as a development tool, as with a lot of engineering , the numbers ,..... well ..lies and damn statistics.....they are good for early development , cad , fea/cfd are a big help, reducing the time for development....but these at the end of the day are still educated guesses,,,,

On a fun note ...ipod/phone has a pocket dyno ..which uses ....gps ,,,,here are the results from the train from tokyo to fujimi ,,,,


max accel 0.18 g
max dist 284.91m
max velocity 83.09 kmph
0~100m = 18.63 sec
0~25kmph = 12.61 sec
0~50 kmph = 22.71 sec

max power needed weight ..... ( i tried to est ,,, 8 cars , 60 people per car ....around 55 000 kg .....i get 276 hp ..for the train .....assuming the units are imperial )

Still a bit of a giggle .....

Stephen

[craisin]

mmm ipod will go wwith your mac SS

[Buckets4Me]

seems to me that HP is the amount of work an bike can do
so you need to load the bike up with weights till it wont pull
them along any more and you have gone past the hp of the bike
you then need to remove the weights till the bike can just pull them
and it gives you an idear of the hp

you then mod the bike till it can pull more weight (means yyou have more
horse power)

[SS90]

seems to me that HP is the amount of work an bike can do
so you need to load the bike up with weights till it wont pull
them along any more and you have gone past the hp of the bike
you then need to remove the weights till the bike can just pull them
and it gives you an idear of the hp

you then mod the bike till it can pull more weight (means yyou have more
horse power)

Well, a Lecturer taught me this.... If you see Torque as how hard a Boxer punches, think of Horsepower as how fast he hits..... Which was the opposite of how I just explained it to him... Made sense to me at the time..... wish he didn't hit me so damned hard though (I got it the first time.....)

Remember though Buckets4me, it's not just a Horsepower figure that Teezee needs, he is looking for the Horsepower and torque curves.... they (the curves) are what best represents the BMEP of an engine.

It is possible to build an tune an engine that has high horsepower (GREAT!), but the power ends so abruptly ("PEAKY"), that it is hard to ride, and changing from one gear to another (say 3rd to 4th), means there is too bigger a jump in the gear ratios, and it "falls too far below the power", leaving a huge "flat spot".

This is why "close ratio" gearboxes exsist!

This is why you pay careful attention to the shape of the curve, and always try to have the Torque (and power) curves as long and flat as possible.

Many is the tuner who has found it benificial to drop a horse power or 2 in order to make changes that enable a flatter longer torque or horsepower curve.

[Chambers]

Erm, yes, I can also paint the walls in my house by putting a grenade in a bucket full of paint, and there will be paint on the walls.

But it's not very accurate.

Sorry it does not happen you don't watch Mythbusters

[craisin]

hey if a bike had 20 HP and you hooked up 20 horses to the back of the bike even if the horse were dead you wont win