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  #61  
Old 08-26-2007, 06:44 PM
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Default Re: How to covert CC to horsepower

Hello everyone...

Couldn't help but notice that there is a fair amount of confusion regarding calculating HorsePower...

IT CANNOT BE CALCULATED ON THE BASIS OF CCs.... PERIOD

(4 stroke mower engines are similar... Motorbikes vary widely... cars vary widely...)

I have owned all of the engines below and they each have vastly different horsepower to cc ratios (with the exception of the two small engines);

5hp Techumsec Mower (207cc)
11hp Briggs and Stratton Ride on Mower (400cc)
27+hp Honda CR250 Motorbike (250cc) (2-stroke)
78hp Kawasaki GPZ750 Motorbike (750cc)
175hp Ford Falcon car (4200cc)

All the best - Sam
  #62  
Old 09-09-2007, 09:09 PM
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Default Re: How to covert CC to horsepower

How much hp for 125 S.E. Kawasaki motorcycle?
  #63  
Old 09-10-2007, 08:14 PM
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Smile Re: How to covert CC to horsepower

Here's my take on all the figures presented so far:
to APPROXIMATE a measure of horsepower, based on knowledge of CC:

perfect (eg racecar, airoplane) quality equipment:
divide CC's by approx 6-10

new/performance (eg new motorcycle ) equipment:
divide CC's by approx 10-12

good quality equipment (eg old motorcycle, new sports car):
divide CC's by approx 12-15

fair quality equipment (eg very old motorcycle, any other car):
divide CC's by approx 15-20

sound right?
  #64  
Old 09-22-2007, 04:02 AM
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Default Re: How to covert CC to horsepower

Previous post has the right idea - compare like with like.

This site has a list of piston engines showing capacity and horsepower from a 2.5cc model aero engine to a 1.5 million cu.in. ships engine.

To go to the site just Google for 'cc to hp' (can't put a link)

It gives the ratio of horsepower to cc so pick the type you want (Briggs and Stratton or outboard or chain saw or Ford pickup, etc) and apply that to your known cc or cu.in.

Gives a 'near enough' estimate.
  #65  
Old 09-26-2007, 07:16 PM
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Default Re: How to covert CC to horsepower

Holy Schmolly I say.

I am suprized that no one tried this sooner.

To the guy that thinks tis can be done:


I have a motor that I know is 50 HP. Please tell me the displacement in ccs.
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  #66  
Old 10-13-2007, 01:57 AM
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Default Re: How to covert CC to horsepower

I am trying to find out how much horsepower in a 305cc craftsman snowblower, I was at a local Canadian tire store the other day and I was looking at a couple of snowblowers...one was 318cc and 9 hp, the other was 318cc and 11 hp....whats up with that?????????
  #67  
Old 11-15-2007, 10:24 AM
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Default Re: How to covert CC to horsepower

I saw a honda engine at 189 cc, now dont tell me thats 18 horse power cos I wont believe it, its for a pressure washer and the engine is no more than 6 horse power so how can 189cc be 6 hp?
  #68  
Old 11-15-2007, 09:27 PM
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Cool Re: How to covert CC to horsepowers

Quote:
Originally Posted by Unregistered
Im having trouble finding a site that can convert CC into horsepower. I was wondering if you knew how to change 246 cc into h/p somehow.
first
horsepower = force * distance by "in how much time".
Force = mass * acceleration

I know what your thinking, that if a certain amount of CC( CI), let say 100, should give you a certain amount of horsepower, always right? will not right, your confused on terminalogy. You alreade know how much power you got, that is, 100cc. "Now" horsepower is a measured in how much distance it can be moved in how much time.

[Ex1] if you have 1000cc and the lat say, ATV weights 500lbs, you going to have alot of horsepower.
[Ex2} Again, let say you have 1000cc, but let say you ATV weight 500tons, your you bike doesn't have alot of horsepower. But it does have alot of POWER.
Power = Work * time
horsepower = work* time* distance
Distance is the keyword in horsepower, if it doesn't have to much, it basically mean it doesn't have alot of horses.

Still confused? remember, when the engine was built, it was suppose to replace horses, back in the 1900. So if you got 1000CC and it weight 500Mtons, it won't move right, so therefore , you won't even have one horsepower. But no dought, you got a big engine.
  #69  
Old 11-16-2007, 10:13 PM
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Default Re: How to covert CC to horsepower

Is this some kind of psychology experiment? It's SO obvious. Asking to convert one of these into the other is like asking how much alcohol a glass can hold without saying what kind of drink or how full.

cc is a measure of volume. 30 cc is something like one fluid ounce or a couple of cubic inches.

A 2 stroke 10cc model airplane engine running 10% nitro on a tuned pipe might make upwards of 2 horsepower. (And I think it's about 1/3 to 1/6 the displacement of a shot glass, to stretch the metaphor.)

Two strokes DO tend to put out more power per displacemtne. I said TEND.

The aforementioned industrial engine is, I think, something like 524cc, but it only puts out 6hp as originally set up. But it probably puts that out reliably for 100 to 1000 times the life of that model airplane engine.

Those two snowblowers were probably set up just a bit different. Change the carburator a bit, fiddle with the head, whatever, you make a change in the horsepower available.

So forget the conversion, do your homework and find out the real number.
  #70  
Old 11-19-2007, 10:30 AM
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Default Re: How to covert CC to horsepower

Quote:
Originally Posted by Unregistered
There are many verables that determine Horse Power. You may have two identical engines that put out different horse power. It is determined by displacement, Compression Ratio, Fuel mixture, engine design, ignition and valve timing.
Horse Power or (BHP) 1BHP = 550 FtLb per second
Example: For Calculating FtLb
Work= Distance X Force (5Ft X 10Lb = 50FtLb)
Power= Work / Time (50FtLb / 2 seconds = 25 Foot Pounds per Second)

If you want to figure out CC for an engine you use

Displacement= Bore X Bore X 0.7854 X Stroke, X number of cylenders
Example 5.4(Bore) X 5.4(Bore) X 0.7854(Constant) X 5.4(Stroke) X 1(number of cylenders) = 123.672 CC
and if you need to convert CI to CC (1 CI = 16.387 CC)

That being said the best way to get an accurate HP is to put your vehicle on a Dyno or call the manufacture.
Just trying to provide some food for thought.
Have a good day.
I could not have said it any better myself.

The Yamaha YZ250F is rated at 32 horsepower (give or take) and If memory serves me around 20 foot pounds of torque. Not bad for a 4 stroke, single cylinder dirtbike.

Displacement is only part of the equation for making power. There are more factors to take into account, numerous factors that would probably fill this post to the brim but I wont.

It is improbable to calculate an engine's power purely based on the size of the engine.

Believe me when I say this, outer appearances are deceiving, you have to actually test what something can do before you make assumptions.


Quote:
Originally Posted by Unregistered
Is this some kind of psychology experiment? It's SO obvious. Asking to convert one of these into the other is like asking how much alcohol a glass can hold without saying what kind of drink or how full.

cc is a measure of volume. 30 cc is something like one fluid ounce or a couple of cubic inches.

A 2 stroke 10cc model airplane engine running 10% nitro on a tuned pipe might make upwards of 2 horsepower. (And I think it's about 1/3 to 1/6 the displacement of a shot glass, to stretch the metaphor.)

Two strokes DO tend to put out more power per displacemtne. I said TEND.

The aforementioned industrial engine is, I think, something like 524cc, but it only puts out 6hp as originally set up. But it probably puts that out reliably for 100 to 1000 times the life of that model airplane engine.

Those two snowblowers were probably set up just a bit different. Change the carburator a bit, fiddle with the head, whatever, you make a change in the horsepower available.

So forget the conversion, do your homework and find out the real number.
I have an OS .12 TZ engine and it is rated at 1.5 HP from the factory (at 30,000 RPM).
2 stroke engines produce more power per size than their 4 stroke counterparts but the difference is at the RPM they make it at. 4 strokes make more power off the bat, 2 strokes make it in the upper RPM ranges
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