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-   -   Kawasaki Vulcan 2000 (http://www.motorcycle.com/forum/mo-reader-feedback/2295-kawasaki-vulcan-2000-a.html)

seruzawa 01-20-2004 03:13 AM

Re: Kawasaki Vulcan 2000
 
That's what's wrong with this world. People just insist on buying what they want rather than listen to certain geniuses.



Just think how much better off the world would be if everyone just did what they were told by the people who "know better".

seruzawa 01-20-2004 03:15 AM

Re: Kawasaki Vulcan 2000
 
I always strive to be irreverent.

macmanjim 01-20-2004 05:15 AM

Re: Kawasaki Vulcan 2000
 
I have seen dyno runs with car engines that disprove that theory. read a recent Hot Rod Magazine article on it. Long stroke increases piston speed which limits HP. If the thing has volumentric efficiency, it'll make the requisit torque for it's size. look at the FJ1300 and ZRX 1200

kawazuki 01-20-2004 07:07 AM

Re: Kawasaki Vulcan 2000
 
Very nice.



-Kawazuki

kawazuki 01-20-2004 07:15 AM

Re: Kawasaki Vulcan 2000
 
Well, I think the issue is that a taller bike can lean over further before it drags things, and a shorter bike can turn faster. So short people can't stand up when they are stationary, and tall people (some tall people, I'm 6'5") end up with their elbows resting on their knees when they crouch into the riding position.



Yeah, I think it is going to come down to naked bikes. Give me a lower seat height, lower pegs (I really don't need to be able to lay over at a 15 degree angle to the road surface) and higher bars. A little more rake, or a big damper, and those tasty extruded aluminum frames. (Or, y'know, anything stiffer then my old KZ-1000, but with the same--or even a little sportier--riding position.)



-Kawazuki

nweaver 01-20-2004 07:35 AM

well, the goldwing...
 
THe goldwing may have the weight, but has much more ground clearance, 150 liters of luggage capacity, seating for 2, much sharper handing, a few more unneeded horses, and reverse gear for getting the big slug back out of parking lots when you inadvertantly park nose-downhill.


kawazuki 01-20-2004 07:36 AM

Re: Kawasaki Vulcan 2000
 
Ok. You've seemingly not ever been told about the difference between horsepower and torque. Horsepower is mostly a calculated number. It is based off the relationship between torque and RPM. When you complain about the V2 not being able to crack 100 HP, you need to consider the fact that it is generating all of it's numbers at a much lower RPM than the ZX-10 is.



http://www.revsearch.com/dynamometer...orsepower.html



Essentially what this means is that if you had an engine that put out just 10 ft/lb of torque, but could do it at 100,000 RPM, it would have 190 HP at that point. But it would be almost totally useless for actually moving anything, in spite of it's giant HP number.



Obviously, this is a contrived example. But it demonstrates that it is important to consider the torque numbers, the ability of the engine to actually do work, rather than just looking at the peak HP number and making your descision.



A better example of this principle is a steam ship I once had the privilege of seeing the engine room of. It had a pair of linear piston (as opposed to turbine) engines each putting out a peak 2000 HP at 30 RPM. Now, the HP number sounds really impressive. But what the real kicker is, each of those engines, at that RPM, was making 350,000 (three hundred and fifty thousand) ft/lb of torque.



In chassis of equal weight, the vehicle with the higher torque producing engine is going to have more kick in the pants.



The reason all of those race bikes have inline 4 motors which make higher HP numbers and lower torque numbers is for reasons of balance and controllability.



-Kawazuki

kawazuki 01-20-2004 07:58 AM

Re: It might even.....
 
what, 2000 rpm redline?



Oh, not even that high I would suspect. I guess it would depend on how much the piston weighed, and what you could make the con-rods out of, and what the con-rod / stroke ratio was.



Ok, so we'll imagine a titanium conrod, with a rod / stroke ratio of about 2, so we don't put too much sideways stress on the pistons. 3 liters at 9 inches (mixed systems, yuck. ;) gives us a piston diameter of 129.3 mm, or just over 5 inches. Dear God.



Well, we should get a nice flywheel effect from the mass we're going to have to put into the crank. We may not even need an external one.



We'll get to use a nicely hemispherical combustion chamber, though, (actually, we'll have to, in order to avoid having a diesel-like compression ratio with that 9 inch stroke) so that should be good for power.



Man, that's gonna be a paintshaker. Let's rigidly mount it in the frame, and then rigidly mount the rear wheel. While we're at it, let's make it a hardnose, too, like an old bicycle. I think I'm going to just stand up when I ride it, so it doesn't batter my nuts back into my torso. It should have quite the exhaust note, though.



-Kawazuki

longride 01-20-2004 10:09 AM

Re: Kawasaki Vulcan 2000
 
Besides butchering the language, this guy thinks your a genius when he agrees with you and you are an idiot when he doesn't agree. We all know you are a full time genius.

sqidbait 01-20-2004 10:11 AM

Re: Kawasaki Vulcan 2000
 
{sound of bait being chomped }





Essentially what this means is that if you had an engine that put out just 10 ft/lb of torque, but could do it at 100,000 RPM, it would have 190 HP at that point. But it would be almost totally useless for actually moving anything, in spite of it's giant HP number.





If the frictional losses in the gearing are too high, then you might have a point. It won't be useless, but it'll be somewhat inefficient.



However, horsepower is the ability to do work. High horsepower means more torque to the road for a given speed. Put that 190HP engine in a bike, gear it right, and you'd have pretty impressive performance. ( Ignoring packaging and weight issues. )





Obviously, this is a contrived example. But it demonstrates that it is important to consider the torque numbers, the ability of the engine to actually do work, rather than just looking at the peak HP number and making your descision.





I agree that peak horsepower isn't the most useful metric in the world.



However, if you want to look at the torque numbers, then you had better factor the gearing into the equation. Engine torque != torque delivered to the rear wheel.



Also...



*Power* is the ability to do work, by definition. Torque is a force.



work = force * distance



power = work / time



power = force * distance / time



in the motorcycle world:



hp = torque * ( revolutions / minute ) * constant





In chassis of equal weight, the vehicle with the higher torque producing engine is going to have more kick in the pants.





If by "higher torque producing" you mean "higher horsepower", then probably...





The reason all of those race bikes have inline 4 motors which make higher HP numbers and lower torque numbers is for reasons of balance and controllability.





No, it's because *high horsepower* means *high power*.



-- Michael











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