horse[ower vs weight?????

[oldbiker]

It has always bothered me that , lets say Nissan can build a 4000 pound , 4 cyl., 165 HP car and get 30mpg. Yet a 750 pound, 2 cyl. , 50Hp motorcycle only gets 40mpg. Based on HP to weight we should be getting about 70mpg. Somethings wrong here!!!

[beezer]

you ain't whislin Dixie

[dogdoc]

you said it old timer,,,:-)

[blowndodge]

Ya think? Kind of stumps me too. It's a question I'd like to ask the Kawasaki engineers. I think if the Nomad could get 60 mpg it would be "The Bike". I don't see why it doesn't get that kind of mileage. A monster GW gets better mileage for crying out loud!!!!

[beezer]

I don't think a big V Twin is an efficient engine nor was it ever intended to be.

[Yellow Jacket]

Yeah, I agree with beezer. My total cummulative milage with my Nomad is 39+ over 7000 miles. My daughter's Honda Civic gets 39 just going to school and work. Moslty urban driving.

[finky]

Who cares how far you can go on a gallon of fuel did you buy it for the consumption or the look and ride,I know why I bought mine and fuel usage never entered into it,it goes well sounds good and is a dream to ride no more to say.

[Top Cat]

GEEEZZZ Finky, chill out. If you could get 70 mpg and have all the features you mentioned wouldn't you take it?
All everyone is saying is if it was engineered right we should be getting a lot more per gallon.

[finky]

Sorry Topcat not getting up any one just stating the fuel useage never entered into the factor when I bought mine I had been interested in one for a few years and when the classic was due for renewal just bought it,and have never looked back I never worry or compare my fuel consumption when I travel as long as I can make the next gas station I am happy.I am the same with my cars the v8 I have eats the fuel but what the hell I love it so I don't care how much it uses.

[blowndodge]

Hey beezer and bob, explain your opinion on why a V-Twin is not an efficient engine as it relates to fuel economy (I'll ask about how that relates to horsepower later) and give me your take as to why you believe it so. I'm interested in your ideas.

Finky, I don't think anyone really buys a big bike thinking about fuel economy up front. I didn't. It's when the price of fuel is going skyward gets one to think retrospectively about it. If gas goes past 5 and 6 bucks a gallon, the 250, 70mpg enduro, is going to get a lot more use. The Nomad will get moved back to trips and excursions, not daily commute to work.

[finky]

I agree BD but over here our travel distance and trafic is not a major issue I live 5.5 mile from work and on a bad day takes me 10minutes to get there no trafic to worry about etc,I use my
Ford Ute(light truck) to get to work and it is a worked 351 fuel injected Cleavland.
It's quite heavy on fuel but evan on a bad week with a heap of extra travel as well it costs me $60.00 AUS to top it up.

[audiogooroo]

I sure didn't buy my Nad for the fuel mileage, but it would be nice if it did better.
My solution to more miles between gas stops was to install a 3.5 gallon aux tank in the trunk.
It's out of site and now I can go 250 miles between stops.

[Top Cat]

Wow, I like that idea audiogooroo.
The only thing that scares me is if you get rearended at a stoplight you could explode http://s2.images.proboards.com/shocked.gif
Keep it in gear with the clutch in and watch traffic approching from behind. Stay back from the car in front of you and aim to a safe escape route.
OK , I'll get off the soapbox now.

[blowndodge]

I like the boom better!

Personally I like to stop more than just once during a 500 mile day on a bike http://s2.images.proboards.com/shocked.gif butt whatever makes you happy GO FOR IT!

[beezer]

I'can't explain it BD

[rlfaubion]

Way to go guys! I hope my wife doesn't see this thread. I convinced her we could pay for the Nomad with the fuel savings. Let's change the subject please. I'm getting 57 to 59 MPG OK?

[socwkbiker]

Personally I like to stop more than just once during a 500 mile day on a bike http://s2.images.proboards.com/shocked.gif butt whatever makes you happy GO FOR IT!

Have to agree with you on that WM! But I see oldbiker's point!

We should be getting much better mileage based on the power to weight ratio. I think it might have something to do with the efficiency of the cylindars, but I'm not sure. If you look at the HP/cyl of that Nissan, it's 41 hp/cyl and the hp/cyl of the Nomad is 25. Could that mean the bike engine has to work harder? I don't really know.

[blowndodge]

Way to go guys! I hope my wife doesn't see this thread. I convinced her we could pay for the Nomad with the fuel savings. Let's change the subject please. I'm getting 57 to 59 MPG OK?

<marquee>gotta love those hybrid Nomads ron!</marquee>

[blowndodge]

[quote:xxkvclj5]Personally I like to stop more than just once during a 500 mile day on a bike http://s2.images.proboards.com/shocked.gif butt whatever makes you happy GO FOR IT!

Have to agree with you on that WM! But I see oldbiker's point!

We should be getting much better mileage based on the power to weight ratio. I think it might have something to do with the efficiency of the cylindars, but I'm not sure. If you look at the HP/cyl of that Nissan, it's 41 hp/cyl and the hp/cyl of the Nomad is 25. Could that mean the bike engine has to work harder? I don't really know.[/quote:xxkvclj5]


<marquee>At least you admit you don't know!!!!!</marquee>

[Yellow Jacket]

BD, I can't explain it either. I don't have any scientific data. It just seems strange that a 2751 pound Civic with a 1799cc engine can get close to 40 mpg while my 772 (dry) pound Nomad with a 1552cc engine gets the same. Maybe it's the aerodynamics. I don't know what the drag is on the Nomad but from just looking it looks like the frontal area would be less than that of the Civic. But like Finky, I didn't get the Nomad for the gas mileage.

[dank]

This has been a puzzle to me too. Part of it has to rest in the engine configuration. The Honda is 4 cylinders. I don't understand why that makes such a difference, but I know my 997 cc Concours with 4 cylinders could way out accelerate the Nomad, had a higher top speed, and got 48-50 mpg consistently. The only place it came up short was low end torque, which just meant using a bit more throttle out of stops and not short shifting. Somehow the higher gas use(less efficient overall gas use?) is part of the price paid for having the low end grunt.

[Top Cat]

Way to go guys! I hope my wife doesn't see this thread. I convinced her we could pay for the Nomad with the fuel savings. Let's change the subject please. I'm getting 57 to 59 MPG OK?

What the he11 are you burning in that thing to get an average of 58 mpg???????? http://s2.images.proboards.com/shocked.gif
Everyone on this site states they get 38 to 42 tops.
Just curious ???

OK, I just reread the quote. You are sayiny you get 57 to 59 in case your wife reads this thread , correct? Sorry if I got you in trouble. http://s2.images.proboards.com/lipsrsealed.gif

[dank]

[quote:6d0g68zr]Way to go guys! I hope my wife doesn't see this thread. I convinced her we could pay for the Nomad with the fuel savings. Let's change the subject please. I'm getting 57 to 59 MPG OK?

What the he11 are you burning in that thing to get an average of 58 mpg???????? http://s2.images.proboards.com/shocked.gif
Everyone on this site states they get 38 to 42 tops.
Just curious ???[/quote:6d0g68zr]

I believe he was winking at us when he said that.

[bobzinger]

I wonder is you had a bigger air box and more revs...I bet that would give more HP like the sport bikes.

http://i170.photobucket.com/albums/u272/DrNickDC/z76407971.jpg

[blowndodge]

I can't believe anyone believed his 58mpg! thats too funny!! ZZZZZZZZZZZZ

I can't believe anyone believed his 58mpg! thats too funny!! ZZZZZZZZZZZZ


Just cause you're so d*mn smart...... who the heck are you anyways???????


<marquee></marquee>

[oldbiker]

I contacted Cruiser magazine. I'll let you know what they have to say.

[blowndodge]

Before the naysayers challange oldtimer let me point out something.

He asked a legitimate question about mileage vs. horsepower. Nothing amuses me more than a "non-answer" ie; "if you wanted a fast bike you should have bought a ZX1400" or "what difference does it make?" It makes a difference to him. If you feel thats how to answer a question with a statement, you need to let the service department handle all of your maintenance.

The "V-Twins are not designed for efficiency" I knew was wrong and was just a guess. Twins come in many configurations parallel twins, V-Twins from 90, 70,50, and 45 degrees. There is one more twin I can think of and it's 180 degrees. BMW's new 1200 CC flat twin.

BMW can take a 1200cc motor with 4 valves and flat twin, the power pulses trying to pull the crank apart due to the configuration of the engine and can pull 100 honest horsepower and 50 plus MPG. The R1200RT is a long distance mount. So is the Nomad. The Beemer "hauls the mail" too. Kind of nice to have a little of everything, mileage, smoothness and some cheese in the engine room. the Nomad is not a typical "cruiser" it's not a chopper designed for short trips! It's outfitted for long distance travel and it has 2 cylinders and a big CC advantage over the BMW. Easily enough displacement to overcome the weight disadvantage to the BMW.

One wonders, at least I do, how Kawasaki designed a motorcycle engine that is the only engine I know that CC for CC is outperformed by the auto industry. 1553cc's I believe and 60 HP.

There is not a 1.5 or 1.6 liter engine out there in a car that doesn't tromp this and it is a mystery to me. I'd like to understand why and I think oldtimer does too

[Top Cat]

I can't believe anyone believed his 58mpg! thats too funny!! ZZZZZZZZZZZZ

Did anyone say they believed it ???

[blowndodge]

Not my fearless buddy topcat!!!! i saw you caught it! still was funny for a moment!

[nsmorgan]

I get 70 mpg on my Nomad going to work and back. It's all downhill from my house, so I just get on and coast the 8 miles to work, never have to start it up until it's time to come home. http://s2.images.proboards.com/grin.gif

I get 70 mpg on my Nomad going to work and back. It's all downhill from my house, so I just get on and coast the 8 miles to work, never have to start it up until it's time to come home. http://s2.images.proboards.com/grin.gif


<marquee>http://i170.photobucket.com/albums/u272/DrNickDC/meathead.jpg</marquee>


LOLOL

[rlfaubion]

[quote:yzdu57vh]Way to go guys! I hope my wife doesn't see this thread. I convinced her we could pay for the Nomad with the fuel savings. Let's change the subject please. I'm getting 57 to 59 MPG OK?

<marquee>gotta love those hybrid Nomads ron!</marquee>[/quote:yzdu57vh]

http://i148.photobucket.com/albums/s31/rlfaubion/GasPricesRising-1.jpg

Hybrid

[nsmorgan]

Back to the original question, I think I can explain it in broad terms. Basically, horsepower and efficiency are the product of many more factors than just cubic displacement. Air flow efficiency is a major factor. Increasing the airflow to a higher rate than the 50-degree V-twin can greatly increase the efficiency with which the fuel is burned. With four cylinders instead of two, (comparing to the Honda Civic, for instance) there is more airflow per cylinder resulting in a bigger energy recovery with each combustion event.

The compromises that have been made for the sake of styling include both length and angle of the pistons as well as weight distribution to give the Nomad its excellent handling on two wheels. Keeping the center of gravity low means keeping the pistons the length and angle of the present design. If you go the other direction, maximizing horsepower with the V-twin, it looks something like this:

http://thekneeslider.com/archives/2006/07/18/wakan-1640-new-french-v-twin-motorcycle/

It's a very cool-looking bike for a mere $35,000, but it's no Nomad.

Another way, of course, is changing the angle. I've never seen the BMW 180 degree BD talks about, but it's a very interesting concept. I can see how it could squeeze more horsepower out of a similar number of ccs by lengthening the pistons and laying them along the length of the frame, but I would guess it would create all kinds of engineering and maintenance challenges, not to mention the styling. The geometry, however, could really lower the center of gravity.

The math, of course, is much more complex than this simple summary, but I think the airflow in the cylinders is the basic issue with old-style classic-looking V-twins.

My 2 cents.

[socwkbiker]

Back to the original question, I think I can explain it in broad terms. Basically, horsepower and efficiency are the product of many more factors than just cubic displacement. Air flow efficiency is a major factor. Increasing the airflow to a higher rate than the 50-degree V-twin can greatly increase the efficiency with which the fuel is burned. With four cylinders instead of two, (comparing to the Honda Civic, for instance) there is more airflow per cylinder resulting in a bigger energy recovery with each combustion event.

The compromises that have been made for the sake of styling include both length and angle of the pistons as well as weight distribution to give the Nomad its excellent handling on two wheels. Keeping the center of gravity low means keeping the pistons the length and angle of the present design. If you go the other direction, maximizing horsepower with the V-twin, it looks something like this:

http://thekneeslider.com/archives/2006/07/18/wakan-1640-new-french-v-twin-motorcycle/

It's a very cool-looking bike for a mere $35,000, but it's no Nomad.

Another way, of course, is changing the angle. I've never seen the BMW 180 degree BD talks about, but it's a very interesting concept. I can see how it could squeeze more horsepower out of a similar number of ccs by lengthening the pistons and laying them along the length of the frame, but I would guess it would create all kinds of engineering and maintenance challenges, not to mention the styling. The geometry, however, could really lower the center of gravity.

The math, of course, is much more complex than this simple summary, but I think the airflow in the cylinders is the basic issue with old-style classic-looking V-twins.

My 2 cents.

More like $2.50 worth of good information. Good explanation smart-brotha!

[blowndodge]

BMW flat twins have been out for probably 50 years. I'm surprised you've never seen the "boxer" engine still in use in today's modern BMW.

I'm a little confused on your logic that 4 cylinder vs. 2 given the same CC is more efficient by an increase in airflow? I've never heard of this and I'm not clear as to the reason. If that was the case, would not economy cars that have small 4 cylinder engines of say 2.0 liters be more economical if they were 2.0 liter V8's?

You haven't addressed parasitic losses (twice times) of additional moving parts that 2 more cylinders bring into the equation. Except for the Nomad, most twins in the motorcycle world beat their 4 cylinder counterparts when it comes to fuel economy given the same size engine and single's even more.

How does a 90 degree twin provide a different fuel efficiency over paralell twins, flat twins 45 degree twins, 50 degree. If I'm reading your explaination correct?

You guys are too smart for me.... gonna go crack a back. ttfn

[blowndodge]

You guys are too smart for me.... gonna go back into someone's crack. ttfn



<marquee>whatever floats your buns!!</marquee>

[nsmorgan]

BMW flat twins have been out for probably 50 years. I'm surprised you've never seen the "boxer" engine still in use in today's modern BMW.

I should have said, yeah, I've "seen" it, just haven't ever really "looked at" it. Afraid I'd spend more than I could afford buying one!

I'm a little confused on your logic that 4 cylinder vs. 2 given the same CC is more efficient by an increase in airflow? I've never heard of this and I'm not clear as to the reason. If that was the case, would not economy cars that have small 4 cylinder engines of say 2.0 liters be more economical if they were 2.0 liter V8's?

You haven't addressed parasitic losses (twice times) of additional moving parts that 2 more cylinders bring into the equation. Except for the Nomad, most twins in the motorcycle world beat their 4 cylinder counterparts when it comes to fuel economy given the same size engine and single's even more.

How does a 90 degree twin provide a different fuel efficiency over paralell twins, flat twins 45 degree twins, 50 degree. If I'm reading your explaination correct?

Let me be the first to admit I may be over my head here, I'm just thinking about it, trying to think logically anyway, because it's an interesting question. I'm no mechanic. I just like an interesting math problem, even if it's beyond my intellect.

Efficiency due to multiple factors moves along a curve with bumps in it if you graph it. Like you say, the multiple moving parts are another factor that makes it impossible just to keep increasing the number of cyclinders and keep getting more and more power in, say, a 2 liter engine. The trees won't grow all the way to the sky. There are also the issues of valve shape and number and cam shape and many more.

As far as the 90 degree twins being more efficient, I don't think it's the angle as much as the length of the pistons -- just a guess. Are the 90 degree twins longer in the piston?

Like I said, I think airflow is A Major Factor. It's certainly not the only factor in addition to ccs. Once you start increasing the angle, the length of pistons, the number of cylinders, you get into all these other variables. I'm thinking that the engineers at Kawasaki graphed it out using calculus with many many variables that is beyond my ability to understand and made some compromises that were necessary for the sake of styling and handling.

Like I say, just my 2 cents, may be in the wrong direction.

I'll have to think about why twins other than the Nomad are so much more efficient than their 4-wheel counterparts. I don't know much about them, what makes them different from the Nomad. Is it angle? Piston length? What else?

[quote:7pzzxgwb]You guys are too smart for me.... gonna go back into someone's crack. ttfn



<marquee>whatever floats your buns!!</marquee>[/quote:7pzzxgwb]

You are more twisted than I thought!!!

Please.... both of you stay in your respective rooms.

[blowndodge]

No, I said twins are more fuel efficient than their 4 cylinder counterparts, not 4 wheel counterparts. I was just wondering how you came up with that because you stated you "I think I can explain it in broad terms." I just didn't see the answer in "because of this, give example, therefore that" of your summation.

the graph you speak of would have a tangent line perpendicular to the fuel maximization point on the curve call Differentiation Calc. Starting from the Constant B in Y=MX+B an engine with more pistons is always starting at a disadvantage for any value of B. It could never equal less pistons, only approach it. A single cylinder recip engine is still and always be the most economical engine from a design point of view when it comes to fuel economy maximization.

I'll leave the length of the connecting rod and distance traveled (stroke) (angle from crankshaft centerline) as opposed to engine speed potential and torque at a later time this also plays into fuel economy to some degree.

[socwkbiker]

http://farm3.static.flickr.com/2130/1922882473_21fb78df06.jpg
Did he just say?

http://farm3.static.flickr.com/2373/1805092531_52b1da7432_o.jpg
Explain this then!

[blowndodge]

that's one bad bike harry!

[nsmorgan]

"No, I said twins are more fuel efficient than their 4 cylinder counterparts, not 4 wheel counterparts."

I see that now. I was thinking of the original question about the Nissan that gets better gas mileage than the Nomad, but the thread was titled "horsepower vs. weight," so I was thinking about HP too. (Horsepower, not Harry Potter)

What's good for HP is not ordinarily good for gas mileage (for instance when you compare a four cylinder Sentra to my V8 truck), but in the comparison of the Nomad and other V-twins, they seem to go together, is that what you're saying? Other V twins have more horse power and more fuel efficiency?

Here's a site in which these guys increase the air flow in a V-twin and claim to increase the horsepower.
http://www.hemidesign.com/pages/technical%20overview.html
(Scroll down to "A Point to Ponder")

They also compare the Harley V-twin with a Suzuki 4 and explain the difference (the Suzuki 4 has more HP) in terms of increased air flow because of the size of the valve stem and shape of the valve on the Harley. Kawasaki claims that the shape of the valves has been maximized for the efficiency of the Nomad, but I have to think that means it has been maximized for that particular design, i.e., the 50 degree V-twin. A different angle, a different configuration, all those other variables come together in comparison to a different twin or even a 4 to increase the cfm of air flow, increase the turbulence, and increase the amount of energy recovery from the amount of fuel burned in each combustion event. I can see your point that with a 4 cyl the additional moving parts and the increased friction will decrease the fuel efficiency, all other things being equal. But IF there is a 4 cylinder that carries more weight with better fuel efficiency than the V-twin, (and there is) then there are other factors that add up to more efficiency than all we lose from having 4 cylinders instead of 2. ONE of those factors, I think a major one, is the air flow which is inherently limited by the design of the 50 degree V twin. I'm sure there must be lots more variables.

The important question, I suppose, since I'm not going to trade my Nomad for a more fuel efficient bike, is this: Which factors, if any, that add to fuel efficiency in the V twin could be affected by modification?

O.K., that's all I got. I can tell you've puzzled about this more than I have. What do you think it is, BD?

[socwkbiker]

http://farm3.static.flickr.com/2292/2066306101_ed268d9f90.jpg

Come on BD, Nico's waiting for an answer!

[blowndodge]

[quote:q50ifooe]BMW flat twins have been out for probably 50 years. I'm surprised you've never seen the "boxer" engine still in use in today's modern BMW.

I should have said, yeah, I've "seen" it, just haven't ever really "looked at" it. Afraid I'd spend more than I could afford buying one!

I'm a little confused on your logic that 4 cylinder vs. 2 given the same CC is more efficient by an increase in airflow? I've never heard of this and I'm not clear as to the reason. If that was the case, would not economy cars that have small 4 cylinder engines of say 2.0 liters be more economical if they were 2.0 liter V8's?

You haven't addressed parasitic losses (twice times) of additional moving parts that 2 more cylinders bring into the equation. Except for the Nomad, most twins in the motorcycle world beat their 4 cylinder counterparts when it comes to fuel economy given the same size engine and single's even more.

How does a 90 degree twin provide a different fuel efficiency over paralell twins, flat twins 45 degree twins, 50 degree. If I'm reading your explaination correct?

Let me be the first to admit I may be over my head here, I'm just thinking about it, trying to think logically anyway, because it's an interesting question. I'm no mechanic. I just like an interesting math problem, even if it's beyond my intellect.

Efficiency due to multiple factors moves along a curve with bumps in it if you graph it. Like you say, the multiple moving parts are another factor that makes it impossible just to keep increasing the number of cyclinders and keep getting more and more power in, say, a 2 liter engine. The trees won't grow all the way to the sky. There are also the issues of valve shape and number and cam shape and many more.

As far as the 90 degree twins being more efficient, I don't think it's the angle as much as the length of the pistons -- just a guess. Are the 90 degree twins longer in the piston?

Like I said, I think airflow is A Major Factor. It's certainly not the only factor in addition to ccs. Once you start increasing the angle, the length of pistons, the number of cylinders, you get into all these other variables. I'm thinking that the engineers at Kawasaki graphed it out using calculus with many many variables that is beyond my ability to understand and made some compromises that were necessary for the sake of styling and handling.

Like I say, just my 2 cents, may be in the wrong direction.

I'll have to think about why twins other than the Nomad are so much more efficient than their 4-wheel counterparts. I don't know much about them, what makes them different from the Nomad. Is it angle? Piston length? What else?[/quote:q50ifooe]

<marquee>Read the last paragraph you'll see why I said that</marquee>

[dank]

Starting from the Constant B in Y=MX+B an engine with more pistons is always starting at a disadvantage for any value of B. It could never equal less pistons, only approach it.

This is not true. They would be equal in any case where B is zero, though I also find it hard to believe that efficiency is a linear function of piston number. But if that is true, and I bow to your expertise here BD, , then what we really need to understand is what factors define the different intercepts for the various motor configurations.

[Scoot]

http://wcse.typepad.com/wcse/images/2007/03/28/huh.jpg

HUH ??????

All this stuff is over my head

[bobzinger]

I wonder if anyone has put a turbo on one of these babies?

[dank]

Here is a web site that has good info on torque and horsepower relative to bore and stroke. The Nomad 1600 has a bore of 102 mm and stroke of 95 mm, so the ration for the table would be 1.07, which puts just so slightly on the hp side of the decision point in the article, so- not specifically designed for torque or hp, which fits it purpose.

Doesn't fully explain the efficiency question, but the relatively long stroke combined with vehicle weight and massive windshield may be a good bit of the explanation.

http://www.flamesonmytank.co.za/Articles/torque.htm

[beezer]

I think when they put the first Harley V Twin together they were surprised it worked and left it alone. They didn't care about mileage. Sure they changed the asthetics and called them different names. You know the old saying "Don't fix it if it ain't broke"

[blowndodge]

[quote:a975ybuq]Starting from the Constant B in Y=MX+B an engine with more pistons is always starting at a disadvantage for any value of B. It could never equal less pistons, only approach it.

This is not true. They would be equal in any case where B is zero, though I also find it hard to believe that efficiency is a linear function of piston number. But if that is true, and I bow to your expertise here BD, , then what we really need to understand is what factors define the different intercepts for the various motor configurations.[/quote:a975ybuq]


I never said efficiency is a linear function, it isn't. That's why you might have read the work "curve on a graph" it's an exponential function. Actually since B is constant and unchanging and since 4 cylinders have more parasitic losses and B intercepts the Y axis, below 0 on the Y axis when compared to non multis. This is because it starts at that disadvantage just like in a profit function. Like a profit function where you factor in the rent that is always there regardless if you make a product or not. Your profit function is a negative number read (loss) until you make enough widgets to cover fixed costs. That too would fall below the line. Y is a negative (loss) number right from the start.

Just pointing out that in reciprocating engines, no engineer will ever tell you that multi cylinder engines are more fuel efficient than a single. Yes they are smoother as their power pulses fire every 90 degrees of crank rotation or 180 depending on design. Three and or two cylinder car engines vibrate too much for most car applications. If our Nomad's didn't have dual counter rotating balancers they would vibrate like crazy.

http://i186.photobucket.com/albums/x260/sueds/9873497.jpg

[blowndodge]

Here is a web site that has good info on torque and horsepower relative to bore and stroke. The Nomad 1600 has a bore of 102 mm and stroke of 95 mm, so the ration for the table would be 1.07, which puts just so slightly on the hp side of the decision point in the article, so- not specifically designed for torque or hp, which fits it purpose.

Doesn't fully explain the efficiency question, but the relatively long stroke combined with vehicle weight and massive windshield may be a good bit of the explanation.

http://www.flamesonmytank.co.za/Articles/torque.htm


Actually good point on the long stroke but you pointed out something very important. Ratio of bore to stroke. As you noted the bore is larger than the stroke, which indicates an engine design leaning more towards HP than TQ. funny thing, Nomad's have 60 HP and 80 lb TQ. Just the opposite of what you would expect the engine to have considering the "oversquare" design.

To understand this phenominom, how many of you know that all engines that can turn 5252 RPM's will see EXACTLY the same HP and TQ number? In other words at 5252 RPM's Nomad's torque and horsepower numbers are indentica, ZX1400's Harley's., Honda's, Corvettes? If you undertand why that is then you can understand the difference of "oversquare" to "undersquared" engine design.

[dank]

[quote author=dank board=general thread=1196020105 post=1196205575]
To understand this phenominom, how many of you know that all engines that can turn 5252 RPM's will see EXACTLY the same HP and TQ number? In other words at 5252 RPM's Nomad's torque and horsepower numbers are indentica, ZX1400's Harley's., Honda's, Corvettes? If you undertand why that is then you can understand the difference of "oversquare" to "undersquared" engine design.


I believe it is because of the formula used to define their relationship and because torque is what is measured and HP is simply calculated using the formula:

HP= (Torque*rpm)/5252 Therefore if rpm=5252, then this reduces to HP=Torque


But I still don't see what the different configurations (V-Twin, V-4, etc.) produce such radically different curves

[blowndodge]

It all depends on what the engineers had in mind during design. Remember Harley 20 years ago came out with "Thunder heads"? Head design is a completely a non factor when it relates to motor configuration. That's why a V-Twin configure has nothing to do with how the head is designed. A 90 degree Ducati has a head designed to turn over 10K PRMs and higher. My point was that there is no evidence that a V-Twin, by design, is less fuel efficient than a 4 cylinder engine. There was talk about head designs as they relate to V-Twins and that plays no part at all and I've outlined the Ducati as an example. Different heads and longer stroke would have made it a torque motor, not a HP motor. the design of the motor configuration plays little part in what kind of power is produced. It was pointed out the by designed V-Twins are at a disadvantage to multis because it is restricted by head design. This is not ture.

A V-Twin by design has longer throws in the crank journal because the connecting rod is mounted further towards the outside of the crank throws. Looking at it another way, which tire iron can open a car door easier, a long one or a short one? The longer one generates more torque because of the length of the "lever". Long stroke engines develop more torque simply because the length of the connecting rod is longer than in a short stroke (multi cylinder) engines. Therefore the twisting force (TQ) is usually higher. Think of a slow turning cement mixer as a torque engine. Slow but tons of twisting power to turn the cement.

Now look at a dremel tool. 30K RPM's spins ultra fast but you can put a grinder bit on it and with little effort, bog down the tool and stop it completely. Multi cylinder engines are designed with more of a "dremel" tool approach and V-Twins like the cement mixer.

The Nomad makes neither big HP or TQ so some of us are just wondering.

[oldbiker]

I have written a letter to Kawasaki Engineering Dept in Irvine, Ca. Can't wait to see what they have to say. They might have a huge ammount of Exxon/Mobile stock and really don't give a damn about fuel mileage.

Got the new Rider Mag.....

2008 HD Ultra Classic... 96 cu. in. 62.4 HP; ................... 88 cu. in. had 65 HP


http://www.moto-net.com/images/nouveautes-2008/nouveautes-harley-davidson-2008/ultra-classic-electra-glide.jpg

[beezer]

New Riders of the Purple Sage? They have a new album out? Far out man

[oldvalleyguy]

If that Auxillary tank was nitrous instead of gas mileage would not be the biggest issue!

[socwkbiker]

Thanks oldvalleyguy! http://s2.images.proboards.com/grin.gif I just got a visual of audiogooroo trying to hang on after a nitrous blast! Would like he was taking off!

[bobzinger]

It seems like some bikes the hp & torque are close to the same, where a Nomads torque is higher than it's HP. Is it HP or Torque that gives you that seat of the pants rush during acceleration?

[blowndodge]

It's torque that gets you moving and HP is the acceleration.

[dogdoc]

Anemic numbers for the Nomad

[dank]

Anemic numbers for the Nomad

The Nomad isn't anemic: What I've seen is 94 ft lbs of torque at 2700 rpm and 66 hp at 4700. If you have a rope on an axle with a weight suspended from it, basically the toque defines how much weight can be lifted and HP determines how fast it can be lifted, corresponding to BD's statement above. So we get the rush of the torque that gets everything going and is the kick in the pants and enough HP for that to carry us forward to relatively high speeds. But the 66 hp also is why we hit a point at a relatively low top speed compared to FJR's etc. where the combination of our windshield and bike weight cause the rush forward to end and a lower top end speed. Not really a big loss for the great low end. I had a Concours. It screamed above 60 and started to rip up the asphalt above 80. It was scary fast. (and I did enjoy it!) But what I found was there were precious few opportunities to go flying down the road at 120 mph or run a quarter mile in 12 seconds. That's not what I'm after. Others are, and that's fine by me. WHereas the Nomad has great power delivery in the range one uses aside from being on a track. The nomad is a nice mix of being able to tractor around in 4th or 5th without changing gears or being able to work the gears and be a bit more aggressive. I think they hit it close to dead on for what this bike is intended to do.

[beezer]

+1 (that's his story and I'm stickin' to it)

[quote:aqxle7ln]Anemic numbers for the Nomad

The Nomad isn't anemic: What I've seen is 94 ft lbs of torque at 2700 rpm and 66 hp at 4700. If you have a rope on an axle with a weight suspended from it, basically the toque defines how much weight can be lifted and HP determines how fast it can be lifted, corresponding to BD's statement above. So we get the rush of the torque that gets everything going and is the kick in the pants and enough HP for that to carry us forward to relatively high speeds. But the 66 hp also is why we hit a point at a relatively low top speed compared to FJR's etc. where the combination of our windshield and bike weight cause the rush forward to end and a lower top end speed. Not really a big loss for the great low end. I had a Concours. It screamed above 60 and started to rip up the asphalt above 80. It was scary fast. (and I did enjoy it!) But what I found was there were precious few opportunities to go flying down the road at 120 mph or run a quarter mile in 12 seconds. That's not what I'm after. Others are, and that's fine by me. WHereas the Nomad has great power delivery in the range one uses aside from being on a track. The nomad is a nice mix of being able to tractor around in 4th or 5th without changing gears or being able to work the gears and be a bit more aggressive. I think they hit it close to dead on for what this bike is intended to do. [/quote:aqxle7ln]


Well put!

[Todd]

The Nomad isn't anemic: What I've seen is 94 ft lbs of torque at 2700 rpm and 66 hp at 4700. If you have a rope on an axle with a weight suspended from it, basically the toque defines how much weight can be lifted and HP determines how fast it can be lifted, corresponding to BD's statement above. So we get the rush of the torque that gets everything going and is the kick in the pants and enough HP for that to carry us forward to relatively high speeds. But the 66 hp also is why we hit a point at a relatively low top speed compared to FJR's etc. where the combination of our windshield and bike weight cause the rush forward to end and a lower top end speed. Not really a big loss for the great low end. I had a Concours. It screamed above 60 and started to rip up the asphalt above 80. It was scary fast. (and I did enjoy it!) But what I found was there were precious few opportunities to go flying down the road at 120 mph or run a quarter mile in 12 seconds. That's not what I'm after. Others are, and that's fine by me. WHereas the Nomad has great power delivery in the range one uses aside from being on a track. The nomad is a nice mix of being able to tractor around in 4th or 5th without changing gears or being able to work the gears and be a bit more aggressive. I think they hit it close to dead on for what this bike is intended to do.

Yeah, I agree to and well put. Like I have said before...I will tinker along the way and maybe open up the intake for some cooler air and liven it up a little because I can...but this bike is great the way it comes.

I don't really have any problems with the stock seat either that many mention. It is as much, or more comfortable, than a Mustang I had on a previous bike.

My days of ripping it up at 90-100 on the twisties are probably over.....I have just a little more sense now than I did in my younger days.....either that or I know I have bills to pay http://s2.images.proboards.com/shocked.gif http://s2.images.proboards.com/shocked.gif

It seems like some bikes the hp & torque are close to the same, where a Nomads torque is higher than it's HP. Is it HP or Torque that gives you that seat of the pants rush during acceleration?

Horsepower = torque x rpm / 5252

Below 5252 rpm any engine's torque number will always be higher than its horsepower number, and above 5252 rpm any engine's horsepower number will always be higher than its torque number. At 5252 rpm the horsepower and torque numbers will be exactly the same.

http://www.vettenet.org/torquehp.html

[blowndodge]

Are you going to leave that camel toe pic on your signature forever? "Camel Toe, KawaNOW and Forever".

Are you going to leave that camel toe pic on your signature forever? "Camel Toe, KawaNOW and Forever".

I know you're upset at how much you had to pay that pretty lady to pose for that pic with you.... to dispell the obvious..... it's only $$$... relax. :-*

[Todd]

[quote:8qd40i1k]Are you going to leave that camel toe pic on your signature forever? "Camel Toe, KawaNOW and Forever".

I know you're upset at how much you had to pay that pretty lady to pose for that pic with you.... to dispell the obvious..... it's only $$$... relax. :-*[/quote:8qd40i1k]

How much did you get paid pretty lady nicolette?

http://i208.photobucket.com/albums/bb50/toddf1_2007/untitled23.jpg

That is sick and wrong! and makes nico look so petite! Ok OK I'm trying to be more open minded and not so judgemental.

[quote:e7h7jc51]

I know you're upset at how much you had to pay that pretty lady to pose for that pic with you.... to dispell the obvious..... it's only $$$... relax. :-*

How much did you get paid pretty lady nicolette?

http://i208.photobucket.com/albums/bb50/toddf1_2007/untitled23.jpg[/quote:e7h7jc51]



Not enough Toddster.... not enough!! :'(

[socwkbiker]

I agree WM. That's just wrong. http://s2.images.proboards.com/tongue.gif

[Todd]

http://s2.images.proboards.com/cool.gif http://s2.images.proboards.com/cool.gif http://s2.images.proboards.com/cool.gif Yeah, what they said...I am shocked! http://s2.images.proboards.com/lipsrsealed.gif http://s2.images.proboards.com/lipsrsealed.gif http://s2.images.proboards.com/lipsrsealed.gif

[socwkbiker]

http://s2.images.proboards.com/cool.gif http://s2.images.proboards.com/cool.gif http://s2.images.proboards.com/cool.gif Yeah, what they said...I am shocked! http://s2.images.proboards.com/lipsrsealed.gif http://s2.images.proboards.com/lipsrsealed.gif http://s2.images.proboards.com/lipsrsealed.gif

I think it would take much more than that to shock you. lol

[Todd]

OK..you caught me............ http://s2.images.proboards.com/cheesy.gif

http://www.bmwmotorcyclesdallas.com/new_vehicle_detail.asp?veh=61730&pov=696611



http://img3.nnm.ru/imagez/gallery/5/6/1/a/c/561ac677e0bd193c19d1b05ce2735a07_full.jpg

[bobzinger]

When my Nad is all worn out maybe I can afford a Triumph Rocket III tourer!

[oldbiker]

Rocket 3, huge radiator and chrome tits, reminds me of a girl I dated in Daytona.

[socwkbiker]

LMAO!

[birdginski]

I pull about 44 miles to a gal. with my 03. But most of my riding is at 55 miles an hour. I figer if your riding 70 to 80 the milage is going down

[rewindgy]

$17900 US money $21800 Cdn money - WTF? Still lots of cash for a crusier - but boss has one and " what a cruiser!!!!!"

http://v8astro.homestead.com/files/502_flames_bosshoss.jpg

[voyager]

If you look at the efficiency of large bore twin engines you will see that most are pretty close to the same MPG ( give or take). Comparing the GW and it's size and fuel economy to the Nomad is unfair because of the drastic design differences in the engines. It's been my experience that any single pin crank engine is poorly inefficient because each cylinder tends to fight the other during the power and exhaust strokes. This is what causes the vibration and why Kawi puts in the counter balance shaft ( and HD does not ) I will say this, that if Kawi added the ability to get more HP out of the Nomad, then I would expect an increase in HP because the bike would not have to work as hard during a run and this would mean less time on the throttle.

voyager

[voyager]

Sorry, I meant increase in fuel mileage not HP

I want to run a 12 second quarter mile, top end of 120 mph, and get 60 mpg on my Nomad.

Oh, I want it to run for 200,000 miles also.

I want............


<marquee>
http://www.pamelapics.info/images/Pamela_Lee_Anderson_Rock_007.jpg</marquee>

[Todd]

Dude...have you not seen the Tommy Lee video........she wouldn't even know your little member was in the same room!!

Dude...have you not seen the Tommy Lee video........she wouldn't even know your little member was in the same room!!

Sure.... you didn't complain the other night! Oh wait... that was BD...

http://www.totalmotorcycle.com/motorcyclespecshandbook/frames/Compare2motorcycles.htm