| Author |
Message |
    
Jkkj
| | Posted on Tuesday, June 19, 2007 - 11:32 am: | 
|
Should I not be able to stay up on my XB? Am I rinding over the bikes ability?
I ride with Several CBR 1000RRs, a CBR 600RR, a R1, a GSXR 750, a couple Z1000s, an Aprilia, a ZX 10, a supermoto, a Ducati, a SV650, a SV 1000, and I'm sure I am missing some.
I was right behind the Aprilia earlier this year when he high sided. A couple of corners in front of him at the same time a CBR 1000RR low sided. Most recently I was right behind a Z1000 when he low sided.
Now that I've figured it out I really like my Buell. It was rocky at first, but now I haven't found anything that I cann't push out of a curve. I tend to be able to stay right up with the track day crowd without scaring myself unless they run away from me on a long straight. Actually I think I may try a track day on my Buell(on the chip down the long straight I am sure).
Niether one is wrong they are just different!
I enjoy my Buell tremendously, and that is what it is all about. |
Trojan
| | Posted on Tuesday, June 19, 2007 - 11:48 am: |
|
The new R6 allegedly works better on the track than it does on the road. And now the euphoria has died down, the 1098 is getting similar comments.
Ducati seem to have made a fundamental blunder with the 1098 as far as track performance is concerned. The design of the swingarm limits the size of rear sprocket that can be fitted, and this has caused a massive disadvantage at certain tracks this year such as Brands Hatch. The bike is fine at the longer/faster circuits but hopeless elsewhere. Because of the Superstock rules they can't just introduce a 'kit' swingarm either, so will have to redesign the bike  |
Spatten1
| | Posted on Tuesday, June 19, 2007 - 11:51 am: |
|
You should do a track day with your Buell. It will surprise you what you can do.
I thought I used to go fast on the street, but a track day fixed that notion.
Now I go slower on the street, as you can't really do as much as you can on a wider track with runoff and no cars, dogs, gravel, etc. Street speeds are fun, but you just aren't pushing it like on the track, it is not really possible. |
Buellshyter
| | Posted on Tuesday, June 19, 2007 - 12:17 pm: |
|
Read the subject of the thread!
I read the subject of the thread and that was my response !! |
Ridrx
| | Posted on Tuesday, June 19, 2007 - 12:17 pm: |
|
Spatten1,
Repli-racers are clinical track 'tools'.
They work pretty damn good on the street too. Ride one, you'll find out.
I didn't mean to imply the replicas aren't fun/useful on the street. More that the comparison is moot.
I've owned and ridden many different makes models, most of which do one thing well. There are a few exceptions. IMHO, the Buell is one of those exceptions.
The japanese have researched, learned, upgraded, updated and modified their formula(I4+RPM+High Speed stability=race wins) over the last 10-15yrs to the Nth degree. It's a proven formula that nets results...that's what it exists for, if there were no racing there would be no repli-racer.
On the other hand the Buell was brought to life to give us an alternative to the track bike on the street. Good low end grunt(how many stoplights are on a race track?), ease of manueverability(it's ok to call it 'twitchy' if you want), and some of the coolest features you'll find...on the street.
I've nothing against the I4 machines, they are great at what they do. My dollar is better spent on the Buell, I don't do track days, mostly commuting and the occasional romp through the hills...on broken, gravel laden asphalt with pot holes and speed bumps and deer crossing...no way I'm gonna use 160-180hp in these conditions. Horses for courses right? |
Spatten1
| | Posted on Tuesday, June 19, 2007 - 12:20 pm: |
|
RidrX: Agreed 100% |
Arcticktm
| | Posted on Tuesday, June 19, 2007 - 01:26 pm: |
|
Thepup: Equal torque at very different RPM's is not the same (if that makes any sense to read). If you have to rev higher to get the same torque as another motor has at low RPM, you will be at a higher horsepower (since power is a function of torque X engine speed).
That's fine if you can keep your bike at the higher revs at all times, and use the higher horsepower (big open road or track). That's not so fine if you are rapidly running out of room and have to slow down for tight stuff. Sure, you can drop to lower gears to keep the revs up vs road speed, but now you have a LOT of engine wound up and ready to spit you off if you make the wrong twitch with your right hand. Sure, it can be handled, but most of us aren't named Mladin, Spies, etc.
It is the same principle that gives Ducati big twins more user-friendly low end vs I-4 engines with more power.
Buell is just a bit further to the extreme. I have had Suzuki I-4, Ducati 2-valve, and now the Buell XB12X, and they all have their merits.
I happen to be a torque person, and that means LOW END torque, so I can be lazy on the shifting.
I also like not needing a chiropractor after and all day ride, but that is a different thread. |
Reepicheep
| | Posted on Tuesday, June 19, 2007 - 02:18 pm: |
|
Acceleration is a function of horsepower to the rear wheel, period.
If you get there by higher torque with fewer revolutions or lower torque and higher revolutions, it doesn't matter. Acceleration is still simply a function of horsepower to the rear wheel. |
Spatten1
| | Posted on Tuesday, June 19, 2007 - 02:45 pm: |
|
Reep:
You are wrong. I feel torque. Math is stupid. |
Arcticktm
| | Posted on Tuesday, June 19, 2007 - 02:49 pm: |
|
Sorry, but I think you missed my point. I was not talking about acceleration. I was talking about torque (work), and having it available at lower RPM's when you come out of tight corners. Yes, if you keep your RPM's pegged you will have more torque on a high revving motor, but most people don't (or can't) do this on the street. Until you get to the higher revs, you do not have the torque.
Acceleration is a function of more than just power to the rear wheel (Force). It also is an inverse function of the mass you are trying to accelerate. Acceleration=Force/Mass. |
Spatten1
| | Posted on Tuesday, June 19, 2007 - 03:11 pm: |
|
Yes, but torque is a measure of force. Horsepower is a measure of work.
By the way, that comment was not aimed at you, it goes back months to other threads. Sorry for the attempt at inside humor. |
Arcticktm
| | Posted on Tuesday, June 19, 2007 - 03:41 pm: |
|
Spatten1:
No worries. Thin skins don't belong on forums anyway.
Hate to disagree again, but:
Torque=work=energy=N-m or ft-lbf (Force is only N or lbf).
Power=work delivered over time=N-m/sec=Watts.
Power is how fast you can deliver work (torque).
Either that, or all those engineering books are wrong. In which case my entire life has been a lie! Hmmmmm.
I only used metric units because they are more logical trying to clarify power vs work. That, and it really annoys some people...
OK - no more stupid math for today. |
Spatten1
| | Posted on Tuesday, June 19, 2007 - 03:50 pm: |
|
I'm not engineer.
Question:
When foot pounds are used as a measure of torque, or moment, is that a measure of work or just force and vector? |
Reepicheep
| | Posted on Tuesday, June 19, 2007 - 05:22 pm: |
|
Heres a simple illustration I used in the last thread, my apologies for hijacking again.
Drill a 4 inch hole in a tree. Stick a 2x4 into it so that it sticks 10 feet out horizontally, parallel to the ground, one end in the tree and the other end floating.
Now hang a 10 pound bag of flour on the floating end of it.
What is the torque on the 2x4?
What is the horsepower being generated by the 2x4?
Torque without Horsepower is like Voltage without Current... it means next to nothing in terms of work.
(Message edited by reepicheep on June 19, 2007) |
Arcticktm
| | Posted on Tuesday, June 19, 2007 - 05:43 pm: |
|
Torque is a measure of work. 1 lb-ft of work is done when a 1 lb force acts through the distance of 1 foot. It is defined as the product of the displacement and the component of the force acting in the direction of the displacement (force vector).
Of course, if you are a sack of flour riding a 2x4, it is all irrelevant (could not resist)!
The 2x4 story is an instantaneous event. When you let go of the flour, it deflected the board (using the lb-force of gravity acting on the flours mass). The length of the board became your moment arm, so the flour created a force vector on the end of the board.
If you measured the displacement of the end of the board when you let the flour go, and multiplied it by the force vector it created, you would have the work.
I suppose if you considered the time it took for this deflection to happen, you could figure the power, but I just made that up and didn't think it through, since I am late to get somewhere.
How did this all get started??? |
Ridrx
| | Posted on Tuesday, June 19, 2007 - 06:15 pm: |
|
...again? How do so many threads end up here?
HP is nothing more than the result of TQxRPM, hence ALL 4 stroke IC engines make the same torque and horsepower at 5252RPM.
The whole purpose of building any engine in the first place is to produce torque( a force) for the purpose of doing work(not a force, think of it as a quantity). The use of gearing, clutches and torque converters(ever heard of a hp converter?) is what permits the engine to cycle(rpm) for repetitive/continuous application of the force...TORQUE, thereby allowing the work to be done OVER and OVER again(all those over and over agains are measured in hp).
Torque has nothing to do with time...if you could stop a running engine by grabbing the crankshaft you would feel the force of torque not hp(engine not spinning=0 rpm=0 hp since tqxrpm=hp)straining against your grip.
All other things being equal(weight,gearing and rpm), the engine that makes the most torque wins...it provides more force.
...all MOOT since the japanese replicas make more of both in the end. |
Reepicheep
| | Posted on Tuesday, June 19, 2007 - 07:07 pm: |
|
Arktic... if your description of torque was correct, the units would be feet squared pounds, not foot pounds. You actually described work, not torque. |
Sshbsn
| | Posted on Tuesday, June 19, 2007 - 10:03 pm: |
|
Was it here that I read the best all-time explanation of torque and horsepower?? Someone said,
"Horsepower is how fast you hit the brick wall. Torque is how deep you end up in it."
Or something very similar anyway... |
Blake
| | Posted on Wednesday, June 20, 2007 - 12:08 am: |
|
Torque is not a measure of work, but it does share the same units. You can apply a BUNCH of torque to a bolt, but not do any work on it. If it doesn't turn, no work has been performed, in engineer-speak anyway.
Work in the form we are discussing is equal to the application of a force that moves through a distance. Multiply the average force applied times the distance through with it was applied and you have the work.
That is entirely different than the application of a force at a distance, like when pushing on a torque wrench after the nut ceases turning. The torque is still there, you can hold it there all day or for eternity, but unless the handle of that wrench is moving, you aren't performing any work.
What is kinda confusing is that to find the amount of work done by a torque that has rotated through an angular displacement, we multiply the torque times the number of radians, which are like degrees except there are only 2p (approximately 6.18) radians per revolution compared to 360 degrees per revolution.
But we don't express the radians in the units of the answer, on account of they are magically canceled out. ![: ]](http://www.badweatherbikers.com/buell/clipart/proud.gif) Not really magically. They fall out since the circumference that a radius of one foot traces in a circle is... yep, that same 2p.
Meaning that if you have a one foot long torque wrench and apply one LB of force to it while it rotates through one entire revolution (2p radians), that one LB of force has been applied through a distance equal to the circumference of a circle having a radius of 1 FT. The circumference of a circle is equal to 2pr, with "r" being the radius of the circle. And some say there is no God. 
So in turning that 1 FT long wrench while applying one pound through one revolution, you've done...
Work = Force * Distance
Work = 1 LB * Circumference
Work = 1 LB * (2pr
Work = 1 LB * (2p * 1 FT)
Work = 1 LB * 2p FT
Work = 2p FT*LB of work
Now solve that same problem using the form of a torque times an angular displacement instead of force times distance. You have the same numbers, different form, no need to know the length of the wrench, and no need to calculate distance via circumference. Just multiply the torque times the angular displacement in radians and you get the same correct answer.
Radians are convenient like that; it's pretty much why we use 'em in engineering to deal with angular displacements in rotating systems.
Anyway, as Bill so adeptly illustrated, torque is not equal to work or energy, but it does share the same units, which is confusing. |
Firebolt020283
| | Posted on Wednesday, June 20, 2007 - 08:57 am: |
|
Horsepower
"Many years ago, when internal combustion engines were invented,
no one knew how to express the amount of work they could do. At
that time, horses provided most of the transportation and power. As
a result, inventors of the first engines developed the idea of horsepower.
They determined that an average-sized horse could produce
approximately 550 ft-lb/s of work. This fact was used to develop the
standard unit of horsepower (hp). One horsepower is therefore equal to
550 ft-lb/s of work.
1 hp = 550 ft-lb/s
Even though horses are seldom used to perform work nowadays, we
still use the standard unit of horsepower to describe the power output
of motorcycle engines. So, the next time you’re looking at a motorcycle
in a showroom and the salesperson tells you it has 80 hp, you can just
imagine that motorcycle being pulled by 80 horses. That’s pretty
impressive!
Today, we rate almost all engines by their horsepower output. Stronger
engines produce more horsepower. Now that you understand how to
calculate horsepower, let’s look at how we measure it.
There are several different ways to measure horsepower. The most
common is to measure the horsepower output of an engine as it runs
on a device called a dynamometer (dyno).
During a typical dyno test, the technician places the motorcycle on
the dyno and runs it at full throttle. The dyno places a load (resistance)
on either the output shaft or rear wheel. Usually, the load is either hydraulic
or electronic. As the load increases, its force tries to prevent
the engine from turning. Therefore, the engine speed decreases as the
load increases. Since the load applied is a known value, the dyno can
determine the amount of torque produced by the engine. If we know
the torque produced, we can calculate the horsepower of the engineBecause this type of test involves the slowing or braking of the engine,
the type of horsepower measured this way is commonly referred to
as the brake horsepower (bhp). The brake horsepower rating is the maximum
power output of the engine. You’ll usually see the specifications
for an engine given in bhp.
In practical use, a motorcycle or ATV engine is normally operated at
a level well below its maximum power output. If the engine was always
run at maximum horsepower, it would have a very short life
span. You can compare an engine that’s running at its maximum
rated power to a person running at top speed. That person wouldn’t
be able to keep up the pace for long, and neither would an engine
running at its maximum horsepower."
torque
"The other method we use to rate an engine is by the maximum
amount of torque it produces. Torque is a measurement of twisting or
rotational force. Remember that an engine’s output is in the form of
rotational motion. The power output from the crankshaft is used to
turn the rear wheel of the motorcycle. You can compare the torque
produced by an engine to the twisting force a person exerts when
opening a jar lid. Engine torque is usually measured in foot-pounds
(ft-lbs) and can be measured by a dynamometer.
As you’ve probably figured out by now, the ideal engine would have
high horsepower and lots of torque. Unfortunately, we don’t see this
combination too often in real life. In a typical motorcycle or ATV engine,
the horsepower and torque that are developed will vary with
the speed of the engine (Figure 4). This speed is measured in revolutions
per minute (rpm). The rpm is a measure of how many complete
turns (360°) the crankshaft makes in one minute.
In a typical engine, horsepower generally increases as the rpm increases.
Remember that power is related to the rate (speed) that work
can be done. Therefore, the maximum horsepower develops near the
maximum rpm limit of the engine. Torque, on the other hand, is produced
somewhat differently. The maximum torque is normally produced
at a lower rpm range and then declines as the rpms increase.
This means that the maximum torque and the maximum rpm don’t
usually occur at the same time. So, when manufacturers design motorcycles
and ATV engines, they compromise. The design usually depends
on the particular application."
this is taken from my text book for motorcycle repair technicain. it is written by Edward Abdo who is the Curriculum Development
Manager for the Motorcycle Mechanics Institute in Phoenix, Arizona |
Rubberdown
| | Posted on Wednesday, June 20, 2007 - 09:11 am: |
|
 |
Spike
| | Posted on Wednesday, June 20, 2007 - 10:07 am: |
|
quote:...all MOOT since the japanese replicas make more of both in the end.
Except for the 600s and 750s that is, all of which make significantly less torque yet still accelerate faster. Even the liter bikes don't really make more torque than an XB12, they're actually very similar in peak numbers, yet the liter bikes accelerate _way_ faster.
Looking at the numbers, one might get the crazed idea that something other than torque determines how fast a vehicle will accelerate.
 |
Spatten1
| | Posted on Wednesday, June 20, 2007 - 10:22 am: |
|
Thanks Blake, great write up.
Firebolt, I like the last section about compromise. |
Tintin74
| | Posted on Wednesday, June 20, 2007 - 04:07 pm: |
|
Firebolt020283 > That textbook sound pretty lame to me:
First there is no mention that horse power is mathematically related (H.P. = Torque x constant) to torque and thus the curves will ALWAYS intersect at the same rpm for a given unit system (metric or whatever).
This incidentaly is how the dyno ALWAYS charts both of them at the same time.
Second there is no explanation of the torque itself, or rather of how to use it. One very important thing to understand is how the same amount of torque can be represented in 2 different ways. We could build scales with a one foot arm holding 2 pounds on one side and a 2 feet arm holding 1 pound on the other side (not exactly accurate either because of the higher weight of the longer arm). In this configuration the scales would be balanced. That's why stunts bike use a much bigger rear sprocket than street bikes. The same torque will not bring the same acceleration nor will the H.P. bring the same top speed depending on the gear ratio in use. |
Kedo
| | Posted on Wednesday, June 20, 2007 - 05:43 pm: |
|
2%'ers!!! |
Blake
| | Posted on Thursday, June 21, 2007 - 03:50 am: |
|
Tintin,
Correction, on account of I'm picky about such things...
H.P. = Torque x RPM x constant |
Firebolt020283
| | Posted on Thursday, June 21, 2007 - 06:03 am: |
|
well tintin if you feel that way you might want to bring it up with the guy that wrote the book you are more than welcome too. Just note this he has alot more experiance with motor cycles than most of us, seeing as how he has worked for most of the major motorcycle brands and seems to know what he is talking about. Also note i did not put the whole book on there just what i thought apllied to this board seeing as how i just read that the other day and thought i would share it with every one. |
Firebolt020283
| | Posted on Thursday, June 21, 2007 - 06:08 am: |
|
oh and i was missing a section on the torque portion here it is:
More torque usually means better acceleration and more towing capacity.
Higher horsepower usually means a higher top speed. The amount
of horsepower and torque an engine develops depends on many design
factors. The displacement, compression ratio, fuel mixture, engine
design, ignition timing, and valve timing (on four-stroke engines) all
affect horsepower and torque. |
Jsg4dfan
| | Posted on Saturday, June 23, 2007 - 08:14 pm: |
|
It's always interesting to me to see this debate pop up. It usually creates a big dust-up, and lots of confusion and finger-pointing. Especially if someone uses a term incorrectly (per those terms studied in a physics classroom). It often gets started with something like "what's the difference between torque and horsepower?". Unfortunately, it's one of those things in life that is both simple and yet can be fiendishly complicated. Horsepower is nothing more than a mathematical formula involving two things -- torque, and time. That's it. That's all there is to it. HP = torque multiplied by RPM, divided by 5252. You cannot have horsepower without torque. Unassailable fact. You cannot have horsepower without time (rpm). Another fact. Loosely translated, torque is 'oomph', horsepower is 'how fast can you oomph?'. You can apply all the torque you have by pushing on the side of a building, but you're not producing any HP at all until that building starts moving. But, all else being generally equal, more HP = faster acceleration. This is where all the debate comes from. It's what we do with those numbers when we apply them to real-world situations that gets folks confused. Take the formula and play with it -- for example, 350 ft pounds of torque @ 6,000 rpm will give you right at 400 horsepower. Put an engine with those numbers in a 2,000 pound car, and you'll have something that will accelerate hard enough to be pretty fun. Put that engine in a fully loaded semi, and you're probably going to have trouble getting it to even move, much less accelerate well (I know, I know, gearing. Bear with me, I'm shooting for a broader point). But, that monster diesel engine that hauls it across the country makes about 400 horsepower as well. It just does it by making around 1050 ft pounds of torque at just under 2,000 rpm. Theorists will argue that 400hp is 400hp, and that either engine will work just as well in the semi if you gear it accordingly. I suppose so, if you don't mind a 35-speed transmission and rebuilding your engine twice a week, but I digress...
We like our hairy-chested thumping V-twins here, so we brag on our man-size torque numbers. That stomping low-end is big fun. So, let's say that 87.5 ft pounds comes up at 6,000 rpm, giving us 'bout 100 hp. It's no secret here that those are some fun numbers. But, let's just say that we could keep that same torque value, but raise the rpm to 10,000. Plug that number into the formula. Suddenly, we have 166.6hp. Would you like that? Some of you are saying "h&ll yes, I'd like that!", but some of you are saying "not if I have to give up my stomping low-end!". That's another area where the numbers don't tell the whole story. The formula for horsepower only tells you the amount of power made at one rpm value. That is important. Peak hp/peak torque numbers only give you part of the story. The reason why some of you may have been in a situation where you whacked the throttle at the same time as the Gixxer next to you and pulled away for a second or two is because your XB12 does make more HP than that Gixxer at low rpm(because of all that torque), but at some point, his lower torque keeps steaming up into a lot more rpm, and off he goes into the distance.
Long story short, it's all about torque, but the question is "torque @ what rpm?". |
Mesa_cityx
| | Posted on Saturday, June 23, 2007 - 08:26 pm: |
|
I explained this to a non-motor head once like this,
Horsepower is just the number of horses,
Torque is the size of the horse... |
Ustorque
| | Posted on Sunday, June 24, 2007 - 09:31 am: |
|
so when i posted this original thread it should have gone like this:
THIS IS AN OPINION, THIS IS ONLY AN OPINION FEEL FREE TO HAVE YOUR OWN:
i love my buell, i'm really glad i bought one.......ah much simpler
can't we all just get along...safe riding guys, have a good one |
|
