| Author |
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Ralph
| | Posted on Wednesday, April 04, 2001 - 06:38 pm: | 
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Man, there is so much flying around in here I hope I don't get hit with anything. I'll stick with one thing and one thing only. Jose, your friend with the 600 and the measly torque. Don't pay any attention to the horse power and torque. Look only at the rear wheel torque. It is a function of gearing, horsepower and rpm. All things being equel,a motor making less horsepower at a higher rpm will beat a slower turning higher horsepower bike. Don't ask me to explain, I can't. I blindly except what I am told. I'm stupid. It makes sense. I'll be back later to be yelled at. See ya.
bighairyralph |
Aaron
| | Posted on Wednesday, April 04, 2001 - 06:49 pm: |
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"All things being equel,a motor making less
horsepower at a higher rpm will beat a slower turning higher horsepower bike"
Explain.
If you swap out the word "horsepower" for "torque" in that statement, I'd buy it. But rpm is already factored into horsepower. That's what horsepower is all about, torque (work) with a time factor.
Like I said, if you have one bike making 100 ft/lbs at 5000rpm, that's exactly the same torque to the rear wheel as another one making 50 ft/lbs at 10,000rpm that's geared 2:1. Both engines make the same hp (95) and same torque to the rear wheel. Assume the same gearbox/final drive and the 2:1 in the 10K motor is occuring in the primary drive. Why do you think the 10,000rpm bike will beat the 5,000rpm bike? The input to the gearbox is seeing the exact same thing on both bikes.
AW |
Jmartz
| | Posted on Wednesday, April 04, 2001 - 07:29 pm: |
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Ralph:
My point exactly. |
Jmartz
| | Posted on Wednesday, April 04, 2001 - 07:33 pm: |
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When propagating energy a constant stream would yied the most. Engines do it sinosoidally so the faster the frequency the closer it resembles a constant. |
Rocketman
| | Posted on Wednesday, April 04, 2001 - 08:02 pm: |
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Aaron : I was informed that my motor had 20 thou shaved off the head but the squish was left untouched. Go figure.
Such choices were out of my hands at that time, and there was also the question of rear cylinder failure of which I'd had two bouts, and these failures were directly responsible for what lead to the creation of my motor. Due to a third party involvement, I kept a relatively low profile (difficult for me too) and let them get on with it. I had some choices with hardware but that's about as much as I was let in to. Much of the stuff I'd liked to have know was kept under lock and key because Just Harleys were tuning their drag bikes using similar tricks, supposedly, that I was going to be using, hence their (JH's) cloak and dagger behaviour. They didn't want the Yanks in on their secrets and perhaps they didn't trust me knowing of my participation on Badweb 
Never the less, I do believe it to be a good package and I'm convinced it works well. Is an 11.25 ET of any significance here ? Wether or not it has anymore to offer would be for you, Merlin of the Dyno, to ascertain, if only I could afford the shipping !!!!
Rocket in England |
Thunderbolt
| | Posted on Wednesday, April 04, 2001 - 08:02 pm: |
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Aaron, you are absolutely correct. HP is HP is HP. RPM doesn't matter a lick if the HP is equal.
However, I think a lot of people are a little too hung up on peak HP. Peak HP is an important number. But, it's no more important (maybe less)than HP at an rpm 20 to 30% below rpm where the peak HP number was achieved (you're at these rpms more often, I bet). In order to accelerate the bike to get the engine to its peak HP rpm, the engine must first pass through its entire HP curve. If this curve is very low until right before peak, and then jumps up to a very high number, getting to your peak HP will be a long and difficult process. I doubt anyone rides around with his bike achieving peak power output for any length of time (certainly not in normal riding with curves, etc.). Peak HP is one tiny piece in the puzzle (although a fun number to talk/brag about).
Aaron, I was hoping you could elaborate on your experience with t-storms and squish. What modifications have you made with success/failures? |
Aaron
| | Posted on Wednesday, April 04, 2001 - 08:07 pm: |
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Yeah, but Jose, that would show up as more torque and horsepower. The claim is that horsepower is more meaningful somehow when made at a higher rpm.
Alright, help me understand this theory.
Let's say bike A makes 50 ft/lbs of torque from 5000 to 10000rpm. Now we put it on the dyno and do a pull from 5000 to 10000 rpm. We don't even bother to hook up the dyno's tach pickup. Let's say the overall gearing is such that we go from 50mph to 100mph over this range.
I contend that the dyno will show a diagonal line from 47.6hp@50mph up to 95.2hp@100mph. Agreed?
Bike B makes 100ft/lbs of torque from 2500 to 5000rpm, and it's geared twice as tall. Now we put it on the dyno, sans tach pickup, and do a pull from 2500 to 5000rpm. Again, the speed will be from 50mph to 100mph.
Again, I contend that the dyno will show a diagonal line from 47.6hp@50mph up to 95.2hp@100mph.
Now, the kicker here is that the dyno has no idea how fast the engine was spinning. All it knows is that while it was sampling, the roller went from 50mph to 100mph at a nice linear rate, on both bikes. So it put out the same result.
What I'm hearing from you guys is that no, the higher rpm bike will beat the lower rpm bike. But you haven't said why.
Are you saying it'll spin up the roller faster? Well, if it does, the dyno will show more horsepower!
'splain to me why they spin up the roller at the same rate but the high rpm bike will "beat" the low rpm bike.
AW |
Axtell
| | Posted on Wednesday, April 04, 2001 - 08:30 pm: |
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BOY IS THIS FUN!
Question....If you throw a buell with stock gearing on a dynojet...the computer spits out that you made 100 hp @ 5000 rpm(5th gear)...How much torque is produced @ the rear wheel?...How much torque is produced @ the front engine sprocket?
Gotta go now and sand on my plastic car..be back later...
Court,its time to bring my 200 mph bike back now! |
Rocketman
| | Posted on Wednesday, April 04, 2001 - 09:18 pm: |
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But does it put out the same result ? Tach hooked or not, the charts will show the nice linear lines you speak of, in different positions, that's all. In the real world environment this will be significant towards forward motion which cannot be seen by the dyno, right ?
One's a torque motor as opposed to a rev motor and a rev motor should always beat the torque motor in acceleration because yet again revs will keep the momentum (stroke) thus maintaining power whilst the torque motor maintains station at only half its potential engine speed. Once either motor runs out of air, the games up. In the case of the torque motor, power will drop if anything impedes forward motion. In the rev motor, if anything impedes forward motion, the revs will help keep the power in place.
Rocket in England |
Aaron
| | Posted on Wednesday, April 04, 2001 - 09:31 pm: |
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"Tach hooked or not, the charts will show the nice linear lines you speak of, in different positions, that's all."
What's different about the positions? Both are 47.6hp @50mph to 95.2hp @100mph. I don't understand what's different.
AW |
Rocketman
| | Posted on Wednesday, April 04, 2001 - 09:53 pm: |
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WE have two bikes.
We have one graph.
One bike makes peak power at 5K
One bike makes peak power at 10K
These motors will be at opposite ends of the graph.
This is relative, even if we can't read the RPM, because the graph is telling us where each motor is producing power within the constraints of the rev range. One's a revver and the others a torquer. There is a difference.
What the dyno can't tell us is how those motors will perform in the real world but they will most definitely perform\ride different, agreed ?
Are we getting closer to my 100 HORSES against Rogers 100 horses ? I suspect not in reality because the HP figures for both our bikes are similar across the rev range. However, if your theory were representing mine and Rogers bikes, we'd be getting somewhere.
Rocket in England |
Aaron
| | Posted on Wednesday, April 04, 2001 - 10:20 pm: |
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Rocket: what do you mean "These motors will be at opposite ends of the graph"? Both graphs go from 50mph to 100mph on the horizontal axis. RPM is not on there, anywhere, on either graph. The graphs produced by these two bikes are identical in all respects, because both bikes spun up the roller over the same speed range at the same rate!
Ron: you may have me on this one, 'cuz I'm a little fuzzy on this point. Let me go out on a limb here and maybe embarass myself.
I don't think a Dynojet is showing torque at the rear wheel, I think it's trying to show torque at the crank. I think it measures torque at the rear wheel and divides it by the overall gear ratio (which it can measure, with the tach pickup hooked up) and that's the torque it shows. That's why it won't give torque unless the tach pickup is used.
If it showed torque at the rear wheel, it would be showing a much bigger number, due to the gear reduction in the primary, the gearbox, and the final drives. And it would vary depending on which gear you're in.
So, to answer your question, the bike you're referring to will have about 105 ft/lbs of torque at the crank. The primary drive will kick that up to about 168 ft/lbs (35T front/56T rear). The gearbox is 1:1 in top gear so you've got 168 at the countershaft. With a 27/61 final drive, you end up with about 380 ft/lbs at the rear wheel. At one foot of radius on the wheel, you'll have 380 lbs. of force.
Correct or not?
AW |
Ralph
| | Posted on Wednesday, April 04, 2001 - 10:21 pm: |
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Don't ask me to explain, I can't. I blindly except what I am told. I'm stupid. It makes sense. I'll be back later to be yelled at. See ya. Maybe I wasn't clear with that Aaron. Read it again.
So, instead of me 'splainin something I can't, you 'splain to me why a 100 hp 600 with 45 lbs of torque will spank a 100 hp Buell with 90 lbs of torque. Mr. Dickey took about an hour to penetrate my thick skull. It's going to take you at least that long.
bighairyralph |
Aaron
| | Posted on Wednesday, April 04, 2001 - 10:52 pm: |
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Ralph: Well, I would assume it's because of the 6-speed gearing and a wider powerband. I suspect that over the rpm range that you're operating in as you're accelerating through all the gears, the 600 is able to keep higher average torque to the rear wheel. It also probably weighs 50 lbs. less.
Read this.
AW |
Chuck
| | Posted on Wednesday, April 04, 2001 - 11:11 pm: |
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So . . . let's see if I really get this . . . On an inertia type dyno, Rocket's bike will show more power with helium-filled tyres mounted on carbon fiber rims . . . right  |
Axtell
| | Posted on Wednesday, April 04, 2001 - 11:17 pm: |
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Aaron..you mean the dyno won't tell you hp if the tach is not hooked up,right?
question 2..
whats torque on same engine in second gear @ crank and rear wheel...
I think that @ the Colorado event that adult beverages and rarified air will make all of this clear
I hope we can keep the ole guy (Court) awake... |
Henrik
| | Posted on Wednesday, April 04, 2001 - 11:38 pm: |
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Well, I'm getting a little hazy here, but if we compared area underneath the graphs instead of comparing only peak numbers, that might explain why 100 HP bike A gets from one point to another faster than 100 HP bike B:
Wouldn't the bike with the largest area, with summation of power to the rear wheel measured an infinite amount of times over a set time frame come up with the largest # and as such have put out the most power in that time frame? Forgot the name of this, but the formula uses this sign ƒ ???
Henrik |
Rocketman
| | Posted on Thursday, April 05, 2001 - 12:10 am: |
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So the dyno doesn't know the RPM therefore it can't predict what either bike will ride like.
To digress, the dyno's a dumb son of a gun because for all its computer cleverness, it believes its the same bike, not that it matters to the dyno of course. This is all b u l l s h i t .
Anyway, both bikes are showing the same power characteristics on the dyno but the dyno can't see where both bikes are delivering the power within its rev range so the dyno graphs are identical. Now if you draw a mental dyno graph in your head with RPM horizontal, stick the torque monster and the rev nutter bastardio bikes on that line and both bikes will obviously be at opposite ends of that line, which in fact is a graph .
This graph will tell US that one bike produces its power low down which means it's a torquer, and the other bike will provide its power high up which means its a revver. Are you gonna tell me they will ride the same because if you are I'm gonna fry up my cap and eat it with salt and bloody vinegar ? And remember, they both got 100 horses\HORSES 
Rocket in England |
Jmartz
| | Posted on Thursday, April 05, 2001 - 08:37 am: |
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I'm bailing out of this one. My final position on the matter is that gearing plays and important part in all of this and Buells just don't have the range.
Jose |
Jmartz
| | Posted on Thursday, April 05, 2001 - 08:48 am: |
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Maybe if an infinitely variable trasmission existed we could test our theories w/o that variable.
Read one time about such a device in Pop. Mech. magazine. It was a system similar to the old DAF 44 (Dutch double conical variable diameter pulley trans/diff system) but interetingly enough they claimed the increase in effciency was only 8%, perhaps the reason it never made it in production.
The slip qualities of a 4 speed Auto Trans give rise to an variable ratio around a gear. |
Aaron
| | Posted on Thursday, April 05, 2001 - 10:00 am: |
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Rocket: The purpose of the example was to demonstrate that the two bikes, one making 100 ft/lb from 2500-5000rpm, and the other making 50 ft/lbs from 5000-10000rpm, are pushing on the back wheel the exact same amount over the course of their powerband. The dyno doesn't care what the engine is doing, it's looking at how that roller is spinning up, and that's a reflection of the forward thrust on the bike.
Jose: I absolutely agree on that gearing comment.
Ron: No, the dyno will tell me hp with or without the tach hooked up, it'll plot it versus speed. It won't show me rpm & torque, though, unless it's hooked up. I'm reasonably sure it works by measuring rear wheel torque (which it doesn't display), and then converting that to rear wheel hp. Then, if it has rpm information, it divides rear wheel torque from the derived overall gearing and gives engine torque.
Actually, there's a more direct way to get rear wheel torque than the way I did it. Overall gear ratio is the 56/35 primary times the 61/27 final, 3.615. 5000 engine rpm / 3.615 = 1383.2 rear wheel rpm. (100hp * 5252)/1383.2rpm = 380ft/lbs of torque at the rear wheel.
Okay, let's cut to the chase ... 100hp @ 5000rpm, 35/56 primary & 27/61 final (3.615), pre-00 gearbox, here's all the rear wheel torques:
1st gear (2.69): 1021 ft/lbs
2nd gear (1.97): 748 ft/lbs
3rd gear (1.43): 543 ft/lbs
4th gear (1.18): 448 ft/lbs
5th gear: (1.0): 380 ft/lbs
Now let's say we have a 100hp @15,000 rpm bike. This bike has 35 ft/lbs of torque at the engine.
To achieve the same ground speed we'll have to gear it 3x shorter. So instead of 3.615 through the primary and final drives, it'll have 10.844.
With a 1:1 top gear, rear wheel torque is 35 * 10.844 = 380 ft/lbs. The wheel is spinning 15000 / 10.844 = 1383.2rpm, just like our other bike, and it's got 100hp, just like our other bike. Assuming the same gearbox, all of those rear wheel torques above will be identical, too.
If this bike is somehow putting more torque to the rear wheel, with 3x shorter overall gearing to compensate for it's 3x higher engine rpm and multiplying it's 1/3 torque by 3, I don't see it. Somebody 'splain it to me. Sure, you could gear it shorter, but then you're not comparing apples to apples anymore.
AW |
Mikej
| | Posted on Thursday, April 05, 2001 - 10:44 am: |
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Okay, I'm cornfused, similar to confused only different, sort of like discussing dyno readings.
So,....
Aaron, or anybody else so inclined, your task, should you choose to accept it, is as follows:
1. Pick a bike, any bike, even one of your dirt bikes, won't matter for this test.
2. Take chosen bike and strap it onto the dyno device, fully connected with the tach pickup and everything.
3. Do a run in 1st gear and plot a graph.
4. Do a run in 2nd gear and plot a graph.
5. Do a run in 3rd gear and plot a graph.
6. Do a run in 4th gear and plot a graph.
7. Do a run in 5th gear and plot a graph. Unless the chosen bike doesn't have a 5th gear.
8. Post the graphs. If the dyno considers the engine RPM's to calculate the final dyno numbers then theoretically all four or five graphs should have similar Tq/Hp graphs. If they do then in my mind anyway that would mean the dyno software and sensors are somehow measuring "real" engine performance and not something else.
Just an idea to consider.
MikeJ (wondering what my dyno graph would look like if I strapped my bicycle to the dyno and peddled like crazy) |
Buellzebub
| | Posted on Thursday, April 05, 2001 - 11:08 am: |
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mikej: i think hoser tried that one already [you really have to have a fluid spin], he was saying it was pretty flat but spiked on the down strokes.
this is definitely an interesting thread |
Thunderbolt
| | Posted on Thursday, April 05, 2001 - 12:34 pm: |
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Aaron, I think you already 'splained to yourself how one 100 hp bike can be faster than another. W I D E R power band, less weight, and I'll call 'more gears' 'more effective gearing.' More effective gearing would keep the bike in the meaty part of the power band more often (e.g. a properly designed 6 speed vs properly designed 5 speed).
Someone mentioned infinitely variable transmissions. They do exist (commonly refered to as constantly variable transmissions or CVTs). You will begin to see them in cars in the near future. They will first show up in light cars with small engines (less torque to transmit--easier to build). THEN your peak HP WILL be what determines your max acceleration because with the accelerator floored, the engine will run at its max HP rpm, and the CVT will adjust its ratio as the vehicle accelerates. That day IS coming. As was alluded to, they are not nearly as efficient as 'regular' trannys (yet), but they do allow the engine to run more effieciently. As a package, they are more efficient in certain circumstances (light cars, small engines), but more $ to build (right now). I believe it is Honda who is planning to release a production vehicle with a CVT this year (in Japan).
Someone also spoke about the 'area under the HP curve'. I think this is much more to the point of describing how a bike will accelerate. Although, I would add that it is the area under the curve bounded by the rpm's (upper and lower) that the bike is operating at. For instance, if on a particular stretch of road the bike speeds up and down such that the rpm's vary between 5k and 6k, it is the are under this portion of the curve that will describe the bike's accelerating characteristics (although not exactly). The smoothness of the curve also plays a part.
I do think, and have thought for a while, that there is a missing 'characteristic' when describing the performance capability of a car/bike. This 'characteristic' would extract information from the HP curve (rear wheel), gearing ratios, weight of the vehicle, and maximum transmitable torque (where the tire(s) break(s) loose). Until that time, I guess the best substitute for all that is an ET. This new characteristic would, however, remove the human element's (rider's) influence. |
Aaron
| | Posted on Thursday, April 05, 2001 - 12:50 pm: |
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Matt: excellent comments all, and I agree completely.
Sorry I spaced responding to your other question. My database isn't that big, 3 bikes, and Rocket basically nuked the theory with his disclosure of .020 shaved off the heads, which I believe will decrease the squish between the side of the dome and the chamber wall.
Maybe I'll pull that S1 apart and put in standard gaskets and see what happens. My guess is they're worth 2-3hp, but I'm just guessing.
Wow, we scrolled off all the dyno sheets, Blake's gonna chastise us here any second 
AW |
Axtell
| | Posted on Thursday, April 05, 2001 - 01:25 pm: |
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Ok...my point was to show that when people say they have 100 hp and 80 lbs of torque @ the rear wheel they are wrong. If they only have 80 I'll race them all day long...
this is not apples to apples,if it was things would be easier
Now plot the whole torque curve to mph.
do it for all gears.
Repeat for a 750 kawasaki.
In these days all bikes have their gearing optimized for their power output and the playing field is not level |
Thunderbolt
| | Posted on Thursday, April 05, 2001 - 01:49 pm: |
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What is meant by @ the rear wheel is 'engine torque measured at the rear wheel'. Not torque at the rear wheel. It is just a way to say that gear train inefficiencies are taken into account vs 'crank shaft' measurements. That is why the dyno needs the tach input for this curve--if you know engine power and engine speed, you can figure engine torque--and that's what it's doing--figuring it. |
Clydeglide
| | Posted on Thursday, April 05, 2001 - 02:30 pm: |
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T-Bolt,
CVT transmissions are here and have been. Got here with the old Subaru Justy (excluding DAF) and now with Honda Civic HX. Just FYI.
Clyde |
Hans
| | Posted on Thursday, April 05, 2001 - 02:58 pm: |
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Aaron:
The dynomometer is set in revolutions only by the tire of the bike. Nothing else. Clear.
The speed at which the heavy wheel is accelerated is measured and after adjustments for humidity, airpressure and moisture the dyno gives horsepower and torquenumbers for the tested engine at different RPM´s. Right ?
Then there are two possibilities:
1. Or the engine has to be stronger then the given numbers as it has to make good for losses in the drivetrain etc. (18-20 % stronger)
2. Or those losses are ESTIMATED and corrected for. Still right ?
In the first case the given numbers are not what the clean engine delivers and in the second place also not because differences between the drive train systems and their condition.
And horsepower is not horsepower:
Any horsepower is exactly defined but in different systems on different ways and with different outcomes:
33000/foot/lbs/minute and measured following SAE specifications 745.6999 Watt´s
75 kilogram/second/meter (ISO) and measured following DIN 735.499 Watt´s
UK horsepower 745.7 Watt´s
The French had in the past their Tax-horsepower: The power of a 250 cc 4-stroke engine.
Last French redifinition: exactly 750 Watt´s
The Americans changed ever their SAE hp numbers of their cars from crank hp to hp´s including all the powerconsuming appendages (or vice versa.)
In this area I thought to find an explanation why a British measured bike could differ in (expected) power from an American one.
It is very right that the "finest parts" are not necessarily the most effective (and thus best) parts: What Rocket described about his bike seemed me pretty good stuff and I recognised some things Pammy used on her high powered bikes.
I think that motortuning and specially porting is partly grounded on understandible principles and partly is an form of art, feed with expirience and feeling.
But I suppose that the differences between those artists on both sides of the pond are not that big.
Long story but found differences are of marginal value.
Rocketman: Maybe you have to listen to Maestro Aaron about dynoing:
Here I found a remark with the same essentials:
"Next time when you read a performance publication and the author tells you that he has spend many hours on the dyno, developing an engine, believe him. Just imagine how many parameters have an effect on the performance output, and remember, all these parameters must probably have some effect on each other. So just when you think you have got the best exhaust, cam timing, ignition timing, fuel ratio, port configuration, valve profile, cam profile, etc., start all over again because you probably forgot to set the fuel mixture after changing the cam timing."
Or..Or… Has the British rain polluted the fuel and covered the ball bearings of the British dynomometer with rust.J ?
Hans |
Aaron
| | Posted on Thursday, April 05, 2001 - 03:45 pm: |
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Well, I guess we digressed a little bit. My original point was that horsepower is a perfectly valid performance metric, and it's not necessary to consider the rpm it's made at or the money spent on the engine work to decide if some horsepowers are better than others. They're not. In fact, that's the beauty of it, if you talked only in torque you'd have to always be referencing rpm.
I never meant to imply that by itself hp fully describes the acceleration rate of a bike. Two different bikes making the same peak hp may be geared differently, have different powerband widths, or weigh different amounts, all of which will affect acceleration.
Ron, why don't you start making 7-speeds for us?!
Matt, I think you need to work on that new formula that considers these things. Maybe in the future we'll all be talking about how many "Matts" our bikes have, and these threads won't go on forever!
Hans, with a Dynojet the answer is #1, the engine is stronger than what the dyno is showing. That's why Buell claims 101hp and we only get 85hp. And, point well taken on the varying definitions for "horsepower". But, I think everyone in this debate is using the 33,000 ft/lb/min definition. Finally, there's a whole lot more to motor building than selecting and bolting together parts, if it was that easy, we'd all be as good at it as Ron! But with respect to Rocket's motor, I don't think we should really be comparing. Especially after what I saw at Hal's at Homecoming '00 ... until that moment, I had always seen a lot of consistency between Dynojets.
Okay, I'm done
AW |
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