jimzx9r
Expert Class
Posts: 451
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posted January 19, 2006 02:16 PM
Another R6 on the dyno...
With proof and an explanation that the 17.5k redline is a scam.
http://forums.13x.com/showthread.php?s=&threadid=99767
  
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trenace
Needs a job
Posts: 3056
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posted January 19, 2006 02:49 PM
 Edited By: trenace on 19 Jan 2006 14:52
That's the first one to break 16K at all.
I guess there's some variance, perhaps in clock speed of the ECU: e.g., 16,200 rpm is only 1.25% higher.
Or if dynos have variance in clock speed, then one dyno being less than one percent high-reading and the bike being less than one percent slower clock than usual would allow a 200 rpm variance.
(Kind of an interesting thought there, I wonder how much variance there is in Kawasaki limiter settings?)
I've seen another at 15.8K, and another at 16.0K even. So apparently it's 16K plus or minus about 200 rpm.
That's for the LIMITER.
The point where the tach reads redline is 500 rpm lower than that. So in other words the redline is really about 15,500 rpm.
BTW, one of the British mags interviewed a Yamaha engineering honcho and he give piston speed figures that prove he knows the rpm claims are total lies -- even from the standpoint of design goals, rather than actual outcomes, they had not planned for the speeds that would be associated.
Yamaha knows it's not true, that their numbers are false by about 2000 rpm. (Of course -- even aside from that, they have dynos too and can measure true rpm.)
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trenace
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posted January 19, 2006 04:42 PM
Edited By: trenace on 20 Jan 2006 08:10
Incidentally, there's an interesting -- but unfortunately flawed on BOTH sides -- discussion of the question of aligning dynographs of bikes with different operating ranges.
That, done correctly, is something the magazines absolutely should do, but fail to do so.
Basically, what matters to the rider is not the absolute rpm but the relative, that is to say, relative to the working rpm range of the bike.
For example, one might put up a Harley "Screamin' Eagle" hp and torque curves with a ZX-6R's.
The naive conclusion would be "Man, look how the Harley is killing the Kawasaki through the midrange!"
The reality though is that the ZX-6R rider doesn't ride at 2000 rpm (less than 1/6th of its redline) anymore than the Harley rider rides at 1/6th of his redline, or about 1000 rpm.
In fact, any time the Harley rider is at so-many rpm, the ZX-6R rider is probably running double that rpm... and has gearing twice as short, so the torque at the rear wheel, which is a product of the crankshaft torque and the gearing minus losses, is improved by a factor of two relative to the Harley.
So, such a means of comparison tends to lead to a very false conclusion. It doesn't represent reality on the road: at the same road speed the bikes do NOT run the same rpm.
The more valid comparison (approximate) is the Harley at 2000 and the ZX-6R at 4000, the H-D at 3000 and the Kawasaki at 6000, and so on.
This way, the hp (or torque) at each road speed is being compared with the hp (or torque) at the same road speed. Plot both engines not on an absolute rpm scale, but on "percent rpm."
There is unfortunately more than one reasonable and valid way to determine what constitutes "100%" on the scale.
(Note, initially I discussed several of them, but it becomes too numbing, so removed all but the best, IMO, two.)
The most desirable method would be one that is not subject to "ginning" in the data handling process nor changed by odd or different decisions by the manufacturer -- e.g. a manufacturer should not be penalized or helped by setting a limiter far above the useful hp range, or by using tall or short gearing.
One method would be to make the center of the torque plateau, defined perhaps as the center point between lowest rpm having say 95% maximum torque and the highest rpm still having say 95% maximum torque, equalized.
Another method would be to equalize based on percentage of the limiter rpm. That way, if say each bike is geared so as to hit the limiter in a given gear at 100 mph, then the dyno curves are matching up so as comparing equal road speed with equal road speed. (A flaw in this system though is if the limiter rpm is a weird value, e.g well past any useable horsepower, so unfortunately, this one could be gamed, but on sport bikes probably isn't.)
Either method would be a far better predictor of how the bikes compare on the road, where operating rpm ranges differ, than failing to make any account at all.
(UPDATE: I now think the best way would be that when both bikes pull pretty well to the limiter, then match up the limiters... e.g. if one bike spins 10% faster, then it can be geared 10% shorter for same speeds in gears. Show each bike in terms of its percent of maximum rpm. But if either bike does not pull well to its limiter, ought to be shifted substantially early, then match up the torque centers.)
A guy on the site sort of tried to do this.
However he did it the worst way possible: first, failing to compress or expand the scale, in other words failing to do it as ratios but just sliding the whole thing over which is mathematically, and for predicting performance, flat wrong; and arbitarily so as to do the best for one bike.
(Why is it wrong? Well, let's use the Harley vs ZX-6R comparison. You'd have to shift the ZX-6R curve over by 6000 rpm to get its peak and redline matched up pretty closely with the Harley's, but then for example its 7000 rpm would be matched with 1000 rpm instead of the 3500 that would be correct, 6000 would match to zero which is obviously wrong, etc. So sliding the curve does not work, but it's how that guy did it. Doing so gave an outrageous advantage to the Yamaha, just as matching 7000 rpm on the Ninja to 1000 rpm on the Harley would be unfair to the hog.)
I do wish the magazines would do the graphs on relative rpm not absolute, as one constantly sees dynographs overlaying two bikes and one "seems" to lag behind the other through almost the whole range and then has more peak hp happening after that for quite some time while the other bike has nothing, and you have no way of seeing for sure how they really would compare with each other. In practice, in many such cases, the faster-spinning bike is just the flat more powerful and torquey on the road at all times, because it's geared shorter while still achieving the same speed or greater in every gear.
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trenace
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posted January 19, 2006 10:54 PM
Edited By: trenace on 20 Jan 2006 00:20
Hell, I should be able to do it with "photoshop" (actually I'll use a different program, but that's not important.)
I'll do what, by the above standards, constitutes a fair comparison, where for equivalent placement in each's powerband, hp at same road speed of one bike is compared to hp at same road speed of other bike. Won't be hard.
OK, I got 'em, but for some reason the image hoster I use isn't working right now, so I can't post them presently.
Results though?
With torque centers lined up, at low rpm the 'Zook had pull whereas the Yamaha was not even on the dyno chart, though dyno operators for some bizarre reason often fail to start a pull as low as they could so that may not be Brand Y's fault. Pretty even performance till the upper midrange, then the Yamaha pulls ahead... but the Suzuki actually has the more overrun! So that would to some extent counterbalance the Yamaha's advantage below that rpm.
In other words, if you gear the Yamaha so the center of its strongest torque is at the same speed as the Suzuki, the Suzuki can extend up to a higher speed before hitting its limiter. Still another way of saying it is, the Suzuki has more working room between its torque center and its rpm limit.
In this case, because of such a difference in overruns, maybe aligning the torque centers was not the best method to normalize things, though it was a better predictor of road performance than the totally-uncorrected graphs I think.
That alignment had the Yamaha running 88.4% as tall gearing as the Suzuki. (It must run much shorter for its torque center to be at the same speed, because that happens at higher revs.)
Next, lining up the limiters, so each bike's dyno curve is at percent of its maximum rpm, or in other words, where if you geared each bike so maximum speed in a gear would be the same for each, then it's a straight comparison, how much hp does each bike have at same road speeds for each bike?
By this comparison, probably the best way to look at these two bikes it seems, the Suzuki does considerably better than the Yamaha up till about 70% of redline (about 11,000 rpm if talking about the 'Zook), then it's even for a little while, and for the 80-100% of redline range the Yammie clobbers the 'Zook (13,000 to 15,000 rpm if talking about the 'Zook.)
This incidentally would have the Yamaha running gearing 92.6% as tall as the Suzuki, so that each could have same speeds in gears.
So, let's say you're familiar with the Suzuki... if the top 2000 rpm, or top 20% of the rev range, is the more important to you than everything up to 11,000 or the first about 70%, the Yamaha has an edge if sprocketed for same speeds in gears.
If you probably would spend more time below 11,000 than above 13,000, though, the Suzuki has the stronger motor more of the time for you.
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trenace
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posted January 20, 2006 07:28 AM
Edited By: trenace on 20 Jan 2006 07:29
With peak torque centers equalized:
With limiters equalized:
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k bryant
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posted January 20, 2006 07:54 PM
I had one on the dyno last month. Peak power was at 14.5k. It completely signed off at 15.9k. Awesome motor, just signs off well before advertised....
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trenace
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posted January 21, 2006 01:41 AM
Edited By: trenace on 21 Jan 2006 01:42
That's good info further backing this up -- with that in there too, it seems clear that the limiter truly is at about 16.0K, with more example so far being below that (either 15.9 or 15.8K) than above it (16.2K).
What with all the wordage above it might be obscured what I think about the engine -- the lying about the redline and limiter rpm I think is a disgrace, but this is probably going to be an outstanding basis for a superstock roadracing motor, and if you can keep the thing over 12,000 rpm it's going to be quite a performer for a 600.
But, if on the street you spend a good bit of time below 12,000, it looks like it's going to be weaker at those times compared to current bikes operating in the corresponding parts of their rpm ranges. Which should be no surprised -- that's the price for being tuned for more high end.
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ninerrider01
Novice Class
Posts: 70
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posted January 23, 2006 04:33 PM
Your comments make sense about comparing the rpm ranges' "windows of driveability" wherever they fall, but there is still a point to looking at absolute rpms for streetbikes. From a stoplight, you start at idle and if this race-rep bike has a tall 1st gear like many crotchrockets do, you might have to be at 50mph or so before having entertaining power.
Also, everything is choppier at high rpms. Okay, it may have a slipper clutch, but you have to roll the throttle back on also and it seems it'd be harder to roll on smoothly at 10,000 rpms.
Seeing the low hp/torque at 5000 rpms shows it may be a tough bike for the average young 600 buyer who wants to ride to work once in awhile, take his g/f on the back to BikeNite, etc.
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