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April 21st, 2012, 01:37 PM   #81
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Quote:
Originally Posted by Kropotkin View Post
Great work that man! About right. Nice, conservative Honda engineering. And so far inside the performance envelope that Honda might even be running at less than the maximum bore, going for torque instead of HP. they've done that in Moto3.


No worries!



Color me skeptical regarding the downsized bore. Wide pistons generally = room for bigger valves = more power across the entire rev band.



Please define 'torque.' Do you mean midrange power (the shape of the power curve), or absolute crankshaft torque output (94 foot-pounds, or whatever they're making.)
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April 21st, 2012, 01:51 PM   #82
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I'm getting only 14.7K for the Yamaha. Probably not a screaming hot lap!



It has an unusual signature, producing a strong pulse once every 4 crank revolutions. No doubt due to exhaust pulses bouncing around in the headers.
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April 21st, 2012, 02:06 PM   #83
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16.1K from the Stoner / Sepang released back in Feb.



( )
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April 21st, 2012, 02:31 PM   #84
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Quote:
Originally Posted by Geonerd View Post
No worries!



Color me skeptical regarding the downsized bore. Wide pistons generally = room for bigger valves = more power across the entire rev band.



Please define 'torque.' Do you mean midrange power (the shape of the power curve), or absolute crankshaft torque output (94 foot-pounds, or whatever they're making.)


Actually, want I mean is a nice fat powerband. These things could easily make 300hp, but you can't use that power. 255 with a nice wide spread is much, much better.
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April 21st, 2012, 02:34 PM   #85
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Quote:
Originally Posted by Geonerd View Post
The Duc was a hard one to interpret. The individual pulses vary quite a lot in amplitude. The best 'tell' I could find was the ascending 'staircase' feature.



I'll go back and watch the Eurosport qualifying vid, in search of on-board sounds during a proper hot-lap.


The big bang config makes it hard. Taking a margin of error, 17250 would put the Ducati right about 16750, which is 27 m/s piston speed, which is what we would expect with a 1000cc engine pushed to the limits. It would also explain Rossi's annoyance at the "lion under the fairing" aggressive power delivery.
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April 21st, 2012, 04:33 PM   #86
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Quote:
Originally Posted by Geonerd View Post
Honda: from 2:08, right before he shifts.



325 samples at 44,000 per second

= .00739 ms

= 135 bangs per second

= 8100 bangs per minute

= 16,200 RPM.





13467:Honda.jpg]


On the Honda ,Cool! well done Geo. I have not even had a chance to convert the vids yet but I did put a hand held frequency meter on the sound out and got around 16,000. Small/short sample and a dicky reading of around 134hz ....... which equates to 16,080 .....



The Ducati was difficult to measure by this method, as its readout varied so much, would not have settled on a definite reading for the Duc. Reading fluctuated between 137 to 147 hz. Its no 19,000 though.
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April 21st, 2012, 06:59 PM   #87
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Quote:
Originally Posted by Kropotkin View Post
Great work that man! About right. Nice, conservative Honda engineering. And so far inside the performance envelope that Honda might even be running at less than the maximum bore, going for torque instead of HP. they've done that in Moto3.


Moto3 is rev-limited. 81mm bore isn't necessary to achieve the rev ceiling and 250cc engines probably need the extra torque. Reducing the bore size in MotoGP would cost tens of horsepower and restrict the breathing capabilities of the engine. The surplus torque would be superfluous, imo.



16,200rpm is almost exactly 26m/s average piston velocity for an 81mm bike at WOT. Sounds right. The Yamaha number is surely too low, unless the rider was "trundling" around. For Yamaha to be down that much on power would be an embarrassment. Duc number seems too high, but who knows.
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April 21st, 2012, 07:24 PM   #88
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I've run the Duc several times and keep getting the same values. Here's a slightly different section of the waveform after running a low-pass. This cleans up the jaggies and makes the periodic signal easier to see. Unless I'm having a blonde moment with the math, 17,100~17,200 RPM is correct.



13469ucati2.jpg]



I'll look for more Yamaha noises, and really want to see what the Kwacker, BMW and Aprillia are turning.





Edit - found one Ducati sample at 17,350 (!) This was averaged over three waveform cycles, so is likely to be fairly accurate.
Attached Thumbnails
Engine Capacity-ducati2.jpg  
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April 21st, 2012, 07:36 PM   #89
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If anyone want to play with this, you can download a demo of Cool Edit Pro that should (?) be able to discern peak-to-peak timings as seen above. http://www.softpedia...-Edit-Pro.shtml



Open source Audacity might also do the trick. http://sourceforge.net/projects/auda...urce=directory



If it works the same as my Cool Edit 2000, click on the horizontal scale, just below the black area, to select the time-base units. Switch from seconds (which don't show enough resolution) to samples and you're good.
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April 21st, 2012, 08:11 PM   #90
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Quote:
Originally Posted by Geonerd View Post
I've run the Duc several times and keep getting the same values. Here's a slightly different section of the waveform after running a low-pass. This cleans up the jaggies and makes the periodic signal easier to see. Unless I'm having a blonde moment with the math, 17,100~17,200 RPM is correct.



13469ucati2.jpg]



I'll look for more Yamaha noises, and really want to see what the Kwacker, BMW and Aprillia are turning.





Edit - found one Ducati sample at 17,350 (!) This was averaged over three waveform cycles, so is likely to be fairly accurate.


All samples are definitely WOT, not overrun? If the rev ceiling is 17,100rpm-17,300rpm, the bike probably is 930cc. The numbers would line up perfectly.
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