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March 8th, 2012, 07:32 PM   #1
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I read on David Emmetts (Krops) twitter, discussion between himself, Dennis Noyes and Matt Birt, discussion about the engine size for the Ducati, Honda and Yamaha motogp bikes. It started off with a photo of Rossi,s dash showing a tach going to 19000 rpm, and the concensus was that the engine would have a redline of over 18000rpm for this to be the case. Therefore an engine of just over 900cc would fit the piston speed to generate such an rpm ceiling. Suggestions of either 930 or 907 cc were made. There seemed also to be a concensus that both the Honda and Yamaha had max rpm of 16-17000rpm, leading to the conclusion that they were very close to the 1000cc maximum.



Surely this difference is significant, as the Ducati"s lower torque would reduce its acceleration out of the corners, but should theoretically increase its abilities at corner speed, corner entry and change of direction. Were these things seen at sepang? The ducati had slower lap times, but was it in sectors with straights or tight corners? And of course you generally overtake on the straights, not mid-corner. Now, if Dorna mandates spec ecus for 2013 with max rpm of say 16000rpm, then will Ducati need to completely redesign their engine, whereas Honda and Yamaha can keep the same stroke? Has Ducati just made a monumental error or can anybody see a subtle stroke of genius in there somewhere? I suspect that they have, in attempting to find an "advantage" over the others, may well have painted themselves into a corner. Again........
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March 8th, 2012, 09:14 PM   #2
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Maybe it suits the tire better? No use having any more power than can be put to the ground. But in the case of a friendly detuned 1000 grunter vs a more highly strung 900 I would take the 1000.
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March 8th, 2012, 09:22 PM   #3
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I remember when the retun to 1,000cc was first discussed, there were people who suggested the optimum engine size would be around 930cc to achieve the right power at the righ rev ranges.
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March 8th, 2012, 10:37 PM   #4
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And maybe related to optimum power for the fuel limits ??
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March 8th, 2012, 11:41 PM   #5
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I would say that Ducati's list of successful engineering achievements is rather small so I wouldn't be surprised if they have failed to kick a winning goal with engine capacity specs.
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March 9th, 2012, 06:04 AM   #6
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Quote:
Originally Posted by Nuts View Post
And maybe related to optimum power for the fuel limits ??
If thats the reason than they are already fucked. Yamaha has already done a full race simulation that was 17 seconds faster than Rossi's winning time in 2010 at Sepang. If Ducati gave up 70-100 cc to make it on fuel, they are way behind the technological curve of the competition.
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March 9th, 2012, 06:34 AM   #7
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maybe theres a special lubricant in the engine that makes the higher revs not go hand in hand with more friction compared to the 1000cc engines, that way they'd get better maneuverabilty with the same fuel efficiency. theres enough power anyways and i have no doubt rossi/hayden are capable of keeping the revs up and marelli to keep a peaky engine under control.



i guess ducati have to think outside the box, who knows, maybe thats the way to stand up to the hondas and yamahas at some tracks at least
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March 9th, 2012, 08:19 AM   #8
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Quote:
Originally Posted by cliché guevara View Post
maybe there's a special lubricant in the engine that makes the higher revs not go hand in hand with more friction compared to the 1000cc engines, that way they'd get better maneuverability with the same fuel efficiency.


I'm pretty sure the teams run thin, F1 style oil. How thin is unknown, but weights in the single digits seem likely. Oil film thickness is a function of surface speed and viscosity, divided by the load. Even with high loads, the engine's extreme RPM reduces the need for thick oils. That's one of the reasons the bikes idle at such high RPM; if they turned slower, the oil film would collapse, causing increased wear.
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March 9th, 2012, 08:32 AM   #9
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Originally Posted by Geonerd View Post
I'm pretty sure the teams run thin, F1 style oil. How thin is unknown, but weights in the single digits seem likely. Oil film thickness is a function of surface speed and viscosity, divided by the load. Even with high loads, the engine's extreme RPM reduces the need for thick oils. That's one of the reasons the bikes idle at such high RPM; if they turned slower, the oil film would collapse, causing increased wear.
informative post ,thanks geo.never thought about the oil film actually ,i thought the high idle rpms were solely about thecompression.these 4 strokes are just too complicated



its just a wild guess that maybe they have something special that allows them to go that route
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March 9th, 2012, 09:10 AM   #10
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19,000rpm would correspond with 840cc-850cc, assuming mean piston velocity of 26m/s.



The old Ducati rev counter went all the way to 22,000rpm. Ducati actually displayed the rev counter for Dorna's onscreen graphics. Imo, the red line on the dash was about 3,000rpm over the actual rev ceiling of the GP11. The current rev counter is about 3,000rpm above the rev ceiling for an 81mm 1000cc engine.



They are all running 1000cc, imo. Running reduced capacity is a big risk for several reasons. First, if the advantages don't materialize, the manufacturer must build another new engine. Second, the rules are not set in stone. If the formula changes to rev limiting, for instance, a 900cc engine would be useless. Even if they use a rev limit as a safety valve to curb top speed, all participants need to be running on the 1000cc limit. Plus, Dorna want the manufacturers to run 1000cc engines for marketing. If I were Ezpeleta, I wouldn't pay unless they were on the 1000cc limit.
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