Ducati V2 at end of cycle - why?

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Fingernails
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Ducati V2 at end of cycle - why?

Post by Fingernails »

Why would it be impossible for Ducati to improve the performance of a V2, but possible for a V4?

https://www.motorcyclenews.com/news/201 ... motorbike/

I can see why they would move to a V4 as there will be more technology transfer from MotoGP, but it is really that much harder to increase performance of a 1200V2 versus a 1000V4.

bikermike
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Re: Ducati V2 at end of cycle - why?

Post by bikermike »

If Ducati say so, then one wouldn't discount it.

Issues -
one way to make more power is to spin the thing faster - bigger pistons can't spin as fast for a given level of technology
Emissions - are making super-clean burn essential - and works against power and tends to make bikes peakier
adding lightness - a faster-spinning engine with more lumpy forces needs a stronger crankcase - they may have reached the limits of what they can do with current technology.

I suspect it is possible to make more power from a v-twin, but not at a cost/practicality point that works (IIRC one of the last iterations of the 998 WSBK bike had crank-cases with a use life of hours - this isn't really practicable on a road bike).

Children not being petrol-heads is interesting, it's all too easy in a bike-fan bubble to think everyone wants a bike - I'd be interested to see what Ducati's knowledge on this is.

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speeddog
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Re: Ducati V2 at end of cycle - why?

Post by speeddog »

The classical architecture of the 90 degree v-twin Ducati started in 1971, with the bevel-drive 750GT.
The next major development came with the belt-drive Pantah in 1979.
The Pantah was roughly a mirror image of the bevel, but with significant upgrades like the one-piece crank, and the much less fussy and less expensive belt drive for the cams.
The fundamental architecture continued unchanged up to the end of the line; vertically split crankcase, one-piece crankshaft, and an in-line transmission (not stacked).
Parts were made stronger, gears bigger, shafts bigger, a 6th gear added, bigger bore, longer stroke, more valves and water cooling.
It was always a long motor, not unusual in the 70's, but more and more of a handicap as moto performance increased.
The engine displacement grew dramatically from the original 500cc Pantah to the final version, the 1198cc Testastretta Evo.
Really stretched as far as the original design could possibly go.
The 500 Pantah was 74mm bore x 58mm stroke.
The final 2-valve motor was 98x71.5 giving 1079cc, and the final 4-valve motor was 106x67.9 giving 1198cc.

The 2012 Panigale was the first clean-sheet redesign of the twin in , well, *many* decades.
The bore was made even larger, 1199 Panigale 112mm, and finally the 1299 Panigale 116mm, both with a 60.8mm stroke.
I'm not aware of any mass produced high-performance engine with a bigger bore.

I think they reached the end of practical development.
Flame front speed is pretty much fixed, so as the bore gets larger it takes longer for all the mixture to burn.
But in pursuit of more horsepower, more rpm was used, which mandates *less* time for combustion to take place.
I suspect that the structural integrity of the piston was becoming marginal as well, 116mm is a really enormous bore.

The largely unrestricted automotive naturally aspirated race engine development seems to have settled on individual cylinders of 250cc to 450cc.
Bores as large as 98mm were used.

So the Panigale was really quite a bit larger than the state of the art car stuff.

warthog1
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Re: Ducati V2 at end of cycle - why?

Post by warthog1 »

^^interesting engineering facts, figures and history. Thanks Speeddog [emoji108]

kenup283
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Re: Ducati V2 at end of cycle - why?

Post by kenup283 »

Great posts! Feel like I'm reading missing pages off Kevin Cameron's book Classic Motorcycle Racing Engines that didn't make the press cuttoff. Good stuff.

I did find it interesting, at least partially, that the Project Director in article below explaining why Ducati went V4 for their MotoGP engine over 15 years ago is now the CEO of the company. So perhaps a gently shift in way seen of past designers, two valve /four valve' air cooled / water cooled, etc etc.

http://www.motorcycledaily.com/2002/02/ ... atimotogp/

Reasons given echo what's been posted already above, combustion limitations seeming to be at fore front, but peak piston accelerations and mass, although not really mentiined, cannot be far behind as well.

At the bore stroke numbers being run puts them in F1 territory in their hey day of high reving short life engines with many times the number of cylinders for the displamcent, so pushing more weight around while doing it could put them up against or at least closer to a materials limit towards a practical end.


====================
quote from article below for easy refernce
----------------------------

The engine design is capable of exceeding 18,000 rpm despite the lack of pneumatic valves, according to Ducati. Here is a quote from Ducati Corse Managing Dirctor Claudio Domenicali regarding the choice of engine design:

After analysing all the possibilities offered by the regulations and on the basis of computer simulations, we are convinced that a massive power output is required to be competitive in MotoGP. It would have been difficult to obtain this power with conventional twin-cylinder engines, which amongst other things are only given a 10 kg weight advantage over 4 and 5 cylinder engines in the regulations. As a result, the bore size would have to be taken to an extremely high value, with the risk of incurring serious combustion problems.

For this reason, in the preliminary study phase, we considered a twin-cylinder oval piston engine to be an excellent layout for the new regulations. With the same weight as 4 and 5 cylinder engines, this layout combines the typical advantages of a twin in terms of power output and delivery, with the performance necessary to compete at the same level as the multi-cylinder units.

But further analysis led us to decide that the best solution was a ‘double twin’ and therefore we designed an engine with four round pistons which, thanks to a simultaneous two-by-two firing order, reproduce the working cycle of a twin. This will generate the ‘big bang’ effect, making the rear tyre work in a way that extends its duration and improves rider feeling when exiting curves.

The Desmosedici engine, continued Domenicali will have a relatively short development period and reasonable costs and it will then be easily available also for external teams, since it is Ducati Corse’s intention to become a point of reference for private teams in MotoGP, as already it is in World Superbike.

The Desmosedici power-unit, designed to tolerate the greater stress generated by simultaneous combustion, is therefore a unique engine with a further advantage: it allows two different versions to be tested. As well as the Twinpulse, we will also be testing a layout with a traditional firing order, which will have a slightly higher power output, but probably to the detriment of traction. Track testing and rider feeling will decide which layout will be used for racing.

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speeddog
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Re: Ducati V2 at end of cycle - why?

Post by speeddog »

I've been looking.
One remotely high performance engine family in that range of bore are aircraft, by nature low rpm and supercharged constant throttle.
Another is some of the drag-race car stuff.
But both are way different use profile.

hdot
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Re: Ducati V2 at end of cycle - why?

Post by hdot »

I think the focus on performance is a mistake. Even on a track, a 200HP superbike is beyond relevance for many.

I think for a lot more people, stuff like their Scrambler sub brand is far more relevant. Even a run of the mill ER-6 is eye-wideningly fast coming from bikes. Ducati has to sell the imagery and lifestyle associated with bikes, which I think they are doing.

And FWIW the 959 Panigale basically has the balls of a ~15 year old liter bike... which again is an effing rocket. Anything that can clear the quarter mile in the 10 second range is more than quick enough.

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Re: Ducati V2 at end of cycle - why?

Post by Mikesbytes »

My signature isn't particularly interesting

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umarfarooq
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Re: Ducati V2 at end of cycle - why?

Post by umarfarooq »

Fingernails wrote:
Thu Feb 14, 2019 3:28 pm
Why would it be impossible for Ducati to improve the performance of a V2, but possible for a V4?

https://www.motorcyclenews.com/news/201 ... motorbike/

I can see why they would move to a V4 as there will be more technology transfer from MotoGP, but it is really that much harder to increase performance of a 1200V2 versus a 1000V4.
I'll wait for others to answer, haha.

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