[jihem]

Bart Crauwels is quite well known in the Ducati world as he had on the market a clutch kit devised to replace the 2 valvers clutches that really weren't never up to the job.
He also had a famous italian motorbikes shop called Motomania.

He's recently been applying his talents in developing a (racetrack only) compressed 498cc monocylinder bike out of a 1000 DS (two valves air cooled Ducati engine) with a special twist: the rear cylinder would be used a a compressor.




I've seen it being tested on the road, it sounds like a big twin morphed with a chaisaw screamer: unbelievable !


This still-in-proto-look monocylinder makes now 102 rearwheel HP and sustains 10.000 rpm without damages.


don't ask me, ask Bart.


Only 40 of these machines will be produced starting mid-year.

[gavo]

good HP figures from a half litre single but why keep the rear cylinder weight and as a compresser surely this would drain power. does the rear cylinder push an extra charge of air into the front pot?

[jihem]

gavo, on Jan 10 2009, 03:07 PM, said:

does the rear cylinder push an extra charge of air into the front pot?

Yes, the front cylinder gets compressed air 2:1 from the rear cylinder.
There's also a 40 bars compressed air tank below the seat that allows for ten seconds burst to the engine.

[Paul Minnaert]

but does this give more power then when it was a 1000cc vtwin? Or what is the reason to build it? And building 40? I will be surprised if there are customers for it.

[dlaing]

Paul Minnaert, on Jan 10 2009, 03:53 PM, said:

but does this give more power then when it was a 1000cc vtwin? Or what is the reason to build it? And building 40? I will be surprised if there are customers for it.

I had theorized doing a similar supercharger, not with a Duck, but building a triple where the middle cylinder is bored out to a larger displacement, reed valves to move twice the air.
But yah, it would be tough to make it make more powerful than a real triple.
Perhaps it would be more fuel efficient????

[jihem]

Paul Minnaert, on Jan 11 2009, 12:53 AM, said:

but does this give more power then when it was a 1000cc vtwin? Or what is the reason to build it? And building 40? I will be surprised if there are customers for it.

15 HP more than the original twin, more torque and 2500 rpm more (and it's about 30 HP more than the legendary Supermono).
sheer enthusiasm and desire to boldly go where only few have gone before.
40 seems to be a reasonable number when you can see the Ducati D16RR sold 1500 copies.
now, we have to wait and see if he does sell them, sure.
But what an exciting adventure !

[Skeeve]

gavo, on Jan 10 2009, 06:07 AM, said:

good HP figures from a half litre single but why keep the rear cylinder weight and as a compresser surely this would drain power. does the rear cylinder push an extra charge of air into the front pot?

Well, since this guy stole my idea [I hate it when they do that! ] I'll try to explain:

Smaller displacement is more efficient on fuel.

Rear cylinder doesn't need same level of sealing as regular piston: replace piston rings w/ O-rings for less friction & better low pressure sealing. Lighter piston & con-rod required than on a firing cylinder too, so it all adds up to less wt. [Or rather, larger displacement for same wt., for more compressor flow.]

Since it's a four-stroke engine, the rear cylinder travels up & down 2x for each firing interval on the front cyl., so you get 2x the volumetric efficiency (actually less; nothing is perfect) than the NA front cylinder alone. VE=power, ceteris paribus.

You still have the perfect primary balance of the 90deg V, so no counterbalancer or excess vibes nonsense of a true single cylinder.

Depending upon class rules, you could still end up with a bike legal to race in a Singles class.

And of course, the final (& possibly best) reason: "Because it was there."

[jcbooghs]

Isn't he racing a Paton, and THE man to beat, in 500 and 750 classic bikes?

[raz]

Skeeve, on Jan 11 2009, 08:08 PM, said:

Lighter piston & con-rod required than on a firing cylinder too, so it all adds up to less wt.
...
You still have the perfect primary balance of the 90deg V, so no counterbalancer or excess vibes nonsense of a true single cylinder.

Wouldn't lightening the piston and con-rod ruin the balance?

This reminds me of http://www.kompresso...i.de/kguzzi.htm - I love those torque graphs

[jihem]

jcbooghs, on Jan 11 2009, 11:19 PM, said:

Isn't he racing a Paton, and THE man to beat, in 500 and 750 classic bikes?

yes, that's Bart

[dlaing]

Skeeve, on Jan 11 2009, 11:08 AM, said:

And of course, the final (& possibly best) reason: "Because it was there."

Good man have died (gloriously) following such logic

[Skeeve]

raz, on Jan 11 2009, 04:18 PM, said:

Wouldn't lightening the piston and con-rod ruin the balance?

Of course, unless you use the difference in mass to make a larger dia. compression piston & get more boost. Read the rest of my post already!

[raz]

My bad!