Ducati V-One – Twin to Supercharged Single Conversion

Ducati V-One - Supercharged single conversion

Ducati V-One - Supercharged single conversion

Some guys come up with really interesting engine modifications and Bart Crauwels is one of those guys. Bart is currently working on a project that converts a Ducati 1000 DS, a 2 valve air cooled twin, into a supercharged single, using the rear cylinder as the blower. The 498cc single has 15 HP more than the original twin putting out 102 HP at the rear wheel, torque is increased and it runs fine to 10,000 rpm, 2500 rpm over stock. It's about 30 HP more than the well known Ducati Supermono. The Ducati V-One, as he calls it, is for racetrack use only and when things get sorted out he plans to build 40 of them for customers.

In recent years there have been some custom builders, Roger Goldammer comes to mind, who have replaced the rear cylinder on a V-Twin with a supercharger. Since the cylinder is already an air pump, Bart just used what was already there. Of course, the first question before doing this is whether the blown single will have more power than the twin it's derived from and the answer, in this case, is yes.

Another cool feature is the air tank under the seat, limited to 40 bars, which is good for a 10 second burst of compressed air when acceleration begins after which the blower's output kicks in. On deceleration, the tank is recharged. It's hard to see everything that Bart has done by looking at the photos, I notice an intercooler in the plumbing, too, but overall, I like this a lot.

Big thanks to Hugo for the tip!

Link: MotoRevue (in French)
Link: V11LeMans.com forum with some discussion in English

More photos below:

Ducati V-One closeup

Ducati V-One closeup

Ducati V-One schematic diagram

Ducati V-One schematic diagram


  1. hacksaw says

    i cant say it makes much sense to cut a twin down to a single and then charge it for more power. i appreciate the engineering and the diligence involved , but still, its a big WHY? to me.

  2. says

    A lot of people asked that question you ask hacksaw. I think the answer can only be “because he can” 😉 Theoratically the bike can be lighter (when the engine would be optimised) and the fuel consumption should be better for a one cilinder compared to the 2 cilinder.

  3. Nathan says

    I love the sound and character of big singles. I would always pick one over twins, tripples or 4 pots.

  4. says

    Improving upon the DS motor is an admirable exercise, especially with the stated increases in hp and torque..

    Supercharging is going on in some automotive production models, why not motorcycles? Increased performance and fuel efficiency. Is there any reason to think longevity would be a problem for the OEMs?

    I like the comment on the Guzzi forum that suggests that this setup acts like a single without the vibes of a single.

  5. Hawk says

    I find that the compressed air chamber is an intriguing idea. Open the tap for a 10 sec. burst of power … wow! Kinda like Nos without blown pistons, eh?

    But I wonder why a roots blower would not be a better idea? After all, the output could be gained without the weight and reciprocating mass of the dead front cylinder. Also, the rotating vanes of a roots should be more efficient than a piston pump.

    My first thought was how would this work with both pistons being the same size an operating at the same speed. Then the light dawned … the compressor operates like a two-stroke, pumping on every stroke, and the power cylinder consuming on every second stroke. Theoretically, this should produce about a 14 psi boost at full throttle, notwithstanding the pressure reserve in the chamber.

    But wouldn’t it be easier to simply vary the crank to vane drive on a roots?

    In any case, they’re getting a lot more HP than my old 500cc BSA GoldStar ever thought of. Good engineering exercise …..

  6. todd says

    nice. I find it interesting that the schematic shows offset crank pins. One other benefit from this is half the number of valves to adjust – the others are now likely reed valves. A piston compressor is also more simple and reliable than other solutions but its output volume is fairly low, hence the air storage tank (“battery”) and limited duration of use. This reminds me of the old DKW “Twingle”.


  7. Nicolas says

    Dang, that’s such a great engineering idea, and I’m amazed of the output.

    This thing is probably a blast to ride, a 100HP single in a ducati frame … where do we place the order ?

  8. says

    Very cool! Love seeing this kind of clever design. Don’t hit the air boost in a turn, though!
    Make a kit for the Monster?

  9. Phoebe says

    I’d like to hear it too. I love the sound of singles, and I’ll bet this one sounds very interesting!

  10. MotoWebbi says

    I’ve heard of this type of conversion being done with two cylinders of a VW flat four….not sure of the result!

  11. FREEMAN says

    @RY –
    My brother has a trailer mounted air compressor that he got for free from somebody just wanting to get rid of it. It had a big block V8 and only ran on four cylinders while the other four charged the air tank. So, I guess you probably could take this one step further with a V8, however, I don’t know if you’ll have the same success on the performance end.

  12. B*A*M*F says

    That’s a fascinating way to pump up an engine. I can think of a few advantages of this over a roots or centrifugal supercharger. This method has its own self contained lubrication system. There might also be the potential of using the engine’s cooling system as an intercooler.

    It would also offer a volume of air that directly correlates with engine’s RPM, as opposed to a pump driven off the crank with gearing to offer adequate pressure. Sizing a pulley sounds like choosing a compromise of engine RPM, air volume, pressure, and pump efficiency. Whereas, the second cylinder pumps in the double the volume of air that the firing cylinder wants to draw in on its own, and does pretty much that across the RPM band.

    If someone had the time, money and engineering talent, the pumping cylinder could be made ridiculously over-square with a lighter weight piston for more air.

    I’d love to see someone do this with a twin rotor Wankel engine.

  13. Prestons says

    I think it was in the early ’60’s a magazine like Popular Science showed the General Motors version of this technique. They had an high pressure compressor bolted up to the engine accessory drive system feeding an air tank in the trunk. On demand the air was released into the intake system through a venturi device to transform low volume high pressure air into lower pressure air with higher volume. The idea was to make a small engine perform like a big engine for as long as the compressed air lasted. It was something like 30 seconds. The idea was the economy of a small engine with a burst of power when needed. The compressor had an electric clutch like used in refrigerant compressor so there was no power used when the air tank was up to pressure. It seemed like a great idea but it never made production.

  14. Ry says

    if the compressor cylinder is pumping like a two stroke , did this require a different cam pulley or cam grind? ( My guess is the pulley ratio , I dont think you could double hump a desmodromic valve train) My thoughts of doing a V8 may require a a bit of figuring for that .

  15. Jonas says

    Neat! If they run it on ethanol thay could possibly do away with the intercooler. At least, some guys here in Sweden run turbo-converted bikes on E85 (85%ethanol, 15% petrol) without the need for an IC. The turbocharger or supercharger compresses air and it gets hot. To maximize the benefit it has to be cooled again before entering the cylinder head. This can be accomplished with ethanol as ethanol cools down when vaporized, much more so than petrol, and cools the air when they mix in the intake manifold. Quite elegant actually.

  16. says

    I like the surge tank idea, but other than that it’s 6 of one and half-dozen of the other. The bike still weighs exactly the same (if not more) since it’s still carrying that extra cylinder around, and has just 15 more horsepower? Why not use a nice compact centrifugal supercharger (Procharger makes one for Hardly Ableson’s, should be easy to adapt to a Duc), and boost both cylinders for twice the power/torque increase? Still super cool though, where’s the sound byte or video of it running?

  17. todd says

    Ry, it looks like the rear cylinder no longer has a head (or cam). In its place is a block with two plastic reed valves (atmospheric inlet and exhaust valves). The is how compressors typically work. Engine conversions like the V8 and VW ones just remove the exhaust rocker and push rod. The spark plug is removed and an air fitting put in its place.


  18. aaron says

    ladies and gentleman: the bike cycle world told us ducati would sell in 1993! (they claimed a street legal supermono was in development with a supercharger)

    jokes aside, I’m glad to see this, it’s kind of a holy grail… I don’t know how many people I’ve heard discussing building their own supermono out of a ducati twin – more than a few planned on supercharging it too. until now, I haven’t seen many people actually DO it. (only one other, and when I came across it on the internet it wasn’t actually complete, or in a chassis)

    why the offset crankpin though? this guy must have had enough one-off parts to make without making a new crank.

  19. Kirill says

    Great job, very nice.

    It gives a boost of power; however, the design would deliver less power on average. you cannot have the compressed air and intake from the atmosphere going in at the same time. when the air is getting to the normal cylinder, it cannot have a pressure more then atmospheric if there is no closed valve for the normal air intake. if you have normal intake open and compressed air going in some the air would escape through the intake instead of going in. i think there should be a valve drawn at the “essence”. there is also lost to friction, i think turbo is more efficient.

    so it kind of works as hybrid cars. when u don’t need all the power, you conserve it.
    so this is actually not that efficient but def a great start and smtn to work with. if you can use one cylinder or all to both ignite and pump air into the air tank (u need some kind of reliable valve), then you have an advantage at the price of adding the weight of the air tank (which isn’t that much). the system can be used with engine break a lot of electronics can make this very efficient.

  20. Rafe03 says

    Ah! A valued true dream of us addictied singles EngineHeads!
    The original 1993 Ducati SuperMono 549cc engine was/is a wonderful adaptation of an existing design (Ducati 851 ?) to compete in a completely different class. I found a great site with pics & specs – http://www.motoliam.com/2006/11/ducati_museum_hallowed_halls.html – if it’s still up?! (If not, I have it on a word document)) Apparently, it single handedly dominated the SoS series so that they changed the class rules & it whithered on the vine. If ya can’t beat it, make it illegal! (Or not! Things get distorted when “the media” is my only source of info!) I think that there was a class in Italy solely on the Supermono.
    The design, parts, & manufacturing were all based on pre-existing assets so development & production costs were minimized. A great illustration of thinking outside the box! More than a few were built (series of 80 units?) & are still being used in anger today. For sights & sounds, go to http://www.youtube.com/results?search_query=supermono+ducati&search_type=) or just google “SuperMono”.
    Though promised, the Ducs never seemed to get around to release a “streetified” version. Perceived market too small? No thundering flood of letters, calls, emails, etc offering a downpayment? Some (like Mr Bart Crauwels above & Christophe at http://www.desmono.org/) made their own. Others thought about it (Prime subject for serious bench-racers of the Duc persuasion!) Nice to see that a production program somewhere/anywhere is being contemplated.
    As a paid-up singles freak (XT500, 250 Ducati) I’d really like to get one or 2 of these jems but I don’t have a sponsor to pay the bills for me. Maybe I’ll just have to make a model & add it to my extensive vehicle collection hanging on the wall of my shop! Along with the Hot Wheels, plastic kits, re-cycled kids toys, garage sale finds, etc! I’m not too proud!
    Damn that reality stuff anyway!


  21. todd says

    Kirill, I don’t think it has an atmospheric inlet – i.e. no carb. The port that is labeled “Essence” would probably indicate a fuel injector of some kind. This design would use compressed air from the rear cylinder at all times and temporary higher pressure from the tank. A typical 500 single puts out between 25 and 40 horse, I’m sure this is quite an improvement over those.


  22. BART CRAUWELS says

    I am very pleased by the possitive acceptance of my development.
    The absolute best thing about this design is that the engine is pressurized from the moment you push the start button. The toque curve is absoltute flat.. compare with other motorcycle engines that give 110Nm !!
    the air pressure in the actual airbox wich feeds the engine is electronically controlled at constant pressure !! that’s the big advantage about this development.. the engine feels exactly as a big capacity atmosferic engine . The driveability needs of a motorcycle engine do not accept the typical characteristics of a turbo-roots- screw compressor … because of their variating efficienty. The patented cilinderhead of the compressor can run 10.000 rpm at almost max efficienty..
    At full throtle it runs at 2 bars pressure ( 1,96 actualy) , and and partial throtle it can even run at higher pressure.
    While braking ( and throtlle is closed) the spare airtank fills to max pressure.. this brake-energy recuperates when accelerating .. the compressor has a kind of “off-switch” so compressor is only used when air-pressur in airbox is lower than the adjusted value ( in this case 2 bars)

    We are currently working on the design , use of lighter materials ( prssure tank is still 2mm steel plate , hence the weight!!) reliability and even better performance. ( a 120 hp engine already exists ,and still a 500 cc , 98octane pump fuell!!)

    We plan to build a very limited nr of only 10 “V-ones'” , basically one for every continent.

    And furhter on I am working on a single to go to the bonneville salts… actually I am looking for partners for this adventure in the US..

    for further requieries o the V-one , you can contact me at bart@ducati.be
    greetings from Belgium

  23. BART CRAUWELS says

    and one other big thing about the V -one

    we all want a big capacity torque engine for acceleration , and if possible a small engine when cruising ( fuel economy)

    well here you jave the two in one … it delevers when you ask for it.. a simple 500 single for cruising and a fat torque negine when you need it!!

    and you should hear the sound!!

    I’ll promise to make work of a decend website about the V-one

    grts Bart crauwels +32 477 59 60 61

  24. says

    Love it, I do the same sort of stuff racing in Supermono, only my bike only has one piston, and uses the underside to pump (twice) through reedvalves to the surge tank and intercooler and injection throttle body into the 4stroke combustion chamber.
    Bart, I hope you get in touch.

  25. todd says

    Sounds like John Ellwood has a great idea on how to do it. Do you stuff the crank case like on old two strokes to see higher pressures? This definitely can’t be done without fuel injection unless you run pre-mix. Hmm…


  26. says

    fantastic. the only thing i didn’t like about the big Dukes was the VTwin….and with the supermono almost non-existent things were looking grim.
    As for the comment – why a vtwin to a single.
    Its obvious isnt it – single is the best. 1 plug, one cylinder, 1 powerband, 1 torque curve…… if the bike sucks against the others all you can blame is the rider….
    That and in traditional single setups the engine is just directly tied to the drivetrain, So the engine doesn’t have to fight the otherside of the motor. That is why sports cars with “v” engines have very acute angles on the V configuration, so less effort is made in fighting the other side

  27. toby says

    a british builder did that in the 50’s or 60’s so it’s nothing new but still bitchen!

  28. Steve Piesley (Melbourne Australia) says

    Wonder if the balance of the engine is effected greatly?, if the “Supercharger”is acting as a 2 stroke. Or would it smooth it out further.

  29. emmett boudreaux says

    Look at what Creel is doing US patent 6,907,850. He is working on utility motors right now and building so much power that the crank cannot stand up to the power stroke. The advantages of supercharging are surfacing since the push for more efficient engines.

  30. punkozuna says

    Bart, very, very clever idea. Do you have any fuel consumption data? The dynamic engine braking made possible by using the compressor to store braking energy while compressing air is intriguing. Have you thought about making your compressor double acting? i.e. collecting compressed air from under the piston too? It would take a couple of reed valves (intake and exhaust) somewhere on the engine casing and a method to discourage lubricating oil from entering the air stream. In theory, you’d double the volume of air through your compressor. Many interesting possibilities for more power or better efficiency. Again – great idea. Great execution of the idea too.

  31. Rick_A says

    Cool idea, but it seems a traditional turbo do the same job with less complexity and more efficiency.

    John Ellwood’s method is brilliant.

  32. RMT says

    Nice job, well done but what’s the point ? An old Honda vtr 1000 Superhawk can make 115 rwhp and 72 ftlb torque with some tuning and will go 100k touble free miles………

  33. todd says

    RMT, some people like 500 singles far greater than 1000 cc V-twins. Besides, don’t you feel pretty anonymous on one of those?


  34. Thom says

    I believe DKW used a similar idea back in the forties or fifties… I may have the manufacturer wrong, maybe NSU, but I remember the name distinctly- “Ladepumpe”. It meant “supercharging cylinder.” Very effective before supercharging was banned in GP bikes… As I recall, the bike was also a “split single.” Basically a parallel twin with a 360 degree crank and a shared combustion chamber. The supercharging cylinder was aimed forward, and had a very short stroke and large bore. I’m sure i have the details wrong, please forgive me, just noting I see where the idea came from, and it has worked in the past, so why not now, with our more modern materials and technology?

  35. Roy the Boy says

    I just happen to have a 1000 monster laid in stock as a doner bike for such a project such as this, My pal Mick (le fooey) has been hankering after making a super mono single for ages using a 916 engine, one of those coverted to a single made 110bhp at the rear wheel, with a chuffer as the rear pot it could top 125, gas it with nitrus oxide… mmmmm serious black line laying properties.. mind Mick would have to eat more pies, to keep weight distribution in the correct area, yet he looked so cool in my silver leathers the other day.. the technical back-of Fag packet drawing would lead to some discussion with the conrods not using the common crank pin, but these projects are exactly what life is all about, it stops the primary female figure demanding you take time to go shopping, especially on those days you just want to watch a gp, road race, or have a beer while working where parts can be crammed into tight spaces. very interesting, just think where the air tank blow off valve coud be situated exiting through a wopee cushon, (the disgust on little old ladies faces)….
    Guys the drawing of the twin crank pins is rubbish, it uses the single crankpin, but it has you lot going.. I reckon total cost of conversion would be around £400. but the time spent in doing it from scratch 4 months@ say £30 per hour, that is the sting in the tail.