So this ducati diavel, it says its an L twin, this L twin makes 162 horse power, how the hell can it make that much power with two cylinders, thats 80 plus per cylinder. I know it must have some fairly big jugs but it just seems outside the realm of a max single cylinder output normally aspirated, what am I missing hear? Never cared for ducati but also never rode one, I had poor friends like me!
When I was showing my chopper that I built. Doc from doc's hd had a "detuned" top fuel twin in his chopper said it was "probably about 450, 480 hp." Biggest juggs uh, cylinders you'll ever see on a motorcycle. Engine almost looked comical. It was so big. He rode it in. (From the trailer)
Quote from: gumby302ho on October 13, 2016, 10:00:38 PM
So this ducati diavel, it says its an L twin, this L twin makes 162 horse power, how the hell can it make that much power with two cylinders, thats 80 plus per cylinder. I know it must have some fairly big jugs but it just seems outside the realm of a max single cylinder output normally aspirated, what am I missing hear? Never cared for ducati but also never rode one, I had poor friends like me!
It's about displacement, not the number of cylinders.
Broadly speaking, 1200cc spread over 2, 3, 4, 5, 6, 7 or 8 cylinders is going to produce similar power (but deliver it differently)
IMO
The KTM 690 Duke single cylinder bike, is close to 80 HP.
Quote from: giantkiller on October 13, 2016, 10:38:55 PM
When I was showing my chopper that I built. Doc from doc's hd had a "detuned" top fuel twin in his chopper said it was "probably about 450, 480 hp." Biggest juggs uh, cylinders you'll ever see on a motorcycle. Engine almost looked comical. It was so big. He rode it in. (From the trailer)
Maybe you're the guy to ask; the H-D's (or at least they call them H-D's) I see on videos drag racing on a track - what's the same and what's totally different about the engines they use from a street issue stock Harley?
Is it about the same as comparing a funny car with a bow tie on the hood to my mom's Chevy Cobalt?
The "Harley" drag bikes have an 800cc displacement advantage, there is NOTHING on those motors that Harley Davidson is even remotely connected to, other than the big cheques they write. Always makes me laugh when I hear guys talk about how great they are at drag racing. If you are given a huge advantage by the sanctioning body you win.
Kind of like when Buell, " Harley Davidson" used a 1,000cc twin to beat the Japanese 600's. Wow what an accomplishment. I would embarrassed to even show up.
Quote from: ribbert on October 14, 2016, 03:53:14 AM
Quote from: gumby302ho on October 13, 2016, 10:00:38 PM
So this ducati diavel, it says its an L twin, this L twin makes 162 horse power, how the hell can it make that much power with two cylinders, thats 80 plus per cylinder. I know it must have some fairly big jugs but it just seems outside the realm of a max single cylinder output normally aspirated, what am I missing hear? Never cared for ducati but also never rode one, I had poor friends like me!
It's about displacement, not the number of cylinders.
Broadly speaking, 1200cc spread over 2, 3, 4, 5, 6, 7 or 8 cylinders is going to produce similar power (but deliver it differently)
IMO
I suspect a smaller cylinder gets a better power:displacement ratio than a larger one. Seems to me that the intake side of the equation favors several small containers over a single large one and there is probably better flow through more valve area. Also, the lower mass of the smaller pistons translates into lower inertial load which allows a higher redline, an issue which is also subject to a more inches = longer stroke = higher piston speed at any given RPM string equation. I wonder what the model airplane motors power:displacement ratio's are. On the question at hand, I doubt that there is an upper limit on the power one jug can produce. Harley dragsters have been making a lot of power for a long time and I wonder what the big naval motors put out.
just my thoughts on the matter.
Quote from: Charlie-brm on October 14, 2016, 08:33:29 AM
Quote from: giantkiller on October 13, 2016, 10:38:55 PM
When I was showing my chopper that I built. Doc from doc's hd had a "detuned" top fuel twin in his chopper said it was "probably about 450, 480 hp." Biggest juggs uh, cylinders you'll ever see on a motorcycle. Engine almost looked comical. It was so big. He rode it in. (From the trailer)
Maybe you're the guy to ask; the H-D's (or at least they call them H-D's) I see on videos drag racing on a track - what's the same and what's totally different about the engines they use from a street issue stock Harley?
Is it about the same as comparing a funny car with a bow tie on the hood to my mom's Chevy Cobalt?
It's pretty much the same as a funny car and your mom's Cobalt.
I'm not a Harley guy either. There is nothing on my chopper that is Harley. The engine is an evolution design. But it's 100% after market(only 120hp. but 120ftlbs! 6 more than my 1350) . And 100 made In the USA . As is the rest of my chopper. Alot hand made in my garage. The only thing that might not be is the ignition.
Picture of my chopper and me. When I was in shape.
Bottom picture is of the mini chopper I made for my daughter.
Quote from: ribbert on October 14, 2016, 03:53:14 AM
Quote from: gumby302ho on October 13, 2016, 10:00:38 PM
So this ducati diavel, it says its an L twin, this L twin makes 162 horse power, how the hell can it make that much power with two cylinders, thats 80 plus per cylinder. I know it must have some fairly big jugs but it just seems outside the realm of a max single cylinder output normally aspirated, what am I missing hear? Never cared for ducati but also never rode one, I had poor friends like me!
It's about displacement, not the number of cylinders.
Broadly speaking, 1200cc spread over 2, 3, 4, 5, 6, 7 or 8 cylinders is going to produce similar power (but deliver it differently)
IMO
I cant agree with you on that Noel, alot of big Hardly's out there with same displacement as the FJ and the ducati(not even close) multiple valves dont count either broadly speaking! I know its apples and oranges but 80 hp in one flipping cylinder, I need to read up and see how this L twin can flow so much air.
Quote from: gumby302ho on October 13, 2016, 10:00:38 PM
So this ducati diavel, it says its an L twin, this L twin makes 162 horse power, how the hell can it make that much power with two cylinders, thats 80 plus per cylinder. I know it must have some fairly big jugs but it just seems outside the realm of a max single cylinder output normally aspirated, what am I missing hear? Never cared for ducati but also never rode one, I had poor friends like me!
It's 162 horsepower, and 96 ft/lbs of torque!
At roughly 600cc per cylinder, they are twice the size of our FJ cylinders.
Air flow into and out of the cylinder is the key to these power figures.
They use 4 valves per cylinder, two plugs per cylinder, and huge elliptical throttle bodies.
I believe they use two injectors per cylinder also.
It has 106mm bore, and 68mm stroke, and 12.5:1 compression ratio.
I have ridden one, and I can say that it has BRUTE power! Instant torque and throttle response in any gear, at any rpm. Handles surprisingly well for such a long-wheelbase muscle-bike also, but it is lighter than our FJs.
Would I buy one? No, it's not really my kind of bike.
They do know how to make power though.
Quote from: gumby302ho on October 14, 2016, 11:18:39 PM
Quote from: ribbert on October 14, 2016, 03:53:14 AM
It's about displacement, not the number of cylinders.
Broadly speaking, 1200cc spread over 2, 3, 4, 5, 6, 7 or 8 cylinders is going to produce similar power (but deliver it differently)
IMO
I cant agree with you on that Noel, alot of big Hardly's out there with same displacement as the FJ and the ducati(not even close) multiple valves dont count either broadly speaking! I know its apples and oranges but 80 hp in one flipping cylinder, I need to read up and see how this L twin can flow so much air.
Noel is mostly correct on this.
Back in the late 60's/early 70's, Formula 1 car engines were limited to 3.0 liters capacity.
The many manufacturers came up with wildly different designs.
Cosworth(Ford) had their popular DFV V-8 engines. Honda, Ferrari, Gurney, and Matra had their V-12 engines. And BRM even had an "H-16" engine! (Basically two flat-8 engines stacked on top of each other, sharing a common crankcase). They all produced right around 400 horsepower.
One of the problems with multi-cylinder engines, is the more cylinders you have = the more internal friction you have, as there is more ring surface area contact for any given displacement. However, the less cylinders you have, the beefier those parts are required to be, and you now have to accelerate/decelerate those more massive parts. (Like having a piston and connecting rod that's designed to handle 100 horsepower, instead or 4 smaller/lighter ones that are designed to handle 25 horsepower each)
I think there is some sort of balance between the two, such that some manufacturers choose to design one way or the other. Like Ducati or Yamaha, 2-cylinders or 4? They do make similar power, but make it in slightly different ways.
Quote from: Firehawk068 on October 20, 2016, 03:06:00 PM
Quote from: gumby302ho on October 14, 2016, 11:18:39 PM
Quote from: ribbert on October 14, 2016, 03:53:14 AM
It's about displacement, not the number of cylinders.
Broadly speaking, 1200cc spread over 2, 3, 4, 5, 6, 7 or 8 cylinders is going to produce similar power (but deliver it differently)
IMO
I cant agree with you on that Noel, alot of big Hardly's out there with same displacement as the FJ and the ducati(not even close) multiple valves dont count either broadly speaking! I know its apples and oranges but 80 hp in one flipping cylinder, I need to read up and see how this L twin can flow so much air.
Noel is mostly correct on this.
Back in the late 60's/early 70's, Formula 1 car engines were limited to 3.0 liters capacity.
The many manufacturers came up with wildly different designs.
Cosworth(Ford) had their popular DFV V-8 engines. Honda, Ferrari, Gurney, and Matra had their V-12 engines. And BRM even had an "H-16" engine! (Basically two flat-8 engines stacked on top of each other, sharing a common crankcase). They all produced right around 400 horsepower.
One of the problems with multi-cylinder engines, is the more cylinders you have = the more internal friction you have, as there is more ring surface area contact for any given displacement. However, the less cylinders you have, the beefier those parts are required to be, and you now have to accelerate/decelerate those more massive parts. (Like having a piston and connecting rod that's designed to handle 100 horsepower, instead or 4 smaller/lighter ones that are designed to handle 25 horsepower each)
I think there is some sort of balance between the two, such that some manufacturers choose to design one way or the other. Like Ducati or Yamaha, 2-cylinders or 4? They do make similar power, but make it in slightly different ways.
Quote from: Firehawk068 on October 20, 2016, 03:06:00 PM
Quote from: gumby302ho on October 14, 2016, 11:18:39 PM
Quote from: ribbert on October 14, 2016, 03:53:14 AM
It's about displacement, not the number of cylinders.
Broadly speaking, 1200cc spread over 2, 3, 4, 5, 6, 7 or 8 cylinders is going to produce similar power (but deliver it differently)
IMO
I cant agree with you on that Noel, alot of big Hardly's out there with same displacement as the FJ and the ducati(not even close) multiple valves dont count either broadly speaking! I know its apples and oranges but 80 hp in one flipping cylinder, I need to read up and see how this L twin can flow so much air.
Noel is mostly correct on this.
Back in the late 60's/early 70's, Formula 1 car engines were limited to 3.0 liters capacity.
The many manufacturers came up with wildly different designs.
Cosworth(Ford) had their popular DFV V-8 engines. Honda, Ferrari, Gurney, and Matra had their V-12 engines. And BRM even had an "H-16" engine! (Basically two flat-8 engines stacked on top of each other, sharing a common crankcase). They all produced right around 400 horsepower.
One of the problems with multi-cylinder engines, is the more cylinders you have = the more internal friction you have, as there is more ring surface area contact for any given displacement. However, the less cylinders you have, the beefier those parts are required to be, and you now have to accelerate/decelerate those more massive parts. (Like having a piston and connecting rod that's designed to handle 100 horsepower, instead or 4 smaller/lighter ones that are designed to handle 25 horsepower each)
I think there is some sort of balance between the two, such that some manufacturers choose to design one way or the other. Like Ducati or Yamaha, 2-cylinders or 4? They do make similar power, but make it in slightly different ways.
Well I do agree on design and they can engineer many shapes and sizes and outputs but with a cost to each, I still believe majority rules up to a certain point. Compare a 400 single to a 400 twin to a 400 four cylinder and easily the power output increases throughout, most likely a cost and production issue with quality not needed to be race proven application, military, aviation etc, etc. Better fuel atomization being spread out over multi valves and multi cylinders will always out compete a single cylinder of same displacement.
Over the years from high school, through the eighties, I owned a number of Ducatis. All tower shaft
cam drives. Some desmo units some valve spring types. Long before Ducati's return to GP racing, I had little knowledge of them beyond their being built by an odd little Italian maker.A decade or so into a career in motorcycle mechanics and I began to acquire an appreciation of what a remarkable machine
they really were .Eng Dr Taglioni who was still the head design engineer had, with no small success, persued the path of increased specific output by increasing usable , safe, higher RPM limits. His preference for oversquare engine dimensions proved successful. as it did for Soichiro Honda. His little singles made more power than many other makes of similar displacement.Add to this, the achievement of his adapting the Desmodromic system of valve actuation to many models to further increase the ceiling RPMs.. Making this standard fare on street bikes. When Burliner motors was the sole American importer for Ducati, Joe Berliner asked Dr T. if he would design a big bike to sell to the Police forces in America. Ducati responded with the 4cyl.Apollo. This was not a commercial success . However when the need for a larger twin to augment their smaller single cylinder bikes arose , Dr T took half of his 4 cyl design and
built his first 'L' twin. This is not a 'V'twin , as the cylinders are set at 90 degrees. The inherent advantage in this design is it's primary balance. Look at the HD v twin They are 45 degrees apart but both rods are on one crankpin. This means there is a huge amount of mass reciprocating nearly together. Both pistons reaching maximum velocity at nearly the same time,(very long stroke, very high piston speed)
and then being halted to zero velocity within a mere 45 degrees of each other. Good as a paint shaker. The Ducati with cylinders disposed at 90 degrees both on the same crankpin is able to cancell out the inertia of each piston as one is at max velocity while the other is at zero velocity.That is perfect primary balance. Easier to make more power when the engine is not shaking itself to pieces All of the subsequent Ducati twins have been built this way . You must drive one of them to really understand just how smooth they are.
Cheers
Simon
Quote from: Earl Svorks on October 28, 2016, 04:38:55 PM
Over the years from high school, through the eighties, I owned a number of Ducatis. All tower shaft
cam drives. Some desmo units some valve spring types. Long before Ducati's return to GP racing, I had little knowledge of them beyond their being built by an odd little Italian maker.A decade or so into a career in motorcycle mechanics and I began to acquire an appreciation of what a remarkable machine
they really were .Eng Dr Taglioni who was still the head design engineer had, with no small success, persued the path of increased specific output by increasing usable , safe, higher RPM limits. His preference for oversquare engine dimensions proved successful. as it did for Soichiro Honda. His little singles made more power than many other makes of similar displacement.Add to this, the achievement of his adapting the Desmodromic system of valve actuation to many models to further increase the ceiling RPMs.. Making this standard fare on street bikes. When Burliner motors was the sole American importer for Ducati, Joe Berliner asked Dr T. if he would design a big bike to sell to the Police forces in America. Ducati responded with the 4cyl.Apollo. This was not a commercial success . However when the need for a larger twin to augment their smaller single cylinder bikes arose , Dr T took half of his 4 cyl design and
built his first 'L' twin. This is not a 'V'twin , as the cylinders are set at 90 degrees. The inherent advantage in this design is it's primary balance. Look at the HD v twin They are 45 degrees apart but both rods are on one crankpin. This means there is a huge amount of mass reciprocating nearly together. Both pistons reaching maximum velocity at nearly the same time,(very long stroke, very high piston speed)
and then being halted to zero velocity within a mere 45 degrees of each other. Good as a paint shaker. The Ducati with cylinders disposed at 90 degrees both on the same crankpin is able to cancell out the inertia of each piston as one is at max velocity while the other is at zero velocity.That is perfect primary balance. Easier to make more power when the engine is not shaking itself to pieces All of the subsequent Ducati twins have been built this way . You must drive one of them to really understand just how smooth they are.
Cheers
Simon
Nice'sa, I alike'a what you a wrote'a! :hi:
Thank you sir, I graduated at Whatsa Matta U .
Lemme start out by saying that I've never driven a Diavel. The only ducati's I've driven were a Cagiva Elefant and my buddy's race 748. That said, I'm somewhat experienced in the vagaries of different engine design.
V-Twin, harley style. Single crankpin, dual cylinder. poTAto. It's inherent in the design, and was originally designed that way not because it made sense mechanically but because it fit in the bicycle style frame they were using.
For those of you who made fun of buell competing with a big cc advantage, let me point you to the beginning of the end of 2-strokes where 250cc 4-strokes competed with 125 2-strokes, 450cc 4 strokes competed against 250cc 2-strokes. Let me also point out that the buell was air cooled. They're not directly comparable cc:cc . If you want directly comparable then look at the CRF450 vs RVX450. Single vs Twin, same displacement, nearly the same HP, but entirely different attitudes.
v-twin, split-crank pin style: by varying the split on the crankpin you can make any v angle act and or feel like any v angle you want. Disadvantage here is crank wobble and weakness between the crankpins.
L-Twin: Ducati, suzuki v-strom, honda vtr, aprilia, etc. Perfect primary and secondary balance. You can spin them like crazy and they don't vibrate.
I-4: Lots of variations, from the big-bang to the crossplane. Big bang fires two cylinders at a time like a pair of linked parallel twins, for discrete power pulses. Crossplane fires one after the other after the other after the other. Same power, different delivery, and different stresses involved. Theoretically a crossplane crank can be made lighter since it only has half the torque applied per event. More vibration though.
I2: Typically considered buzzy, can be either 360* or 180*, with the difference being the same as crossplane vs big bang.
O2-4-6. BMW, goldwing. Perfect balance in nearly every way. Seriously, youtube for 'the nickel trick' Disadvantage is weight.
Ok, single or parallel vs twin, as defined by separate heads: This means anything from a single, parallel twin, I3, 4, or 6 vs a v-twin or v-4 (discounting the odd other style) The more cylinders you add other than inline, the more weight increases relative to the displacement. I4: 1 cylinder head, one or two cams, one cam chain, one water jacket/cooling fin set. V2, two cylinder heads, 2 or 4 camshafts, two camchains or gearsets, two water jackets, etc. Narrower but heavier for the same displacement.
Where do I bring useful info into this? Who knows. I've had both a vstrom 650 and 1000, (L-twin) and have their counterpart the Versys650. (parallel twin) I've had a VFR700 and a VFR800. (Both V-4, which are more accurately considered either linked parallel twins or linked L-twins) I've had an XR400, XR416 and an XR650R and a buell blast. (all of which are single cylinder thumpers) and I have a Dnepr MT16 I've got a GL1000 (Opposed twin and O-4) Plus I've had any number of I4 bikes, not least of which is the FJ12. Pretty much my only lack of experience is in I3s. Any engine can be made to do nearly anything. The 'character' a bike has is largely determined not by it's HP number but it's delivery of power. The VFR8 has an awesome engine, quick to rev but torquey as well. The Stroms made good power and were so smooth that revving them was irrelevant. The versys has a much more sporty feel than the strom, but is still half the power of a modern 600cc supersport.
To directly answer your question as to how the diavel can make so much power, look at it this way. A cylinder only makes power for about a third of the crank's rotation, the rest is drag including the whole second rotation. If you can get more than one cylinder to share that drag you can free up lots of 'extra' hp. One cylinder fires, then the drag begins. Before it gets too far, the other cylinder fires, it's power stroke overcoming the drag stroke of the first. It's drag stroke begins, the first cylinder goes back to work and makes power again. Gestalt, as it were. More than the sum of it's parts.
Plus ducatis are built by hot Italian women, which inherently makes them faster. :mocking: