New Ducati Panigale V4 Superbike Is A Giant Leap Forward | Cycle World
Courtesy of Ducati

New Ducati Panigale V4 Superbike Is A Giant Leap Forward

Years of V-twin and MotoGP development has resulted in a combustion model that works superbly

Ducati has released its 214-hp desmodromic-valve Panigale V4, ending development of ever-larger V-twins in favor of a direct connection to all the company has learned in MotoGP. The 1299 Panigale pushed cylinder bore to an amazing 116mm, straining the limits of combustion control. In future, engineers say, 100mm will be the largest bore produced (in the form of the Panigale 959).

Ducati school

Ducati Panigale V4: School is in session.

Courtesy of Ducati

Bore and stroke of the V4 are “inspired” by the MotoGP limit—81.0 x 48.5mm—dimensions chosen to prevent factories from exploring the extremes of Formula 1, where at one time bore/stroke ratios closed in on 2.5:1 (which, in MotoGP cylinder size, would give dimensions of 92.6 x 37.0mm!). Adding 5mm to the 48.5mm stroke of MotoGP gives 53.5mm, which, with the 81mm bore, delivers a displacement of 1,102.7cc or 67.3ci. The power curves shown to me in Bologna revealed peak power at a moderate 13,000 rpm, at which point the V4’s peak piston acceleration is less than that of decade-old 600 sportbike pistons.

Ducati V4’s exhaust system

A side view of the road-going V4’s exhaust system. Tapped ports are for the oxygen sensors that allow modern bikes to continuously adjust their fuel/air mixture for temperature, barometric pressure, and altitude. When you see an oxygen sensor, think of Kel Carruthers or Erv Kanemoto, staring into the depths of a spark plug, the old way of measuring mixture strength.

Courtesy of Ducati

With the Speciale version comes an all-titanium Akrapovic exhaust system that raises power to 226 hp at a claimed dry weight of 414 pounds. That is a weight-to-power ratio of 1.83 pounds/hp. To give my 1966 Yamaha YL2C that ratio would have required 100 more horsepower than it actually had.

They say that bears reach as high as they can on a tree trunk and make deep scratches with their foreclaws, giving notice to smaller bears that this territory is taken. As once observed by actor Robert Mitchum, you can’t become tall by taking lessons, but Ducati has pushed its claw marks far up the tree with this V-4.

That results from:

  1. Ducati’s proven ability to develop reliable high power

  2. Claudio Domenicali’s insistence that every Ducati part be the result of weight reduction and performance improvement

  3. Incorporation of what MotoGP can contribute to mainstream motorcycling

Julien Clement

Frenchman Julien Clement, the V4’s stylist, designed what is now Ducati’s Scrambler while an intern in university.

Courtesy of Ducati

Yes, mainstream. For this is a production motorcycle to be ridden every day, not a collector’s curiosity to be hung in static ignominy above some hedgie’s fieldstone fireplace. A major goal of V4 engine development was rideability. In general, the greater the valve event overlap in an engine’s cam profiles, the fussier and peakier its performance becomes. At the height of racing two-valve sophistication (Manx Norton, Velocette KTT, etc.) valve overlaps of 90 to 100 degrees were commonplace. The other end of the spectrum is Harley-Davidson, whose big twins have valve overlaps near zero. Close on its heels is Ducati’s Diavel power cruiser with just 11 degrees overlap. At the other current extreme is Suzuki’s GSX-R1000, with something like 70 degrees of overlap.

Ducati torque

There it is, clear as day: 214 hp at 13,000 rpm. Of even more interest is the wide region of essentially constant torque from 9,000 to 11,700. I suspect that the small wiggles in this curve result in part from the machinations of the variable-length intake system. Torque is essentially 92 lb.-ft. in this 2,700-rpm-wide zone.

Courtesy of Ducati

Where does Ducati’s V-4 fall in this spectrum? Twenty-six degrees. That means good strong torque and drivability. A look at the actual curve shows peak torque maintained from 9,000 to 11,500 rpm with plenty below. That’s drivability.

Contributing to this is a two-position, variable-length intake system. Intuitively we expect variable-length intake to be a kind of slide trombone affair, but there’s no room and no need. If correct intake length is 7-1/2 inches at 10,000 rpm, then we’d need 15 inches at 5,000 rpm. Where would we put all that 52mm tubing? Intake systems have already commandeered most of what used to be the fuel tank.

Ducati aluminum casting

Several views of the forward chassis, revealing how air flow from fairing nostrils passes the steering head. For an idea of how thin those struts are, look at the edge of the beam. This aluminum casting weighs 9 pounds.

Courtesy of Ducati

So why have a system that varies length by just an inch? Intake length is chosen so it is a positive pressure wave that arrives at the port as the valves are closing. That can boost torque by as much as 10 percent—well worth having. But what happens at some lower rpm, when it’s a negative wave that arrives at valve closure? You guessed correctly: It kills torque to the tune of 10 percent, creating a weak place in the torque curve. The Ducati system dances around that weak place, avoiding the negative wave peak by going long/short, long/short as the engine pulls across its range of highest torque.

Ducati V4 engine

On its arty Lucite stand, here is a V4 engine with its intake system in place. Each of the four bell mouths has two positions. In the “down” position seen here, intake length is long. Moving the links between the two lifts one set of bells up to give a shorter intake length. Motion is two positions 25mm apart. Intake length does not follow rpm; its purpose is just to smooth out air delivery in an rpm range in which it would otherwise become chaotic as a result of the engine’s wave action.

Courtesy of Ducati

The two biggest generators of torque are intake flow (the gross amount of charge trapped in the cylinder) and compression ratio, which determines how much “push” the combustion of that charge gives. A third partner is combustion itself—its speed, completeness, and margin of safety against detonation. The number for this engine is 14:1. Here, Ducati’s long development of ever-changing V-twin superbike engines and 15 years in MotoGP have given it a combustion model that works superbly. While the Japanese companies flailed about in the late 1980s and early-to-mid-’90s trying to learn how to burn big-bore short-stroke combustion chambers, Ducati moved with assurance that really impressed me.

Now for weight control: There are other machines with close to 200 hp but they are really power stations on wheels, 500-pounders on long, slow-turning wheelbases. They have their place.

Weight becomes doubly important when parts rotate (clutch, crankshaft, wheels) as well as passively move with the vehicle. In the past, the engine and wheels rotated in the same direction so that their several resistances to direction changing added. But because the V4’s engine rotates opposite to the wheels, its resistance is subtracted from theirs, making this bike much easier to flick right and left. Reverse engine rotation is now universal in MotoGP. In this V-4 it is achieved by placing an idler gear between the crankshaft pinion and clutch gear.

Ducati steering head

On the left, the steering head and its “spider,” which by allowing some lateral flex improves tire grip in high-angle cornering and provides confidence-boosting “feel” to the rider. On the right, the production exhaust system and under-engine muffler body. In the past, we most admired exhaust systems that resembled upswept classical megaphones or 4-2-1 collectors. But today we must accept the valve of mass centralization; the motorcycle whose mass distribution is most like that of a cannonball is the easiest to maneuver. This leads us straight to the under-engine muffler as a best solution.

Courtesy of Ducati

The goal of the Panigale V4 was to be a usable normal motorcycle of tremendous performance. To make it light, every part had to be considered. To this end, the “chassis” is just two separate elements totaling 20 pounds. The 9-pound forward frame’s job is to support the steering head from four points on the engine, such that braking and twisting forces are strongly resisted while giving enough lateral flexibility to keep the front tire following pavement irregularities, even at high lean angles when the normal suspension is pointed the wrong way.

Luca Bandiera

That is engine guy Luca Bandiera speaking. The presence of the black plug in the right-hand face of the forward head locates the cam chain tensioner, indicating that this engine does indeed rotate backward.

Courtesy of Ducati

Ducati starter

Yes, what they say about the extraordinary power of rare earth magnets is true; that’s how that tiny starter can get the job done. I like to stare at things because that’s how I eventually notice interesting details.

Courtesy of Ducati

Display crank

A display crank that has been plated to prevent our moist and salty fingers from darkening it with rust. Crankpin oil holes bypass the hollow crankpin bores, and oil is fed to them from the end, racing style. Note the generous fillet radii where journals join the cheeks, necessary to reduce stress concentration there. Large counterweights are likewise necessary because in 90-degree V-twins (this is a pair of them, with crankpins offset by 70 degrees) the counterweight 100 percent of one cylinder’s reciprocating mass (one piston, its rings, wristpin, and the rod’s small-end weight).

Courtesy of Ducati

To achieve this, the four legs of the forward frame had to be symmetrical. But where one of the legs had to go there was nothing to which to attach it. So, in Panigale V-twin fashion, a three-legged bracket was bolted in place to provide the necessary anchorage.

Ducati pistons

The lovely nine-cavity forged pistons, whose simple crown shape is designed to minimally interfere with flame-speeding charge motion. The pale straw color of the crown and ring belt results from hard anodizing their surfaces (conversion to hard aluminum oxide ceramic) for its wear- and erosion-resisting qualities. The 81mm pistons are cooled by crankcase oil jets aimed up against one side of the crown’s underside. This oil, in splashing across the underside and down as it hits the far skirt, usefully cools the metal, allowing a thinner-domed and lighter piston—essential to operation at high revs—to survive. Middle cavity struts parallel with the wristpin have had “windows” milled through them to create this pathway for cooling oil. Although some high-performance pistons today are made asymmetrical (thicker-skirted on the thrust side, thinner on the opposite) these are symmetrical. In former times, pistons in air-cooled engines rid themselves of heat mainly by extensive contact with the cylinder wall, but pistons today can have short, narrow skirts as you see here.

Courtesy of Ducati

The rear frame is just the 11-pound single-sided swingarm, conceptually consisting of two elements. The first is the very stiff box-section arm itself, and the other is its forward section, whose job is to provide lateral flexibility just as the forward frame does. In this case, it is implemented as a pair of vertical “blades” joining the arm to its pivots on the back of the gearbox.

Ducati V4

This is the road-going V4 with Showa BPF fork, aluminum wheels, and standard exhaust. Its style shows several influences: the organic grace of the 916 tradition, the darty points that were made popular by the original Yamaha R1, and the up-thrust seatback seen in Europe’s “streetfighter” trend. There is also the “peek-a-boo” revelation of functional parts that leads the curious eye to explore. The MotoGP look comes from the far-forward riding position and the visual de-emphasis of the headlights to invisible positions inside the “nostrils” of the fairing nose.

Courtesy of Ducati

The engine itself is always the heaviest element, but through modern casting, detail design, and liberal application of magnesium, that package weighs 142 pounds, just 2 pounds more than the engine of Yamaha’s nine-time Daytona-winning TZ750 two-stroke.

S version of the Panigale V4

This is the “S” version of the Panigale V4 with Öhlins suspension, Marchesini forged magnesium wheels saving 2.2 pounds, and titanium Akrapovic exhaust.

Courtesy of Ducati

Zach Courts

Zack Courts has a close-up look at the V4’s dash.

Courtesy of Ducati

These solutions deliver MotoGP flexibility, save weight, and please the many Ducati owners who love the single-sided swingarm.