~ Auto Buzz ~: Ducati Desmosedici Stradale V-4 Engine Revealed

Ahead of the San Marino MotoGP round at Misano World Circuit Marco Simoncelli, Ducati revealed its much-anticipated new Desmosedici Stradale V-4 engine that will power it’s next generation of superbikes. Ducati claims a maximum output of 210 hp at 13,000 rpm and 88.5 lb-ft. at 12,250 rpm.

The 1103cc (more on that later) 90° V-4 engine has a 14:1 compression ratio and at 143 pounds, weighs about 4.9 pounds more than the Superquadro V-Twin engine powering Ducati’s current bikes. The engine uses four valves per cylinder, each activated with Ducati’s signature desmodromic system. The crankshaft is counter-rotating, turning in the opposite direction from the wheels to offset gyroscopic effect of the rims while using its inherent inertia to help mitigate wheelies.

The crankshaft is counter-rotating with crankpins set at 0°, 90°, 290° and 380° for a Twin Pulse firing order.

The crankpins are offset at 70° to incorporate a “twin pulse” big bang firing order, with ignition points coming at 0°, 90°, 290° and 380°. Assuming the cylinder on the front bank closest to the alternator fires first at 0°, the cylinder on the same side but on the rear bank fires next at 90°. This is followed by a slight pause before the two cylinders on the clutch side fire 90° apart. According to Ducati, this firing order offers easy-to-handle power and strong traction out of corners.

The Desmosedici Stradale engine (right) shares the same configuration and dimensions as Ducati’s MotoGP engine (left).

The choice of presentation venue helps highlight the engine’s connection to the V-4 powering Ducati’s Desmosedici MotoGP race bike; indeed, the Stradale shares the race engine’s dimensions and 90° V-4 configuration, including its 42° rearward rotation. According to Ducati, the engine dimensions and geometry allow for a compact powerplant, centralizing the mass and making it easier to incorporate into a motorcycle.

But the Desmosedici Stradale does differ from the MotoGP engine in one surprising way: the 81 mm bore is the same as on the MotoGP bike but the 53.5 mm stroke gives the Stradale engine has an 1,103 cc displacement, making it a 103cc larger than the MotoGP engine. It also means the Desmosedici Stradale engine exceeds the the current 1,000cc displacement limit for four-cylinder engines in World Superbike championship where Ducati’s next superbike is presumably intended to compete. Ducati says it will introduce an R version of its new bike with a smaller displacement to be homologated for competition.

The Desmosedici Stradale uses four oval throttle bodies with variable-height intakes to optimize intake across the rev range. The intakes use a fixed horn on the throttle body and a mobile horn that moves along steel guides, modulated by an electric motor controlled by the ECU. Each throttle body has two injectors, a sub-butterfly injector for low-load use and an injector above the buttefly valve for higher engine performance needs.

Ducati redesigned the demsodromic system, reducing its overall size for smaller cylinder heads. The 16 valves are controlled by four camshafts that run on a pair of timing chains. Instead of using springs, the valves are mechanically closed, allowing for steep cam profiles and radical cam timings as the engine revs up to its 14000 rpm limit. Following a company trend in recent years, Ducati has increased the maintenance intervals, so the valves only need inspection and adjustment every 15,000 miles (general service remain at the same 7,500-mile intervals for the Superquadro engines.)

Like the MotoGP engines, the Desmosedici Stradale uses a semi-dry sump lubrication system. The circulation system uses four pumps: one delivery lobe pump and three recovery pumps. One recovery pump is dedicated to drawing oil from the head via two ducts while the other two are to ensure efficient oil recovery in all conditions, maintaining a low pressure state and reducing power loss from aerodynamic resistance from air and the splashing of oil in the connecting rod casing. The oil tank with integrated filter housing is in the magnesium sump below the crankcase. A dedicated radiator mounted below the water radiator cools the lubrication.

Attached to the engine is a six-speed transmission, ready for a quick shifter. The wet clutch is hydraulically controlled, with 11 driving plates and a progressive self-servo mechanism for a lighter clutch feel. This also reduces pressure on the clutch plates for a “slipper” action.

With the Desmosedici Stradale engine introduced, we now have to wait for Ducati to introduce its new superbike. We’ve already seen spy photos and video of the motorcycle being tested, and we now know a few more details. The engine is designed to act as a structural element of the chassis with mounting points in the upper crankcase in the front and in the rear cylinder bank head. The crankcase also has a mounting point for the swingarm and rear suspension system.

The video below gives us a taste of how the new superbike sounds while rounding a lap of Mugello. Pay close attention to the display overlaid on the bottom left corner – it may turn out to be what the instrument cluster on the new bike’s presumably TFT display will look like.