The basic dimensions of the Testastretta engine used on the new 999R remain the same as those of the previous version. The cylinder bore is thus still 104 mm and the stroke stays at 58.8 mm, for a total displacement of 999 cc. However, the maximum power and torque have been greatly increased. Compared to the previous model's 102 kW (139 hp) at 10000 rpm, the new engine produces 110 kW (150 hp) at 9750 rpm. The torque itself has been increased from 108 Nm (11 kgm) at 8000 rpm, to 116.7 Nm (11.9 kgm) at 8000 rpm.
In order to fully understand what these figures mean for the new 999R, it is instructive to take a look at the variation in MEP (Mean Effective Pressure). This value is an important parameter in rating the engine, and measures the work the engine is capable of doing throughout a complete cycle (i.e. through all four phases). The Testastretta engine of the 999R '04 has a MEP at maximum torque of 13.6 bar. The new model, on the other hand, exceeds 14 bar, a limit which no series production Ducati engine has ever reached before. At maximum power, the MEP value for the 999R model year 2004 Testastretta engine is 12.3 bar, while on the MY '05, at the same power output, the value increases to 13.5 bar. It is clear that in the two cases under consideration, the volumetric and thermodynamic performance of the new engine (in other words, its capacity to take in and burn the fuel/air mixture) are significantly improved, thanks to the substantial technical upgrades to the cylinder assemblies. In this context, it is worth noting that the air flow rate in the intake ducts (permeability) has been increased by 22.8% (!), while the exhaust duct flow rate has increased by 5.8%. The overall optimisation of the engine is confirmed by the fact that the improved maximum power value is now achieved at an engine speed which is lower by 250 rpm than the corresponding speed of the Testastretta engine mounted on the previous 999R model. The engine speed limiter is set to 11000 rpm.
New cylinder assemblies
In order to improve performance, the cylinder heads and pistons have been completely redesigned and should really be regarded as completely new components, designed specifically for racing. The pistons are forged and constructed from an aluminium alloy with high mechanical specifications to ensure outstanding geometrical stability during the wide thermal excursions to which they are subject. The variation of the geometrical specification, as well as the new shape of the combustion cavity in the head, has resulted in a compression ratio of 12.45 +/- 0.5 :1 (slightly greater than that of the previous R version of the Testastretta engine, which was rated at 12.3:1). The valve seats are deeper due to the increased valve lifts. The heads have undergone a radical fluid-dynamics redesign. In order to make it possible to use larger diameter valves, their centre distances have been increased which means that the routing and dimensions of the intake and exhaust ducts have also had to be modified.
Still in comparison to the previous 999R Testastretta, the squish surfaces have been increased to improve the turbulent flow in the combustion chamber, resulting in significantly increased combustion efficiency. To summarise, the improvements to the new 999R engine's cylinders have greatly increased the engine's ability to "breathe" as well as its combustion output. The result of these modifications is evident from the significant improvements in overall performance of the road version, which means with absolutely standard exhaust system, silencer and intake system. The engine also meets established emissions standards. It should be noted that metal gaskets are not used between the head and cylinder of each assembly, but rather special seal rings (called Wills seals) around the perimeter of the combustion chamber. The large cylinder bore makes this necessary if a perfect seal is to be achieved. The overall redesign of the cylinder head has also made it necessary to respecify the cooling ducts. The valve covers are now in magnesium for lower weight.
To limit the temperature of the timing belts and not only to keep down the overall weight of the vehicle, Ducati's competition bikes have never been fitted with protective timing belt covers. However these units are necessary to protect the belts when the bike runs onto the gravel at the side of the track, and this year the Ducati R&D; department has installed timing belt covers with dynamic cooling on the 999R, as already done on the 749R. The horizontal cylinder timing belt cover has an intake with a small sponge filter which attaches to the front fairing. The air is taken in at this point, circulates in the timing belt housing and exits via a NACA opening in the top of the vertical cylinder timing system cover.
The engine speed and phase timing wheel
A new element is the timing wheel on the timing drive shaft gear which, along with an magnetic induction sensor, generates the signal used by the ECU to detect the engine speed and operational phase. The timing gear teeth are not used, as on previous Testastretta engines, but instead the system uses a timing wheel with bumps machined onto the outer circumference of the gear face itself. This results in a cleaner electrical signal from the induction sensor.
Engine casings and low sump
The engine casings are sand-cast, to highlight the exclusivity of the product. The dimensions of the units are no different from those used on the previous 999R Testastretta engine. The studbolts which mount the cylinder assemblies are located in such a way as to make it possible to mount such large bore cylinders (104 mm). The lubrication circuit retains the "low sump", a fundamental feature of race engines, as this allows the oil pump to always draw the lubricant in all vehicle positions (e.g. bike cranked over, under harsh acceleration or with the front wheel in the air).
The components in the engine casing of the Testastretta mounted on the new model 999R have not undergone significant modification compared to those used in the previous version, with the exception of the crankshaft. This component now has a new configuration. It is almost completely machined, to optimise its form. It has thus been possible to obtain a weight reduction while maintaining a perfectly balanced crank layout. The lubrication ducts inside the crank pin are also completely new: they no longer run horizontally, but diagonally while directly communicating with the duct along the two main journals. In this way it has been possible to reduce (from three to one) the number of plugs required to close off the surface borings necessary for machining the ducts themselves. The conrod manufactured by Pankl is in titanium to reduce the weight of the crank linkages.
The Testastretta engine of the new 999R uses titanium valves, both on the intake and exhaust. The weight saving is considerable, especially if we consider the strong accelerations imposed by the high engine speed. The valve diameter is 42 mm on the intake with valve lift of 13 mm, and 34 mm on the exhaust with lift of 11.5 mm. On the previous 999R's engine the intake valve diameter was 40 mm with 11.71 mm lift and the exhaust valve diameter was 33 mm with 10.5 mm lift. The use of titanium has obliged Ducati to use special valves seats and guides. The timing diagram has not been substantially changed relative to the previous 999R engine, although the cams are of a completely new shape. The intake valves now open by 21 before the TDC, compared with a previous value of 16, and close 53 after BDC relative to the previous 60. The exhaust valves open at 60 before BDC as before, while they close 20 after TDC compared to a previous value of 18. The inclination of the intake and exhaust valves on the new 999R is no different from that of the old version, at 12 and 13 respectively off the cylinder-head axis. In line with Superbike race engines, the retaining system on the closing register valve stem has been changed. This register is acted on by the desmodromic timing rocker to close the valve, and its thickness determines the play between its surface and the fork-shaped ends of the rocker itself, with which it contacts. This play must be adjusted with great precision, since it greatly affects the mechanical stress on the timing components, as the valve returns to its seat. It also affects the timing diagram, which must be close to the nominal diagram. The closing register retainer system normally used on series Ducati engines exploits the action of two half-rings seated in a cavity machined near to the upper end of the valve stem. These two half-rings engage the register. However, this system has evident limits on a race engine which is often run at its top engine speed. In these conditions the half-rings are severely stressed and tend to deform plastically (they are crushed) and hence do not guarantee a constant play between the register and the rocker. For this reason the Testastretta engine of the 999R uses two titanium half-cones which encircle the valve stem. They have a circular section bump on their inner surface which engages with the groove machined near to the end of the valve stem itself. This groove is however not as deep as that used for the half-ring system. Furthermore, the two half-cones, when the steel closing register is pressing against them, grip the valve stem under friction, thus considerably reducing the stresses around the groove. This enables the valve stems of the new 999R to be not 7 mm (as used on the other Testastretta engines) but 6 mm, resulting in a further weight saving. It is also worth noting that the half-cones, since they perfectly couple with the register, are not subject to deformation even though they are highly stressed. This means that the valve closure play remains constant for a longer time when the engine is running. As already indicated, the valve centre distance has been increased over that on the previous 999R's Testastretta engine. It has thus been possible to use parts with a larger diameter head. Each valve has been moved outwards (orthogonally to the ducts) by 0.75 mm, for an overall increase in stem centre distance of 1.5 mm (the new centre distances are 43 mm between the two exhaust valves and 46.8 mm between the two intake valves). The valve seats also have a higher position relative to those of the previous engine. It follows that they protrude more into the head combustion cavity, which has been completely redesigned along with the larger squish surfaces. The volume of the cavity is thus less than that in the heads of the previous model engine. As already indicated, the consequent increase in the compression ratio has been limited by reducing the height of the piston head.
The intake and exhaust systems
Nothing has changed in the new 999R's intake and exhaust systems compared to the previous version. There is a single, large volume silencer, and the manifolds have no intersection points. In particular, the difference in length between the front cylinder manifold compared to the shorter rear cylinder manifold has been compensated for with a number of differing cross-sections (varying from 45 to 55 mm for the front unit, constant at 45 mm for the rear unit), so as to ensure identical fluid-dynamic behaviour of both exhaust systems. Furthermore, the rear cylinder manifold penetrates into the silencer. The Testastretta engine used on the road version of the Ducati 999R is equipped with catalytic converters. Each cylinder assembly has a dedicated three-way catalytic converter. The one on the front cylinder is fitted about halfway along its exhaust manifold, while the rear cylinder unit is integrated into the initial section of the silencer. The airbox has a large volume (12.5 dm3 ) and is not closed off by the lower surface of the fuel tank. The ducts which lead the intake air from the dynamic scoops on the front fairing to the airbox are equipped with a Helmholtz resonator to reduce intake noise without penalising engine performance. The RH duct is integral to the coolant tank.
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