The D4-260 DP is the Aquamatic version with the new Duoprop DP drive. It is a package that has been optimized for maximum performance.
“To obtain optimal acceleration and really exploit the unparalleled performance potential of the new DP drive, we have equipped the D4-260 DP with both a mechanical compressor and exhaust-driven turbo. The reason for adding the compressor was to obtain a high charge pressure directly from low rpms, which is then transformed into torque, creating – as a result of the Duoprops grip in the water – a remarkably strong acceleration potential. At higher rpms, the compressor is replaced by the turbo to produce high power at cruise speed and top speed,” says Rickard Stefansson, technical project manager at Volvo Penta.
Tests conducted by Volvo Penta show that the D4-260 DP lives up to its promises. Two identical Nimbus 250 Nova R boats were taken for a test run – one fitted with a D4-260 DP and the other with a Volvo Penta 5.7GXi, a 320-horsepower five-liter V8 with a Duoprop drive.
The D4-260 diesel engine accelerated faster than the gasoline-driven V8. For up to 25 knots, the D4-260 was 1.5 seconds, or 15%, faster. Moreover, fuel consumption at cruise speed is about 30% lower for the D4-260 than for the 5.7GXi.
Very low emissions
Similar to the D4-210, the D4-260 will meet the comprehensive emission requirements to be introduced in Europe and the US in 2006/2007.
But we have done even better.
“For smoke and in fact any visible emissions, we have really good levels for the D4 – both the 210 and the 260 versions. The levels are well below our own stringent requirements,” says Rickard Stefansson.
The low emission levels are due to the advanced design involving common rail fuel injection and total electronic control of all engine functions. Due to the electronics and to the completely new design of the D4, it offers the potential of truly precise steering and full control over the engine’s combustion.
Due to its powerful engine block, a fully cast cylinder head and a special ladder frame as bottom reinforcement, the engine has low level of vibrations. Integrated balance shafts offset the vibration forces of the engine, creating high stability. Common rail fuel injection also contributes to the low, comfortable noise level without diesel knocking sounds.
Extensive testing
Like the larger D6, the D4 has been very carefully tested. Testing has been carried out during the development stage and later in the project, to verify quality and performance.
“We have conducted extensive testing at sea combined with lab work. Our focus has been to achieve optimal drivability; we wanted the feeling created by the new engines to be better than anything else on the market,” says Rickard Stefansson.
Technical data
Model D4-260 DP
Crankshaft power 260 hp at 3,500 rpm
Max. torque 615 Nm at 2,000 rpm
Configuration In-line 4-cyl. diesel with compressor, turbo and charge-air cooler
Generator 115 A
Cyl. volume 3.7 l
Transmission DP Duoprop drive
Weight with Duoprop drive 656 kg
Emissions Will meet comprehensive emission requirements to be introduced in Europe and the US in 2006/2007.
Model D4-260
Crankshaft power 260 hp at 3,500 rpm
Max. torque 615 Nm at 2,000 rpm
Configuration In-line 4-cylinder diesel with turbo and charge-air cooler
Generator 115 A
Cyl. volume 3.7 l
Transmission Hydraulic reverse gear and V-drive with electronically controlled shifting
Weight, excl. transmission 482 kg
Emissions Will meet comprehensive emission requirements to be introduced in Europe and the US in 2006/2007.
