New Volvo Penta D6-350 and D6-370 models: Diesel engines with real high-speed potential

Volvo Penta is now launching three truly high performance diesel engines: the D6-350 DP, the D6-350 DPR – which with their 350 horsepower are the most powerful diesel engines with sterndrive in the world – and the D6-370, the inboard version that delivers an additional 20 horsepower. Using the very latest technology, the new engines combine speed and performance with low noise and vibrations as well as really low exhaust emissions.
All three engines are from the same engine family as the highly popular D6-310 launched last year. The main differences between the new engines and the D6-310 lie in their performance characteristics. The engine control system has been reprogrammed, the turbo has been optimized and the powerful engines with Duoprop drives also have a mechanical compressor.

Most powerful engine in the world
The D6-350 DP is the Aquamatic version with a Duoprop drive. With its 350 horsepower, it is the most powerful diesel engine with sterndrive in the world. A 5.5-liter cylinder volume, common rail direct injection, a mechanical compressor combined with turbo, charge-air cooling and four-valve technology – all electronically controlled and monitored by the EVC system. The D6-350 gives fantastic performance under all operating conditions. The acceleration is particularly powerful, due to the mechanical turbo that revs up the torque straight from low rpms.

The D6-350 will be installed in twin installations in flybridge boats and sportcruisers of up to about 45 feet in length. Another attractive area of application is as a single installation in sport boats, as a highly attractive alternative to gasoline-driven V8 engines. The D6-350 gives the same acceleration and cruise speed as a V8, but has significantly lower fuel consumption, higher reliability and longer life.

Over 50 knots
The market for fast boats is steadily growing worldwide, encompassing everything from sport boats to sport fishing boats and more cruising inspired boats. The most common engine types today are gasoline engines with sterndrive and double or triple outboard engines. Volvo Penta is now launching an entirely new type: the D6-350 DPR.

”The D6-350 DPR combines performance and amazing high speed characteristics with low fuel consumption, reliability and safe driving. It makes it possible to combine high speed with a sensible cruising range without requiring an enormous amount of fuel. The performance characteristics of the D6-350 DPR are so good that its acceleration and cruising speed are on a par with the gasoline-driven alternatives,” says Conny Frick, head of product planning at Volvo Penta.
The D6-350 DPR has the new DPR drive that was developed especially for speeds of
47–60 knots. The drive is identical to the DP version but has a smaller lower-housing that is optimized for high speeds, and stainless-steel propellers.

370-horsepower inboard engine
For inboard installations, Volvo Penta is launching its D6-370 engine, with electronically controlled hydraulic reverse gears or V-drive. The design of the engine, involving a powerful engine block, fully cast cylinder head and a special ladder-frame bolted on as bottom reinforcement, results in a very low level of vibrations and a high degree of onboard comfort.
The noise level is also very low, partly owing to the common rail fuel injection, which eliminates the characteristic diesel knocking sound.

Very low emissions
Like the D6-310, the D6-350 and the D6-370 will meet comprehensive emission requirements that are to be introduced in Europe and the US in 2006/2007. For smoke and visible emissions, the new engines have very good levels, which is another factor in onboard comfort.

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 D6, it offers the potential of truly precise steering and full control over the engine’s combustion.

Extensive testing
Like the smaller D4 engine, the D6 has undergone really thorough testing, during the development phase 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. We have also devoted a great deal of attention to the apparent noise, and we are very pleased with the results we achieved,” says Rickard Stefansson, technical project manager at Volvo Penta.
Technical data

Model D6-350 DP, D6-350 DPR
Crankshaft power 350 hp at 3,500 rpm
Max. torque 856 Nm at 2,000 rpm
Configuration In-line 6-cyl. diesel with compressor, turbo and charge-air cooler
Generator 115 A
Cyl. volume 5.5 l
Transmission DP or DPR Duoprop drive
Weight with Duoprop drive 766 kg
Emissions Will meet the comprehensive emission requirements to be introduced in Europe and the US in 2006/2007.

Model D6-370
Crankshaft power 370 hp at 3,500 rpm
Max. torque 877 Nm at 2,000 rpm
Configuration In-line 6-cylinder diesel with turbo and charge-air cooler
Generator 115 A
Cyl. volume 5.5 l
Transmission Hydraulic reverse gear and V-drive with electronically controlled shifting
Weight, excl. transmission 580 kg
Emissions Will meet comprehensive emission requirements to be introduced in Europe and the US in 2006/2007.