Since Suzuki invited us to this event in Miami, we've been asking ourselves a few questions: why does Suzuki Japan bring the world press together? Which event announced as innovative will they present us well?
No leaks, no information managed to get out. It was not until Friday, June 9, 2017 at 10 a.m. (Miami time) that the new DF350A outboard was discovered. The largest 4-stroke outboard engine ever produced...
Mr. Suzuki (son of the company's founder and CEO), Mr. Osawa (Marine Manager) and Mr. Vassas (Director France) gathered around the new 350.
A 4.4-litre V6!
Certainly the other manufacturers (Mercury and Yamaha) already offer 350 hp, but the Mercury is an in-line 6-cylinder and the Yamaha a V8, both with smaller displacement than the Suzuki. The DF350A is a 4.4-litre V6. So that's what Suzuki is all about: the biggest engine (but with the same power as the competition).
We were able to discover this novelty, accompanied by Japanese engineers in charge of development. All our questions and concerns were answered around the engine presented in split pieces or even dismantled into spare parts spread on a workbench for the occasion. A treat for the technicians that we are, which allowed us to dive into the heart of mechanics and its secrets.
A cylinder head and injection bars with 2 injectors per cylinder
Innovations that make a difference
In terms of innovation, the Suzuki is built around the same engine block as the 300 hp. A 55° V-shaped 6-cylinder engine whose displacement has been increased by a longer stroke (but with the same bore). This engine is powered by injectors (like the entire Suzuki range), but this time to improve performance and fuel consumption, each cylinder is powered by 2 injectors.
The air circuit has also been particularly worked just under the engine hood so that the air entering the chambers is not too hot. With the new circuit, visible through the large air intakes on each side of the engine hood, the air entering the engine is never more than 10° above the ambient air. Good fresh air ensures good combustion.
Suzuki DF350A's dual propeller system
One base with 2 propellers
The most visible innovation is undoubtedly the base plate with its 2 propellers. This engine is equipped with dual propulsion. Two propellers on the same shaft that rotate in one direction each. This type of propulsion is not new. Yamaha had tried to use it on a 150 hp outboard (before abandoning it). But above all Volvo on its Z-drive uses it on all subbases. Unlike Volvo, which has a 4-blade propeller at the rear and a 3-blade propeller at the front, Suzuki has installed 2 3-blade propellers.
The use of 2 propellers avoids the phenomenon of torque, when the single-engine boat skids at acceleration or sails with heel at full speed (visible on deep V hulls). In addition, in the case of bi-motorization (or more) there is no need to control the motor according to its direction of rotation. Here all 350 hp rotate in the same direction, but with 2 propellers...
Bi-motorization on the Scarab 35''
The first sea trials
Not only did this presentation in Miami allow us to have a detailed discussion with Suzuki engineers, but we also had the opportunity to preview pre-series models. The final series will only be available from September 2017.
On the water, Suzuki had provided us with 7 boats with very different hulls and engines. There were V-shaped hull boats with 1, 2 or 3 x 350 hp. Single or twin-engine pontoons. And a catamaran on which were installed no less than 4 engines of 350 hp: 1400 hp!
42.3 knots in single motor on a SouthDay pontoon
Ah, the sweet castling sound of the V6!
At the first acceleration, the 350 climbs into the rpm quickly with a hoarse sound characteristic of the V6. It is both soft on the ear and at the same time gives a real impression of power.
In terms of performance, no problem, the 350 hp seems to meet expectations. 43 N on a single-engine pontoon or 46.5 knots on the Dusky with 2 x 350. and on the catamaran with 4 x 350? We posted the 60.7 knots at full speed. Very good performances!
Controlled consumption
But it is above all in terms of fuel consumption that the 350 stands out, as it consumes as much as the 300 hp with much higher performance. However, its larger displacement of 0.4 l should encourage it to consume more. However, the consumption curves between the 2 engines are very similar. This is a sign that the developments have borne fruit.
As we have said, this engine will be available in Suzuki dealerships from September 2017. As for the price, it has not yet been definitively fixed, but rumours are circulating that the price will be comparable to that of the competition.
Technical specifications
- 55° V-6 engine Double overhead camshaft 24-valve
- Weight: 330 kg
- Chain drive with valve opening variation system
- Fuel injection by electronic injectors (2 per cylinder)
- Displacement: 4,390 l
- Bore stroke: 98 x 97 mm
- Max. power: 350 hp (257.4 kW)
- Maximum speed: 5700 - 6300 rpm
- Oil capacity: 8 l
- Electronic ignition by transistor
- Electric start
- Alternator 12 V 54 A
- Base ratio 2.29:1
- Front three-blade propeller: 3 x 15.5 x 19.5 x 19.5 - 31.5
- Three-bladed rear propeller: 3 x 15.5 x 19.5 x 19.5 - 31.5
