Two-stroke of genius?

Chris Beattie | VOLUME 29, ISSUE 4
What's better than one 300hp outboard? How about three new G2 Evinrudes to launch its new range of two-strokes. Evinrude used this triple installation on a Scarab at its world launch in the US.
Evinrude has launched a bold new range of two-stroke powerplants that raise the stakes in the outboard engine wars.

As I pushed the throttle forward on the Scarab 35 Offshore walkaround and the outboards produced a deep-throated howl, it occurred to me that it is not that often that I have driven a boat with a combined 900hp hanging off the transom. Acceleration was, not surprisingly, instantaneous and within seconds the shoreline was blurring at the rate of 60mph (97km/h). It was certainly an exhilarating introduction to Evinrude's all-new Generation 2 E-TEC engines, with the official worldwide launch held near Milwaukee on Lake Michigan in the US in mid-June.

Earlier we had attended a special briefing conducted by company engineers and designers, beginning with the official unveiling of the strikingly styled new powerplants. There was much secrecy and hushed anticipation surrounding the launch and the company did well to keep the lid on its announcement for as long as it did.

Underlining the significance of the launch, Evinrude invited more than 2000 dealers and journalists from around the globe for its Club Evinrude 2015 event, hosting a number of presentations and even a street party to celebrate the G2 unveiling.

Clean slate

It quickly became obvious that Evinrude had undertaken a major engineering R&D program to maximise the industry-leading, direct injection two-stroke technology it has developed over the years. The G2 program began five years ago and started with a clean slate, so that the new engines share virtually nothing with their forerunners, apart from the basic vee cylinder layout and the injectors that form the basis of its fuel system.

Outwardly the most striking and obvious departure from the company's current outboard engines is the new 'Transformer'-like appearance of the G2 powerhead. It has a much more angular and aggressive 'exo-skeleton'. Removable side panels and a range of colours and graphics will allow buyers to customise their engines with a huge range of combinations available.

Engineers explained that while the current generation of E-TEC powerplants performed to a very high level in terms of power delivery and fuel efficiency, they had started completely from scratch when developing the G2 engines, which initially will comprise two series: the High Output (HO) series, incorporating 200, 225 and 250hp V6 engines, and the RAVE V6 range, incorporating 225, 250 and 300hp engines.

All engines are based on the same 3.4lt, 74-degree V6 engine blocks, while the RAVE (Rotax Automatic Variable Exhaust) series also incorporates special valves that raise and lower the exhaust ports for a broader power curve.

A better burn

Engineers began by delving into the heart of the internal combustion process, exploring what exactly happens when fuel and air meet in the combustion chamber. Fundamental to the G2 development was refining the combustion process to maximise fuel burn and distribution and minimise the loss of unburnt fuel into the exhaust ports, explained engineers.

Evinrude's Manager of Advanced Engineering, George Broughton, said that engineers discovered that the fuel/air mixture wasn't doing exactly what they had expected as it swirled into the combustion chamber.

By using world-leading computer simulation software, they were able to map precisely how the fuel/air mixture behaved once it was inside the cylinder, which allowed them to refine internal porting to extract maximum fuel burn and combustion efficiency. The new fuel injection and combustion process even has a name - PurePower Combustion.

"In an engine, when you get the combustion right, that's when the magic starts to happen," said Broughton.

We were shown graphs that depicted gains of 20 per cent in torque over equivalent rival four-strokes, in particular in the low and middle ranges where it is most useful in the majority of applications. Evinrude also claims the G2 series provides 15 per cent better fuel efficiency than current leading four-stroke engines.

Other internal modifications included adopting a 'Starboard-Starboard' exhaust port layout in which both banks of cylinders expel their exhaust gases to the same side of the engine block, which alleviates problems associated with piston side-loading placing excessive angular stress in the area of the super-hot exhaust ports on the power strokes.

Clean 'n' green

Importantly, Evinrude also says the G2 range produces the lowest emissions of any engines currently on the market. During the presentation we were told that the G2 engines produced 75 per cent fewer regulated emissions than competitor four-strokes.
Other G2 innovations include a new dual-axis rigging system, a new i-Trim automatic engine trimming system, an in-built 7.5lt oil tank, a new hydrodynamic SLX gearcase and in-built Dynamic Power Steering.

The 'clean' rigging system incorporates all engine cables, hoses and wires into one fixed tube, which maintains position as the engine turns. Evinrude says because the tube doesn't move, it frees up space in the engine well for boat designers to allocate for other uses. It also has less wear due to reduced friction.

The G2 i-Trim system automatically trims the engine to suit varying conditions and boat speeds, although trim can still be controlled manually, if preferred.

The in-built 7.5lt oil tank resides inside the powerhead and, according to Evinrude engineers, could deliver up to 100 hours of normal running before needing a refill.

Employing engineering principles from heavy earth-moving equipment, engineers have also designed a much stronger engine mounting system that is stiffer and absorbs more load, while transferring less stress to the transom.

The all-new hydrodynamic SLX gear case incorporates new water inlets and is claimed to reduce steering effort without sacrificing speed.

The G2's new Dynamic Power Steering system is integrated directly into the midsection of the engine and provides three levels of power assistance based on operator preference. It is designed to mate up to pretty much any existing power helm system.

Fully integrated digital controls, including an optional floor-mounted accelerator pedal, come with the new range, along with a selection of three different Icon touchscreen displays to keep track of engine and boat functions.

And all of this comes underwritten with a new G2-specific five-year engine and corrosion warranty, with dealer servicing only required every 500 hours or five years.

At the helm

Out on the chilly waters of Lake Michigan, just offshore of the city of Milwaukee, it was impossible not to be impressed by Evinrude's new engines.

We had a large fleet of boats at our disposal, including the aforementioned Scarab and even an Australian Quintrex Trident 690, which drew plenty of positive response from international dealers for its unique graphic treatment.

We peaked a little early in the horsepower stakes, with the 900hp, triple-engined Scarab being our first test craft of the day, but we were able to evaluate a broad range of other engine/boat combinations, including such novel applications as a 29ft Premier plushly-appointed pontoon boat with a pair of 300hp outboards ready to transport its guests to the next party at warp factor speeds.

One notable 'hot rod' in the test fleet, a glistening, metal flake painted Ranger Comanche bass boat with a 250hp HO providing motivation, was particularly memorable in terms of performance on the slightly choppy waters. While we nudged just on 100km/h perched barely centimetres from the water's surface, I was informed that around 115km/h is not out of the question on flatter waters.

There is no doubting the torque-producing abilities of the new G2 series, with an abundance of prop-churning grunt available virtually from zero throttle upwards, but it's particularly noticeable in the mid and upper rev ranges, providing instant acceleration where many other larger outboards tend to flatten out. Seat-of-the-pants, I'd have to say that if it's sheer, stump-pulling torque you're after, you need to try the G2 E-TEC on for size.

Evinrude has obviously placed a lot of energy, resources and faith in its new generation of powerplants, with the G2 platform set to spread throughout the range in coming years.

As company vice-president and general manager of Global Sales and Consumer Experience, Chris Dawson said: "This engine stands alone, in the industry and on the water. Until now, achieving these levels of performance and integration was unheard of. Add to this the fact that this engine produces, by far, the fewest emissions of any outboard engine on the water, and it's clear to see why the new Evinrude E-TEC G2 engines will change the face of boating."

From the factory floor

Included in the global launch was a visit to Evinrude's spacious and spartanly clean factory at Sturtevant, a half hour south of Milwaukee.

Spanning more than 37,000 square metres, it employees around 500 staff and is pretty much entirely self-contained in terms of its ability to produce E-TEC outboards.

In recent years Evinrude has centralised all its manufacturing staff and facilities under the one roof, with the only major outsourcing being some aspects of design, which are taken care of by parent company BRP in Canada.

But all the hands-on engineering and slide-rule stuff is done at Sturtevant, including engine manufacturing, assembly, emissions and performance testing.

We toured the plant during a work shift and it was fascinating to witness the automated, computer-controlled manufacturing processes running alongside actual human assembly and testing of the final products.

The company's history is also on show, with displays from the early days over 100 years ago when founder and outboard pioneer, Ole Evinrude built and ran his first engine on the same Lake Michigan that is a few minutes' drive from the current factory.

There is an air of free-minded innovation within the factory walls and obvious pride in the company's achievement with the launch of its G2 E-TECs.