Originally, the tournament strategy was to stay on the Pro-Line 24 4-stroke outboard, and they head offshore at nearly 50 mph to join the rest of the fleet, which has a several-hour head start on the trio of anglers.
Shouldn't that be 4-stroke outboards, as in, more than one? That's not the case when you have
Suzuki's game-changing DF300 mounted on the stern. Once again, Suzuki takes the lead in the
4-stroke horsepower race with a 24-valve V6 engine that has the largest displacement in its class -
something Suzuki likes to do - measuring a whopping 4.0 liters. Actually, it's the biggest
displacement outboard ever. Not only is this significantly larger than Suzuki's own 3.6-liter
DF250, but it also dwarfs the Mercury Verado 275's relatively small 2.6-liter block, extracting 300
hp without relying on a supercharger or even premium gas. Despite being the most powerful 4-stroke
on the market, it weighs about the same as conventional 225/250 4-stroke engines and less than the
supercharged models. But perhaps the most readily noticeable feature is its relatively compact
size, thanks to its narrow 55-degree, V6 design and offset drive shaft, which also puts more weight
over the transom for better balance. After running at full bore, a weedline is spotted, and
Ted drops down to trolling speed as the other two crew members ease their baits into the
wake. It might be here that the DF300 is most impressive. The DF300 is downright
civilized; with an incredibly quiet idle, measuring just 58 decibels at idle from the helm, it has
minimal vibration and no exhaust fumes.
Soon, Randy gets a
massive hit, and a large dolphin (mahi-mahi) rockets into the air, so Ted shifts the unbelievably
smooth fly-by-wire electronic control into neutral. Suzuki's new system, called Precision Control,
is especially adept at handling multi-engine applications. For triples, Suzuki uses only two
controllers. At running speed, all three engines are controlled by one lever, and at the dock, the
middle engine remains in neutral while the outer motors are controlled independently. As Ted shifts
into forward to help Randy regain some line, another dolphin nearly as large quickly inhales a
piece of cut bait. Now you've really got some excitement with two large fish hooked on light tackle
that aren't cooperating in the least. Despite having no gaff, Ted wrestles both fish aboard by
hand, and the 26- and 20-pounders place first and second.
At Suzuki's DF300 coming out press party at the Ocean Reef Club near Key Largo, writers test
engines on a wide variety of boats, like the 6-ton-plus 340 Stamas Express with twin DF300s that
has a top speed of 46 mph, a Yellowfin 36 with triples that runs nearly 66 mph, and a 29-foot
Everglades center console that's rigged with twin engines. A common belief about 4-strokes is that
they lack snappy acceleration, especially out of the hole; for skeptics, a quick run on the
Everglades 290 will put any performance doubts to rest. The twin 300s push the 5,000-pound center
console on plane in 4 seconds, reaching 30 mph in just 6.4 seconds, and
continuing on a linear rate of acceleration to a top speed of nearly 56 mph (6200 rpm), despite
running in 2-foot seas with a topped-off, 200-gallon fuel tank. Perhaps even more thrilling is a
later test on the St. John's River in Jacksonville, Fla., aboard a Crest Caribbean pontoon boat.
The 26-foot-plus, triple-tube pontoon - powered by a single DF300 - rockets to a
jaw-dropping 50 mph.
Fuel burn aboard the Everglades 290 is impressive at an econo-cruise speed of 23 mph (3000 rpm),
with the pair of Suzuki outboards using around 10 gallons per hour to yield 2.4 miles per gallon
(according to data provided by Suzuki). One advantage of having a lot of horsepower is the ability
to go faster without taxing your engines, and at 4000 rpm, the DF300 outboards seem to be loafing
along as they push the Everglades to a happy cruising speed of 35 mph, while still achieving more
than 2 mpg.
So, aside from the large displacement, how does the DF300 produce all this power? Suzuki uses
only proven technology gleaned largely from its all 4-stroke lineup, and
especially from its revolutionary DF250, the largest 4-stroke built when it was introduced in 2003.
For plenty of low-end torque, Suzuki uses an innovation called Variable Valve Timing (VVT).
Camshafts control when the intake and exhaust valves open and close; unfortunately, they're most
efficient at only one speed. However, Suzuki uses an aggressive, chain-driven dual overhead cam
profile to ensure the engine gets enough fuel and air at top rpm, then employs an actuator to alter
the intake timing at low to middle rpm ranges. This creates a momentary overlap with the exhaust
valves (except at no-wake speeds) to give it an extra kick in the seat of your pants, right where
you need it.
To maximize power throughout the power band, with an engine that has different air supply needs,
Suzuki employs a Multi-Stage Induction Module that uses two sets of air intakes to feed air into
the combustion chamber. At a lower rpm, the air goes through a curved chamber, but at a higher rpm,
a valve on the direct intake opens to allow air in directly through short, straight chambers that
have almost no resistance, ensuring that plenty of air gets to the combustion chamber. Fuel cooled
to a higher density is fed to the combustion chamber via the Multi-Point Fuel Injection system,
which delivers high pressure for a more dispersed mist, allowing the fuel to burn more completely.
This efficiency allows the DF300 to be classified by the California Air Resource Board (CARB) as a
three-star, Ultra Low Emission engine. The new racing-style lower unit also reduces drag by 18
percent for greater efficiency.
Now, you might initially
experience a little sticker shock at the DF300's list price of $23,625 ($1,330 extra for the
electronic shifter), but the Suzuki can actually save you money, and not just in reduced fuel and
oil costs. Consider the difference in a boat with triple 225-hp 4-strokes versus a pair of
DF300s: While the twins have 75 fewer ponies, there's now about 600 pounds less weight on the
transom, and with one less engine, there are fewer things that can go wrong. If you consider that
the average 225-hp 4-stroke costs around $20,000, you're looking at about $10K
less. The same goes for replacing twin 150s with a single DF300. These days, the motto seems to be
"bigger is better," and with the new crop of mega-outboard-powered boats on the market, they need
the ultimate in power, and its name is DF300.
Suzuki DF300
Test results were gathered on an Everglades 290 Pilot with twin DF300s and 200 gallons of
fuel.
Engine Type: V6 4-stroke EFI DOHC 24 valve
Weight: 604 lbs. (with 25" shaft)
Displacement: 4027 cc (245.6 cu. in.)
Warranty: 3-year transferable plus 3-year optional
Price: $23,625 (25" shaft), $24,940 (30" shaft)
Top Speed 55.9 mph
Time To Plane 4 seconds
0-30 mph 6.4 seconds
Decibels @ Idle 58 dB-A
Decibels @ 30 mph 84 dB-A
Decibels @ WOT 94 dB-A
Supersizing It
How far can Suzuki take its horsepower race? A clue to the potential of 4-stroke outboards can be found in the company's motorcycle division, where you'll find the world's fastest production motorcycle (according to the Guinness Book of World Records), the Suzuki GSX 1300 Hayabusa, which in Japanese probably means "hang on for dear life." Not to infer that the DF300 is derived from the two-wheeler's 1298-cc in-line 4-cylinder engine, but nonetheless, they're both fuel-injected 4-strokes that sport a DOHC configuration. The stock Hayabusa engine and transmission weighs around 160 pounds and produces 172.6 hp from its compact design, which means that if it were the same 4028-cc displacement as the DF300, it could, in theory, produce 536 hp. But at the 2005 DynoJet Horsepower Challenge, Hank Booth of Great Falls, Mont., mated a NLR turbocharger to his 1999 Hayabusa and extracted an incredible 701 hp, so if you did the same with an engine of the same displacement as the DF300, it could, theoretically, produce 2,175 hp. Some boaters would probably still put three of these engines on the transom. - A.J.