With the introduction of the 450R, Mercury Racing now has the most powerful outboard pound-for-pound in the marine industry. At 689 pounds for the 20-inch shaft in the lightest configuration, the 450-hp engine has a power-to-weight ratio of 1.53 pounds per horse. Compare that to the 627-hp 627SV from Seven Marine, which weighs 1,094 pounds and has a ratio of 1.74 pounds per horse.
The performance division of Mercury Marine introduced the engine last evening at an unveiling event in Nashville, Tenn.
“What we make is intended for the few who value highly refined products,” Stuart Halley, Mercury Racing general manager, said in a statement. “They’re not only fast, they’re durable and elegantly designed.”
When Mercury introduced its 4.6-liter V-8 outboards in 2018, maximum output for the naturally aspirated engines was 300 hp. It was assumed that eventually the company would come out with a supercharged version that would deliver more power than the 2.6-liter supercharged inline-6 Verado 400R. When the Miami International Boat Show came and went without a new 450-hp engine, some questioned if a big, new outboard from Mercury was in the cards.
Mercury answered that question.
A few years ago, I tested a Formula 430 ASC powered by quad Verado 400Rs. The performance was impressive, but the outboards worked hard to get the boat on plane. Acceleration was steady, though not overwhelming. With the same model powered by 450Rs, the 25,720-pound boat planed more easily, and the extra power gave the boat better midrange acceleration.
An MTI 340 X catamaran reached 108 mph at Mercury’s Lake X test facility with twin Mercury Racing 300R outboards, two people and an average fuel load. With the 450Rs, a full load of fuel and five people, the boat hit 116 mph. The boat ran 121 mph with twin 400Rs and 127 mph with twin 450Rs, and Halley told Trade Only Today that there’s more fine-tuning to be done.
Click here to watch video of MTI cat with the new engines.
On a Nor-Tech 450 Sport, which weighs about 22,000 pounds, quad 450Rs pushed the boat to 82 mph, 10 mph faster than with 400Rs. “With the 450s, the boat is peppy,” Nor-Tech co-founder Trond Schou told Trad Only Today. “The torque makes this boat feel like a smaller boat with punch.”
A Wright Performance 420 catamaran powered by twin 450Rs hit a top speed of 104 mph carrying two people and 180 gallons of fuel. Most 40-foot performance catamarans with sterndrives would require almost twice the power.
Mercury Racing estimates that the 450R makes more than 40 percent more torque than the 400R. Much of that is due to an additional 2-liter displacement, but Halley added that the 450R is designed to run on 89 octane. The 400R can run on 89 or 91, but it makes maximum power on the higher-octane fuel.
Like the 400R, the 450R features a belt-driven twin-screw supercharger, which is water-cooled and has twin air-charge coolers. An electronic valve controls the boost. Even with the extra components, the outboard fits the same cowling as the naturally aspirated 300R. This is important because the narrow profile means the 450R can be mounted on 26-inch centers. Also, the alternator output is 115 amps, which is 64 percent more charging potential than the 400R.
A new integrated tie-bar bracket gives the outboard a streamlined look, and up to six engines can be controlled with a single digital throttle lever. The outboards can also be equipped with Joystick Piloting for two to six engines, as well as Skyhook station-keeping. The 450R has selectable exhaust for quiet operation around the docks.
The outboard’s midsection has heavy-duty guide plates with stiffened mounts to absorb vibration and keep engine noise from transferring to the boat. The 450R is being offered with two gearcases: the Sport Master for boats that run faster than 85 mph — a sleeker design with low-water pickups — and the 5.44 HD for boats that run below 85 mph. On a couple of test runs, we triggered an alarm for low-water pressure when the engines were trimmed too high, but a simple push of the down-trim button took care of that.
For propellers, the Sport Master runs with Max5 wheels, and the 5.44 can be equipped with the Max5, Bravo 1 FS, Enertia ECO XP or a lab-finished Rev 4 XP.
The 450R comes with a 3-year factory warranty plus 3 years of corrosion protection. Owners can opt for up to 5 years of protection.