Mercury’s New 450R

Image Courtesy of Tommy Gun Images - Tom Leigh
Image Courtesy of Tommy Gun Images – Tom Leigh

Mercury has just upped their game once again with the announcement of their new and much anticipated supercharged 4.6 liter V8 – the Mercury Racing 450R. Announced June 18th of this year Mercury says their new offering is “purpose designed for the high performance disciple craving unrelenting power.” With this motor there is no shortage of power or performance and as a result should draw many disciples.

Mercury’s new offering was designed and is built in Wisconsin at Mercury Racing’s own production line. Based on the 4.6 Liter V8 powerhead found on Mercury Racing’s normally aspirated 300R outboard, this engine produces 450 horsepower under a cowling the same size as the slim 300R while utilizing only 26 inches center-to-center for mounting. With these dimensions this motor allows plenty of room on the transom for multi-engine installations or repowers. All of this performance comes in a package that is 300 pounds lighter than the competition and doesn’t need high-octane fuel to get its performance as it can run happily on 89-octane fuel. It is capable of producing 40% higher torque than its sibling, the 400R. Weighing in at 689 pounds, or 313 kilograms, in its lightest configuration, the end result is an outboard with a truly impressive power to weight ratio. Mercury claims it has “the best power-to-weight ratio for outboards rated 400 horsepower and above.”

All of this is possible because the 450R is built with a proprietary aluminum block with aluminum cylinders and utilizing a QC4 (Quad Cam Four Valve) system, chain driven dual overhead camshafts and a high performance intake cam profile. A 2.4-liter belt driven twin-screw supercharger is then added that utilizes Mercury’s advanced supercharging engineering. The end result is smooth and instant power when throttling up with no lag. That translates to incredibly fast hole-shots and an impressive throttle response with no midrange lag. The advanced supercharger is water-cooled coupled with specially designed twin charge air coolers. In this configuration Mercury claims increased air density and power output resulting in more power.

Apart from being lightweight and powerful Mercury has designed and built this new outboard to be robust and “run wide open all day long.” On this motor wide open is in the range of 5800 rpm to 6400 rpm. Because of this there is a wide array of possible Mercury propeller options that will allow maximum performance over a range of applications.  Every part of the motor was scrutinized and built for maximum performance. This includes the Advanced MidSection (AMS) that is reinforced, designed to be sturdy and also isolates the engine vibration from the boat’s transom. Slim in form the engine can work well for a variety of installations in multi-engine set-ups and on otherwise challenging catamaran designs. Electro-hydraulic steering is standard on these outboards, as are some high output alternators. They can crank out 115-amps, keeping up with the high power demands of today’s electronics and electrical systems. This system even increases the alternator output at idle speeds when low voltage is detected until the batteries are brought up to standard levels. 

There are a couple of gearcase options with the new 450R. The Sport Master surface-piercing gearcase is the option to go with if the boat it will be mounted on can go faster than 85 miles per hour. It has the expected low water pick-ups along with a hefty 1.25 prop shaft. Suggested Mercury props for this motor would include the MAX5 or Outboard CNC Cleaver line of props. If opting for the 5.44HD gearcase that is best suited for lower speed (and we say that with a grin because we are still talking about a racing engine here operating at sub 85 MPH range) the prop selection could include BRAVO I FS, Enertia ECO XP or REV 4 XP props, all of which are Mercury Racing high performance propellers.

Other innovations this motor boasts include pre-programmed timing advance that produces the torque needed for maximum hole shots and rapid acceleration. These engines also have Adaptive Speed Control that can maintain RPMs in towing watersports, tight turns and rough sea conditions. This translates to less throttle work for the captain and better efficiency. These outboards are fully compatible with Mercury’s Vessel View, joystick piloting and Mercury Racing Zero Effort fly-by wire controls that can control the throttle of up to six outboards with a single lever. Regular maintenance is even easier on these motors with access through the Top Cowl Service Door, eliminating having to remove the cowl completely.

Not only are these engines modern in their engineering, they also look the part too. Available in Cold Fusion White with Devil Red Eye accent panels or Mercury Phantom Black with Graphite Grey accent panels these outboards would look good on any boat designed for speed and performance. Of course, as is popular on many outboards these days, the accent panels can be painted to match hull color. Mercury Racing warranties these outboards with a three-year limited factory warranty and a three-year corrosion warranty. These can be extended by purchasing a Mercury Product Protection extended service plan for up to an additional five years. Production of these impressive outboards is already underway and as of the time of writing were shipping to dealers. 

Glenn Hayes
Glenn Hayes is a writer and photographer based out of west central Florida and has marine industry background spanning almost a quarter century. He can be reached through his web site www.HayesStudios.