Mercury Racing announces launch of 4.6-Liter V8 450R outboard engine

Mercury Racing 450R © Mercury Racing

The new Mercury Racing 450R outboard is purpose designed for the high-performance disciple craving unrelenting power. Steeped in Mercury Racing DNA, the 450R features a 4.6-liter V8 FourStroke powerhead boosted by an exclusive Mercury Racing supercharger to produce 450 peak propshaft horsepower and 40 percent higher torque than the powerful 400R.

At over 300 pounds lighter than the nearest competitor, the new 450R delivers industry leading power-to-weight in a compact, efficient package. The 450R writes a power prescription that combines unprecedented acceleration and top speed potential with rugged reliability and the latest technology from Mercury Racing. Multiple gearcase, control system, tie bar, and styling options are available to create the ultimate customized outboard performance package, ready to run Wide Open all day long. Best of all, the Mercury Racing 450R delivers all of its performance on readily available 89-octane (95 RON) pump fuel.

Supercharged Performance

Designed and developed in-house and manufactured in Wisconsin on a dedicated Mercury Racing production line, the 450R is based on the same 4.6-liter V8 powerhead used for the normally aspirated Mercury Racing 300R outboard models. The proprietary 64-degree aluminum block is topped with aluminum cylinder heads with a Mercury Racing Quad Cam Four Valve (QC4) design and double overhead camshafts (DOHC). The valve train features a high-performance intake cam profile and race-spec Inconel exhaust valves. The camshafts are chain-driven and run in an oil bath so there is no timing belt to maintain.

Mercury Racing applies its supercharging expertise to extract incredible power from the 4.6-liter V8. A 2.4-liter belt-driven twin-screw supercharger delivers pressure charging with zero lag for instant throttle response. The supercharger is water-cooled to reduce the temperature of the intake charge and increase power. Twin charge-air coolers engineered by Mercury Racing reduce the temperature of the compressed intake charge to further increase air density and power output. A custom designed intake attenuator is tuned to cancel the harshest high-frequency supercharger noise while retaining a throaty high-performance sound.

To maintain peak performance, a boost bypass valve automatically adjusts maximum boost pressure in response to changing ambient conditions. To better manage engine heat, the Mercury Racing 450R is fitted with a special high-capacity oil cooler and an exclusive poppet valve in the midsection to provide a higher volume of cooling-water flow on-demand. Electronics and other engine components are designed and positioned to create the tightest package possible while maintaining good service access. The carefully considered design and placement of the new supercharger and charge-air coolers allow the 450R to use the same slim-line cowl as the 300R model while incorporating higher flow intake vents. Like all Mercury Racing outboards, the 450R accommodates 26-inch center-to-center mounting on multi-engine transoms, perfect for maximizing transom space on brand new boats or re-power installations.

Mercury Racing engineers addressed every aspect of performance in designing the 450R outboard, and the weight and design of each component was scrutinized to achieve maximum power with minimal weight. The result is outstanding power density; 450 horsepower from an outboard that weighs as little as 689 pounds (313 Kg), the best power-to-weight ratio for outboards rated 400 horsepower and above.

The wide-open throttle (WOT) operating range extends from 5800-6400 rpm, allowing for a full complement of Mercury Racing propellers to optimize acceleration, efficiency, and top speed.

Inspired Engineering

The exclusive Mercury Racing Advanced MidSection (AMS) features heavy-duty stainless steel guide plates and stiffened engine mounts that stabilize the outboard and enhance high-speed handling. An optional rear tie-bar bracket integral to the AMS provides a strong, ultra-light mounting point and uncluttered installation for catamaran and other high-speed applications.

The AMS also isolates the powerhead from the transom to insure run quality is smooth and quiet. Standard electro-hydraulic power steering offers confident and precise control at all speeds.

The 450R also has high-performance charging capacity. The 115-amp alternator is a match for extreme audio systems and power-hungry electronics. When the Idle Charge battery-management system senses low battery voltage it automatically increases engine idle rpm to boost alternator output until batteries are charged to the proper level.

Pop open the industry-exclusive Top Cowl Service Door for routine engine oil checks and top-offs without removing the cowl. An integrated latch and carry handle eases cowl removal for service.

Gearcase Options

The surface-piercing Sport Master gearcase, designed for boats capable of speeds in excess of 85 mph, features low water pick-ups and a crescent leading-edge for maximized efficiency, and for the 450R application, a stout new one-piece 1.25-inch diameter stainless steel propshaft. From single-engine performance runabouts to multi-engine catamaran sport boats the Sport Master - in the correct application - will enhance boat handling, speed and efficiency. The available cambered skeg counteracts prop torque for improved performance and handling in single-engine applications. The 450R is also available with the 5.44 HD gearcase for lower-speed and traditional submerged applications. All 450R gearcases have a 1.60:1 gear ratio for enhanced acceleration and speed.

The new Mercury 450R outboard. - photo © Mercury Marine

Mercury Racing Propellers

Mercury Racing propellers are designed to maximize boat performance and handling in any application. Our artisans handcraft each propeller to precision-tuned works of art, customized for specific boat types and performance goals. Each individual propeller is then zero balanced and measured to ensure consistent performance every single time. On the new 450R models, the popular MAX5 and Outboard CNC Cleaver props are required for use with the surface piercing Sport Master gearcase. For 5.44 HP gearcase applications, Mercury Racing's Bravo I FS, Bravo I LT, Enertia ECO XP, and Rev 4 XP are excellent options.

Intelligent Technology

Mercury Transient Spark Technology applies pre-programmed timing advance to optimize torque output for stronger hole-shot performance. Adaptive Speed Control with a custom Mercury Racing calibration automatically holds engine rpm regardless of load or condition changes - such as rough water, tight turns, tow sports and lower speeds on plane - to maintain boat momentum with less-frequent throttle control adjustment.

The 450R is compatible with Mercury Racing Zero Effort Digital controls or any Mercury Marine digital control system, which can throttle up to six outboards with a single lever in some applications. Digital throttle and shift technology enhances the high-performance boating experience by providing smooth shifting and instant response while eliminating cable rigging and maintenance. Optional Joystick Piloting for Outboards (JPO) is available for boats rigged with two to six outboards and provides intuitive, fingertip 360-degree boat control for docking and maneuvering in tight quarters, plus the convenience of Skyhook® sea-holding features and integrated auto piloting.

An available Mercury VesselView offers more systems information and engine data than with any other display system in the boating industry. VesselView can simultaneously monitor the RPM, speed, fuel flow and efficiency, temperature, trim and more on up to six outboards on an intuitive seven or nine-inch touchscreen display. VesselView also enables Advanced Sound Control, a dual muffler system that can be toggled between an ultra-quiet mode and a deep sport tone with a stirring growl on start-up.

Unmatched Reliability

Designed to thrive in the abusive environment of high-performance boating, the 450R was tested, tested and tested again - in the lab and on the water - in a never-ending quest to exceed the highest expectations of the most-demanding customers. Run Wide Open with confidence. The Mercury Racing 450R outboard is backed by a three-year limited factory warranty and a three-year limited corrosion warranty. Extend that coverage for up to five additional years with a Mercury Product Protection factory-backed extended service plan.

Color Options

The Mercury Racing 450R is available in Cold Fusion white and the legendary Mercury Phantom Black. Cold Fusion White models are finished with Devil Red Eye cowl accent panels with a white Advanced MidSection (AMS) and gearcase. Black models are finished with Graphite Grey cowl accent panels and matching Graphite Grey AMS and gearcase. Devil Red Eye, Graphite Grey and Carbon Fiber accent panel kits are available to custom-match a 450R outboard to a boat color scheme.

Production of the all-new 450R is under way and customer shipments have begun.