June 19 2019
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.
Considerable 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 95 RON pump fuel.
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 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.
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 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.
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