Mercury Racing’s new V8 500R outboard is ready to dance
There is definitely a thrill speeding along atop the water at 110 mph. It coincides with the wide-eyed, half-smile fear that intensified within me once the boat surpassed 80, which only took about 20 seconds from the hole shot. No, I’ve never gone that fast in a boat. Heck, I was amazed when I reached 70 mph on a pontoon boat. Our family pontoon only has a 90-hp outboard, so it was a bit nerve-racking, to say the least, but it was a testament to the power behind the new Mercury Racing 500R outboard motor.
I was fortunate to join Mercury Racing in Charleston, South Carolina, when the new engine was unveiled to the world at a black-tie event that made me feel like James Bond discovering a new gadget from Q. Modeled on a rotating pedestal under the spotlights, the new 500R took center position on the dance floor for all to gather around and take a close-up look. After all, Mercury Racing is celebrating 50 years and with age comes wisdom. The 500R outboard showcases all the lessons learned and innovations created throughout those years.
Under the Cover
Also dressed in black but with a red racing stripe along its seam, the new V8 500R outboard engine continues Mercury Racing’s understanding that it’s what’s under the hood that counts. Development of powerful and technologically advanced powerplants for high-performance sport boats has always been the directive, and the 500R is a 4.6-liter, 64-degree V8 FourStroke powerhead boosted by an exclusive Mercury Racing supercharger that does just that. The boost pressure increased by 26 percent and the torque by 10 percent compared to the 450R model, and performs this way using 89-octane fuel.
There are a host of new components introduced in this model required to meet the power demands, such as in the powerhead, cooling system, midsection, gearcase, and steering system. The engineering team also designed the engine to keep it compatible with different transoms and repowering applications, one being the weight, only 726 pounds dry.
With the scaled-up power output comes the need for increased airflow, so the 500R integrated a new attenuator with a larger intake. In addition, the throttle body diameter was increased by 15 percent, and the shape of the supercharger inlet was redesigned to enhance flow. The charge air cooler fin density and flow pattern were also optimized to improve efficiency.
A really innovative feature is the ability for the engine to detect air humidity levels. The idea is to have consistent performance throughout a broad range of atmospheric conditions. A new sensor is located in the intake attenuator to measure the humidity level of the incoming air. This allows the engine control module to combine reported humidity with air pressure and air temperature data to determine the ideal spark timing. It’s the first time humidity compensation technology has been applied to a marine engine which, as Mercury Racing puts it, “makes it possible to maintain the most aggressive calibration to optimize performance under virtually all conditions.” What that does is provide a gain in power in very humid conditions. When tested on a Tidewater 2700, the 500R outboard gained up to 30 additional horsepower than would be available without humidity compensation and a 15-second reduction in zero-to-70 mph acceleration. That’s significant.
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It Doesn’t End There
Another exclusive feature on the 500R is the Advanced Racing Core, a new midsection that adds to the engine’s durability and performance. The addition of a seventh mounting hole on a stronger, redesigned transom plate allows for three inches of vertical adjustment, twice that of the six-hole 450R transom plate. As for trim, two main hydraulic rams plus two new booster rams provide extra trim ability under full load, and by reducing the speed of the trim adjustment, a more precise trim is achievable at high speeds. Precision-fitted heavy-duty guide plates and stiffened engine mounts also help stabilize the engine for high-speed handling.
Mercury’s hydraulic power steering system also has been upgraded with a newly designed and stronger steering arm, steering tube, and steering cylinder to support more torque. For catamaran and other ultra-high-speed setups, an optional rear tie-bar bracket provides a strong, ultra-light mounting point for solid precision steering.
One of the new design features for the 500R is the gearcase. The “R-Drive” is available in two versions, one to handle submerged and transition (semi-surfacing) applications, and the other for full surfacing applications (those ultra-high-speed vessels ranging in speeds beyond 100 mph). When in the submerged and transition attitude, the R-Drive performs well beyond the speed range of the Mercury Racing 5.44 HD gearcase and is capable of boat speeds between 85 and 100 mph, perfect for high-speed center consoles. Both versions are engineered with a long-aspect torpedo design with an adjustable nose cap based on the application to optimize cooling water flow.
A new water pump also helps increase cooling, and both versions incorporate larger, more robust drive and prop shafts than the 450R. In addition, a new intermediate spray plate reduces drag in submerged and transition applications, and a longer skeg with a wedge shape is used in the Sport (full surfacing) version to maintain steering control while underway.
The 500R’s technological features are designed to enhance the boating experience, including the precision of its Digital Throttle and Shift system and the Adaptive Speed Control that maintains engine rpm as loads change due to sea conditions or turning maneuvers. The engine supports all Mercury SmartCraft technologies, such as the Engine Guardian monitor system and VesselView multifunction displays. To dress up accordingly, the 500R also comes in Cold Fusion White with that Devil Eye Red trim as well as custom paint options for looking good on the dance floor. mercuryracing.com
-by Steve Davis
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