It's here - Mercury racing's 360 APX Competition Outboard
by Mercury Marine 22 May 2021 09:38 PDT
The New Mercury Racing 360 APX Outboard is here in Australia - and it's ready to rumble.
In fact, it sounds so good that the Mercury Racing website has a special audio recording of the new engine under load.
The new Mercury Racing 360 APX competition outboard is a potent four-stroke V8 designed specifically to power Formula One tunnel boats on the UIM F1H2O World Championship.
It's the first model in a new Mercury Racing Apex Series of outboards designed for closed-course competition.
"We are very excited that this fantastic engine is now available in Australia," said Glen Eadie, Sales Manager for Mercury Racing Product.
"It combines a durable, low-emissions, four-stroke powerhead with amazing performance, and will require much less maintenance than the two-stroke outboard currently in use in the F1H2O World Championship."
The UIM F1H2O World Championship is the flagship international series of single-seater inshore circuit powerboat racing. The series attracts up to 20 of the world's leading drivers competing in tunnel-hull catamarans that hairpin turn at more than 90 mph (145 km/h) and top 140 mph (225 km/h) on the straights.
Tech Specs
The 360 APX is based on a modified version of the Mercury Racing 300R 4.6-litre V8 powerhead. The engine is normally aspirated and retains its double overhead cam/four-valve architecture. The compression ratio is increased from 10:1 to 11:1 and peak rpm is boosted from 6400 rpm to 7000 rpm. The powerhead is fitted with a short-runner intake manifold mated to a cold-air induction system vented through the cowl.
The engine calibration is modified to take full advantage of the powerhead modifications. The 360 APX uses a 24-volt starter for faster dock-side starting in competition. A digital control offers smooth and precise throttle application. Additionally, this engine offers 90% lower emissions than current two-stroke racing engines.
The 12-inch midsection is all-new and designed specifically for Formula 1 tunnel boat applications, with a structural wet sump driveshaft housing and integrated power trim and lift with remote pumps.
An overdrive spur gearset between the crankshaft and the gearcase increases the input shaft speed to the gearcase to match that of the current 9600-rpm two-stroke race engine and produces the left-hand propeller rotation desired for Formula 1 circuit racing.
The overdrive gears are designed to accommodate multiple gear ratios, so the teams can select the ratio that best fits each particular race.
"The primary purpose of the overdrive is to increase the input speed to the gearcase," said Glen Eadie.
"While the 360 APX produces about 45 percent more torque, it doesn't match the rpm of the 2.5-litre two-stroke. With the new 360 APX we can trade some torque to increase propeller rpm via the overdrive, which will also improve the life span of the gears."
An evolved version of the Mercury Racing Super Speed Master (IV SSM) outboard gearcase is direct-drive with no neutral or reverse shifting. Above-water exhaust offers unrestricted flow and produces an exciting tone for racing fans. The motor is equipped with integrated, light-weight steering arms for tunnel boat cable steering. The top cowl and driveshaft housing covers are lightweight carbon-fibre composite. The cowl features robust latching and sealing systems, while the driveshaft cover has quick-release fasteners to ease access to the midsection.
Mercury Racing 10W-30 MRX engine oil, a new high-performance full-synthetic lubricant, was engineered alongside the Mercury Racing 360 APX outboard and specifically formulated to withstand the extreme heat and stress the engine will encounter during F1 tunnel boat competition.
Learn more about the new 360 APX here, or to watch a technical explanation, visit our YouTube channel here.