THE SECRET LAKE:

A rare visit to the hidden proving grounds where Mercury revs its engines before you do. Code name: Lake X.

a visit to Mercury’s hidden testing grounds.

IN 1957, MERCURY MARINE founder Carl Kiekhaefer bought a 582 ha body of water that he called Lake X. It was perfect for covert testing, close enough to his Orlando headquarters to be convenient, but far enough away to ensure that nobody outside the company would end up there by accident. In 1984, Mercury sold the property to the Kirchman Foundation, a non-profit conservation group, ostensibly because Mercury’s racing programme outgrew the confines of the 5 km lake. Now, Mercury is back at the compound, leasing the property from Kirchman to test production engines. Five kilometres is still plenty of water, it seems, as long as you keep it under 160 km/h or so.

Lake X is surrounded by 4 000 ha of forest and swamp. There’s a guard at a gatehouse, the sole access point, at the terminus of a dead-end road. But security is provided by the army of alligators, some of whom occasionally wander out of the lake to lounge in the sun. The lake’s original boathouse and shoreline observation tower are still standing and look straight out of early-’60s sci-fi: metal structures with convex round windows that were meant to evoke a boat’s (or perhaps a spacecraft’s) portholes. Neglected for decades, the buildings len dan eerie J. J. Abrams abandoned-compound vibe. The rusted observation tower, itself overtaken by birds and various opportunistic plants, looks like the kind of building a Lara Croft type would step inside and say, ‘This is where the experiments happened.’

Over the years, Mercury has used Lake X for both product development and publicity stunts. On the latter front, the company conducted a 80 500 km endurance test in 1957, running boats 24 hours a day around a 9.3 km course. But engineers wouldn’t bother doing that today. According to Mercury’s research, the top concerns from their consumers are performance and ease of maintenance. Reliability was something like fifth, which I was surprised by, since breaking down on the water must be a unique type of nightmare. ‘These days, people take reliability as a given,’ says John Pfeifer, Mercury Marine president. ‘The other day, I got an angry letter from a customer because he had to spend $1 000 for maintenance on his 2005 Verado. A 13-year-old motor! But that’s where expectations are now.’

I got on to Lake X today because Mercury has a new product, something that would give itself away the first time it fired up at a public marina. Previously, Mercury’s big-horsepower Verado outboards have been supercharged straight-sixes. But when a Mercury test driver turns the key on a new 300 hp Verado mounted on a centre console at the Lake X dock, it doesn’t whisper like a six-cylinder does. It sounds like a Corvette, the unmistakable burble of a big-bore, naturally aspirated V8. And that’s what it is, a new 4.6-litre double-overhead-cam V8 hiding beneath the angular engine cover. Like its high-performance automotive brethren, the Mercury V8 announces itself with a cold-start exhaust bypass.

Re-engineering the company’s entire big-horsepower line-up, including a new 3.4-litre V6, is a ton of work. But there’s a pretty major clue to why Mercury did this, and it lies in the engine’s breathing architecture. Since the current topdog Verados are supercharged, you might expect Mercury to eventually slap superchargers on these new designs, ultimately surpassing the six-cylinder 400R’s horsepower. But the intake and exhaust setup on the new blocks hints otherwise. Supercharged V8s put their blowers in the vee of the block, close to the intake valves. But the Mercury blocks are a reverse ‘hot-vee’ setup, meaning that the intakes are on the outside of the block, and the exhaust dumps into the centre. And why would you do it that way? For turbocharging. Since turbos are powered by exhaust gases, putting a turbo in the middle of a hot vee gives it the shortest path from the exhaust valves, minimising lag. Most new turbocharged V6s or V8s are a hot-vee design – MercedesBenz, BMW, and even Ford’s 6.7-litre Power Stroke diesel. So, here’s my bold prediction: 500-hp turbocharged V8 outboards. But maybe such a thing exists already. Maybe it has already been on the water at Lake X. You’d have to ask the gators.