Quad-LS3-Headed, 16-Cylinder Powerboat Beast Dyno’d!

It was a modest opening performance, but the 14-liter V16 LS-based marine engine from Sixteen Power spun the dyno for the first time and pumped out 1,103 horsepower with 1,115 lb-ft peak torque. Officials say that initial testing priorities are validating sub-system developments and that power is being restrained in the interest of durability.

“1,100 horsepower coming from 854 cubic inches and 16 cylinders is very conservative, but it is also going to be very reliable,” says Tom Robinson, sales director at Sixteen Power. “Peak power occurs at 5,800 rpm. This may seem like low rpm for a LS based engine, but it is intended for customers who want the ultimate in reliability.”

Artist’s rendition of the Sixteen Power V16 marine engine.

Starting from a baseline of 1,100 horsepower naturally aspirated, the V16 can reach [2,000 horsepower] with moderate supercharging.–Tom Robinson, Sixteen Power

Designed primarily for the marine market, the V16 features an advanced cooling strategy to take advantage of its package size. Fresh sea water is pumped at a rate of 120 gpm through two engine-coolant heat exchangers that flow coolant to and from the engine at a rate of 150 gpm. There are also twin oil coolers and a transmission cooler to help reduce stress on the drivetrain components.

“No high rpm, no high compression, no high valve lift numbers, no supercharging. Maintaining low rpm torque is paramount however, because you have one high gear and a wall of water to push before the hull gets up on plane,” says Robinson.

Bespoke block With 10 Main Bearings

The V16 is unique in that engineers developed a cast-aluminum block that supports four equally matched LS cylinder heads. The conventional method of building a V16 from scratch is to basically weld together two blocks, two cranks and two sets of cylinder heads. Sixteen Power chose to design a bespoke block with a gap between the front eight and rear eight cylinders so that any type of 6-bolt LS head can be installed at all four corners. The heads also take LS intake manifolds that match up correctly with the intake ports.

Initial dyno setup was conservative as early goals are to validate sub system components.

Since cylinder heads are the key to the power output in a naturally aspirated configuration, this strategy allows Sixteen engineers to choose from a variety of proven aftermarket products to suit their needs. In addition to the custom block, a special billet crankshaft has to be machined as well as a 32-lobe camshaft that is gun drilled for the full length. The former has 10 main bearings while the cam rolls inside nine bearings.

To help improve durability, the crankshaft is machined with BBC-sized main journals and is fully counterweighted. The engine features a 6-stage dry sump lubrication system with five scavenge stages, including one that pulls from the top of the engine. One of the unique design features is the oil drainback system. The lubricant flows to a central pocket located between the fore and aft cylinder banks, preventing oil from falling on the crankshaft throws.

The 14-liter displacement is achieved with 16 cylinders sporting a 4.125-inch bore and a 4.000-inch stroke. It’s basically two LS7 engines mated together.

With a mild tune and camshaft specs, the first dyno run produced 950-plus lb-ft of torque from 3,300 rpm up through 6,000. There was at least 1,500 lb-ft from 3,900 rpm up through 4,900 rpm.

Here’s the V16 on the Superflow dyno.

“Of course in the performance business, there is always a lot of interest at the high end of the scale, which for the marine guys is 2,000 horsepower. Starting from a baseline of 1,100 horsepower naturally aspirated, the V16 can reach this power level with moderate supercharging,” predicts Robinson. “Think of a supercharged or turbocharged LS 7.0-liter making 1,000 horsepower. That’s a pump gas street engine these days, and a recipe that Sixteen Power doesn’t hesitate to double in a marine application, as long as engine components are upgraded to maintain reliability in the extreme environment of Superboat Unlimited racing.”

Admires 5,000 Horsepower From Devel Sixteen

This dyno configuration is basically a LS3 setup that would be good for 550 horsepower in a street V8 application. Consider that twin-turbo LS drag engines are making upwards of 2,500 horsepower, it’s conceivable that a properly equipped V16 would make close to 5,000 horsepower. Steve Morris has already demonstrated that his quad-turbo Devel Sixteen engine, which is loosely based on LS architecture, can surpass 5,000 horsepower in full race trim.

“It’s awesome, we love it as a proof of concept, and it’s Devel’s best marketing tool, but it’s not a recipe that we would apply to a marine application,” adds Robinson.

A closer look at the V16 oiling and cooling systems.

With 16 cylinders, engineers can spread the stress levels around while still striving for improved power numbers.

“The proof of lower stress is easy to understand when comparing a 1,750-horsepower V8 engine making 219 horsepower per cylinder and our 2,000-horsepower configuration making 125 horsepower per cylinder,” says Robinson. “We have less stress on the components – but more cylinders.  This creates a formula for higher outputs with lower component stress.”

As development continues on the V16, the company will offer the engine in different horsepower levels according to customer preferences. A likely scenario is a baseline setup of 900 horsepower followed by 1,200 and 1,400 horsepower in a naturally aspirated configuration. A supercharged setup could deliver 1,600 horsepower, and a quad turbo could be tuned for 2,000 horsepower.

“The power is made with highly developed, race proven heads and valvetrain with greater control over oil and engine cooling than any other package,” sums up Robinson. “It can be seen in the dyno video how smooth idle is, this combo is making the power so effortlessly.”

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About the author

Mike Magda

Mike Magda is a veteran automotive writer with credits in publications such as Racecar Engineering, Hot Rod, Engine Technology International, Motor Trend, Automobile, Automotive Testing Technology and Professional Motorsport World.
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