When people think of boats they often associate them with big, slow-revving diesels or oil-spluttering outboards. Pretty tame stuff. But when you go to the other extreme of engines and dream about mega-hp V8s, what could be better than a force-inducted big block with the works? Well, roll this unlikely pair together and this is what you've got - a genuine, 265 km/h (165 mph) trail of water spray!
This is not simply a boat though - it's a hydroplane, and it spends more of the time hovering above the water than in it. It's much more like an aircraft than you might think - especially with its safety capsule, on-board air supply and fire prevention systems!
Keith Harrison is the man who owns Spellbound - this composite material 8.5 metre Jones Tri-Wing hull. Participating in the Grand Prix Hydroplane class, the rules specify that engine capacity mustn't exceed 510ci but supercharging or turbocharging is allowed. So bound by these limits, both Keith and his engine builder Geoff Sheldrake set out to build a weapon that would push out maximum power while still retaining race reliability.
Here's the formula they used...
A US Keith Black aluminium block was chosen as the base of the engine due to its weight and durability advantages over a conventional cast iron Chev block. Geoff fully prepared the imported block with O-rings, careful deck heighting, iron sleeves and, of course, a full blueprint. Inside, it swings a 4 inch stroke Crower billet crankshaft supported by Vanderval bearings, Carillo rods and a set of 10.0:1 compression JE flat-top forged pistons. Iron type rings were fitted to compliment the 4.5 inch iron bores. And as you can see, an aluminium flywheel is used too.
Sitting atop of copper gaskets, a pair of Brodex aluminium cylinder heads are nutted down to provide a substantial improvement in flow and lightness over stock Chev ones. These US-made jewels are usually worth around A$6000, and have also been spec'd up with titanium inlet and exhaust valves (2.25 in, 1.9 ex), Crane springs, T&D shaft-type rockers (1.7 ratio) and Manley forged pushrods. After much trial and error and collaboration with cam manufacturers, a "specialised turbo grind" cam is used to deliver the torque curve necessary from about 4000-8000 rpm.
Geoff Sheldrake used heavy duty exhaust tubing to construct these tuned-length extractors that collect bucketsfull of spent methanol gasses. On the lower half of the collector, there's also an enlarged and flow-tested Garrett external wastegate to vent gas that would otherwise cause over-boosting.
Just one of these turbos is good for flowing 700-plus hp - let alone two! Built specifically to suit this engine, these Garret T04 units are equipped with modified compressor and turbine housings and boost up to 20 psi - a level that's non-adjustable. The post-turbo exhaust is merely two short lengths of pipe out of the turbine and the wastegate. Noise is of zero concern!
As a safety measure, one of these large pressure relief valves is fitted to the compressor outlet of each turbo. Their role is to vent pressure that may cause turbo damage in the event of a backfire.
The intake that feeds this 509ci bruiser could flow enough air to cool an apartment building! At first glance it would seem that the large box on top of the engine houses an water-to-air intercooler, but it's nothing more complicated than a volume of air that feeds into the modified Crower 8-throttle intake manifold. You see, despite pushing 20 psi boost into a 10.0:1 compression engine, detonation is suppressed only by running methanol fuel - which cools the intake hugely.
Keith says he'll look at setting the engine up with an electronic management system in the future, but for now it makes the goods with a Crower mechanical (fuel only) injection system. He also said that it functioned best as a wide-open throttle (WOT) system, and "because they've been around for hundreds of years they're a bit agricultural in the mid-range and low-down".
Flowing methanol-only, around twice the volume of fuel is required from the fuel system in comparison to normal petrol. So to cram enough in, there are two sets of eight methanol jets, with the second set staged at around 4000 rpm. Mixture control is via altering the size of the capillary jet that's hooked into the return line to the inlet. A gear pump driven by the camshaft delivers the necessary fuel pressure.
Another "latest and greatest" aspect of the engine is its ignition system. There's no old school version of a magneto system here, it's the state of the art MSD ProMag set up - which Keith says is probably one of the most powerful out there.
It puts energy through a set of specialised MSD leads down to 'cool' NGK plugs. It does the job without hassle.
To protect this near A$70,000 engine from oil starvation - and to also pick up a few more hp - a 4 stage dry sump oil system is rigged up. A 20 litre oil tank is placed in front of the motor, with a gear-driven pump used to push oil through an oil cooler and filter and then to the engine. After it drains down into a shallow pan, it's then sucked back into the tank.
A cooling system more akin to a car's is used instead of a more traditional boat set-up. On-board Spellbound, water is picked up from the lake or river and a custom car-type pump puts it through the engine, with it finally dumping out the side of the boat.
But because the water feed to the pump gets pressurised as the boat's speed goes up, a pressure relief valve before the pump opens at around 10 psi.
Tuning and power runs are conducted in Nizpro's relatively new dyno cell. The 1300hp-rated dyno struggles to hold the 509ci monster on load, while a full Dynolog software package analyses its every action.
You can also see on the far wall an 8 channel MoTeC air/fuel ratio meter. You wouldn't dream of running an engine like this without having it fully dyno'd.
Interestingly, the engine runs an exhaust gas oxygen (EGO) sensor off each cylinder - but only while it's being tuned on the dyno. The readings from these probes are interlaced with those from exhaust gas pyros which are being used simultaneously.
So when it's race time, the team can fit just the pyros and be able to determine the approximate air/fuel ratio. Using a MoTeC data logger, once the pyro temp exceeds a predetermined level, a warning light inside the cockpit lights up to indicate a possible lean mixture.
During its most successful dyno run, the big block has reached a measured 1303hp before the dyno started to lose its grip. However, it's conservatively estimated that it's good for 1400-plus hp at 7000 rpm and a stomping 1250ft/lb of torque at 5500 (phew!). Spellbound is also backed up by a spare engine, which has similar specs to the 509ci-er. Displacing 496ci, this engine will produce around 1400hp and at a similar cost to the race engine (around A$70,000), it just goes to prove how much money is invested in this outfit. In fact, Keith tells us you'd be looking at over A$250,000 for the boat rig (plus the trailer etc!).
Oh, and it costs a packet to run - a total of 90 litres of methanol is consumed for every 10 kilometres of race distance...
The driveline of Spellbound is kept simple to keep it strong. It uses a direct drive (called a Z-drive) where the flywheel drives a set of gears, which passes torque on to another gear that's located directly below. A 1½ inch Aquamet shaft then connects straight to the propeller, which is a custom US-made chrome-moly unit ("You'd strip the blades off a normal prop!", explained Keith.)
Because there's no clutch system, the boat starts moving as soon as the starter motor (a high-torque Tilton unit) kicks in. That means there's no "glide" through the water in neutral for berthing.
Oh well, what kind of machine as extreme as this doesn't have any compromises?!
Sponsors:
Melton Toyota
03 9743 3233
Harrison Ford
03 9743 1777
Melton Suzuki
03 9743 3233
Contact:
Nizpro
+61 3 9761 1522
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