Powerhouse Performance/Chantry Haulage Jetboat

Adopting a different approach to tried and tested methods can lead to all sorts of dramas, but not for the Powerhouse Performance/Chantry Haulage jetboat squad.

With 8.0lt-plus big block Chevy and Keith Black engines dominating the Super Boat class in this competitive, action-packed sport, a mere 4.0lt of engine capacity might well be laughed out of the water. Add the fact that the engine in question is a Toyota V-eight as found in various Lexus and Landcruisers and the whole thing might start to sound like a bad joke.

With internal modifications and a pair (that's right - two!) of Whipple ET3150 superchargers - more at home on Top Fuel drag racing motorcycles - the reality is that this Toyota Super Boat is pumping out a minimum of 800hp, boasting a power-to-weight ratio that the big block boys can only dream about.

Although yet to score a major result, the Powerhouse Performance/Chantry Haulage jetboat creates intense interest wherever it goes - including America.

Testing and development of the Toyota powerplant and the application of supercharger technology is important for Powerhouse Performance, which has been developing this particular package for an assault on the World Jet Sprint series later this year.

Danny Williams is the man behind Powerhouse. Those in the automotive trade might recognise the name as that behind Sprintex superchargers. These days Sprintex and its technology is owned by Transcom International, while Powerhouse is the link with the public.

With the supercharged Lexus V-eight on the road producing close to 300kW at the rear wheels, a supercharger kit for the new Series 100 Toyota Landcruiser now available and an agreement just reached with Toyota Racing Development in California, you could say that Powerhouse have a liking for Toyota products! The fact that Toyota Marine Sports have released two Lexus-powered skiboats in the USA just adds spice to the whole deal.

PERFORMANCE PLUS
While an unconventional choice to power a ski/jetboat, the Toyota/Lexus powerplant has impressive, performance-orientated specs.

With a forged steel crank, webbed and cross-bolted block with press-in six-bolt main caps, the engine is one of the toughest stock V-eights available.

The crank and rods are therefore untouched in the Super Boat, although with those twin superchargers producing up to 40psi of boost, custom forged pistons from AAEP were added while the block was also studded and bolted to cope with the extra combustion pressure. And yes, the static compression ratio is low - around 6.0:1.

The real secret to this particular engine's performance is in its headwork and careful balancing of fuel mixtures, ignition timing and heat management.

High octane VP C16 racing fuel is mixed with air by two Barry Grant Gold Claw carburettors, more usually seen on American speedway circuits. The superchargers then suck the cocktail into a custom fabricated common intake manifold which has its temperature regulated by a couple of water-to-air Kenworth truck heat exchangers (the boat is sponsored by Chantry Haulage after all!).

While the valves are stock and the valve angles untouched, high performance Kawasaki motorcycle valve springs are employed, although they're certainly not the most radical aspect to the heads on this engine.

With such a high boost pressure, both camshaft lift and duration can be wild - both lift and duration are "off the scale" in terms of naturally aspirated engines in order to allow as much of the fuel/air mixture in as possible.

The problem area is of course overlap, because with 40psi at work, even the slightest amount of overlap will see the unburnt mixture get blown straight out of the exhaust ports.

Although it was said that overlap has been reduced to a practical minimum, no cam figures would be given - suffice it to say that the stock 0.250-inch lift figure is now at least double. Indeed, the heads had to have channels cut in them for the Ivan Tighe custom cams to actually fit!

Greg Gower, well known as a headwork specialist in Perth, performed the work and extensively ported, polished and flow-tested the heads as well. Incidentally, it's worth noting that this is a quad-overhead cam engine, with the cams driven by belts on the front of the motor.

This typical European configuration is completely different to the de rigueur Yankee single-cam/pushrod engine that powers 99% of inboard performance boats Down Under.

On the exhaust front, the sweet smelling exhaust gases exit via a pair of custom Butler 4-into-1 ceramic coated headers. Large can-style mufflers do little to quell the sound when this baby is on full noise!

Meanwhile, keeping the whole plot in perfect working harmony is a Mallory high energy ignition system taken straight from a Top Alcohol dragster.

The 800hp-plus produced is ultimately fed into the obligatory Scott jet unit.

LIGHT AS A FEATHER
While the Powerhouse Performance/ Chantry Haulage Super Boat is a little down on horsepower compared to the opposition, its one big advantage is its power-to-weight ratio.

The Toyota/Lexus V-eight is a featherweight compared to a big block and it's estimated that this boat with the superchargers and some fuel included, weighs in at just under 300kg. Generally speaking, Super Boats traditionally weigh around 400kg.

The twin-supercharged boat has been driven thus far by David Bailey who came out of retirement for the team.

Although this particular boat is of aluminium construction, Dave's claim to fame is his fibreglass-hulled craft which scored third in the 1998 World Series Group A division and won the '98 WA State Championship and East-West Challenge.

For now, Bailey is happy to brush up on his driving skills, while Williams and the Powerhouse crew pump up the power.

What you see here has only taken six months to achieve and while there have been teething and development problems, everyone who has seen the boat perform has been stunned.

With Powerhouse confident of ultimately squeezing 1000hp out of the engine, this is one Super Boat that won't be following in everyone else's wake for much longer.

Box Story: IN THE HOT SEAT

What's jetsprinting like from the inside? Herald-Sun motorsport columnist Andrew MacLean gives us a clue...

I've done some silly things in my life - bungee-jumped into a rainforest, scuba dived with sharks, and even hung onto the back of Superbike whiz Mark Willis as he flung his Suzuki GSX-R750 from side to side at 200kmh through Calder Park's flip-flop. But nothing - and I mean nothing - could prepare me for a weekend alongside V8Supercar driver Jason Bargwanna in a 1400hp jetsprint boat.

You've probably already noticed the spectacular halt to our weekend's racing, but we'll get to that later... You can take it from me, jetsprinting is awesome. It's fast. It's dangerous.

And it hurts.

Basically, jetsprinting is a high-horsepower blend of boating and rallying over a maze of shallow water channels in something that looks like a flooded paddock.

Bargwanna's boat, True Blue Aussie, is powered by an 11.0lt alloy big block V-eight driving a two-stage Scott Jet system. It is alloy and around 4.25m long.

While the boats are quite simple, the racing side of the sport is actually complex. There are five islands in the race track and each channel surrounding an island is numbered. Therefore, the track has a huge variety of circuits depending on which way you travel through the channels.

A track map for each event has a sequence of channel numbers. The driver and navigator work out the track by simply following the numbers. It's a bit like joining the dots.

You get four qualifying runs to make it into the top 16 fastest boats. From there it is a sudden death elimination process with the fastest winning the event.

Enough of the dribble, let's get behind the wheel.

Perhaps 'navigator' was not the right term for my role alongside Bargwanna in the South Australian round of the International World Series Jetsprinting. Passenger was more like it.

From the moment Bargs planted his foot I knew I was in for an awesome ride. True Blue Aussie flies from 0-160kmh in a shade over three seconds, and it feels f-f-fast.

The initial acceleration slams your head back against the seat and unlike a racing car, where you slow down to turn corners, a jetsprint boat needs more power to turn faster.

When Bargwanna fired into the first turn I thought I was about to die. With a flick of his wrist he smacked the boat around the right angle turn like we were on a Scalectric set.

During our first 50 second run, I probably only took about three or four breaths as the walloping power of the huge V-eight pushed any air I could get in my lungs right back out again.

It wasn't scary, it was just violent - everything happens so fast and with such brutal force.

It wasn't until the third qualifying run that everything went wrong. We'd bolted out of the blocks and got through the first half of the course without a hiccup when the boat ran wide and clipped one of the plastic barrels that line the outside of the circuit.

The rest of the ride was over in a split second. The boat skipped to the right, bounced to the left and hit the grassy bank on the side of the circuit. From there on we were in the air!

I remember seeing grass... sky... then grass... sky and couldn't help thinking my life was about to end. Then we crashed back to earth and I knew I was okay. By the roar of the crowd we had just given them the part of the show they really came to see!