Hello guys, I was just informed that you had tripped over our ski race engine and wanted some info on it.
It does start life as a VK engine. We have successfully campaigned a VH45 DETT in Australia ski racing, including a trip to the world ski racing champion ships last year in New Zealand. The 4.5 engine develops 1177 hp and we get a service life of around 50 hours per engine. We run 22 psi of boost pressure and run it to 8300 rpm. Boat speed ends up at 126 mph. It’s in a 21 foot Force hull and run by the owner Ian Kilpatrick. You can see a down load of the boat footage on our web site.
http://www.nizpro.com.au/videos.html
It has achieved many Australian and state championships in the 8.0 litre class, over the last coupe of years. Mechanically it has 100% finish rate.
However we have always been a little low in the outright horse power stakes when competing against the 9.0 litre twin turbo Chevy’s. We have normally been able to run in the top 5 outright using the 4.5 VH.
During this time I have been developing this 6.0 version with the intension of running outright speeds. It is the acceleration from corner that’s hurts us compared to the big capacity engines not the outright speed.
Starting with the VK block and cylinder heads most other component are new. The intake manifold is a combination of magnesium intake runners CNC billet alloy valley plate and carbon fibre intake plenums. The plenums weighs in at 700 grams or 1.5 pounds each keeping the centre of gravity low. The rocker covers are also mag with carbo coil cover for a similar reason.
Internally it has the best parts money can buy billet crank, Ti rods and valves and the rest of the normal high quality parts you find in this style of engine. We have also cast a magnesium sump of 12 litres and it holds the internal oil cooler
The reason for the quad turbo set up is so there was no need to run a gearbox, ever the 9.0 TT boats runs auto gearboxes and use low gear to get out of the water with skiers. Our 4.5 VH didn’t even need this.
However I always say if it’s worth doing bludgeon it to death with over kill.
The turbo’s are stage similar to BMW’s twin turbo 3.0 litre diesels. The small turbos carry the engine to around 600 hp at any engine speeds, where the large unit takes over. The advantage is the large turbo’s can be very large giving very easy top end. With peak boost arriving at 1900 rpm on the little turbo’s and 800 ft lbs and the big turbos running 20 psi and 1500 hp on Australian 98 octane fuel, it makes light work of it.
I am unable to say how much power it would make as our engine dyno will not hold power levels above this. I would believe that 2200 to 2300 hp would be achieved especially if the duty cycles were lower than we see in ski racing.
Intercooling is taken care of from two large water to air intercooler built into the hull charge temps are around 5 degs C above river water.
All up including the forward/reverse gearbox the engine package weighs in at 320 kilograms 704 pounds maximum engine rpm is limited to 8500. The engine management system is Visteon using twin drive by wire throttles, coil on plug and electronic boost control.
Hope this is the info you were after.
Cheers Simon.
