Hunton RS28 - Repower/Refit

[Charlie Hunter]

Pics of new diesel engine ready for fit. Its the new Marine Diesel VGT-500.

[Charlie Hunter]

Another pic

[Coronet Kip]

There's a lot going on there

What drive are you going to be using (Konrad?)

Is your avatar a photo of your 28? is so it looks quite different to mine...is yours a 4 berth?

Keep smilin

Chris

[Charlie Hunter]

The avatar is my boat and she had a number of modifications which are unique as it ended up the last 28 produced. The engine is based on the GM 6.6litre Duramax unit (some 3.5m out there in trucks etc). It has the usual latest generation diesel kit, common rail fueling, variable geometry turbo (greatly reducing turbo lag, aftercooler (water cooled), electronic engine management, 4 valves per cylinder and so on. The Konrad drive requires a gearbox within the engine bay to do the shifting. This was not an option due to the limited physical space in the engine bay plus the Konrad drive and gearbox combo is very heavy. The straight 6 cylinder diesels on the market were also ruled out due to limited space. Initially I am using the Bravo 3 X drive with the engine's power and torque mapped back to 350hp and 537lb ft form. Once Marine Diesel release their new drive leg (shiftable like a Bravo and bolts straight onto the 6 bolt assembly), the MD-X1, which is designed specifically for this engine hopefully next year, I will swap over and remap the engine to its claimed 500hp and 843lb ft torque (will need different injectors over 450hp). Check out the numbers at: www.marinedieselengineering.com/md/
This engine, incredibly, occupies less physical space than the outgoing small block volvo v8 and weighs in at only 125lbs heavier! I have scoured the market and nothing can touch the power/weight/dimensions in the 350-500hp segment including the straight 6's.

[larby]

Would it be lighter than a BBC then? Price? Fuel consumption? Sounds like a very interesting motor, I'm liking the one with the twin blowers!

Cheers, James

[Charlie Hunter]

What's a BBC? The 350/400hp VGT unit with Bravo3 was £29k incl vat. The new MD-X1 drive will be extra as will the remap to a 450hp variant and extra again fot the 500hp remap and upgraded injectors. No prices for this yet as it is so new. I am probably first recreational punter to have one. The military seem to be buying them as fast as they can build them. The minimum fuel consumption is quoted for the 350/400hp unit as 215g/kwh which means absolutely bugger all to me, however, apparently it is very economical and up there with the best of them. The 500hp minimum consumption is 230g/kwh. The twin blower motor is still in development and not yet released. This I gather is a complete torque monster but not so efficient in the high rev range due to the power required to drive the blowers. It will also be very expensive.

[Peterjfinch]

BBC = big block chevrolet. So these are basically beefed up duramax engines? I have read so mane things about the faults with the chevey 6.5 diesel and yet, add .1 and the duramax is the best thing since sliced bread. Now they are adding to this engine and making monsters.

I guess that the monster is there, waiting for the right combination, to let it out.

Just my opinion, and I know nothing.

Pete

[slomo]

nice looking engine should be a good set up
lets hope the b3x can stick the pace even @350hp
what weight is your boat

[Cookee]

Get the dyno sheets for the motors before fitting them - maybe poor information but I have been told the HP ratings are a little on the optimistic side .........

[Charlie Hunter]

Got BBC after I thought about it for a minute - am new to forum speak!

The 6.5l engine is based on the GM Optimiser unit and is an entirely different engine to the 6.6l Duramax. Marine Diesel's Hammerhead 300hp unit is based on the Optimiser and is supercharged. I bought one originally for my repower but changed to the VGT when the VGT became available three months ago. (MD gave me 100% credit towards the VGT). The Hammerhead is not as technically advanced as the VGT and will not grow beyond 300hp and a respectable 519lb ft of torque whereas the VGT provides me with a future power upgrade path. The Hammerhead is a lot cheaper and would still have been a considerable upgrade on my old petrol SBC. The Hammerhead is very simple and reliable and is fitted to taxi boats amongst other commercial applications. The military are fond of them too.

I have never weighed my boat, however, I believe it is about 3 tons. I intend to weigh it asap.

[Boatless-Again]

Originally Posted by Charlie Hunter

The avatar is my boat and she had a number of modifications which are unique as it ended up the last 28 produced. The engine is based on the GM 6.6litre Duramax unit (some 3.5m out there in trucks etc). It has the usual latest generation diesel kit, common rail fueling, variable geometry turbo (greatly reducing turbo lag, aftercooler (water cooled), electronic engine management, 4 valves per cylinder and so on. The Konrad drive requires a gearbox within the engine bay to do the shifting. This was not an option due to the limited physical space in the engine bay plus the Konrad drive and gearbox combo is very heavy. The straight 6 cylinder diesels on the market were also ruled out due to limited space. Initially I am using the Bravo 3 X drive with the engine's power and torque mapped back to 350hp and 537lb ft form. Once Marine Diesel release their new drive leg (shiftable like a Bravo and bolts straight onto the 6 bolt assembly), the MD-X1, which is designed specifically for this engine hopefully next year, I will swap over and remap the engine to its claimed 500hp and 843lb ft torque (will need different injectors over 450hp). Check out the numbers at: www.marinedieselengineering.com/md/
This engine, incredibly, occupies less physical space than the outgoing small block volvo v8 and weighs in at only 125lbs heavier! I have scoured the market and nothing can touch the power/weight/dimensions in the 350-500hp segment including the straight 6's.

I'd use the arnesons on it they do not require the engine to move forward

[Jon Fuller]

Originally Posted by Charlie Hunter

The Hammerhead is very simple and reliable and is fitted to taxi boats amongst other commercial applications. The military are fond of them too.

I wouldn't believe 'too' much hype. I've witnessed plenty of aggro and disappointing performance from the blown 6.5 litre MD motors. The 6.6 (joint GM/Isuzu project I think) is supposed to be very, very strong, the yanks reportedly have marine versions running at 1000+ hp, but we saw a plethora of problems on every single leg of the Round Britain 2008 race with the boat fitted with a pair rated at 400-ish hp, mainly turbocharger failures, but other issues too.

Hopefully the latest generation of motors are sorted.

[Scand]

There is also the bankspower version of this engine:
http://www.banksmarine.com/
Looks nice, but not sure if its any good though...

[Charlie Hunter]

Im aware of the 2008 round Britain problems and contested those issues before selecting the engine. The engine was rushed out for the race and was simply not sufficiently tested, it was still very much in its development stage. The bigest problems there related to aftercooler (its now a completely new design) and turbo back pressure, both of which have now been resolved. I must say however, I am astounded that MD campained an engine that was rushed through without proper testing for such a high profile event. The engine has since undergone thorough development and testing over the last 2years. I only received my engine in October and it was built in the second batch released (military had the entire first batch) and I am probably the first recreational punter to get one which makes me a bit of a guinea pig! Even my engine has received various upgrades which will be rolled out as standard on subsequent units. My point is, this engine cannot be compared to any previous variant as it is significantly different. I just hope that they have got it right now, because if it is it will take some beating.

[Charlie Hunter]

I looked at the Banks unit, it was never released apparently due to a load of technical problems relating to those twin turbo's. Doesn't look likely that it will be released any time soon. Nice looking motor though.

[cosworth mirage]

I think they will be a great package when sorted there has been so much development over the past 10 years in both diesel and petrol ,variable vane turbo,s variable cam timing ,variable valve lift(also altering compresion ratio)and diesel pre inj and much more but it is amazing how a boat can show gaping holes in what you would think is a bullet proof setup (my setup is literaly shot to pieces after a few hundred hours flat out) and its not really that modern or fast

[Jon Fuller]

The motors that went round britain, or didn't, were using the automotive, air cooled turbo, which I reckon was half the problem.

[cosworth mirage]

changed my turbo to raw water cooling from the heat x output seems happy to run at 950c and is one of the few parts to prove reliable (turbodynamics hybrid )

[Bus Pass]

Air cooled exhaust manifold and vastly undersized intercooler. Underneath probably a fairly sound block.

As Charlie says, unbeleivable that they supplied these to Garmin. Failures in every leg including a couple of fires and a spectacular small explosion in the middle of the Irish sea.

[Charlie Hunter]

I am very relieved to confirm the engine now has a water jacketed exhaust manifold, stainless steel water cooled shroud around the turbo and a new giant aftercooler.