High performance diesel outboards?

[codprawn]

http://www.megoutboard.com/30L_vision.html

Just come across these - they are claiming similar performance to a 300hp 4 stroke with a WOT fuel consumption of 8 US gallons an hour!!! And it's lighter than the Yamaha 300..........

[Nos4r2]

Originally Posted by codprawn

http://www.megoutboard.com/30L_vision.html

Just come across these - they are claiming similar performance to a 300hp 4 stroke with a WOT fuel consumption of 8 US gallons an hour!!! And it's lighter than the Yamaha 300..........

Looks like it's available just as a powerhead to fit to a Merc leg too.

I'm intrigued.

[codprawn]

Me too but I am a little sceptical of the power outputs. Only the very latest cutting edge car diesels are producing anywhere near that power but then again sea water is a VERY effective cooling medium - the intercooling etc is far better than any car.

[prairie tuber]

As long as your able to cool the charged air adequately, you can boost the snot out of a turbodiesel and get some amazing power output from a relatively small displacement engine.

[ribit]

Great idea but very very sceptical as well, I think it would take a large corporation like Brunswick to develop this kind of engine or some Euro manufacture like VW to do joint venture and Merc are never going to let you cannibalise their engine's and advertise such on the internet, secondly as yet the Americans have no market for this engine read all their forums they are very happy with petrol in outboard...it is only in the large offshore powerboats with twin 600+ in petrol where they are starting to look at some kind of performance diesel as this sort of power can burn through 80+ gallons per hour

[codprawn]

Originally Posted by prairie tuber

As long as your able to cool the charged air adequately, you can boost the snot out of a turbodiesel and get some amazing power output from a relatively small displacement engine.

Very true but when you look at the power outputs of engines from people like Volvo or Cummins etc - they are still really pushing the envelope.

Maybe they know something all the world's leading diesel engine makers don't.........

[bernithebiker]

It's interesting that they don't actually quote the power output but simply say the performance is 'similar to a 225 or 300hp 4 stroke petrol'. (they have 2 models).

Even though you can use the seawater to intercool your turbo inlet charge, it is hard to see them making this kind of power, when the best 2 litre diesels are currently making 175hp.

However, diesels like these put out close to 400Nm of torque, compared to only about 200Nm for a similar power petrol engine.

Doubtless their diesel also has very high torque figures, great for driving large props at relatively low rpm (Note WOT is only 3800/4000rpm).

So I would imagine that the actual power output is a good bit below 225 or 300hp, but this is compensated for by a healthy torque figure. Probably quick to plane, and keep the plane in tight turns, etc.

Also, I would imagine that such a high performance diesel would demand car quality DERV, i.e. EN590 standard euro diesel with cetane of 51 min. As far as I know, marine diesel does not meet these standards, having been designed for large, low tech engines. So goodbye to any fuel cost savings.

[codprawn]

Even modern diesels will run on any old rubbish - such as biofuels etc - red diesel is still better for your engine than cooking oil......

Another alternative is jet fuel or heating oil/kerosene - just add 5% cooking oil as a lube!!!

[jwalker]

Originally Posted by codprawn

Another alternative is jet fuel or heating oil/kerosene - just add 5% cooking oil as a lube!!!

You've posted that a couple of times, Codders but Kero +5% oil does not equal diesel.

...So I would imagine that the actual power output is a good bit below 225 or 300hp, but this is compensated for by a healthy torque figure....

You speak as though torque and power are not related. If you have high torque at a given rpm, you'll also have high power at that rpm. Diesels generally produce more power at lower rpm than equivalent petrol engines but they run out of breath as their revs rise so they don't ultimately manage the high power that a petrol motor does. The fact that they have lowish maximum RPM doesn't matter because the lower unit gearing can take care of that to ensure a satisfactory prop speed.

[codprawn]

In many cold countries winter diesel is just Kero. Many armies now have a single fuel policy. Basically they use jet fuel in everything. The only problems they have had has been in very hot countries like Iraq. Even then it's only after a long time of hard abuse. They use an additive to add lubricity - basically what you are doing by adding the cooking oil.