I've read some mixed reviews about the fuel mileage comparison. Is there others with experience on them being very similar? It is not a huge issue but here in Canada fuel is not cheap and we use our boat a lot.
Without putting a 3 litre in a boat and running it under control conditions and recording the results, then pulling the 3 litre and dropping a 4.3MPI in and doing the same thing under exactly the same conditions, it's very difficult to get a direct comparison.
We can however use some logic and mechanical principles.
The 3 litre produces about 130hp. So up to the point where the 4.3 is producing 130hp, the amount of fuel burnt by each engine is going to be very similar (x-hp will require y-litres/hr to produce)... Once the 4.3 is making more that 130hp, it will use more fuel (more hp requires more fuel). So on a straight litres/hour, then yes, the 4.3 will use more beyond 130hp. The other side of that coin is that by producing more hp, the 4.3 will push the boat quicker, so will cover more distance than the 3 litre. So the miles per gallon will be similar, or could even be a tad better with the 4.3. And you'll get to your destination quicker, allowing more fishing time
ok, before the bandwagon comes along and jumps all over this saying that as the boat speed increases, the hydrodynamic drag will increase by the square, also consider, on a moderate Vee hull, as the boat speed increases, it rides up higher on the Vee and the amount of hull in water, and therefore the drag, decreases, so they 'balance out', roughly...
I have done all the fuel flow vs boat speed vs rpm for my boat, and my most economical speed is 27 knots, which is quite fast.
Just remember, bigger more powerful engine doesn't always equate to more fuel used. (a lot is controlled by your right hand too
) Example. I have a Toyota Landcruiser. Had the dog 4.2 litre Toyota naturally aspirated diesel in it when I bought it. Got about 15 litres/100km... I pulled that and dropped a 6.5 litre V8 turbo diesel in, and I get about 12.5 litres/100km now... And the difference when I am towing the boat is even more.
Hope this helps....
Chris..........
BTW, we (Australians) are paying about $US3.75/USGallon. (about $AU1.35/litre). What's the price in Canada? (and the US if anyone would like to chime in...) Canadian dollar is very close to 1:1 with the Aussie dollar...
Just found a website with Canadian fuel prices. Look about the same as Australian (very slighly cheaper in Canada, a few cents).... Same site gives USA prices...
we're paying around 40% more than what they are in the US... NOT FAIR!
