Originally Posted by Ex-Calif
I expect the incremental costs are negligible, the increased full burn when pushed is negligible and as any mechanic
will tell you, "There is no replacement for displacement
Of course the mechanic
is going to say that they get paid by the hour.
, 5-10% more installation
time. 25-50% more time redoing the engine
beds, 5-20% more time dealing with assessories in an engine space that is more crowded with a larger engine.
The change from a D1-20 to a D1-30 is going to be an extra $1000 or so from what prices I have been able to find. The mechanic is also going to have an incentive into getting you to upgrade a lot of the ancillary equip to go with the larger engine.
It's starting to look like the incremental costs are not so negligible.
At full throttle on the D1-20 it will be burning about the same fuel
as the D1-30 at 2/3 throttle, lets say 0.7 gal/hr. At full throttle the D1-30 is going to burn 1.05 gal/hr, 50% more fuel
. In flat water
that might get you and extra 1kt.
Increased fuel consumption
at full throttle doesn't look very negligible either.
Intelligent decisions regarding compromises can't be make without some understanding of the reals costs involved.