Originally Posted by Mollers
A Merc (GM) 5.7ltr V8 puts out 260hp and more torque than the Queen Mary as it's in a very low state of tune.
A 3ltr TDI BMW lump with virtually half the cubes, would be a total wet fart by comparison.
Small capacity, diesel turbo/intercooled engines don't marinise well due to their narrow powerbands. No gears on a boat, it's all about grunt right through the rev range.
Hmmm, well my knowledge of petrol v turbo diesel is quite vast, tuned & standard stuff. So I pulled up some dyno plots as reference.
530d lump, grey lines are stock, red lines are tweaked
And the Mercruiser lump think its the pokier one listed here obviously
So the TD lump makes 500nm or 350ft/lb ish at 2k and peak hp is at available for 2/3 of the rev range. The V8 graph starts at 2500 rpm with 360ft/lb
and only makes its power in the top 1/4 of it rev range.
So according to those graphs the TD is pokier up till it runs of puff at 4500rpm, a tweaked one makes 150% of the V8 torque & will use 1/3rd of the fuel to do it
So going by that I think the little 3.0 smoker would need a V8 spec outdrive at least