If we look at the big picture, 1.8Ts have been modded to the 1000 HP range. So it's not that I don't think we can get similar HP/L on a Diesel - I'm rather confident it can. The bottom end would likely look quite different from stock - heavily reinforced and modified, Maybe even having to resort to a custom iron head as one of our own members (andy2) has done, or machining the block and head from billet.
I suppose if you go sky is the limit and fab heads etc. This is my first foray into diesel after age 10-40 wrenching and growing up in a household and family who were gen 1 haltech users and tuners when turbocharging was less reliable even to OEM.
Bought a MKVI JSW solid top 6spd TDI and loved it so much I picked up basket case ALH beetle to toy with and take miles.
Closed deck block becomes completely closed deck. Fill the coolant passages.
That diesel torque and the cylinder pressure. That's what I worry about.
Again admittedly I am NO diesel expert. It's like being clueless again to an extent
I did half that daily driven on a stock block while being told I would throw a rod or mangle a motor. In a small port 1.8T with small wrist pins, cheap cast pistons you could sand with (Audi motors had mahle power pack) that had timing belt collision marks and 200,000 on the bottom end. Stock headbolts. 100% high mileage stock motor. Had a dealer head done at 100k for timing collision.
Heads are mid 200cfm if I recall.
My newbie diesel understanding is that there are much higher overall pressures involved during the suck squish bang boom. Less revs. So **** tons of boost, fuel,