You can get plenty of fuel out of the 616 ip. Ideally larger elements should be put in. But even without them there is plenty of fuel. 5.5mm is the standard element size for both the turbo and non turbo pumps. Basically both pumps are identical except for the number of elements, 4 for the 4 cylinder 5 for the 5 cylinder.

I don't know what hp level you are going for, but if not to high then proper adjustments to the stock pump have gotten about 100 or hp for others. I've heard of as much as 250hp dyno proven, with pump mods. I am not sure what turbo that engine was using, it was posted in superturbodiesel.com

I am looking a 10mm elements on my 240, possibly with a differant ip cam. Right now I.ve just adjusted the stock ip, but would like to get fueling quicker, i.e less degrees of crankshaft revolution. This is one of the advantages of larger elements. If fuel is injected too long(in degrees of crankshaft rotation) then it gets past the point to which it can be effectively burned. Smoke and high egt's are the result.

You may want to look at the posts by josha37 in the performance section of this forum. Granted you want your engine to live, but you get an idea of what these engines can be pushed to.

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1977 240D turbo