GUIDE REQUEST for turbo map

[cwspellowe]

can I ask again as an idiot....is volumetric efficiency different for diesels??

as all my calculus are showing even GT series to be way outa efficiency for what I need.

PS yeah, been looking a GT2052 or 1752. but the maps say 2052 so far

PPS I will probably only port n polish exhaust side as theres 2 inlet valves but the single exhaust valve is still small...
I gasket match as routine anyhow too.

I'd take a punt at a VE of 80-85% for a clattery old XUD, higher for an HDI. Is the 2.1 a 12v motor though? Go for 85% and see how that works out.

Unless you know the EXACT VE of the engine though you'll never get a 100% accurate comparison. At that point you just go and fit it and see what happens, having decided what looks best given your tolerances.