Hello.
"You can probably do anything you set your mind to, but whether it's a good idea is another matter."
It takes a minimum of 5000 euros to build a new engine from existing parts. I don't want to go into the details now, because people who ask the above question will likely fail at such a project anyway.
Or you end up with situations like the modification in the TDI forum, where it's clear that people don't understand how the engine management system works, and the turbocharger pressure/temperature sensor is connected to the wrong place.
Don't take it personally, but that's just the way things are.
Tip: First, research how other engines are designed and what components they use. You can find information about this, for example, here:
http://www.all4engineers.de/cgi-bin/get_all.cgi?language=de&aktion=retr_con&hauptkategorie=Antriebsstrang&subkategorie=Neue+Motoren&detailkategorie=Dieselmotoren&info_alle=&info_firm=&info_doc=info_doc&info_news=&info_book=&info_event=¶m1=0¶m2=98¶m3=28¶m4=9¶m5=19
Best regards, Rainer.