[mwebb]

Originally Posted by mechman600

That would be bad. Systems with return lines need the flow for cooling and fuel pressure regulating purposes (I think). It probably would not run if you blocked it off, or it would run poorly. New cars do not have return lines, so maybe something could be done there. But I wonder what hot fuel will do to the life of a fuel injector.

I would listen to mwebb - heating fuel will probably have little effect on anything.

you can not bypass the return line on cars that have return lines .
new er cars have fuel pressure sensors and they duty cycle current to the fuel pump to regulate fuel pressure using a feedback system with the fuel pressure sensor.... but
why not just heat up the air ? tap into the radiator shroud , the air will be regulated at whatever coolant temperature is ... low tech ... easy ....
and you are heating up 14 times more mass of combustion charge without any drama or safety issues .

will there be any benefits ?
a definate maybe or ,
i dunno . but if not the modification will be easy to un modify .

there are no significant "suction throttling losses" on diesels as they do not have , throttles .
unless they have EGR
and are computer controlled then there is a throttle of sorts that is used to lower pressure in the intake and some have a throttle in the exhaust to increase exhaust pressure at the same time so that
EGR will flow from hi pressure to low pressure ..
and
they all have EGR