I am of the opinion that any appreciable pressure will muck up the timing advance curve. I think a lift pump is a great idea, but plumb it so it will do a full circuit right back to the tank. That way excess fuel under zero pressure is directly available to the injection pump (eliminating problems caused by resistive filters), but the pressure doesn't mess with the timing advance. Best of all worlds, eh.
Andrew
i sat there and got out all my old notes from tech school
the return fuel being put back into the inlet is the way most every pump that has a built in regulator works
thats why i didnt make a seperate return for the bypass
and you also have plenty of feed to the pump that way too
it seems to get quicker the more psi i run to it
but i turned it down to low/mid 30s since then,and it doesnt drop more than 7-8 psi between idle and full load(a better regulator fixes this)
actually the other part of the tee that doesnt have the regulator,goes up to the filter
thats totally unrestricted
if you open the regulator itll cycle fuel all day in the cis pump
when you close it,you restrict the return side on the regulated part,and create pressure in the feed line
the part before the regulator is where the pressure is held,the regulator is just bleeding it off basically
i use a electric (digital) oil psi guage in the dash for a fuel psi guage
with the sender mounted in the outlet of the filter pad