i don't know phil to be honest. as i said, i've never put a pressure gauge on my rail to see what happens. i was just going by what was said by both Stu and Karl on the first page of this post
Originally Posted by Karl
Yes as Stu rightly pointed out its amazing that many folk dont realise why we use a rising rate fuel pressure regulator!
Put simply any liguid or gas will always flow from a region of high pressure to a region of lower pressure until the pressure is equalised.
If we set our fuel pressure to 4bar at atmosperic pressure then we have an effective 3 bar fuel pressure above atmospheric. For every 1 bar boost we add, we must increase the fuel pressure by the same amount in order to keep the 3 bar differential pressure.
Failure to do this will result in a diminishing injector flow rate as we increase boost!
and it hasn't been changed / corrected since.
