This is all the info I could find.
Quote:
Originally Posted by piero
the multicolor  small "bell" is a regulator for the fuel in returning"flow" 
(I'm sorry ,but I just tell you what I heard today by the workshop
and in such a technical forum I feel a little shame |
It sounds like it restricts returning flow off the fuel distributor.
I am guessing it would sense off of manifold boost pressure in addition to being in-line with the fuel return line off the fuel distributor.
Thus, if the fuel pumps can handle it this should increases system pressure on boost which should increase potential delivery pressure at the fuel injectors.
A maxed out CIS delivers less fuel at higher boost pressure. That is, a 425hp .8bar 3.5 motor will have more fuel than a 1.2 bar 3.0 425hp build.
This could be a way to offset this.