930 CIS return line pressure? Adjustable?

[e p slick]

What pressure should one see on a 930 CIS fuel return line? Is it controlled by a popett valve? Adjustable and variable? Have not found the answer in print yet.
Thanks - EPS

[935 lover]

hello, i just read your question on the return fuel pressure line, on the 930 cis system the fuel pressure is fully adjustable on the 1 fuel dist. 2 waqrm-up regulator, on the fuel dist. there is a spring loaded valve with shims will set the system pressure and if my memory is correct it should be about the area 4.7 to 5.3 bar. if you look into the factory spec. book it will tell you the stock settings. by using a fuel gauge attached to the warm-up regulator you can read the preassure. if you remove the valve on the fuel dist. and remove shims from the valve it will raise the fuel pressure. cis works as lower the pressure richer it runs and higher the pressure the leaner the system will run. i use to do this to 903's i had improved with cams and porting and k27 turbos. but i have also used a Mercedes fuel dist from a 5.6 v8 and used it on a 935 engine that was mechanical injected originaly. and i used a mechanical type regulator insted of a warm-up regulator. let me know if this helps you or i can answer any outher questions. dave good luck

[e p slick]

Thanks for the response. This info will help me learn how to fiddle with the CIS. I am familiar with Enderle and Crower systems used on supercharged cars but am new to the CIS. Again - Sincere thanks - EPS