BigJake

M-1 Pro-charger on MPI 502s what is the fuel pressure requirements.

Pro-Charge manual requires 23# PSI Diff From idle pressure at WOT. What is WOT mean in RPM to Pro-charger?
I have approx.38# at ide.
At 4000 RPM the starboard engine increase PSI approx.6# and the port 8# is this normal. As of now I didn't want to run it up to 5000 RPM for the fearer of running too lean.
Looking for a graph or matrix with a relationship RPM, fuel pressure and Boost.
When should the Boost start (RPM) and what should be the related fuel pressure be?


Thank You

BigJake

obnoxus

YOu should be at about 42# at lidel from what I remember. Also from what I remember it took that much to even make it idle correctly.

BigJake

Didn't seem to have an prob idling at 37#

Mate 229

I have 502 mpi procharged running 5lbs boost. WOT is 5050 to 5200 rpm depends on ecu programing and rev limiter. Manual says 48 to 52 lbs at wot. Dont want to run it lean or you'll melt piston tops

Kanookstr

Mine is at 42 psi at an Idle, w the boost reference line connected.
At WOT I am in the low 60's. Your pressure should reflect the manifold atmosphere. So at an Idle if you see 42 psi at 13 in/vac. Then at 6 psi boost you should be around 61 psi....

42 psi @ 13 in/vac .
At "0" boost/vac you should be (42 + 13 = 55 psi)
At "1 lb boost, 56 psi
At "2" lbs boost, 57psi. ect.....

Mbam

Procharger provides for the non-linear flow of the injectors above their design pressure and additional fuel requirements for cooling by having "gain" in the regulator. It is not a 1:1 relationship between manifold pressure and fuel psi, it is some multiple. The gain is changed by a washer in the regulator. We run the stock fuel pressure at idle, and will play with the gain if needed to arrive at the desired full load pressure. You cannot really check it accurately unless you are running at full throttle either on the dyno or better yet in the boat.