Need Advice for setup

[VeryFast2gDSM]

I'm helping a friend with his car. He bought a 90 Shell which had certain mods done to it. The ECU was converted to a 91+ ECU because of the eprom, maf plug was swapped to 2g Maf.

So he's on a budget to get the car running for now, and does't have the money to buy a engine management device, So right now he has a rebuilt stock block with APR main, and head studs, and rebuilt head with aftermarket valves. He's running a 2g Exhaust manifold with a 14b for now. Stock side mount... stock intercooler piping... But he's going to run a 2g maf, and FIC 550cc injectors. Having both of those should equal each other out. But should we use a 2g fuel pressure regulator or a 1g? Reason i ask is Fic 550cc injectors are rated at 43psi. if we use a 1g, the fuel pressure is 37psi... and the injectors wont be flowing 550cc. Or are we over thinking this?

 

[steve]

he's going to run a 2g maf, and FIC 550cc injectors. Having both of those should equal each other out. But should we use a 2g fuel pressure regulator or a 1g? Reason i ask is Fic 550cc injectors are rated at 43psi. if we use a 1g, the fuel pressure is 37psi... and the injectors wont be flowing 550cc. Or are we over thinking this?

550cc injectors and a 2G MAF aren't actually a null sum game but it's close enough to make the car drivable.

While it's true that the injectors won't flow 550cc at the 1G base pressure neither do the 450cc injectors flow 450cc. The percentage difference between the two remains the same as long as the pressure for both remains the same.