OK, I am failry mechanical, but this is my first foray into FI. I have done some reasding here and on MY350 as well as general sources on-line.

Blower system: Used Vortech V2 with 3.12 pulley, Vortech FMU, RC 550 injectors, Walbro 255 fuel pump.

Car: 04 sedan 6MT with 100,000 miles (just rolled over last week). New plugs and coils.

Intake mods: for now 3/8 Skunk2 spacer, maybe upgrading to Kinetix SS manifold.

Exhaust mods: free-flow cats, HR Y pipe, coupe mid, Magnaflow muffler (may go back to stock muffler)

Other details: Original clutch, original HG. Will be replacing leaky valve covers when installing new injectors. I will be tapping the upper oil pan for the oil return line. Adding oil pressure and boost gauges (mechanical). Car is a daily driver but I have a work vehicle so it sometimes sits for a while. I average about 2000-3000 miles a year if that. I live at sea level, and the most altitude this car may ever see is maybe 1200' ASL.

I'm keeping the tune very conservative. Like probably 7psi or less. I have no intention of taking it higher unless I one day want to upgrade the internals. Will be running 94 gas, or when necessary 89 with additive.

I will be tapping the upper oil pan for the oil return line.

Questions:

with a good pro tune and the 255/550 combo, can I run the system on a modified ECU *without* the Vortech FMU? Is any other fuel managment required?

Will I be causing problems using 550cc injectors? Should I use smaller ones?

I know this has been addressed a few times but therte seem to be all kinds of opinions on what can and cannot be done without putting the engine at risk.

So.... what say you?

 

depending on how free flowing your system is that 3.12 pulley might be closer to 8 or 9 psi at high rpm.... my intake and exhaust is OEM (for now) and thats where I am at 6500 rpm

 

hmmm I am leaning toward going back to the OEM muffler because the magnaflow is a little loud for me. With the OEM that should be a little restrictive.

Oh and I am adding the Kinetix manifold. Bought a used one.

So would going up a pulley size be advisable?

And what about the FMU? Necessary?

 

3.12 will get you closer to 8-9 psi at stock redline like ge35es said. You can use uprev or ECUtek to flash in tunes for the voltages the maf will see. I feel like you might get close to maxing out the stock MAF. 550cc should work but they will be kind of high in their duty cycles.

For reference, I am on a 3.12 and get around 13-14 psi at 7k rpm.
660cc / 300lph
75mm TB / 5-8" Skunk2 plenum spacer / CAI tube
HR megan shorty headers / kinetix HFC / Invidie gemini dual 2.5" catback

 

Hey I guess I should update this thread. Went with a 3.25 pulley and - although I was hesitant to go this route - an ECUMaster3 piggyback.

So far, so good. a couple of signal issues at the beginning (a false reading from the crank sensor was causing all kinds of craziness). A quick tweak - and adding a wideband sensor -and it's been good ever since.

I will probably upgrade to a Haltech unit at some point, although with the moderate amount of power I'm producing seems to be managed pretty well so far.

 

Good to hear! Did you upgrade the clutch or go with a different manifold?

I retuned mine with a 1 piece charge pipe plus uprev GT maf and boost pressures dropped to 10-11psi (from better efficiency) while power increased to almost 420whp.