ok i searched, but couldn't find any exact answer. i'm a little confused about hos to calibrate the sfmu in my situation. i'm planning on running 5-8psi w/310cc injectors and a walbro 255hp intank. what ring/disk/spring combo should i be using? should i be using the "small, black, hard spring". some say it comes w/ the sfmu, some say it doesn't. here's what came with mine.



is that spring the small, black, hard spring? it looks black. i checked vortech's website and there is no where to purchase any optional spring. also in tuning it, should i set a vac or boost cutoff? in other words, you can set at what vac/psi the fuel press starts rising, and when it stops. tia

Use the 2.72" disk and ring. The ring will fit around the 2.72" disk with a 1/4" gap all around the disk, thats normal. Put in that short dark spring thats in your pic. Keep the "vacuum" and "boost" ports on the SFMU untouched, as you dont need to adjust them. I suggest using the optional bleed valve that can screw into the "bleed" port, the port that is capped off. This can bleed off some boost pressure from the sfmu, if you run too rich with that disk/ring, and can fine tune your boosted fuel pressure. Set your full idle fuel pressure(16-19 Hg's), to around 22 psi. This should give you *close* to the same amount of fuel as your stock injectors at 55 psi at idle. Your static fuel pressure (0 psi) should be around 30 psi, and fuel pressure at 5 psi should be around 55 psi. Fuel at 8 psi boost should be around 65-70 psi. This should be a very good starting point. I always suggest to datalog your fuel trims and to monitor your o2's whenever you run larger than stock fuel injectors.

as always, you're the man... thankyou very much