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>How do you use the bleed valve to fine tune it when the check >valve is connected to it? Unless there is an adjustable screw >that I don't know about?
The bleed valve should have a small knob on the end of it, you can turn it in and out. Its just a needle valve that lets more air out of it, when you turn out the knob. When you turn in the valve, it closes off, and does not let any or very little air through it. This bleed valve is tapped into the main air chamber inside the SFMU. This air chamber is what gives you your higher fuel pressures under boost. Boost pressure enters this chamber, and pushes down on the diaphram, and then closes off more return fuel flow that should be going back to the tank. This in turn raises your fuel pressure at the fuel rail. Now, when you open up the bleed valve, that boost pressure inside the chamber is being let out, or "bled off". This in turn lowers your fuel pressure because the SFMU and diaphram is not seeing as much boost pressure, its being bled off. That's how it lowers your fuel pressure under boost. It basically lowers the disk's rise rate, just like using a smaller disk/ring combo. If using the largest disk, lets say you have like 2 turns open on the bleed valve. Some of that boost pressure inside the SFMU will be bled off, and lowers the rise rate to lets say the 2.72" disk. Make sense? Then if you close off the bleed vavle, it will let less air by it, hence increasing your fuel pressure, because the SFMU is seeing more boost pressure now.
And you said to tighten the boost >screw? I thought the 2.72 disk, small spring, and largest >ring was the best setup for 30in injectors? What spring do I >use with the largest disk then?
On the top lid of the SFMU, there is a "boost" port hole on it. Inside that port hole, is a allen head adjustment screw, that has a very tiny hole in the center of it. If you loosen this screw, it sets a maximum fuel pressure under boost. So this can set you total max fuel pressure to lets say 80 psi. If your boost pressure spikes for some reason, the fuel pressure will NOT go above 80 psi. That is why you DO NOT want that boost screw to be out at all, and you want it tight all the way in, so as the SFMU will still raise up your fuel pressure if your boost spikes or you run more boost pressure in the future. IMO, the best SFMU setup is the largest disk, the longer silver spring, and the bleedvalve with check valve. YOu will prob need to have one or two turns out on the bleed vavle to lower that disk's rise rate a bit. The check valve needs to be on the small hose barb off of the bleed vavle. The outlet of the bleed valve should have that small hose barb, then you connect a short piece of vac hose to that, then the check valve connects to the hose. This check valve lets the bled off boost pressure out the SFMU, but it closes off under vacuum, so no air gets sucked back into the SFMU, creating a small vac leak really. Since the bleed valve is directly tapped into the main air chamber of the SFMU, and if the bleed vavle is open, then not using the check valve will create a small vac leak, and the SFMU will raise the fuel pressure a bit too, since it's seeing less vacuum..
 13.5 @108 MPH-2.2 60ft(stupid FWD!) S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential fuel injection) My webpage: http://eclipsed4evr.home.comcast.net -1998 Mitsubishi Eclipse RS-T- "Toy" -1992 Plymouth Laser Turbo AWD(SOLD) -2000 Honda CR-V(daily)
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