okay, running 310cc injectors, 5-7psi intercooled boost, SFMU with static initialy set to 32ish psi, idle right at 30psi, and 60psi at 7psi boost. Im still hitting 1.06-1.08v A/F.

how do i dial in this SFMU so i dont need to drop fuel with the SAFC by 50%(not really, but a lot). Vaccum screw no good for us, boost screw not doing a whole lot either from what i have read or am i wrong on that?
do i need to turn down my idle psi an few? should i use the SAFC more, or a combo of both???
thanks guys

tim

Perhaps change discs? Which disc are you using?

black spring, and 2.72 disc with ring that has a 1/4in. around it.

hmmm, are you sure that the sfmu and vac lines are hooked up right? do you have the restricter in line? where is your vac source coming from?

when you set the static fp on the sfmu, once you reconnect the vac line, your fp should drop b/c of the vac the the sfmu now sees(usually 16-19hg at idle). the fp should drop significantly after the vac line is connected. my static fp is right around 31-32 and my idle fp ends up being about 21-22. there should be about a 7-10 psi difference.

you don't have to touch the boost screw. have you adjusted the idle screw at all? after making sure all of the above connections are correct, you might try adjusting the idle screw to get your fp at idle to be around 7-8psi less than your static fp. maybe someone messed w/ the idle screw and that's why you're seeing only a 2psi drop for static to idle. the only other thing i can think of is, in your pic your sfmu looks a lot different than mine, or any other sfmu's i've seen. i know it's a dumb question, but are you sure you have the sfmu and not the fmu or something. i haven't looked at the pic recently, maybe you just mounted it upside down or something.

no matter what though, you should not have to use the safc at all, and you'll be at a disadvantage if you do anyway, b/c of the way it advances timing.

EDIT: one more thing i saw, if your static is set to 32 then you should have about 67psi fp at 7psi, if you are using the 2.72" disk and dark spring. 60 is too low.

tim do you have the optional bleed valve from vortech??? you can use that to fine tune the fuel curve.

hmmm, are you sure that the sfmu and vac lines are hooked up right?
**yes. theres only the one vaccum line on the top of the SFMU.

do you have the restricter in line?
**Yes. about 2-4 inches away from SFMU.

where is your vac source coming from?
**i have it T'ed from the 3 pronged vaccum fitting on the back of the manifold. *** should it have vaccum from a single source only, without any other vaccum draw for other componants?***


when you set the static fp on the sfmu, once you reconnect the vac line,
**i initialy had the vaccum line connected when i set the static to 32psi, but when i tried to reset it with line off, my fuel press. needle didnt budge more than 2-3psi from 0. ???



have you adjusted the idle screw at all?
**the screw on the top of the unit? yes, to set static and idle.

are you sure you have the sfmu and not the fmu or something.
**yes. very much sure. i have 2 of them, the vortech SFMU's.


no matter what though, you should not have to use the safc at all, and you'll be at a disadvantage if you do anyway, b/c of the way it advances timing.

EDIT: one more thing i saw, if your static is set to 32 then you should have about 67psi fp at 7psi, if you are using the 2.72" disk and dark spring. 60 is too low.
***thats what i was thingking, but im still running way rich at 1.06-1.08 A/F.

No. no bleed valve yet. thats next on list.

by idle screw, i mean the idle adjustment screw on the side of the sfmu, not the allen key static set screw on the top. the idle adjustment screw on the side should be fine at it's factory preset location, but it sounds like it may be off. i think that might be the reason why you're only seeing a 2psi drop when you connect the vac lines.

i have my sfmu at it's own vac location(pcv barb on intake mani), but you should still be ok with it teed off where you have it.

make sure when you set the static, the car is on and no vac line if connected to the sfmu(0psi). set it to 31-32psi. then connect the vac line, if you still don't see a 7-8psi drop at 16-18hg vac, then adjust the idle screw on the side of the sfmu(i believe it needs a flat head screw driver). adjust it until you see about 21psi at idle. this is probably your problem. unless the unit is broken, but it sounds like all that is needed is to adjust the idle fp.

btw i looked at your pic again, and i must have been thinking of someone else when i said your sfmu looked different.

>No. no bleed valve yet. thats next on list.

definately get that bleed valve and the check valve fitting (it screws into the bleed valve so you can attach a hose to it in order to keep air from coming in under vacuum) as soon as possible.



EDIT: if anyone so desires, save this image somewhere and put it in the "things we've seen before" or something. personally, i would have killed for this diagram 3 months ago, but i had to figure most of it out on my own.

okay. so the VERY FIRST thing to set on the SFMU is the static, correct?
this is done with the vaccum line off and the: car on, but engine NOT running, or WITH the engine running??

i bought a used unit and i did play with the vaccum screw on the side but from what i have read on other posts everyone says it pretty much doesn't do anything one way or the other. IF it does do something, should it be screwed all the way in or all the way out or where? any idea?

I played with boost screw as well, so where should that one be set to also?

>okay. so the VERY FIRST thing to set on the SFMU is the
>static, correct?
>this is done with the vaccum line off and the: car on, but
>engine NOT running, or WITH the engine running??

the engine should be running. unhook the vacuum line, and tune the screw on top until you get your desired static pressure.

>i bought a used unit and i did play with the vaccum screw on
>the side but from what i have read on other posts everyone
>says it pretty much doesn't do anything one way or the other.
>IF it does do something, should it be screwed all the way in
>or all the way out or where? any idea?

i haven't touched mine. i'd guess that it's suppose to be screwed in all the way by default.

>I played with boost screw as well, so where should that one be
>set to also?

put it back, screw it in all the way. 100% sure on that one.

yes, i'm sorry, i meant the vacuum adjustment port. i don't know why i was calling it the idle adjustment screw, however, it does adjust idle fp, and is probably your problem. juat set the static fp as described above, then w/ the vac lines connected and the engine idling, adjust the vacuum screw until you get the idle fp down to ~21psi.

btw here's a link to the instructions. don't pay attention to any of thier fp recommendations though

http://www.vortechsuperchargers.com/pdf/manuals/superfmuim.pdf

YOU GUYS ARE GODS!!!!!!!!!!!

Thank you very much. I will do all that tomorrow and let you know the results.

Tim

i hope it helps. let us know how it turns out :)

Okay. static set to 33psi with vaccum line off while engine running. with vaccum line on, idle dropped to 22psi. At 6psi boost fuel pressure was 56psi, with 1.01-1.03 on A/F gauge. Boost set screw all the way in, and vaccum screw does absolutly nothing in or out, idle just sits @ 22psi.

Any ideas?

Tim

that sounds like it's working correctly then. although, you should probably be seeing more like 60psi at 6psi. you're definitely not too rich. your a/f may have a bad ground or something. you should datalog it now, to get it fine tuned

just spoke with vortech tech support who confured with the engineers and at the end of it all they said that i should keep lowering my static fp till i get the end product of acceptable A/F readings.

they also said that they are beginning to think that the vaccum screw doesnt work for our cars. he said they have had 4-5 other calls concerning the same thing.

Could i have got bigger injectors that what i initialy thought? I thought i bought accell 310cc's. would bigger injectors cause me to be running rich at a lower boost fp than expected?

the vacuum screw does work with our cars, you just have to keep unscrewing it, you will see the FP go down, i guarantee it.

Lates
James

I know when i ran 8 psi on 310's, my fuel was around 65-70 psi. At 6 psi boost, you should be around 55 psi, so i think you are close. 1 volt is very, very rich, which it shouldnt be using those injectors with that fuel pressure. Its very possible you may have larger injects than you think. Also, i have tried using the vacuum screw on my SFMU, but it didnt do much at all. I have called Vortech too about that, i'm sure i was one of those guys they mentioned. The vac screw is used to make your vacuum fuel pressure more even, with less fluctuation from full vac to 0 vac. You can turn out that vac screw, and this creates a vac leak inside the SFMU at engine vacuum, and your fuel pressure raises(less vac=more fuel pressure). This way, your fuel pressure under vacuum, will be closer to your static pressure(more like 2-3 psi difference, rather than 7-10 psi in vacuum conditions). At first, I thouhgt your vacuum screw may have been missing that check ball that is behind that screw. That is what regulates the "vac leak" throgh the vacuum screw(there is a pin hole in the center of that vac screw). Basically there is a small spring, and small plastic ball behind that vac adjustment screw. But it sounds like you got it figured out for now, just seems way too rich still for those fuel pressures. If you can, put a data logger on it. If you are running larger than 310 injects, at idle, your fuel trims will be most likely pegged at -25% @ 20-22 psi of fuel pressure.

oh yea, my EGT's are around 1400 also at 6psi.

anybody wanna rent me a datlogger? Or better yet, sell me one? palm or windows!

i know personally w/ my 310's i'm seeing a little over almost 60psi at about 5.5psi boost. i am running a little rich, but aside from my wot a/f voltages, all my datalogged fuel trims are right in spec. my a/f volts at wot are about .96-7, i've got to open my bleed valve a little more.

you may have gotten bigger injects, but before anything i would datalog it to see your fuel trims. however, your engine would probably be throwing a code for being too rich if your fuel trims were pegged at -24. again, you may also be getting a faulty a/f reading.