First of all...God damn boost is fun :P I will admit I am hooked.

Anyways Today while tuning my set up, I had to release the bleed valve all the way out, and the static screw all the way in (where the top is flushed with the unit) in order to get 50psi at idle. Does this happen to everyone else? I read somewhere that this is bad to push the screw far in...help :(.

Curently on stock injectors and 3.62 ratio Sfmu disk that caem preinstalled if this helps.

thank you all.

kaiser

I assume you are using the Vortec S-FMU the way it sounds?

For one, I would go with the optional spring if it indeed the one you have allows for a higher idle. The one that came in that I am assuming you are using yielded the same results for me as you are having to deal with now(having to turn the screw all the way in).

You're right...the directions warn NOT to have the static pressure bolt screwed all the way in. I would be cautious about leaving it that way.

Second, the 3.62 disk describes the size of the disk, not the boosted fuel ratio. It's actually closer to 6:1.

Murix: yeah it is the SFMU.

Jason: to change spring, you mean to swap out with the one that came with the SFMU kit, or the optional one that I should have bought but didn't know about until one reads the instructions?

thank you all soo much.

kaiser

the optional springs is that the one included extra in the box, or the third spring spring #7x100-050 the stiffest springs available separate?
also i took it for a sorta hard drive boosting around 6psi only around 5-6k rpm and when i got home it was not leaking around the same area? but looking at it in the sunlight in the crack around sorta looks wet a bit? weird part is when i set my idle fuel before going out today at 53-55psi i did not have to adjust it each time ( 3 times ) each time i started my car...
cool


Michael 99gs
Boost It!
Mods:
Hrc Stage 2
Greddy Type S Bov
VC-2
Road Race Catch Can
Greddy Profec B & Switch
Apexi WS Catback
Super Afc
Autometer Boost,
Egt
Air/Fuel Light & Digital
Tokico Adjust Struts
Eibach Pro Kit Springs
Front & Rear Upper Bar
CarCraft Interior
Sound System= Bring it On

Yup it is the other spring that came in the box. I just replace my standard SFMU spring with the one in the kit and adjusted my idle at a rock steady 55psi after bleeding off some. The static screw is no longer in there. Actually it is about half way out. yipppie :P

But I did notice that at 5psi (4.5 psi by the gauge) that the fuel pressure went up to 80 lbs. I thought that is reserved for 6psi people? how do I lower that as I think it is too high.

kaiser

someone told me we got to use the 2.72"disk and also change the spring? correct me if im wrong hey kaiser did you get my email? let me know

Michael 99gs
Boost It!
Mods:
Hrc Stage 2
Greddy Type S Bov
VC-2
Road Race Catch Can
Greddy Profec B & Switch
Apexi WS Catback
Super Afc
Autometer Boost,
Egt
Air/Fuel Light & Digital
Tokico Adjust Struts
Eibach Pro Kit Springs
Front & Rear Upper Bar
CarCraft Interior
Sound System= Bring it On

nope Didn't get an email from you. Drop me another one.

Not sure about the 2.72 disk as they are 5.4:1 ratio.
I thought with stock injectors we should be running roughly 6:1...any other input...

kaiser

Where did you hear that the 2.72" disk is 5.4:1 ratio?

If that's the case, that's the one to use.

At idle, fuel pressure should rest at 47-55 psi.

Under vacuum, fuel pressure goes to 60 psi.

At 6 psi, fuel pressure should be at 80-90 psi and 9 psi, the fuel pressur should rest at 105-110 psi. But, I think it's best for stage 2 people with intercoolers to use the 9 psi ratio and stage 1 people to use the 6 psi ratio. I would assume HRC figured in different fuel ratio amounts for people that have intercoolers or not (requiring a different amount of fuel for each). The stage 2 level can be figured by dividing 50 psi of additional fuel (based on the higher 110 psi amount) by 9 psi of boost which equals 5.55. There's your ratio. Thus 5.4:1 ratio is pretty darn close and would be the perfect disk if that in fact is the ratio.

I've been using the 6:1 disk. I may have to change. It is a tad rich at full throttle as my fuel pressure has been approaching 120 psi at 9 psi.

I see your point Jason. my 6.5:1 ratio is currently getting my 55psi at idle and about approx 78 psi of fuel at 4.5 lbs of boost So in theory i am runnign rich (Don't have a A/F gauge yet). I am on 5 pound wastegate with stage two IC.

I got the ratio form Corbin or is it james a while back. But let me confirm that.

kaiser

The biggest disk is supposed to be about 6.5:1 (but it performs less than that). For stock injectors and 6 psi, I suggest using the hard spring and 2.72" disk (about 5.4:1). Pull the vacuum line from the S-FMU and set pressure to 55 psi. This should put you at 84-85 psi at 6 psi boost. Your full vacuum idle fuel pressure will be like 42 psi. This is what I was running on stock injectors.


Corbin

'95 ESI-T
HRC+FMIC+ETC...

the harder spring you speak of is that the extra one included in the box of the s-fmu? or is the stiffest one which is a option you got to buy extra? also i got the bleed valve would the setup be different? and i could use this setup for also 9psi or would i have to use a different spring/disk combo? and if i use the setup you mention i would just have to play around with the bleed valve/ idle fuel pressure?
cool

Michael 99gs
Boost It!
Mods:
Hrc Stage 2
Greddy Type S Bov
VC-2
Road Race Catch Can
Greddy Profec B & Switch
Apexi WS Catback
Super Afc
Autometer Boost,
Egt
Air/Fuel Light & Digital
Tokico Adjust Struts
Eibach Pro Kit Springs
Front & Rear Upper Bar
CarCraft Interior
Sound System= Bring it On

>the harder spring you speak of is that the extra one
>included in the box of the s-fmu? or is the stiffest one
>which is a option you got to buy extra?

It is a short, dark colored spring. It used to be an option that you could order separately. Now it comes with the S-FMU in the box.

>also i got the bleed
>valve would the setup be different? and i could use this
>setup for also 9psi or would i have to use a different
>spring/disk combo? and if i use the setup you mention i
>would just have to play around with the bleed valve/ idle
>fuel pressure?

You don't need the bleed valve for 6 psi. You may or may not need it for 9 psi. I would keep it closed and see if you can get the right pressures with just the static pressure screw. If you can't do it with just the static screw, then try out the bleed valve. You may have to put a check valve on it to keep it from leaking vacuum at idle.

Corbin

'95 ESI-T
HRC+FMIC+ETC...

what should i set fuel pressure at idle to with the bleed valve closed? and to run 9psi? i know you said disconnect the vacuummm and set it at 55psi? and if at 9psi its to much fuel open the bleed valve a little, and if its too little ?
for this setup i should use the stiff spring ( dark color ) and the 2.72" disk and ring?
corbin should i use the super-afc to adjust any if so with stock injecs?
BAME

Michael 99gs
Boost It!
Mods:
Hrc Stage 2
Greddy Type S Bov
VC-2
Road Race Catch Can
Greddy Profec B & Switch
Apexi WS Catback
Super Afc
Autometer Boost,
Egt
Air/Fuel Light & Digital
Tokico Adjust Struts
Eibach Pro Kit Springs
Front & Rear Upper Bar
CarCraft Interior
Sound System= Bring it On

Check the other thread for most of this. If you get too much fuel (unlikely) you can lower your static fuel pressure some. Or you can open the bleed valve some. If you get too little pressure (likely), you can raise the static fuel pressure some. Don't forget to hook the vacuum line back up once you set the fuel pressure. Don't bother with the SAFC unless you want to fine tune at certain RPMs or something. If I get some spare time I may make up a page on adjusting the AFC...so many people send me e-mails about it.


Corbin

'95 ESI-T
HRC+FMIC+ETC...

to set idle fuel pressure we got to disconnect the vacuum line to the s-fmu to whatever we want then hook it back up correct? after i hook up the vacuum line back to the s-fmu what should i expect? lower or higher?
also the restrictor to insert in the vacuum line to the port do we need this? and i notice one side has a bigger hole, which side goes where?
sounds like a good idea to make a page on the afc make it alot easy for us and yourself hehe
thanks dude


Michael 99gs
Boost It!
Mods:
Hrc Stage 2
Greddy Type S Bov
VC-2
Road Race Catch Can
Greddy Profec B & Switch
Apexi WS Catback
Super Afc
Autometer Boost,
Egt
Air/Fuel Light & Digital
Tokico Adjust Struts
Eibach Pro Kit Springs
Front & Rear Upper Bar
CarCraft Interior
Sound System= Bring it On

Fuel pressure goes up when intake manifold pressure goes up. Fuel pressure will go down when intake manifold pressure goes down. When the car is idling, there is a vacuum in the intake manifold. That vacuum is about 8 psi below atmospheric pressure. I did put my restrictor in. I don't know if it matters at all which direction you choose. I believe it is there to act as a damper for the pressure pulse. When you quickly open up the throttle, there will be a pressure pulse traveling down each vacuum line. The restrictor should take some of the momentum out of the pulse. This may get rid of fuel pressure spikes.



Corbin

'95 ESI-T
HRC+FMIC+ETC...

thanks corbin for your help as well as the others =)
now i just got to wait to for some free time and wait for kaiser to help me get the fittings ...

Michael 99gs
Boost It!
Mods:
Hrc Stage 2
Greddy Type S Bov
VC-2
Road Race Catch Can
Greddy Profec B & Switch
Apexi WS Catback
Super Afc
Autometer Boost,
Egt
Air/Fuel Light & Digital
Tokico Adjust Struts
Eibach Pro Kit Springs
Front & Rear Upper Bar
CarCraft Interior
Sound System= Bring it On