I just got my sfmu, I am running 50 lb injectors. What disk, spring, and idle fuel pressure should I set at? Say if I wanted to run 20 psi. Can someone help me out here? Thanks guys.
#67879, "RE: SFMU Setting question (not a repost)" In response to Reply # 2
I am also thinking very seriously into going to 50lbs injectors. I would say go with the one smaller than 2.72 disk/ring combo. I cannot recall wich size is it, but it should work and do some fine tunning with whatever you are using to fine tune.
#67881, "RE: SFMU Setting question (not a repost)" In response to Reply # 3 Mar-29-04 06:49 AM by mkerley
My estimate using 440's and the T3/t04e (my car) was to use the smallest disk w/ static FP at 40 w/a large AFC offset. I know you have the same turbo kit, but more displacement and bigger injectors, and I haven't actually run this yet, just calculated and fit the lines theoretically. If you can give a HP est, it would help to run the numbers.
EDIT I've got a spreadsheet of this stuff if you're interested in seeing it. /EDIT
#67901, "RE: SFMU Setting question (not a repost)" In response to Reply # 5
Start out using the 2.72 disk/ring, and the bleed valve, run around 11 psi of fuel at a warmed up idle. You will have to open up the bleed valve at least 2 full turns to lower the rise rate a bit. See how that works, and if its too rich, open up the bleed valve some more. If you still can't get it to lean out enough, go with the next smaller disk/ring, and keep the bleed valve closed, then go from there. You may have to use a SAFC to lean out the idle and low rpm, if that low of idle fuel pressure makes the car run like crap...this means you will have to raise up your idle fuel to around 15 psi, then compensate using the SAFC, and try to keep it no more than 10% correction(to avoid any timing advance)
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)
#67931, "RE: SFMU Setting question (not a repost)" In response to Reply # 6 Mar-30-04 02:03 AM by brynden29
Thanks for the help guys, here is what I am running...
I am using the smallest disk/ring combo, static fp is set to 35 psi and idle is 25 psi. Bleed valve closed. My afc is zeroed out up to 5000 rpm on the high throttle. My car is running really well. I did a 3rd gear pull and I was in the 13’s on my wideband. At about 16 psi. I am a little concerned that I need to go with a bigger ring/disk combo. I want to turn the boost up higher, and am worried that I will not have enough fuel. What do you all think? Do I need to go up one?
Edit: Oh and my car idles better than it ever has.
#67933, "RE: SFMU Setting question (not a repost)" In response to Reply # 7
Originally posted by brynden29 Thanks for the help guys, here is what I am running... I am using the smallest disk/ring combo, static fp is set to 35 psi and idle is 25 psi. Bleed valve closed. My afc is zeroed out up to 5000 rpm on the high throttle. My car is running really well. I did a 3rd gear pull and I was in the 13’s on my wideband. At about 16 psi. I am a little concerned that I need to go with a bigger ring/disk combo. I want to turn the boost up higher, and am worried that I will not have enough fuel. What do you all think? Do I need to go up one? Edit: Oh and my car idles better than it ever has.
13's on the wideband? That way too lean for 16 psi..I'd up to the next larger size disk/ring, and maybe run 20 psi of idle fuel pressure. Keep the bleed valve closed, and go from there. How were your EGT's? At 16 psi, you want to have around a 12:1 A/F I would think..even that is a bit on the edge. Just watch your EGT's and listen carefully to the motor..Sounds like you are pretty close to where you need to be though..
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)
#67937, "RE: SFMU Setting question (not a repost)" In response to Reply # 8
Sounds like Matt is right. Brynden also when you put in the larger disc/ring combo if you are running rich up top instead of taking out fuel through the afc start opening up the bleed screw little by little. This should adjust your rise rate lower (please correct me if I'm wrong). Not on the tune of like jumping from a 6:1 to a 4:1 but in terms of decimal points upto about 1 full point.
#67994, "RE: SFMU Setting question (not a repost)" In response to Reply # 9
I have been browsing this post for the past few days cause I have always been wondering how to richen my car up....and was never able to get a solid response.
So the larger the ring/disk combo...the RICHER you will run? IF so I need to change that isht out quick!
#68017, "RE: SFMU Setting question (not a repost)" In response to Reply # 10
Yes Jon, the bigger diameter disc and rings increase the overall rise rate of the unit. Say the smallest disc in the S-FMU gives you a 3:1 rise rate and the next size up will give you a 6:1 rise rate assuming the bleed valve is completely shut. Obvisouly I don't know what the advertised rise rates are for each S-FMU disc but the large it gets teh higher the rise rate.
It has to do with the pressure having more area (larger disc) to exert force on the little plunger do-dad (very technical term I know ) that in turn moves said plunger do-dad in to the fuel return path which in turn decreases the area allowed for the fuel to return to the tank which then in turn increases your fuel pressure.
#68018, "RE: SFMU Setting question (not a repost)" In response to Reply # 10
Originally posted by 95greenhrcgs I have been browsing this post for the past few days cause I have always been wondering how to richen my car up....and was never able to get a solid response. So the larger the ring/disk combo...the RICHER you will run? IF so I need to change that isht out quick!
Yes, the larger disk/ring basically gives you a steeper fuel pressure rise rate. Then, if you find out you are running a bit too rich, you can open up the bleed valve to let some of the boost pressure escape from the SFMU chamber, which will lower the total boosted fuel pressure just a bit..makes it very fine tunable really. For example, lets say you run 10 psi, and you are running too rich at 10 psi. You can open up the bleed valve some, and lets say now when you are at 10 psi, the SFMU now only sees like 9 psi, and your fuel pressure will be at what it was at 9 psi, when you run 10 psi..Thats why i really like to run a larger disk/ring then what i need, and then fine tune it down with the bleed valve..
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)
Search
Printer-friendly copy
1 User in Chat
) that in turn moves said plunger do-dad in to the fuel return path which in turn decreases the area allowed for the fuel to return to the tank which then in turn increases your fuel pressure.