i installed my SFMU as well as #30's, a 255lh HP pump, 60mm TB and other stuff. FYI: all the lines are 4AN, except for the return its 6AN. now, i set static to like 40 psi, and with vac, my idle is 28~30 psi. im using the 2nd biggest disk/ring, the 2.72 i belive. it seems to idle fine, vac is ~19 hg at ~900 rpm. i have wideband and EGT. so my ? is what wide band #s am i looking for at idle, crusing and WOT? i have my wide band set up for a/f (14.xx) not voltages. tia

setup:
420a
hahn stg2
FMIC
s16g

Originally posted by streetlightning
i installed my SFMU as well as #30's, a 255lh HP pump, 60mm TB and other stuff. FYI: all the lines are 4AN, except for the return its 6AN. now, i set static to like 40 psi, and with vac, my idle is 28~30 psi. im using the 2nd biggest disk/ring, the 2.72 i belive. it seems to idle fine, vac is ~19 hg at ~900 rpm. i have wideband and EGT. so my ? is what wide band #s am i looking for at idle, crusing and WOT? i have my wide band set up for a/f (14.xx) not voltages. tia setup: 420a hahn stg2 FMIC s16g

My first thought is your idle fp is pretty high from everything I've read it should be more like 20-22psi, the wideband should show this. Second, you're looking for about 11.5 under boost. Sorry don't know the rest of the numbers you're looking for.

Do you have a datalogger?

If you did you'd see that your fuel trims are out of wack because as /\/\ said your idle is too high. I would get it down to around 25psi or so without the vac line connected to the sfmu. then connect it and it will drop a tad.

do you have a fuel pressure gauge in the cabin so you can actually see the rise rate and pressure before you go stomping on it ?? :shrug

k. i was doin some more searching and saw that my fp should be round what ur saying, ill lower it to ~23 and watch my wb, so around idle im looking for 13.8~14.2 and wot 11.5 correct? and no, i dont hav a logger, and no its not in the cabin, which im kinda kicking myself for, im gettin an incabin ont tho..just makes more sence..

your idle should be at 20-22psi . under boost wot tune for 11.5 . you cant really tune with wb02 for idle as its regulated by the ecu . cruising is roughly around 13-14:1 . egt should be around 1450 -1550 .

cruising definately doesn't need to be rich. I'm talking when your driving at 35mph with little throttle you should see around 16-17 ish

imo.

what are you seeing on the wb at full deceleration?

14.7 is the perfect a/f ratio, now mind you that when your boosting you want to be on the rich side to keep egt's down and avoid detonation so tune for about 11.5ish, cruising is a different story, you want to be on rich side while accelerating, it all depends how heavily and if your comming into boost at all while accelerating, but keeping a steady pace low throttle your a/f should bounce between 14-15. while at idle you want to keep your a/f as close as you can to 14.7 for a perfect idle.



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ok, i turned it down , and at wot, it was going below 11.5, so i turned up my idle fp , and my wot pressure is a little better,. is turning up the idle fp via the big screw the correct way to tune untile my wot fp is~11.5? or do i need to tune another way? tia

Originally posted by streetlightning
ok, i turned it down , and at wot, it was going below 11.5, so i turned up my idle fp , and my wot pressure is a little better,. is turning up the idle fp via the big screw the correct way to tune untile my wot fp is~11.5? or do i need to tune another way? tia

I'm lost here, but I'm going to give it a shot. The SFMU is a unique FMU mainly because you are able to freely change the rise ratio of A:F based on boost. You do not want to change idle fuel pressure in order to get more fuel at a set boost level. You need to change the ring/disc combo or bleed valve. I don't know what you meant, but I'm going to assume you were running rich. I ran 30#'s for awhile and adding a bleed valve to the 2.72 disc is the best option. As said, at idle you want to be in the low 20psi range and you want a 14.7:1 AFR. At part throttle our ECU's are set to maintain a 14.7:1 AFR. Tuning with only SFMU this would be what you want, 14.7 at part throttle (don't go boost happy part throttle). WOT should be richer depending on your air flow/boost. I'd shoot for a low 11 to be on the safe side and that will be a fair tune. SFMU can't do it all so do not expect to get a perfect tune.

then im lost to, what is rich 14,7 or 11.4? b/c at wot boosting it goes to 11, so i let off thinking i was lean, is that the case? and im running 30s to with 2.72 disk/ring. so i need to get a bleed valve?

(Rich is 10.0-11.2) (11.3-11.8 is where you want to be while boosting) (14.3-15.5 is good while not boosting)

14.7 is stoich . higher is lean . lower gets richer . you got it backwards .

ooooh, ok, so lets say, if i was wot and geting like 13.5, thas lean, but if i was wot getting 11.0 thats a little rich? so when i shift and the wb goe to the red, like 16 or 17 thats normal too?

Originally posted by streetlightning
ooooh, ok, so lets say, if i was wot and geting like 13.5, thas lean, but if i was wot getting 11.0 thats a little rich? so when i shift and the wb goe to the red, like 16 or 17 thats normal too?

yes to all of that

great thanx guys!!