im way to rich at WOT. whats the deal?

Running VAFC
310s
Vortech FMU (8:1)
Inline pump


I am fine at mid throttle and idle, i read around 14.2 or so on my apexi guage, however when i go WOT ill get as low at 11.0 and even into the 10s for AF ratio.
my autometer guage dives right for green and i feel a decrease in performance from mid range to top end, to much fuel.

how can i be ok at mid range and not at WOT? do i need to lean out more on my VAFC? any thoughts?

 

Wait:

VAFC & FMU & Inline?

Wouldn't it be better to just use the AFC w/ the 310's, richen them up a little bit w/ a FPR and ditch the inline/FMU? Or am I retartedded?

jB

 

i dont know? ive never had anyone ask me that before....anyone have any thoughts? or ideas as to why im so rich top end?

 

Ok, crap; had to thinkg about this one for a few mins.

If the VAFC wasn't there, it wouldn't be much of a problem I don't think (And I don't think you would be running as rich).

What do you have the VAFC set to across the board? What is happening is this:

1. Midrange/Partial throttle, the FMU isn't doing very much. When you hit partial throttle, it's upping the fuel psi a little bit, but not much.
2. As the FMU raises the psi, the VAFC also richens out the mixture throughout the RPM range.
3. When you hit WOT (Before much boost), the VAFC starts to richen out the mixture; then when you hit full psi, you're pushing almost 100psi (Not sure what psi you're running, but it is going to be ~100) PLUS you still have the VAFC richening out that PSI.

Unless you have the VAFC set to - numbers, you're going to run WAY rich, cause youre doubling making it rich (VAFC richening + FMU). The other alternative (Which you might be doing already), is the VAFC set to - number, in which case it's the VAFC vs FMU showdown of the century. Either way, it's not good.

The injectors should be able to handle enough fuel to keep you rich/stoich throughout the entire RPM range without having to have the FMU. Keep the inline for now, as it can be useful in case you do need to richen them up a little bit. Get a FPR so you can up the psi somewhat if you need to (On top of the VAFC). But right now you're running a combination of too much fuel psi along with too much of a richened mixture; and I think that's why you're experiencing such a decline in performance (And gas mileage for that matter).

jB

 

no no no, trust me i have my VAFC set to negative across the board, thats not the issue hehehe.

im running -35ish at 1000 rpms and at 8000 im at roughly -15

so im def not ADDING fuel. do i need to take out MORE?

 

bump!

 

DO you have a fuel pressure gauge? Check your static fuel pressure at idle. Then if you have a Fuel Pressure gauge make sure you aren't getting crazy amounts of pressure when doing a pull to 8grand. I have the same problem up top but not down low. Sounds like a FP problem.

 

what can be done to remedy our problem then?

 

weird...i run lean with 12:1 fmu/ 310cc / inline pump / 255 intank pump / vafc.

 

A sure way to fix the problem is take your car to a dyno and use a wideband 02 to monitor your a/f readings, im sure you knwo the apexi a/f meter isnt the most accurate thing in the world.

 

im aware, i have my Autometer that just dances around on the dash and makes cool beats to the songs, but i have a little more faith in my Apexi since at least its numeric.

i guess dyno is my only anwser since i have no concrete #s

 

moves to the beat of songs?!?! I'd ground that a/f meter to the sensors ground under the hood. I think you are probably getting a completely bogus reading. It should NOT be affected by load on the electrical system. I can't believe that you are rich with your set-up, especially with that much fuel trimmed out.
if you're really concerned, sell your 310's, FMU, check valves/Missing Link and pump and buy some DSM 450cc's. you'll have a better fuel system and a couple hundred bucks in your pocket.

Don't try to run the AFC 'hack' with just the 310's as someone suggested/supposed...it will not work. you will either run lean or throw a MAP CEL.

 

Here's what you want to do buddy, just hook up your VAFC to work under vac/boost. it might help you fix your problem:

http://www.alltrac.net/mods/boostedSAFC.html

 

no no it was just sarcasm, it dances around from rich to lean not literally!

 

ok, you say your running a little to rich up top. Why not just lean it out a little more, maybe -20 when your up at the 6.5k rpm range. I can't believe nobody suggested this to you yet. Honestly your setup is fine. I have almost the same-vortech fmu 12:1 disk, 440's, safc, missing link, 255lph pump. The fmu setup is fine, don't listen when people tell you to ditch it, the argument about fmu vs. hack is never ending. Since you already have the fmu stuff, stick with it.

Start off by leaning it out little by little. Don't do the full -5% i was saying, but decrease more as you go, when you feel that it's perfect from the butt dyno, add 1% so you will be safe.

 

Try turning up the boost!!

 

ya know i thought about this, but i have no idea of when im getting into dangerous "lean" territory. i never fathomed ditching my FMU etc, i already have it, so it will stay. until i get on a dyno (not till spring) im just gonna have to lean it out across the board. good suggestions, what are your settings?

 

honestly, i dont' think my settings would work for you. I'm not saying that to be a dick. But on my sohc, i had to run the 440's on the 12:1 disk at -15 so that i would run lean, and that would be rich as **** on most other motors. Now yea, that sounds not bad, but 440's and a 12:1 disk should stall most non built 5psi sohc's. The motor was wierd and loved to run rich. But here it is
i went from -35 to -15, i forgot at which points i had it set. I'm sorry i can't help you on where to set it, i haven't had my car for like 2 months now( getting a new setup). I think -20 at arount 6.5k rpm and up would be just fine though.