dwilson

I now have all my items and motor to complete my turbo project. My problem now is coming up with the proper fuel set up. I have two ways i can go. 1. use the AFC hack or 2. use the FMU and the AFC together. My question is which way do you guys think is the better of the two? I see alot of people running the hack, but then again just about every set up i read that is not running standalone fuel management has the FMU running with the AFC for tuning. I have all the items to run either way just need to know which one would be the best. Any input would be useful.

rjardy

Pesonally i would not use the "hack" it just doesnt make sense to me to put all of your fuel managment on a piggy back band-aid computer. if i was going to go your route i would run fmu, and vafc to tune fuel in and out where needed. HTH


(i know ima catch it for this one)

Rob

zojirushi

i'm running the hack now with no problems whatsoever. high fuel pressures doesn't float my boat.

dwilson

That is what i was thinking also. I mean im not trying to get a feud going or anything, but it seems to me with the hack u would have to be leaning out at some point around the transition into boost. Now on the other had if u run the FMU and AFC together with each other u have the best of both worlds. It would work just like the hack because u would still be using the AFC to lean out the bigger injectors (450cc in my case), plus u would have the added protection of the FMU at boost transition to make sure u wasnt leaning out or running stioch( i think thats how u spell it ). Granted u would have to run a missing link or something to trick the map, but u would also to tune a little more. I am kinda just thinking outloud here so if i am way off please correct me.

dwilson

Also what FMU disk should i start out with running the 450's. Would a 6:1 ratio be to rich. Just need a starting point.

ion_four

There are a few problems with attempting to use an FMU and the AFC 'hack'.

If you use the 450cc injectors, you'll have to use an extremely low fuel pressure at idle, or you'll still have to really lean it out with the AFC.

You'll also still need check valves or a Missing Link (which defeats the purpose of the hack, and it's ability to work properly). By using the normal 'hack', you trim the MAP output by ~~40% and thus allow the MAP to read boost, but have it intercepted before the ECM reads it and throws a code. If you are using the FMU, you won't have to trim the fuel as much and thus will be able to run less, if much at all, boost.

I don't think there is a problem with leaning out during the transition into boost, because the computer doesn't know it's boosting! It just thinks it's going from high vacuum, to low vacuum very quickly! Just as if you punched the gas pedal (does anyone worry about hittin the gas in their turbo car? There are a couple dynos posted on here, somewhere, that have dynoed the AFC set-up and I haven't seen anything about leaning out in boost.

if you do a search and find the original post about the AFC 'hack', where liam was driving through the mountains with checkvalves and the AFC, you'd see that it kept ******* up, but when he ripped those turds out and just used the hack, it was flawless...
so, yeah...just use teh 450's and the afc