Originally Posted by MrMoPar
Web 3.0, have you monitored the voltage for the map sensor versus the voltage for the MAF sensor? I am curious how close they are across the rpm range. The SRT6 map sensor is different, likely a 2.5 or 3 bar sensor, so it will need changed. The unit I use on my turbo Hemi has a MAF simulator function, although I have not used it yet. I have been studying the functions and inputs, and if I were to turbo my NA, then I would likely clamp both the stock map and MAF sensor. I only need them to function in the vacuum range. I can handle fuel addition with the fuel table for WOT, and O2 sensor control in closed loop part throttle boost.
I have not heard anything positive about the f/ic, their methods of table inputs are very strange, primarily they seem to be percentage based. Mine is tuned in degrees of timing, and milliseconds of fuel pulse.
I've been all over every aspect of the AEM to the nth degree for over a year. The plan you layout is textbook AEM but no where near granular enough for the tune I seek.
The problem is that going the maf clamp route you are fighting several things. 1st, the max maf voltage per rpm that the ecu wants to see without crying foul. So you clamp the voltage to 2.2v at 1,200 and add fuel above that via map, but the occasions you reach the same cell with the same air flow at this intersection vary greatly. So you end up with varying afrs and fuel trims, tweaking endlessly trying to find the perfect balance and you still experience variations. Then, if you cap the voltage too low, it screws up the way the ecu confirms the egr is functioning and you get a cel.
The O2 system is also VERY picky and the textbook AEM O2 tap and resistor doesn't work. I've had control of the O2 but get weird cels and/or the trims stop calculating after three minutes. Very weird stuff but not the worst. The good news is that there isn't much need for O2 control with the Rotrex as I am above the maf clamps and in open loop quickly enough. Now, going with a turbo versus my Rotrex that might be another matter. You may very well need to grapple with that monster.
Going maf delete has been the best by far to get the exactness that I want. The map sensor itself is easy, cap at 3.8 volts all the way across at 14.7 psi and .89 at 2.9 and scale up. Perfect map sensor correlation for the NA.
Focus time on matching the internal AEM map to your stock maf readings while clamping at 4.51 volts and all is good. That said, this is by far the most complex method as you really need to have a grasp on simulating maf voltage curves at each load level. I should have a great map by the end of this week while I'm waiting on my other stuff to come in.
The cool thing about this is that when done you can add a temp sensor and delete the maf all together!
Also, the ecu determines load based on a combination of map and maf. If you wanted to get real technical with it you can manipulate both of these curves to make the ecu think you are at less load than you are and effectively increase spark even though the AEM doesn't actually provide for spark increase. You'll have to be careful though at low loads as this can impact your shift patterns with the greatest impact on downshifting with an automatic.
Half my problem now is that I should have just bought a new AEM harness as the one I have has too many quirks. The p0335 IIRC started after simply getting under the dash to double check my vacuum hoses and "touching" the wires! That pisses me off!
I think where I am at now is pretty simple, I've explored the AEM to the extreme and it has been found wanting. I just don't like having to lean SO HARD on a piggyback to make it all work. If I still need it after the ecu swap at least it will be in a minimalistic fashion.
I had started looking for other tuning methods to do this properly and simply can't justify spending the money to buy the tools that eurocharged and others use. If I was going to make a production kit, that would simply be the cost of doing business and I might take the gamble on making it back. That said, my options are full ecu replacement and spend the next year figuring out wiring to make everything else on the car happy just so I can tune it myself, go to eurocharged and let them tune it and be done with it, break some ground by swapping ecu's, map sensor, and fool a couple others and potentially have a pretuned ecu. Hmmm, it might have been cheaper to just go to eurocharged but I so like to tinker
When you get into the thick of it, I'll be glad to share tunes, maps, etc.