Originally Posted by
Cringer
In general, no one is going to agree on the correct or best way to handle SOI/EOI. The OEMs are going to focus on Emissions, Drivability, and Power (in that order). And as for aftermarket tuners, most won't even touch EOIT at all, even if you give them the cam specs. Count yourself lucky if your tuner adjust the Normal ECT table in order to clean up raw fuel smell at idle.
The other fact of life is that there is nothing you are going to be able to log in the scanner to objectively tell you if your SOI/EOI settings are good or bad...well except for fuel trims/wideband...which is your only objective guide. The other guideposts are idle smell, seat of the pants drivability and a dyno (which most of us peasants do not have at our disposal).
I have found a few spreadsheets floating around for this stuff and was underwhelmed by them. This is why I created my program to help with this and make it as powerful as possible. I created a video to arm everyone with the background knowledge needed to understand the HOW and the WHY to tune SOI and EOI. Of course not every "expert" out there will agree with my thoughts on this, and that is fine. And you know what? I am totally happy if they share what they know with me/all of us and we all get better. I am always willing to put away my ego for something better for the sake of learning.
The previous tune I revised for you on that thread a long time ago is exactly how I would set up the initial EOIT stuff if it were my vehicle. And this is a *starting point* for you to advance and retard SOI for the low/mid RPM stuff to find the best fuel trims, and it sounds like you did for idle. Making any improvements here is going to be a slow and arduous process. You are going to have to make small adjustments and analyze the long term fueling trends. I am not talking about LTFT, I am referring to getting familiar with you fuel trims and being able to identify 1% swings in the right or wrong direction. Part of this is being consistent in the way you drive. These are 2D tables that are setup in RPM increments...they are not setup in a 3D format with RPM and MAP (which I would prefer). So in other words, if you use more throttle you are spraying more fuel at a given RPM...so be consistent in how you drive/log/tune. More throttle = longer pulse width = a later EOI during closed loop.
Additionally, if you are finding the car is getting a little lazy, throw a couple of degrees of timing in that area to see what happens. Optimal fueling is going to reduce the chance for knock anyway. And as you will find as you make changes in one area, it is likely to impact multiple other areas as well. MAF/VVE, O2 voltages, rich/lean PI settings, EOIT, and timing are all related.
Just to clear the technical stuff up, the correct formulas are:
1) For normal low RPM/Closed Loop operations with short IPW
1a) If Make Up Mode is enabled (set to Single or Multiple)
SOI = Boundary Angle - Normal ECT - Normal RPM - M/U ECT - M/U RPM
1b) If Make Up Mode is disabled (set to None)
SOI = Boundary Angle - Normal ECT - Normal RPM
2) For high RPM/PE operations with long IPW
You have to understand that SOI is moveable and floating while EOIT (or the Boundary Angle) is not. SOI will be forced to moved when IPW becomes excessive. The definition of excessive is when the engine RPMs are high enough that the window (in milliseconds, not degrees) to spray all the fuel needed is not long enough. So a new SOI has to be calculated.
2a) SOI = Boundary - IPW (expressed as degrees)
My approach is to spray as early as possible (and disabling Make Up mode goes hand in hand here) for closed loop. So long as:
1) you do not short circuiting the fuel
2) do not cause any drivability issues
Other people like spraying late as possible. This is accomplished by setting the Boundary Angle to whatever number you want (520 - 580 or whatever) and then zeroing out the Normal tables. This then forces the ECM to back calculate the SOI every time using the IPW as degrees. I do not like this method personally. Feel free to experiment and report back. This is the same as formula 2a (however, these people also probably have Make Up Mode enabled, so add the default 30*).
So in conclusion:
1) For low RPMs, think of the spray window in degrees and focus on a specific SOI that will be driven off valve events.
2) For high RPMs, you have to ignore SOI since it is floating and you are going to spray on the back of the intake valve and thus some fuel will be short circuited, and there is nothing you can do about it (unless you get bigger injectors and sacrifice idle quality), so focus on EOI which will be best found on a dyno.
The quick formula to convert MS to Crank Degrees:
[RPM] * [0.006] * [INJECTOR PULSE WIDTH IN MS]
The quick formula to convert Crank Degrees to MS:
[CRANK DEGREES] / (RPM * 0.006)
Note we use crank degrees here and not cam degrees since the Boundary Angle and all the EOIT tables are based on 720? for two rotations of the crank for a 4 cycle engine and the cam shaft's valve events are also listed as in relation the crank (TDC and BDC).
I am hoping other folks chime in here as I would like to learn their viewpoints as well.