LNF Fueling

[MikeM173]

So if you are reading this, hopefully you understand how to set up your histograms, and hopefully you know how to do some more of the basics.

So first thing is always first. Make sure you take your MAF Correction table, and set it to all 1's. Next, make sure you set up your PE table (See picture I provided, Top Right). Next make sure your HOM Single Low Table is correct, usually you only need to adjust this if it is absolutely needed, but I would smooth it over some, this is an example of how Bill has done his (See picture, middle right). Next, make sure fuel pressure is correct, such as raising idle pressure as I discussed in the idle thread, and making other changes to the rest of the table to make it smooth (See picture, middle left).

All tables should always be smoothed over. I apologize because the PE table I provided is definitely not as smooth as I would like it. For ultimate smoothness, which results in ultimate transition from one cell to the next, I highly recommend changing the row and column axis numbers. Be careful changing those values in tables though. Some tables you can't adjust at all because otherwise the table will not utilize the values, and other tables you can adjust, but you can only shift it so far before it doesn't allow that section of the table to be used. It's a hard lesson to learn, so be careful in trying that, but honestly it is the best option for ultimate tuning in my opinion. There is other ways to do it without doing that method, but that would take a lot more calculating and time smoothing out, but it would still be worth it in my opinion. Moving on.


So some very IMPORTANT steps for tuning fuel, in my opinion is having proper Spark and OP Spark Tables. I fully understand that if you are still learning how to tune those tables, it is impossible to have proper tables.

After you have all of your tables set up, you need to start with stock MAF Calibration table, unless your setup does not allow for that. Next shift your injector constant for your fuel (if you are changing fuel, otherwise keep it stock).

Log the car.

After you log it, you need to see what the LTFT + STFT trims look like in MAF Correction Base format (See picture, bottom left). Please forgive me with the picture because I have not finished setting up my scanner, and the details in the picture are inaccurate, but the values will play a good enough learning curve that I can still use it to explain this. When you open it up, take a look at the values. In my picture you will see in the 20-85% load range, and the 2000-3000 rpm range, you are up some positive numbers. Don't mind the high numbers in the high load column, because if my histogram was set up correctly, this would not be how it is shown.

With those positive numbers in the range I discussed, I would adjust my Injector Constant 3%. Maybe even 4%. Then I would log again. I try to find a spot where the numbers are either all close to zero, or on one side of the rpm range it is negative or positive, and on the other side of the rpm range I listed, it is the opposite. The reason behind this is because you can only get it so close to zero with injector constant before you start shifting the other side too much. You should be able to find a happy medium.

After you find that happy spot, that is when you adjust the MAF Calibration Table, and you compare it to the MAF Calibration table in the histogram for MAF Calibration. I would not make adjustments to all cells unless all cells need adjusting. After you make adjustments, make sure you look at each cell, and make sure that all cells go in ascending or descending order (whichever way you look at it). Reason I bring this up is because certain setups and certain adjustments to fuel can cause an issue with this. It doesn't happen often, but I would still check just so you can avoid issues later.

After you dial in MAF Calibration the way that CSSOB demonstrates in his videos, while utilizing my way, then you want to move onto the MAF Correction Base Table. Assuming you need to make adjustments to this table. Depending on your car setup, will depend on if you need to make any adjustments to this table or not. I have seen some cars dial into zero with next to no adjustments, while I have seen other vehicles act finicky as all can be.



This is my preferred method for tuning. I always make Injector Constant changes first and base it off of roughly around that range I described.





Hopefully I described this process well enough. If I didn't, just ask some questions, or point out what you think I messed up on, and I will update it with a better way to explain it.



Fueling.jpg

[powermizer]

Thanks Mike

Can you explane to me what injector constant is doing? I know it adds or takes fuel. How does it effect injection timing?

[MikeM173]

Think of it like a percentage of fuel that is flowing for a certain amount of air. It takes more fuel to reach lambda when using ethanol vs regular fuel. Because amounts of ethanol change, and things don't work out to an exact science, this is why I prefer to tune this part first. It can make the major changes, but not dial things in perfectly. There is a happy spot though that you can find and its that spot I prefer.

It's basically just a set amount that flows. There are other tables that we don't have access to that effect fueling, and it's that reason why we need to do a global change, then a MAF Cal change, and IF and only IF we need more control, then utilize the MAF Correction table by changing only the cells needed from 1.00 to whatever you need them to be.

When making changes, I almost always use multiply by % half. The reason I use half is because I dialed in close enough with Injector Constant that I am usually pretty good on everything else (depending on the setup).

As far as Injection Timing, changing the Injector Constant won't change that. There is a table that controls that. Adding things like ethanol and it needing more fuel will effect it by making the injectors spray longer, but that is about the extent of it.

[cobaltssoverbooster]

i always adjusted injector offset at low load ranges such as those under 2k rpm and under 40% load. this is where the motor tends to run the same regardless of setup so changing the value becomes more accurate. another side note is if the constant is adjusted to the average of the cells around idle then it also makes adjusting the idle quality that much easier.

good stuff going around here

[MikeM173]

Numbers shift too much (in my opinion) to do it that way. Not saying it can't be done, because it definitely can be. It's still a good way, it's just not my preferred way. I have definitely seen some crazy methods. Your way would definitely help with idle, but once you know how to tune it, that shouldn't make a big enough difference. Again, this is just my preferred way, and not one way is really the best, so if you prefer CSSOB's method, then definitely use it. Either way it is similar to what I just said, you are just using a different area.

[powermizer]

As far as Injection Timing, changing the Injector Constant won't change that. There is a table that controls that. Adding things like ethanol and it needing more fuel will effect it by making the injectors spray longer, but that is about the extent of it.

I really don't know what I was thinking about timing!! Lol. the only thing I wish is our hp pump had more volume. Oh well I don't feel that there is a huge disadvantage to having a fifth injector to help control some of the soot on the intake valves.

I hope you can give some insight on tuning for a fifth injector. Thanks Mike!!!

[MikeM173]

I'll post up something on 5th injectors later when I have some more time. Tuning wise I know them, but I won't lie and say I know everything when it comes to picking the right choice for one. I will explain everything I can about tuning them though. I honestly think that having a 5th injector is a great idea. In fact I think multiple injectors (if you have the power for them) is a good idea. That we would be talking extreme power, but I will say, having the best controller you can have is the best solution. I'll get into more detail when I do the write-up.

[powermizer]

I have therioised about injector size until I couldn't sleep. Lol I have some thoughts on sizing that I would like to add. Of coarse my thoughts only come from theory. I just started my engine build. It will be a some good learning there. Thanks Mike!!!

[TurboCobalt]

Hello MikeM173,

Thanks for taking the time to write this out, i have some quick questions to make sure i understand your sequence.
1) It states it in your description but i just want to make sure i get this right, changing injector constant is ONLY done when you change fuel, such as adding some ethonal perecentage, correct?
2) Sequence of events was slightly unclear for me, but i think it's as such:
2a) if you are not changing fuel (or injectors) leave injector constant alone.
2b) Follow CobaltSSOverboost guide to make MAF Calibration table changes first
2c) once you get MAF Calibration "good enough" - up to the individual; you may or may not need to manipulate MAF Correction in certain cells.

I bring this up because you talk a lot about injector constant and i dont think you meant to change that unless you change fuel type. Although I never messed with changing fuel type, theoretically you should be able to change the fuel constant by just calculating the additional amount of fuel needed for the extra ethanol.

[MikeM173]

Answers:

1. No. It I use it as my first step, even when I am still sticking with regular premium fuel. I always dial Injector Constant in first.

2. Change MAF Correction to all 1's. Change Injector Constant. Change MAF Calibration. Change MAF Correction if needed.

Hope that helps clear it up. I prefer Injector Constant changes as the initial change.