I'm looking for a little help/ direction. I have a 13 XF with the 5.0 SC engine. A little back story. My first modification was to have the car tuned by a reputable tuner. This seemed to turn out well. After several months I made the decision to install both upper and lower pullies along with have the charger ported by kong. I also installed a larger low pressure fuel pump and meth injection. Meth is a 20% mixture and comes on at 5psi. This has been working well to keep my charge temps in check. My tuner told me I wouldn't need a tune after these modifications. After the mods the car ran smooth but was not any faster then before. It trapped the same and ran about the same 1/4 mile times. My tuner agreed to retune the car after giving me the run around claiming I had an engine issue. The new tune was much better and the car makes great power now with one big caveat. In any gear after 2nd at 5500 rpm it pulls boost and falls on its face. First and second gear it does not do this. I told my tuner about this issue and he claims its my catalytic converters causing this issue. This makes no sense and I think he just cant figure it out.
Fast forward to now, I have decided to try and correct this poor tuning my self. I purchased HP tuners and pulled the file off the ECM. I have been teaching myself all I can about torque based tuning. I have changed table after table testing each change as I go for a few weeks now. Nothing I do makes any difference in the way the car runs. It traps the same and pulls boost after 5500 in 3rd and 4th gears. I have even looked at the trans tune which was factory and raised the tq limit there. My last go around I even attempted to lower limits to try and see if I have control over anything. This did nothing as well and the car ran exactly the same. After one map upload I did, the car actually ran through the whole rpm band in 3rd without pulling boost but then on every pull after that reverted right back to its previous behavior.
A lot of tables don't make a lot of sense to me. I'm not sure if this is just my ignorance or if some of these tables are not correct. I feel like there is some stuff missing as well. If anyone has any direction or suggestions I would greatly appreciate it.
Im going to make a few more posts asking about specific tables I do not understand. This first one is "Max Aircharge WOT" What exactly does "aircharge" refer to and why do the numbers in the table go well about 100%. Is this intake manifold pressure where 100% would be ambient? Max Aircharge.png
Ok I think I have answered my own question. Aircharge is basically a calculated weight of air moving through the engine calculated using map, maf and ve? The only thing I dont understand is how the air charge conversion actually works.
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