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I promised a summary of all the things that needed to get done to "fix" the canned tune. Here's my list as I recall it. Please do your own research, and don't assume this is a comprehensive list. I'm still learning, and I have probably missed some things that I haven't discovered yet.
I do NOT recommend using the canned procharger tune at all except maybe as a way to initially drive it for tuning purposes, but for the additional cost.... not even sure its worth it if you have access to helpful folks on the forum like I was fortunate to have.
The steps below describe starting from that canned tune. There are many more changes needed if you are starting with the stock tune.
- dont assume because it's an official canned tune that it is safe. IMO, it is not. And you will not get the advertised power gains using it.
- wideband definitely needs to be installed and logging done after an install
- maf frequency needed tuning
- canned tune doesn't trigger power enrichment at WOT at high rpms. Commanded afr/lambda is 1.0 at something like 5400 RPMS and higher.
----> fix power enrichment trigger points and enrichment %
- canned tune uses "odd" timing curve that starts very low at low rpms, and ramps up very high at the top end.
---->honestly i'm thankful my engine is still in one piece with the high timing and afr I was getting.
---->I found the opposite curve to be needed. Starting at higher degrees of timing at low-mid rpms and taper down to somewhere in the neighborhood of 11-13 degrees at the top.
- stock low side fueling is TOTALLY inadequate with proper afrs.
---->with proper power enrichment at between .790-.825 lamda (depending on who you ask), low side was running out of fuel (down to 30 psi at times) and starving the high side.
---->during hot weather (90+ degrees F ambient), it was very borderline about keeping up, close to leaning out, if not actually leaning out at the very top.
---->during cooler weather (80 degrees F or less), it was absolutely running out of fuel at .8 lamda over 5500 rpms and leaning out. Obvious points in the log where high and low side fuel pressure plummeted and rpms were not increasing.
---->fix was adding an aux low side fuel pump, could have also replaced the in-tank pump with a higher flow pump instead of, or in addition to the aux pump. The aux pump should support any future mods up to 900 HP, whereas installing an OEM LT4 in tank pump had much less potential.
- high side fueling marginal at best
---->with the low side fueling keeping pressures at approx 80 psi the high side is still extremely borderline.
---->while high side psi is being maintained at around 2300 PSI, the injector pulse width is close to 6 ms across a significant rpm band, and still exceeds 6.2 ms under certain conditions.
---->fix (yet to be implemented) is to install at minimum the oem LT4 high side fuel pump and the oem LT4 fuel injectors, which (i believe) flow 30% more than the LT1 injectors.
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