[radz28]

Update: 11/23/23
Another little update...

With some cooler weather (bottom-60s and 102-103kPa barometer) and clean air, I'm taxing FUELING near as much as I'm going to in my area and at about 75% pump-E'. I've still been fighting my fight, and have conceded some losses I didn't want to here and there, but more importantly, I think I understand why, and if I wanted to, could choose to fix that later, if I want to. I'll cover a little of what I think I understand and what I'm seeing.

I'm starting to blend a little of the existing calibration trend for adding PORT INJECTION to our DIRECT INJECTION architecture. With the 85mm upper, I'm seeing some higher CYLINDER AIRMASS and MAF FREQUENCIES than I was last year (90mm upper) at this time, and similar conditions. Duh. Other than going higher in the MAF range, it didn't seem to be effected too notably, and I know some of that's covered by the REFLEX, but the compensation hasn't changed too much since September, when I was running in 30-40* higher ambient temps'.

I've been running, probably, about the maximum safe pressure the OEM LT4 HPFP will run at. I went back to my older INJECTOR PROFILE MULTIPLIER [33355] table settings, wherein I commanded the maximum factor GM allows (I did confirm that HPTuners cannot increase this more as it is a GM hard-limit). From 20mPa of DESIRED RAIL PRESSURE [17071] to the maximum, I am commanding "2.0000", and from 20mPa down to about 14mPa, I am blending to OEM values. I also copied this MULTIPLIER 3 TABLE to MULTIPIER 2 [33354] so CLOSED LOOP (CL) will behave, and be smooth. I have also commanded 24mPa, in the DESIRED RAIL PRESSURE [17071] table, from around .90g or so, but still need to go back to polishing this table for CL operation. I have some old files that will get this going pretty easily.

I'd been seeing RAIL PRESSURE and INJECTOR PULSEWIDTH go crazy at times, and especially if I was pedaling the throttle for WOT. I had been getting WOT PRESSURE/IPW holding well if I didn't pedal, but PRESSURE would drop after getting back into the PEDAL and would only start to creep-back into okay a little. Raising DESIRED RAIL PRESSURE seemed to enable more consistency than lowering RAIL PRESSURE. So - while I had tried to bring COMMANDED RAIL PRESSURE down earlier, I feel more confident that HIGHER PRESSURE (as suggested) is the better bet. If I could stay in the PEDAL and not let-off and get back into it, it seem okay. IPWs were a pretty consistent 5.0-5.2ms - right on the edge. Going back to E92 MAF - I haven't dropped that at the top of the curve - it's still about where it was a year ago. I had, in fact, added a little fuel to that curve, now, just because it was right at, about, a 0% error, so I wanted to pad that a little. I did have to increase above about 9900Hz (where I was about topped out last year) because my new 85mm upper is getting me past 10,100Hz, but that's about all I added (about 5%).

Where I am starting to concede is in the mid'-MAF-range. I introduce the REFELX around 5500Hz - just trickling it in. It's nearly imperceptible when it comes in like this, and it starts to work around 5800Hz. I'd been seeing RAIL PRESSURE/IPW issues, when pedaling, around 7000-9000Hz, so I have started pulling E92 fueling from about 6000Hz, to about the mid-8000Hz-area, and blended into the existing E92 MAF curve. I'm already a little fat in this area on the REFLEX anyways, so I'll let the REFLEX CL correct and I'll massage those corrections into either E92 or REFLEX curves, depending on IPW (as - again - already pointed out). If I need to, I'll rape the E92 MAF at the top-end, but I don't think I'll need to, too much. I've pulled about all of the POWER ENRICHMENT (PE) out of the E92, and am, pretty much leaving ALL of the PE FUELING to the REFLEX. As stated earlier, I've already moved my VIRTUAL TORQUE tables around/higher, so I believe I have that covered, for the lower TORQUE the ECM might calculate for almost no PE FUELING, so hopefully that works out as it's thought to. My reported TORQUE doesn't seem to be low anyways, and I don't see hardly any notable slip from the tranny or converter in the logs. I'll be watching in the mid'-MAF-range more, having pulled FUELING from the E92 MAF, but it should be high enough the way it is, I believe.

So - there is the latest information I have. I have several more drives since the last update, and I think I'm limited by my stock cam, for this method. In talking with the trainer, he doesn't have problems the way I'm having. To reiterate: I have reasons why I'm using the combination I am, otherwise, I'm pretty confident this method could work for anyone else with a FUEL LOBE and supporting fueling mods'. I can't validate that, so I can't offer much more reassurance than what I am directly experiencing. It DOES seem to be effective though. As I had been told from the beginning, though - my combination is simple enough such that the typical method would work just fine, and I do believe that. I came this far, though, I figured I'd follow it through as far as it would take me. And - I know I can switch over to the known method very easily. BUT - for now - back to a little more driving to finally validate this method, at least as far as I can with my combination, and for my specific reasons. Traction on the street, even with MT SSs, is if'y much cooler than this, so, practically, it might not matter to try to tune for too much cooler weather since I won't have traction anyways, lol... My OCD will argue that as valid, though, I'm sure...

I want to, also, take more time to THANK the guys out there than have been very helpful, even if I seem thick-headed. In no particular order, I want to thank: toohighpsi, laynlo15, Joshinator, jlaudio11, KingLT1, and Megahurtz. You guys have taken more time than you had to so I could continue pushing my boundaries and knowledge, and even if I am not completely successful - you helped me burn a lot more gas in my dream car, and it's been stupid fun. Thank you, gentlemen.

Another update after some more trials and validation...