[radz28]

12/14/23 UPDATE (minor):

There's still a little homework to do, and I'm working on that, but it seems like I have a little improvement for WOT fueling.

My last hits were in 52* ambient temperatures. I'd been focusing on on-and-off-the-throttle-fueling, where I'd been struggling, and 3 out of 4 times RAIL PRESSURE held. I commanded 21MAp of rail pressure, and that's what I received. IPWs were holding well at about 5.1-5.2ms, through 5700RPMs, where I ran out of b@ll$ because of traction, but tracked right on top of some other low-50*s runs, so I'm not too worried about consistency. I'll try again to confirm, through 6500, but getting bottom 5s for IPW was good. I had played with SOI a little, and think that may have helped a bit. I was running into part of the SPARK TIMING map that I hadn't been in before, so I wasn't too comfortable staying there, which is also part of the reason I didn't stay in the throttle, but I've made adjustments to correct that now. I, still, had the one hit that RAIL PRESSURE dropped when pedaling.

The particular instance where RAIL PRESSURE didn't quite come back was where I waited about a second before getting back on the THROTTLE (this was about 4700 RPMs). That was enough time for commanded RAIL PRESSURE to fall close to IDLE, and just didn't have time to recover at WOT, or, it was just not going to recover. I raised commanded pressures above the last tune revision to see if that would help. So I'll see what happens.

Thinking back to why this situation was created, I lowered a lot of the DESIRED RAIL PRESSURES because I was trying to compensate for the fueling in CL. I can't remember trying before, but this time, I'm going to try to bring more fueling in, for these areas, with the PORT, and see if that will cover this area, and help the DI recover RAIL PRESSURE easier. In the past, I thought I would be throwing PE off with the PI in these spots, but I was probably confusing myself, so we'll see which thought process was right. So - I've lowered the E92 MAF in this range, and bumped the PI to try to compensate. Additionally - I thought I might try to bring PE (from DI and PI) in a little sooner, too, in an effort to cover this part of the RAIL PRESSURE table better. I had PE set to about 45% PEDAL until now, and dropped it to 40%, so we'll see. I didn't want to constantly be in PE, so I'll see if this helps, or not. I really, just have this small part of the curve I think I need to play with, and this will be as good as I can get.

So - it sounds like, if I wanted, I could probably command a little more RAIL PRESSURE than I am now, but don't really want to do that yet. I'm hoping that fattening up the PI MAF in this area will help the DI PRESSURE recover. If I stay in the THROTTLE, there is no issue, but this pedaling is killing it. There's probably something to be said about working this hard to get this method to work when it's this cold (and this time of year), there's hardly any traction on DRs, on the street, but my OCD won't let me give up quite yet. It's not like I street race, and the track 5-minutes away is closing, so it's not like this is going to matter much, but I just can't help myself. I just have to know. I've added a more SOI lower in the RPMs and retarded cam timing back to where I usually have it advanced to, which may have helped a little also (if I understand that relationship well enough). My SOI came down a few degrees (from 378 to about 370, in cooler conditions), so I'm wondering if that helped a bit. I'm wondering about retarding cam timing a little more from where I have it, to try that out, but we'll see...

Some more hits over the weekend if I can beat the rain and it's cool enough to tax everything...