VVT Questions - VCP PDA table and mechanical limits of advance/retard?

I have been searching for about a week without luck or mixed info, so here are my questions:

What is VCP PDA spark? Says for when the swirl valve is closed? I can't find any more information on this table.

What is the limit in the L83 advance and retard? HPT has a huge range, but then I read you could not actually advance the cam any more than 0 deg. I was going to try to taper to more retard towards higher RPM WOT. Stock is 8 deg, was going to try to work up to 12 deg and test it out.

Bonus, does anyone have the cam specs of the 5.3L/L83? I was trying to see what the ground in advance was, I found 8.5 deg but not sure if that is for the 5.3L.

Thanks.

For VCP PDA my guess is that the table is just there for the whole GEN5 group even though there is no swirl valve on most of them. Interesting that the table actually has figures in it though???

Not sure what the mechanical limit is. On GEN4 and I think the same for GEN5 the cam is parked (0 on the tables) at 8.5 advanced....so as the table starts to show retard numbers it is actually taking away from the advance. So if the stock table maxes at 8 degrees of retard it is actually just about .5 advanced at that point. I have messed with retarding L86 cams more on top and I don't see a power or airflow increase. With such a small cam I would think that a few degrees more retard on top would make a measurable improvement but I have not seen it to be that way. This leads me to...

Great question! Maybe GM grinds the GEN5 stuff retarded a few degrees (I would guess 4 degrees for this example) so that when it is idling (parked) it is actually not advanced 8.5 (more like 4.5) and up at 5800 RPM it is not .5 advanced (but more like 3.5 retarded). I have never seen proof of any of this but it seems to me that it has to be this way.

My 2 cents
If that makes sense

I've tried bumping it past 8 and saw no increase in airflow.

I messed with it a little today. Going to try more later this week.

Curious if less retard will help up top. Advancing and retard will only get you so far, curious if GM had any intent to improve power or purely emissions/MPG/to run on 87.

I don’t care enough to dyno. I have a low and high tune set for comparing some 3000-5600 RPM pulls. If I see anything I like I will keep it. Otherwise stock will do.

IARLLC - have you tried to reduce any VVT values at the top end?

I just wonder the effective range of advance and retard of the factory cam, with factory heads, etc.

I also wonder as you open up the intake without much exhaust, if retard hurts more opening the exhaust valve too late.

I have gone up to 11 and 12 with L86 and saw absolutely no advantage on top. Maybe it would have helped more if it had less back-pressure? I have not spent as much time trying this on the L86 rigs with freer flowing exhaust. I have not tried lower than stock numbers on the GEN5 rigs. I have seen very marginal gains on the GEN4 L92 (with stock cam, stock exhaust) going from factory 12 degree maximum down to 11 degrees.

With the GEN5 my biggest VVT change is reducing the "EGR affect" (over-retard) at loads just a bit higher than cruise on the highway. You still get the tiny mileage boost from EGR affect on the highway but a bit more throttle gets you A LOT more accel without even a downshift.

Thanks. I wonder how much GM uses advance to control cylinder pressure for lower octane fuel at higher RPMs too. Everything I look at seems 4?-6? is about the usable range of advance or retard in total. Outside of that you may still see changes, but it may be for economy, emissions, etc.