Injector boundary values and EOIT

[maudyZ28]

hi everyone, I had to get into this recently (still waiting for the car to run the new tunes) because the mild/medium cam (218/237 ish - proprietary spec so we don't know the size) has way more bucking at low throttle. I figured the exhaust is open when we are spraying so the fueling is off - I can richen up a smidge in open loop and it cleans right up (more fuel in the cylinder where I want it), but then I have to watch out for goosing the cats and poor economy.

Basically I see all the injector timing values in EFI live - but we don't have a boundary table. I saw an old post (2016) about a cax file for this, but surely it could have been added (I think not now as the E38 is old hat). It that cax still around?

My other concern was the values in EFIlive are a factor 2 (exactly) more than all the vcm HP tuner stuff (I don't have it but there is info online). Any ideas about this, i'm literally just doubling my changes as calculated.

My final point, although i've run the calculations (but don't have a camaro tune to hand) is that everyone says the boundary values are 520 (deg), but actually the Corvette tunes (for which I have form 4 independent cars) actually use a changing boundary condition for EOIT calculation (510 at low rpm <1500 ish, and then around 470 to 480 ish for higher RPM). I don't know if the other values change for the camaro, but from material I have access to, it seems not. So basically the camaro's (all things being the same) would have a way later injection EOIT and thus for a given spray time, a later SOIT. The vette tunes are like 50 deg advanced.... what gives?

[maudyZ28]

In addition I did run the calculation (I don't have the notes right now but it is sufficient for some comparisons) and then anyone can chime in with other ideas:

infor from elsewhere on standardized valve events for LS3 circa 0.004 or 0.006" lift (advertised duration) - where 0 is TDC starting the power stroke (then exhaust, intake, compression)
IVO 371 IVC 585
EVO 135 EVC 347

at Idle, say 600 rpm here: this does 3.6deg in 1ms

Boundary for Camaro tune would be 520, Vette is 507.
Run the numbers and EOIT are 380 deg and 367deg respectively (only normal ECT and multi-spray angles have populated tables). We could take off ~5-10 deg to work out start of Injection assuming a 1-2 ms pulse width. (just for ball park numbers)

Although these are more of less the same, the camaro more or less sprays with a closed exhaust valve (347) but more or less as the intake is opening.
The vette sprays is a bit more advanced, to EXHAUST is 'just' closed, but more importantly the INTAKE is also closed (371deg) - my theory to hit to closed value briefly before to allow better 'atomization' (wrong word it was explained elsewhere, but I forget)

When we move to higher RPM, the camaro tune only shift slightly advance for the RPM table getting populated, so more or less still around exhaust closing, and just before intake opening.
The boundary for the vette shifts to ~470-480, so it always sprays way way before (50 deg) than the camaro, and when the exhaust is full open, but the intake is 100% still closed. Why, better atomization, or the way the intake works with the runners - this I don't get.

Either way now adding a cam to the LS3 vette i'm tuning plays havoc at low RPM. And the suggested fix to retart timing by 10-20 deg I cannot see working as the boundary is so different vs the camaro, I can never get this sensibly when the exhaust is closed - or I take 50-60 deg out.