shortturn

Looking for help on 6.0 trk 06. Has heads long tubes cam . Engine ran out of
injector (stock) .Replaced With Delphi 44 shorty ,after rescaling for injector
writing new ve grams per cyl went up. Scaled injector lower value changed
ve .Now g/cyl flatten out at .80 .Is this air mass actual measured flow or a
calculation of fueling ?

SSpdDmon

iTrader: (10)

From what I understand, grams/cylinder is calculated based off of MAF measured airflow or, depending on RPMs and throttle transitions, MAF/VE blended calculated airflow.

CRAZYCUTER4.8

iTrader: (2)

Hmmmmm..... Your Situation Throws Convential Logic Out The Window

dc_justin

iTrader: (13)

In speed density, air mass is dependent on the VE table. In MAF mode, it is calculated based on a combination of MAF input and VE calculation. Both injector pulse width calculation and spark reference utilize this same air mass calculation.

shortturn

I do have it in sd maf failed at 0 but still pluged in will this still calc air

dc_justin

iTrader: (13)

Then your VE table is directly responsible for airmass calculation.

VE is stored in GM Specific units.
GMVE = grams of air * temp in Kelvin / kPa
thus
g = VE*MAP/charge temperature

shortturn

dc justin
How do you map your ignition if your running in speed density?

SSpdDmon

iTrader: (10)

EFI Live's scanner pulls grams/cylinder using the PCM's RAM. When the MAF is active, we log GM.CYLAIR_DMA to grab air mass. The airflow value is either provided by the MAF or a blend of the MAF and VE calculated airflow.

When the MAF is off (SD), we log GM.DYNCYLAIR_DMA. GM.DYNAIR provides a calculated airflow value based on the VE table and several other sensors (same as the blended part above - only minus the MAF).

DMA pids: These are the instantaneous values the PCM is using to make it's fuel/spark calculations. The "DMA" on the end of our pids means Direct Memory Access.

CRAZYCUTER4.8

iTrader: (2)

YET ANOTHER DIMENSION

RedHardSupra

iTrader: (1)

remember the values you get through DMA PIDs (EFI nomenclature)/MPIDS (HPT name) are just lookup. it's not what's real. if you set your VE table to something really low, your DYNCYLAIR is going to be low, no matter how much air you really got going through there. if your tune been raped and pillaged by an IFR tweaker, most of the time your VE tables will be left completely stock, so your newly modded ride will show the exactly same airflow as before. this is of course wrong, but this is how it usually is.

the only way to arrive at more realistic VE (which effectively will change DYNCYLAIR) is to start with as good of an estimation of IFR as you can get (it will never be perfect as neither injectors nor the fuel pressure are linear) and then adjust VE until the AFR on the wideband follows your commanded AFR.

AFR=airmass/fuelmass and
fuelmass=IPW*IFR

if you don't adjust airmass, you can get AFR to still 'agree' by tweaking fuel mass. also, if you're changing both airmass and fuelmass at the same time, there's an infinite number of solutions to this problem. thus set your IFR to what's most realistic, point that AFR where it should be, and let the VE describe the real new airflow.

shortturn

redhardsupra
Do you know correct injector scaling for Gm 8.1 non marine injectors ?

RedHardSupra

iTrader: (1)

never worked with them, post all the info you got and we'll figure something out. but try not to hijack this thread

dc_justin

iTrader: (13)

From a stock 8.1L truck tune from holdencrazy:
30#/hr

To be accurate at all load levels though, you'll also want to copy the other related tables as well (injector pulse width voltage adjustment, minimum injector pulse width, default minimum injector pulse width, small pulse adjust)

shortturn

Thanks guys for your advice