evilstuie

I read an article somewhere, one of the intake shootouts I think where the guys tested different intakes on their motor and they adjusted fuel pressure and timing to get the best 1/4 mile runs for each.

That was the TPI intakes and OBD1, and all on the same motor, but I'm just wondering to what extent that can be used to tune from a base tune on an 0411 PCM SBC?

Going through the tuning options, tables, flags and scalars etc it's very overwhelming to a first timer tuner, and I guess I'm trying to understand how to get started and primarily what are the key tables to modify to ensure no damage is done to the motor. HP/TQ improvement will come later, and most likely at the hands of a professional tuner.

My thought was that OBD2 was meant to be better because there were more sensors, higher resolution of those sensors, and more logic in the controller that would read sensors and act on those readings, but it seems like that was more wishful thinking.

Fuel seems easy enough, for each rpm and load table, change the values so the AF ration is in optimal range, but then MAP/MAF stuff complicates that, and then high/low octane and so it goes.

Spark I don't have a clue where to start on that, and yeah it gets worse from there.

My engine build is moderately mild (SBC406/AFR heads/ HSR-30lb/XE270HR cam) and I'm just wondering with a VX commodore LS1 tune how horrible my car would run on it without modifying the tune, and how much gain from that I could get from increasing the fuel pressure to get the AF ratio up, and adjusting the initial timing?

Orr89RocZ

iTrader: (20)

So you have software to read the tune, look at tables and edit them? Hp tuners or something equal?

If so dont mess with fuel pressure. Use the main air flow table and disable maf. Go speed density.

Timing table you are looking at 34-36 deg at wot, 36-38 cruise areas, and 25-26 ish idle. In 411, the table is based on grams airflow per cycle or so. A na motor typically sees .80 or so gram/cycle. I would have to double check my logs but the max value of 1.2 i hit at 3-4 psi boost by 3600-3800 rpm so i think na motors see .80-.90 and not much more. I'll confirm that later

In general stock ls1 timing table could be used but add 3-4 deg to it in the higher rpm higher flow areas as a ls1 sees best power around 26-28 deg while a sbc typically is 34-36. Ls1 cruise timing could be used. Idle areas may need increased due to larger cam

evilstuie

Hi,
I have EFI Live to view the files, and can modify and save, but not back to .bin format.
I'm using TunerPro RT and the Dimented .XDF files to modify the .BIN so there's a little discrepancy between them, but most tables/parameters seem to be identifiable.

RBob

iTrader: (1)

The difference between OBD-1 and OBD-2 ECMs/PCMs is the diagnostics. OBD standing for On Board Diagnostics.

The newer PCMs tend to be better then the older ones, but that isn't due to them being OBD-2. Note that they are also more complicated, have larger and higher resolution tables and such that helps with driveability.

RBob.

JP86SS

iTrader: (1)

They also do sequential control so events are aligned better with the right calibration settings.
Older stuff is "rough" in comparison with lower resolution.

Fast355

iTrader: (2)

5.7 Vortec running a 3.5" LT1 style MAF, making about ~400 hp at the crank, I see values in the .9-1.00 and in cold weather up to 1.06 or so. On a stock timing map that would have me running with nearly no timing advance. My buddies stock longblock truck runs about .76.