MAF calibration

[Gelf VXR]

Out of interest, what are the average adjustments being needed when calibrating the MAF, for example I am seeing roughly -11% across the Hz range, is this normal?

I'm starting to suspect the injectors that came with the L76 complete intake manifold are smaller the 42lb hr? I use LS3/LS7 injector tables. Its an LS2.

I should check the fuel pressure too

[joecar]

I sometimes see 10-15%.

[Gelf VXR]

Its odd this doesn't get highlighted that much, its quite a drop, is the factory calibrated MAF really that far off, or is it the injector data?

Strange I did find the EROD 2010 LS7 tune file has much lower injector flow base, looks close to stock LS2 injector flow base data actually.

[statesman]

Its odd this doesn't get highlighted that much, its quite a drop, is the factory calibrated MAF really that far off, or is it the injector data?

Most likely the injector data.

[Gelf VXR]

Logic suggests that the MAF and base injector flow rate should be correct from the factory, after all the development they have done, any issue with the fuel trims must be with the hardware or the rest of the tune, imho we should leave both the MAF and injector flow as stock as load, traction control, spark, MPG etc. are dependent on these calibrations. It seems that GM make corrections across different platforms to the B1210 MANVAC/VOLTS calibration, when I tried different B1210 map from the one I was using the trims trended towards zero from quite negative.

I'm logging volts and baro/MANVAC to make changes to B1210 only, although you can not apply BEN or trims directly, I'm trying scaling this map up or down to achieve zero trims on this map. And I'm calibrating VE dynair to stock MAF airflow. See how I get on.

[statesman]

Logic suggests that the MAF and base injector flow rate should be correct from the factory

Good luck with that.

when I tried different B1210 map from the one I was using the trims trended towards zero from quite negative.

Lowering B1210 will lean out the fueling, but so will raising the IFR or lowering the MAF curve... so which of those tables really needs to be adjusted? If your actual fueling in PE doesn't match the commanded fueling for PE, then you've probably adjusted the wrong table.

[Gelf VXR]

Lowering B1210 will lean out the fueling, but so will raising the IFR or lowering the MAF curve... so which of those tables really needs to be adjusted?.

That was the point I was making, adjusting the MAF or base IFR will affect other calculations for load, TC, spark etc


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[statesman]

That was the point I was making, adjusting the MAF or base IFR will affect other calculations for load, TC, spark etc

No, only adjusting the MAF will alter those calculations. Adjusting the IFR will alter the amount of fuel supplied but will not alter the calculations for load, spark, etc.

[joecar]

That was the point I was making, adjusting the MAF or base IFR will affect other calculations for load, TC, spark etc

+1 what statesman said...

IFR and OLFA and PE tables affect fueling only.

MAF and VE affect airmass, load, spark, TC, torque calculations/lookups (and transmission line pressure calculation).


Fueling and airmass/load are dealt with separately.

[Gelf VXR]

+1 what statesman said...

IFR and OLFA and PE tables affect fueling only.

MAF and VE affect airmass, load, spark, TC, torque calculations/lookups (and transmission line pressure calculation).


Fueling and airmass/load are dealt with separately.

Yes I agree, as in what I said altering either the base IPW or MAF will have knock on affect on MPG calculations in case of IFR or load, spark and torque in case of MAF.