LS1 MAF table differences

[02_TA_RamAir]

I have been looking at the 3800Pro.com forum in which "Mr Intense" has a MAF table repository. The tables shows that the 1998-2004 Corvette all has the same numbers while the 1998-2002 F-body and 2004 GTO have different numbers. The AC Delco site indicates that the MAF, #213-4657 fits them all. My question is, how can the SAME MAF meter be used in these cars but have different MAF numbers?

[Iam Broke]

The intake air flow velocity will affect the freq the sensor generates. Different air intake designs will skew it. Even dropping in a K&N will affect the MAF tuning. Smaller diameter at the MAF increases air velocity and reads higher, larger decreases it. I know they all have the same diameter MAF sensor by what you posted, but the shape, length, ect. all affect the readings.

You think it's bad, try tuning a card MAF sometime.

[jimmyblue]

There's a whole raft of cars that used the 85mm Delphi and
they all are subtly different in the table. Inlet tract shape
and how it biases the airflow across the duct, counts for
a lot. The 4th gen F-bodies have a pretty benign straight
shot, other models have bends that can mess up the air
distribution, especially when descreened.

F-body OS versions had different ranges of frequency they
could index. But the curves agreed, where they overlapped.
The best table for the 75mm MAF in my book is the Holden
Commodore one.

[02_TA_RamAir]

I understand that the inlet system can effect the total amount of air that the engine could ingest (essentially the differences in pressure drop), but a set velocity across the MAF will trigger a set frequency. If the intake system is less restrictive, then the engine has the capability to pull in more air; the MAF will still register the same amount (mass) of air with a certain velocity because the MAF has not changed in cross sectional area.
You mentioned that the Holden table is the one to use but it has a total different curve than all the rest. This MAF must be characterized with the mass flow numbers that are present in the tables. To use these numbers on my '02 TA would send an incorrect signal to the computer since the TA's flow numbers are different (according to the forum).

[Iam Broke]

Airflow is dynamic, two identical setups are going to be different. Log your setup & use the histos to dial it in.

In theory they should all follow the same curve based on MAF airflow, in reality they do not.

Flow is not laminar nor identical across the MAF cross section. Any difference in the intake tract affects measured flow.

[murphinator]

maf table repositories are handy to get a new setup up and running "in the ballpark" but a maf tune is the only way to get it correct.... like said above use your histo's - more specifically set it up for mass airflow error and repeat until the error reported is minimal