102 maf sensor took less frequency than stock ls3 meter??

[CactusG8]

To get the afr on the dyno into the low to mid 12s we actually had to scale back the hz readings about 6 percent. And the g8 has large ported heads, cam, ported intake/t.b., headers, etc.

Everything I have read is that the frequencies would have to climb about 10 percent over stock.

So what is happening?

[LEDbetter]

The larger diameter flows more air. The same volume of air will flow, but at a slower velocity. So that's why you see less Hz.

[CactusG8]

I am trying to use common sense. I understand that at a given rpm the speed of air coming into the maf is slower. But it is making it up with volume. Sort of the concept of a small straw may be flowing very quickly. But of course not with the volume of a large pipe which is maybe moving water slower. But with more volume.

But if it is moving slower; but with more volume would you not want more fuel? Reckart performance states it will take about 10 percent more hz frequency. Maybe I am misunderstanding him.

I am sure you are right. My brain though is not comprehending.

[ZZMike]

Try equating it to sucking air through a straw, versus sucking air through a paper towel roll.

Your lungs are sucking the same amount of air, but the volume of air is moving at a slower, but more efficient rate.

The MAF uses a thermistor to gauge airflow by the amount it is cooled by the rushing past it. Since the air is moving slower in the bigger tube, this equates to less airflow being sensed and measured by the MAF. You therefore need to reduce your scaling to compensate.

[DSteck]

The MAF doesn't measure volume. Air also moves slower closer to the wall of a tube. Make that tube bigger, and the same volume of air moves slower. Move the MAF closer to the wall, and it'll spit out a lower frequency for the same mass air flow.

[ZZMike]

The MAF doesn't measure volume. Air also moves slower closer to the wall of a tube. Make that tube bigger, and the same volume of air moves slower. Move the MAF closer to the wall, and it'll spit out a lower frequency for the same mass air flow.

This is exactly correct. The MAF generates a frequency based on the speed of airflow past it that we then interpret by assigning the sensor's frequency output with a specified volume measurement in the calibraation.

[CactusG8]

I am sort of understanding it now. First off I have a ported intake and throttle body. Not a 102 Fast intake/throttle body. So as you said your lungs only need so much air. As in the engine needs so much air. If I went to a 102 intake/throttle body it then could utilize the maf meter to it's fullest. And that makes sense. I dynoed with the stock maf with out the screen and the 102 maf with my tuner dialing in the hz. They literally laid on top of each other. No advantage or disadvantage to either. Except the ls3 meter idles better.

[TimC]

Simple. More air goes around the sensor when you have a bigger tube.