MAF placement

[yzriders182]

I am building a twin turbo 5.3l. I want to retain the MAF for now but am wondering if the placement if it will work or not. Thanks for the input/advice

[eficalibrator]

MAFs do not like either bends or diameter changes immediately upstream of the sensing element. This design appears to have both...

That said, you could 1)re-fab with a smoother approach angle between the two banks to reduce turbulence, 2) add a screen in front of the element as a flow straightener, 3) make the junction one continuous diameter as it enters the MAF housing, and 4) change from your older LS2 style MAF to the newer LS3/7 card style element using a weld-on saddle mount with a constant diameter for smoother flow and a MUCH more stable signal.

[yzriders182]

Got ya. If i switch to the card style MAF does the tube diameter matter? Also does it just plug in and work or do i have to re-scale it or make other adjustments in the tune to recognize it?

[eficalibrator]

The card style MAF works in pretty much any tube diameter, it just changes the working range. (How much total flow you can measure before hitting the PCM's frequency limit.) The good news is that even in a 3.5" tube, I only see about 10,700Hz with 68#/min airflow, which is enough for about 680 flywheel hp.

ANY time you modify the plumbing near the MAF or airbox, you should expect to have to recalibrate the MAF transfer function. This is no different. It may be off by a bunch when you start, but if you are able to force a stable commanded AFR and take accurate steady state measurements with a a good wideband, dialing it in is not a big deal.