I recently had a discussion with Natedogg concerning the GM MAF. From what we had heard the 3" MAF is only good for up to 800CFM. Some of the turbo upgrades going on around here will pump more than this figure. So the 3.5" MAF has been employed.

In a recent discussion with Dejon though, he said that the 3" MAF is good for far more CFM in a 'Blow Through' set-up. I currently have a 3.5" GM MAF with 2.5" blow through piping and 3" couplings. I can either get a 3" MAF or the couplings flared for my 3.5" MAF.

Does anyone have definitive numbers on the GM MAF's flow numbers, draw-through and blow through?

Stock 94-up LT1 MAF Sensor w/o screen -- 719.0 cfm

http://dtcc.cz28.com/flow/

It only has that one so I'll have to keep looking for the LS1 sensor.

The MAF will flow considerably more in a blow-through setup. You might want to surf some LT1/LS1 Camaro boards and see what kind of power numbers they are putting down running blow-through turbo setups with stock MAF's.

Ideally you want the piping to be close in diameter to the MAF to avoid cross-sectional area changes that will introduce turbulence at the sensor, which is bad for sensor accuracy. The 2.5" piping should become a flow restriction before the 3" sensor does, so I think the important thing is how high can the 3" MAF read before it maxes out?

Marty

That is exactly what I was referring to with the 800 cfm per minute number. I believe I got that number from fullthrottletech.com. The guys who created and support the GM MAF translator. But now I can't seem to find it. It might be on the older yahoo groups translator list.

Hmmm...Ok. Good info so far. I apparently asked the wrong question.

Can we get some definative numbers on what each GM MAF sensor will read as Nate and Marty mentioned then.

Did some searching around on LS1tech.com. Came up with this:



75mm maf = 3" maf
85mm maf = 3.5" maf

From last post in this thread.

http://www.ls1tech.com/forums/showthread.p...ghlight=maf+cfm

But is the 750cfm limit a flow limit or a sensor range limit? I have a couple contacts at GM...I will see if I can get some insider info on this.

Marty

I'm not sure. This is all I could find that gave any kind of clear definition for cfm through the maf. Hopefully your contacts can clear this up.

The statistic I posted was for overall maximum air flow, not sensor maximum.