maf interchangeability

[captainluigi]

are there certain maxima maf,s that are compatible with a 96Q? i often see 90mm mafs selling inexspensively. what's that all about?

as always, great to be here & thanx

[Q45tech]

MAF are sized so that at the peak air flow [ redline] that the voltage will be ~~4.4-4.5 volts at say 20F ambient.

A 274 ci [4.5 liter] 274/2 x 6900 rpm / 1728 x VE [say 0.80] = 430 CFM

CFM is a volume unit because air density varies by temp, baro, humidity!

The ecu uses grams per second so convert CFM to gm/sec.

In ecu software the MAF voltage gets put into an equation [translation equation---tranfer equation] that is used to calculate the fuel injection time to create the desires air fuel ratio.

MAF must match this transfer equation otherwise the AF won't be correct.

MAF and ecu are paired to a specific engine.

Using a larger MAF on a smaller engine will seriously lean the AF unless the transfer equation is changed inside ecu or some type of black box is insert between ecu and MAF to fool ecu.