lilcrate

This may sound like a stupid question, but if I have an 85mm or 90mm MAF housing, but were to use the stock MAF sensor, does that matter? or our the sensors different too?

cliffyk

Does is matter with regard to what?

Assuming the OEM sensor fits the housings it will work, however the transfer function will be different for each housing and have to measured and programmed into the tune...

Here's a post I made in the Delta Force forum that explains why this happens in some detail...

lilcrate

Ok, I have a MAF, this is for a friend, but he found a 90mm MAF housing on craigslist without the actual sensor. So he can use his stock sensor with that housing as long as it is calibrated for the larger housing?

cliffyk

Sure, however the MAF does not need to be "calibrated"--it needs to have its transfer function measured, or calculated as I described in my posting on the DF forum, and then that transfer function will have to be loaded into the tune.

Our cars use a 30-point transfer function--this is for the stock '03 GT:


Using the OEM sensor in a larger housing will mean that for any given MAF output voltage more air will be flowing than shown in the table above--the table will need to be altered for the new transfer function.

For a 90mm housing I would start by multiplying the table values by 1.32, something like this: