The MAF sensor measures flow based upon the set OEM inside cross-sectional area (CSA) of the MAF housing.
The MAF measures speed and the calculation with the MAF housing CSA gives a resultant volume of air passing at that point in time.
If the MAF housing is larger than stock then the MAF will still measure the actual speed of air being drawn in but will still use the OEM CSA of the MAF housing to calculate the volume flow instead of the larger CSA of the aftermarket intake.
The problem with going much larger will be that the air fuel ratio (AFR) will be wrong and could cause running issues with the car, like running lean,hot etc.
....Thanks for explaining that, John.
So, the MAF isn't SMART technology but does its calculations according to OEM presets which don't take aftermarket air intakes into account.
However, if the AFR plots an undesirable shape on a rolling-road, the remap can be adjusted accordingly to possibly solve the problem. JKM have done exactly that via my Revo settings but that's not the same as recalibrating ECU tables of information (is it?). But it would appear that some tuners such as APR do take the MAF into account in their code by using the recalibration method.
So by strictly adhering to the OEM 67mm MAF dia, ITG may have an important advantage.
I want to try and get some comments on the Twintake's MAF solution from Forge.
Given the retail cost of many of the aftermarket high-flow tubular air intakes, you would have thought that most of them would have bothered to get piping manufactured which matched the OEM 67mm size!
