Originally Posted by builthatch
thanks for the responses and clarification. i was not sure if the maps meant for intakes would overcompensate for a stock intake with panel filter, sort of like choosing a 91 map over a 93 since it would have richer trims and less aggro timing. but i understand that this is not possible.
Bill, you said "If you are retaining the stock intake, regardless of stock or aftermarket panel filter, you must use the stock intake map."
in your experience, is there a high liklihood that the car will have to be protuned based on the flow differences of a panel filter upgrade vs. the stock filter? i noticed in the map notes that it specifies in all caps a stock intake and stock panel filter.
it seems a lot of people on this forum are against changing the panel filter with the stock tune, so i'm thinking this must apply to the AP OTS maps meant for stock intakes as well.
Subarus we are support MAF-sensor based, which means increases in airflow are not the problem as this can be measured by the MAF sensor. The issue is when you change the diameter of the intake and/or how air flows around the sensor due to the design of the intake. In that case, the tune would need to be calibrated so that the proper airflow is determined at each point.
A panel filter could, technically, impact the accuracy of the MAF sensor, but it is a much less of concern than an intake change and is generally not a problem. It could also vary with the type of intake filter. We only test with the stock intake filter, so that is why we recommend using that but you can generally use an aftermarket panel filter without issue.