This is misleading information.. or am I just confused?Anytime you enlarge the diameter of the MAFS housing, you'll have to tune for the difference or you'll run too lean. Conversely, you could run correspondingly larger injectors (that is, upgrade the airflow AND fuelflow proportionately at the same time) without having to change the tune.
I don't think this is correct. The PCM has NO IDEA how large the MAFS housing is.SVT and standard zetec housings are different sizes. IIRC the difference in size will be detected by the MAF and will cause the ECU to go into safe mode (or something to that nature) to prevent the engine from running lean, and then in turn it will throw a CEL, and possibly cause a drop in MPG and power. i read that in my performance repair manual awhile back. i think it was chilton xtreme or something to that effect. i apologize if my terms are not exactly correct as im awful at remembering the names of people, books, places, famous battles, and technical terms, but the gist of it is there.
I've never tuned the Ford ECU, but I have tuned several others, and on those, a small change in maf housing diameter (one that affects flow <10%) would be effectively compensated by the long term fuel trims in both OL and CL operation. Most other ECU's allow +- 25% fuel trims to allow for differences in fuels, etc, and have 4 or more maf ranges to store unique trims. Does the Ford ECU operate this way?OK.... heres the skinny.
This is NOT "old" the Mustang world you can not change injectors to match the MAF without tuning.
If you change the MAF housing size you need a tune.... going to a larger MAF houseing will cause the sensor to read lower air flow than what you actually have which in turn will definitly cause a lean condition.
Changing to a larger injector will pretty much cause you to run insanely rich...almost undriveable rich even if you have a larger MAF housing.
Now you can go slightly larger on the housing and make some power, but thats still because you're running lean.
Running calibrated MAFs are STONEAGE tech for people that dont comprehend tuning.