[Hi Volt]

I wouldn't think this mod would actually alter fuel mileage anyway. Under normal cruising you are probably not running past 40 - 60% throttle, and at that point my tests never showed any airbox vacuum, so the engine was supposedly getting all the air it needed anyway. Under snap acceration where WOT would be commanded, or actual pedal to the metal operation, the stock system did have airbox vacuum, this is the point I noticed the improvement after the mod. Unlike most CAIs that alter the airflow past the MAF, this mod doesn't so I think the fuel trims should remain unaffected ( except at WOT ). Would be interesting though to actually have some repeated testing, other than the very basics I used. I am still planning to get a scanner and log fuel trims with and without the mod ( easy to plug the hose and be back to OE ). With my inlet behind the headlight, the bottom of my airbox is about the same as it looked before the mod. But to be fair, I haven't offroaded that much lately, but have had plenty of long rain soaked highway drives.