Spent $180 on a "performance" air filter for my Civic, gained nothing but noise
I saw all these forum posts about how a drop-in K&N would free up 5 to 8 horsepower on my 2012 Civic, so I grabbed one at AutoZone in Dayton for $180 with the cleaner kit. Three tanks of gas later, my butt dyno felt nothing and the intake noise at 3k rpm just made my commute annoying. Has anyone actually measured a real gain on a basically stock engine, or did I just buy a $180 whistle?
Did you actually measure before and after, or just go by feel? A drop-in filter on a stock Civic is basically a breathing mod, and the ECU fuel trims and MAF sensor are calibrated for the stock airflow. Most guys who "feel" a gain never ran a baseline dyno, they just want to believe the money did something. The 5 to 8 hp claims come from filter makers testing on a built motor or with the airbox lid off, not your stock 2012. The noise at 3k is the intake tube resonating, that is real, but sound is not power. If you want proof, do three back to back dyno pulls stock then swap the filter and see. Bet the difference is inside the run to run noise.