I've seen the flow testing that showed K&N filters outflowed paper filters, but I've personally ran into 2 situations where it seems the K&N panel filters are more restrictive than paper filters.
One is a 2000 Crown Vic. My dad drives it all the time, so I decided to throw in a new K&N panel filter I had gotten awhile ago. I never told him this and let him drive it for a few days. He just told me that for the past few days, the car felt like it had no power and it would stumble badly on idle. I swapped out the air filter for his original paper filter, and the problems went away.
The next situation is my 2007 Mustang GT. I threw in a new K&N panel filter and noticed the engine only flows a max of about 31 #/min, and whenever I clutched in or came to a stop in neutral, the engine RPMs would drop very very low to about 500 RPM and it sounded like the engine would stall out. I also didn't hear as much exhaust burble (FR500S mufflers) or even snapping when free-revving. I replaced the K&N with a paper filter and the snapping is now back, I hear a lot more burble, and the engine RPMs only drop to the commanded RPM when I clutch in or come to a stop in neutral.
I didn't notice any of these things with my EcoBoost SHO with the K&N panel filter. But I've heard more than once that turbochargers will flow as much air as it needs - whatever that means?? Wouldn't there be a bigger pressure drop at the same flow rate if the filter was a restriction? Wouldn't that make the turbo work harder and create more heat?
Any thoughts on this? Am I alone with these observations? Those are two N/A Ford modular V8s that reacted rather negatively to new K&N panel filters and it wasn't because of MAF contamination.
One is a 2000 Crown Vic. My dad drives it all the time, so I decided to throw in a new K&N panel filter I had gotten awhile ago. I never told him this and let him drive it for a few days. He just told me that for the past few days, the car felt like it had no power and it would stumble badly on idle. I swapped out the air filter for his original paper filter, and the problems went away.
The next situation is my 2007 Mustang GT. I threw in a new K&N panel filter and noticed the engine only flows a max of about 31 #/min, and whenever I clutched in or came to a stop in neutral, the engine RPMs would drop very very low to about 500 RPM and it sounded like the engine would stall out. I also didn't hear as much exhaust burble (FR500S mufflers) or even snapping when free-revving. I replaced the K&N with a paper filter and the snapping is now back, I hear a lot more burble, and the engine RPMs only drop to the commanded RPM when I clutch in or come to a stop in neutral.
I didn't notice any of these things with my EcoBoost SHO with the K&N panel filter. But I've heard more than once that turbochargers will flow as much air as it needs - whatever that means?? Wouldn't there be a bigger pressure drop at the same flow rate if the filter was a restriction? Wouldn't that make the turbo work harder and create more heat?
Any thoughts on this? Am I alone with these observations? Those are two N/A Ford modular V8s that reacted rather negatively to new K&N panel filters and it wasn't because of MAF contamination.