The inner side of my stock airbox is bowed out a little, and the filter didn't appear to seal very well. So I figured I'd give the ol' K&N filter a whirl. I have one left over from a previous car. It only had 2 weeks of use on that car. It's a standard cone with flat top.

I used some aluminum piping and connected it with flex connectors for HVAC systems, just as a test. I stuffed the filter back in behind the headlight, where the stock intake snorkel begins, and it went back pretty far...nice and out of the way. I was even a little proud of myself for how nice everything went together.

But when I drove it, I remember why I took that cone off my other car years ago. There's a real SAG in engine response just off-idle. When you crack the throttle and leave it there, like just to slowly leave off a stop sign, the engine is pretty flat. You've got to step into it some to wake it up. I didn't care for that at all. I also didn't notice any difference at the top end. I figured I would, given the exhaust is changed. I lost about 10% fuel economy with this filter on my previous car...and with the extra throttle I've got to give to the truck, I don't doubt that I'd see a similar loss now. Oh well...

So, back to the stock airbox and paper filter. I'm going to fix the stock airbox with a small threaded rod passing through the box with nuts on both sides, to draw the sides closer together, to achieve a good seal. I was disappointed that the K&N filter didn't work out better, but I'm glad I only spend $11 on materials instead of ordering something much more expensive.

 

I have a K&N drop in and i gotta say i like it. It gives it a more aggressive sound and a bit better throttle responce. Maybe that would be an option to the paper filter.

But that is good info to know, If i didnt offroad I would have probably done that already.