After reading the thread about the 5.9l air filter I am wanting to try a new filter in my truck. So what do you think a stock 5.9 filter, a performance 5.9 filter (AEM or AFE) or a green filter that I see they make for the 6.7? I don't want to do an intake yet because of warranty issues, but I figure a drop in filter only takes 5 min to change if I need to go to the dealer.

 

I think the jury is still out on the stock 5.9 filter vs the stock 6.7. I don't know about the after market stuff yet but the one think I would not do is show up at the dealer with the 5.9 filter installed while still under warranty.

 

Whatever you do you may want to just stick with a filter and not bother with an intake system. The latest issue of TDR had a really interesting article on the effect of hot engine bay air getting drawn in through aftermarket intake systems. Basically the benefit of more airflow is more than offset by the higher intake air temperature the engine gets. It was really interesting to see real world data that showed higher intake temps and therefore reduced power. What I took from the article was that the stock filter box was a pretty good setup unless you're going boost the power quite a bit.

 

What about the spongy thing that supposed to seal the box to the hole in the fender?? On both my 04.5 & 07.5 this spongy thing is never in place whenever I open the hood. I keep puting it back in but it never stays. Was thinking of glueing it in whenever the truck sits still long enough for the glue to thoroughly dry before running again. Does this mean I'm losing power by sucking in engine compartment air vs. the ram induction?

 

In a word, yes. The degree of loss you probably won't feel with a butt-O-meter but it would show on a dyno.