Originally Posted by not08crmanymore

After years of buying so called CAI's (they may all be called that but not all are) I finally figured out that the stock units nowadays are good for 436,505 and 638 HP right out of the box and they filter the air according to factory specs..How can you improve on that? There have been multiple tests done on K+N and other filters....they do not "filter" the dirt anywhere near as good as OEM and GM put out a bulletin or something a few years ago about that oil in the filters getting into the throttle body and messing things up.... Search this forum,the results are posted somewhere in the archives....as for gains?? 0-2,3,4,5,maybe...on a good day with the likes of a VARARAM or CALLAWAY that actually takes outside cooler air in...BIG FILTER??0-0...years ago during the c5 run,some magazine did a real world test- not just on a dyno -unless you plan on riding around with your hood up all day- on a big filter that showed a whopping 19 HP gain on the dyno.Well,as soon as they close the hood,drove the car for a while and it heated up under there,guess what?The car not only gace up the 19 it gained but it actually gave up 1 or 2 more...Don't believe most of the marketing hype. They are there to sell a product-and good for them in this free enterprise-but gains??Nope,not happening. VARARAM real world has shown 2/10ths or so at the drag strip...a couple of hp gain I guess...if it was that easy GM would have done it.They spend millions on reaserch.

Originally Posted by stsouldier

This guy knows what he's talkin about. Bigger filter equals more dirt in the engine. I've experienced this first hand on my motorcycle. The HP gains won't be noticeable even with a good tune.