Question for the original poster: On the LS1, did you install just the filter or did you install a new Cold air intake with the K&N filter? Also, what type of car was it? I am but a lowly vette owner (86' and 99'), but I do know that on the LS1 vette's (especially the 97-2000's) replacing the air intake box will give you an honest 10-15RWHP increase. The factory box is seriously restrictive, and if you have seen it, it makes you wonder how the car makes as much power as it does. As for the benefits of any aftermarket air filter, I will say this. I have dynoed my 86' several times during my header and intake manifold installs, and during one of my trips I did 1 run with no filter at all to see what type of difference it would make. Answer: NONE. (I normally run the stock GM filter in that car) I don't know about other cars, but on the vettes I would not expect a HP gain with just a filter, it would need to be a new intake box design to be effective.
I would, but the little man in my tummy is telling me to go on a rampage and eat as many children as I can.......
HA HA! But I have proof if his misgivings! We are so far off topic it's not even funny! What was this thread about again?