I know some people said they bought another air filter for their K&N FIPK 2nd gen to increase air flow. Can anyone tell me which one they have or post a link? With the increased air flow, have you actually been able to tell/feel a difference? How about filtration, because of the better air flow does that mean less filtration?

 

the different filter is a 6x9 K&N filter. round in design... the one drawback is the flange is not long enough and you have to move your heat shield back to accomidate it on the tube. otherwise it'll pop off under the vibration. go to the K&N website and have a look at their universal filter selection. I dont have the p/n handy so I'll have to go find it as well.

edit: oh yeah, it rocks... much better top end, not much low end loss.

 

http://www.knfilters.com/search/prod...x?Prod=RD-1460

 

The filter that comes with the FIPK is a RC-4780 which flows 659 CFM...The RD-1460 flows 1055 CFM...While I'm not sure the differnce it will make, that is the data that I have gathered. Also an option that has the same size flange in length is the RF-1027 which flows 829 CFM, while that's not as much as the other, it is a good jump over the standard that comes with the kit.

I don't know what the stock air filter that comes with our worthless air boxes runs for CFM, but the 5.9 that you have only needs 646 CFM at 5200 RMP...But I'm sure that some of these tech guys around here might be able to fill you in more.

 

the filter I mentioned rocked in the mtns when I put it on... pulling up grades was much easier. mileage may have dropped slightly but it's a tradeoff when your going to a bigger filter.

 

so would I be best sticking with the filter that came with it if I'm looking for the most low end I could get?

 

I'd consider something in between or just stick with the stock one. (k&n filter)