I'm going to get a k&N air filter for my ranger. I don't really know anything about air filters. I went to the k&n website and there are all kinds.what kind should I get ? What would go the best with my flowmaster 40? Should I get round? Oval? Dual? Then should I get straight or tapered? Or a cold air instake system? Help?

 

I wouldnt get a k&n, just use oem. Oil on a filter is garbage. Save your money.

 

the oil from the K&N filter will screw with your MAF sensor

 

Not if you clean your MAF regularly. That being said, if I could do it over again I would just get a drop-in AEM filter (high flow cleanable filter that doesn't use oil) and do the stock airbox mod. That's about as good as it gets

 

Motorcraft is all your engine will ever need.

 

AEM make one for these now? I've looked, but it was years ago...

Screw K&N overpriced junk that they won't follow up with the replacement warranty... I'm on filter number 4 ( different ones for different vehicles ) and this last one I got hasn't held up to 20k miles. It's afu.... the other 3 are fine. I called them about it and told them I have a few others and they've held up fine, I'm treating this one the same as the others and only this one is falling apart....

 

weird, I've had the same K&N cone since 2002 and its held up great. I clean it twice a year and no problems

crap, I guess I assumed wrong. I lust looked and they don't have drop-in's for the 4.0s, they only have the full intake kit. bummer. Oh well, still better than a K&N lol