Can someone tell me what the diameter is on these air filters everyone is using? My filter is from my last truck which was a power stroke. The diameter on it is 4". I read somewhere that Cummins owners are using a bigger filter than the PS because of the room. Thanks in advance.

 

the neck on my Fleetguard BHAF is 4". My air intake pipe is 4".

 

You can do just about anything , BHAF just refurs to big , I think that most are taking out the factory air box , then adapt to fit , pad or mnt. for it not to rub , & fit air tube .
I had one from the classifides here ,with an Outerwears bag , then moved on to the new airfilter from Amsoil , needed to make an adapter for air tube becouse it was the only one that DuluthDiesel brought to the dyno day , then built a box out of that plastic cardboard , it was the some color as the filter .
If your handy make what you want and save big bucks .

 

How does everyone get these huge air filters to fit the factory accordion pipe?

 

Loosen the clamp, push it on, then tighten the clamp back up.

 

Smart-****. And that works for the generic fleetguard air filters?

 

Yes, it works. 4 inch works. The intake tube is 4". Those BHAFs are pretty restrictive compared to other filters. I tried it, but then I took it back right away. The air flow is like 620 CFM and then filter I use is like over 900 CFM. With the BHAF, turbo noise was gone and top speed reduced 5 mph. I got my filter at autozone for $38. The BHAF was about $72 for me.

 

I used a scape piece of exhaust pipe , 4" is not that comin , make a run to the hardware store and see if PVC , whatever , works .

 

Are you talking about putting some type of hard pipe in the air filter if it is soft rubber so you can camp onto it with the intake tube? That's what I had to do with my filter. I went to Ace Hardware and found a plastic tube that worked. The rubber filter connector had to strech a little to go over the tube. The tube I got is a little thin though and it bends a little when I clamp it so I can't have it too tight. I recently got a hold of some extra 4" exhaust pipe, and you have just reminded me to try it out.

 

So what filter was it that you got from autozone? Have a part number?

Shawn

 

42790 thats the napa part # I think..or maybe its just 2790,either way a good parts man can figure it out.

 

Yea, but the napa equivalent is about 75 bucks around here. 35 bucks would certainly make me happier

 

As far as dim's the bhaf from NAPA is 10.5x10.5 with a hard plastic neck that your stock intake hose will clamp right onto without crushing. After removing stock airbox I made my heat shield and the bhaf sits just right on the heat shield and I am not planning on clamping the whole filter down

 

I just put mine in yesterday.The turbo whine is insane, way louder than the stock air box. The filter cost me $49.08 Canadian. I bought it from a Kenworth truck shop. Fleetgaurd AH19037.The local auto parts store wanted $65 plus shipping.