Huh. First time I've ever heard of that happening. Every truck I've ever taken a K&N off of got better in every way.

 

Was a K&N model 880 (I think). Cone about 14" long w/ about a 5" end cap and 4" outlet. New one is about the size of a bathroom garbage can.

 

That sounds quite a bit longer than any K&N I've seen, which could account for it.
But yeah, the BHAF is definitely a BIG HONKIN' air filter.

 

bigger is better ... unless its inefficent at removing the stuff your engine dont wanna be breathin ....

 

Here's the one I was using: RE-0880 - K&N Universal Air Filters, Universal Rubber Filter direct from K&N Model number was RE-0880, not just "880"

 

I would have to say that it was too small .... calculate the leingth by the circumfence ... Sq. In ... trubo engines need Massive filters ... two of those would have been good ..

 

Did you have your "sarcasm" key locked? That one flowed for 30psi and rarely, if ever got to 900 EGT (post-turbo) My new BHAF is the one with less pressure and higher temp..... There's also the possibility that my intercooler (original) might have developed some pinholes here and there, and that I'm losing pressure. There are some places where the paint's flaking away, leaving exposed aluminum tubing.

 

Here's my little piece of update:

Filter may or may not have been a restrictor. Probably wasn't since my son borrowed it for Da Beast, and can now pull 35psi. Intercooler not leaking. Boots and plumbing all tight. Turned out that my BD brake's "butterfly" valve wasn't opening all the way anymore. It'd still close when I wanted deceleration, but, was acting as an exhaust restrictor, when it was supposed to be full-open. Would have been $1000 for a new one, so I had the guy remove the controls for it, and torch it out of the "elbow"... I no longer have mountains, a trailer, or big jobs for "Tiny", so, the loss is not too awful painful. Runs like a raped ape, now.

 

I noticed a large increase in EGT when I did the BHAF, but in its defence, there was no divider in place to keep the hot air from the exhaust and rest of the engine from getting to it. With this truck I have a smaller air filter with a fitted heat shield that keeps the hot air out of it. I would suggest making a shield for the hot side of the filter and see if that solves your EGT issues if they are still high.

 

Only thing I will run is afe intake or s&b