Just replaced my original AEM Brute CAI dry filter for my Tj. It was the original GREY dry filter that came with the kit. It was washed every 6 mo for nearly 10 yrs. the part was 21-2039D and bought a 21-2039BF. They added red which is 21-2039DK. I changed due to dry rot.

There is a difference. The newer one has less pleats (36 vs 50) leading to app 28% less filter area. Currently I have no measure to indicate it is more restrictive. I don't expect a difference at idle or low rpm but at higher I'd expect more resistance. Also I'll be cleaning more due to the efficiency dropping faster with less filtering area.

Not sure why the change. Better design or cost savings. You know change the size of the tuna can not the price.


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