Is a complete replacement filter system needed for supplying the engine with enough air for BOMBing? Or is a simple pop in filter enough? Or...just leave it alone and keep the OEM parts with a clean filter?
There is no real value on the DMax. Stock paper element produces pretty much the same numbers as AFE, Donaldson based upgrades, or any other "upgrade" until you hit 500-600+hp. That is based on a multitude of dyno runs AND ETs as well as laboratory tests which show that the stock filter flows plenty of air to support lower HP output. Some users "report" faster turbo spool, but no empirical test that I've seen or heard of supports this, and we all know how "reliable" the seat-of-the-pants dyno is. It has also been proven under laboratory conditions that the stock AC Delco filters !!MUCH!! better than all of the after markets "upgrades" except the Donaldson (also paper/gauze) which was a fairly close match. And to put my money where my mouth is, in the past I was seduced into running a UNI in mine for a while, but I have since returned to the AC Delco paper element and notice NO difference in my chipped truck. Anyone want a "slightly used" UNI for a DMax?
On the 7.3L PSD I noticed a small drop in EGTs when I went to a large open air system. The most noticable increase was in turbo whistle, which I was happy with anyway. I am running a Donaldson filter on my setup, so I figure my filtration is equal to stock, but with some cooler EGTs, so for me it was worth the 75 bucks I put into it. This is coupled with a 140hp chip. Stock it wouldnt have mattered I dont think, but with the chip it seems to help.
