I’ve been using the Kiggly HLA for 7 or so years in my white Evo, and while I touched on it in this post, I think it deserves its own thread. The HLA was pretty much one of the earliest mods I had done on my white Evo, during the great migration where I moved a bunch of parts from my black Evo to my white one. Being sensitive about oil, especially with the future goal of going on track more, the Kiggly HLA is a no brainer. With the valve cover off for other reasons, I was finally able to snap a couple pics of it.
The Kiggly HLA regulates oil supply pressure, effectively reducing oil oversupply to the head. Without this, the head will get more oil than it needs. Though this alone is not necessarily a bad thing, less oil in the head means more oil in the pan, which is a very good thing, especially on Evos. This also reduces oil pressure in the head, which means less blow-by, and also helps reduce aeration of oil. This is an all-around great part for the evo, and a must have in any kind of build. It’s located on the driver’s side of the head, held on by 3 10mm bolts.