Ram Air Cowl Mod Part 1
This first picture is my starting point. Under the cowl is an IO-360-M1B with a horizontal sump. The engine was built at Don?s Dream Machines in Griffin, GA and has 9.5-1 pistons, dual Lazers and 4 in to 1 exhaust. I purchased a ram air/alternate air valve from Airflow Performance in Greeneville, SC. Now it is time to modify the cowl to allow for the ram air induction to work with the horizontal intake.
Here is a picture of the ram air valve with a pliable rubber fitting installed on the end. Ultimately the rubber fitting will mate with another smaller male fitting that is attached to the aft portion of the cowl air intake inlet. The rubber fittings were purchased at Pep Boys. The smaller fitting slides into the larger fitting and creates a very nice seal and transition that requires no clamps or other means of securing together. This is important because you need a way to get the cowling on and off easily. With this setup you simply fit the two rubber pieces together while you are attaching the bottom cowl.
The first step in the process is to cut a hole that allows the cowling to fit around the ram air valve. The hole needs to be large enough to allow for the valve mechanism to move freely. Additionally the hole is cut in an asymmetrical fashion to allow room for the alternate air valve which protrudes from the ram air valve at a 45 degree angle.
I purchased this intake scoop kit from the Holy Cowl folks. This picture was taken after I cut a portion of each side off. I also installed the aluminum intake ring prior to snapping this photo. The ring and flox come with the kit. You simply cut the hole and insert the ring. The intake ring is permanently set in place with a thick epoxy/flox mixture. I used five minute epoxy so I could get on with the project.
Next I attached the scoop to the cowl with epoxy. I used liberal amounts of epoxy on all contact points. The scoop and the cowl will require additional cuts at a later point. Of special note, I clamped a piece of sheet aluminum to the forward face of the cowling, so that I could get the scoop set in perfect alignment.
Here you can see that the aft portion of the scoop has been cut off. I used a die grinder with a fresh blade to make these cuts. This picture also shows the mesh that I used to create the contour and smooth transition between scoop and cowl. The material is screened window mesh. You can purchase aluminum or fiberglass screen (Home Depot or Lowes). I used aluminum in order to hold the contours better. I would probably use fiberglass if I had the choice again. The aluminum ends can stick up and poke through your fiberglass layers and your filler. No big deal, but it is something to consider. As you can see, I used clecos to shape the mesh to the desired contour. After I got the shape that I liked, I cut the excess away.
Here I used a thick bead of epoxy to attach the mesh to the scoop and cowl. If you look closely you can see a black Sharpie line, just inboard of the epoxy, the line was used to space out clecos to mark the outer edges for the epoxy bond. The clecos remained until the epoxy was dry.