SOHC Cold Air Intake

[2000StreetRod]

I decided that while I had the front bumber, grille and side lights off to add oil coolers and remote oil filters I would perform some of my future cold air intake modification. My first problem was to determine a suitable hose size. Shop vacuums use two standard hose sizes (2 1/2 inch and 1 7/8 diameter). I decided that 1 7/8 would be easier to work with and fit thru more existing and potential openings. I will need a total of 5 hoses of that diameter to equal or exceed the cross sectional area of my planned 90mm MAF sensor. I purchased the hose kit shown below from Home Depot.

The coils are parallel (not spiral) with a minimum outside diameter of a 1 3/4 inch and a maximum outside diameter of 1 7/8 inch. This means that a section can be cut and installed in a 1 3/4 inch diameter hole with no associated fitting or attachment.
Below is a photo of the front of my Sport less bumper, grille, etc.

The only thing directly behind the area marked with an arrow is the flexible radiator overflow tube that can be easily moved aside. The area is shielded from frontal direct flow (rain) with a plastic deflector that has been temporarily removed. I decided to cut a hole there for a flexible tube to be connected to a future airbox enclosure for my high flow air filter. The photo below shows the results of about 10 minutes of drilling with a hole saw that supposedly is for cutting metal and wood.

I was not impressed with my progress and will be switching to a chassis punch in an attempt to finish cutting the hole.

 

[IZwack]

Dunno which holesaw you use but I use the Rigid ones (from Home Depot) and it eats holes pretty well. I've used it on stuff as thick as 1/4" steel. On average, I'd say it takes just about a minute and a half to cut a 1.5" hole through 1/8" steel. Of course I am using a drill press so that helps a little bit.

 

[2000StreetRod]

I have the rigid ones also but they're about 20 years old. I used them to make the openings in bird nesting boxes. Maybe I'm wrong in assuming that my old ones have the same capability as the new ones for either wood or metal. Your holes look superb! I may buy a new one and try it.

I used my chassis punch to finish cutting the cold air inlet as shown below.

You can see the flexible radiator overflow hose behind the new inlet. I wanted to cut another hole where the red arrow is but there is an immovable rigid line connection to the air conditioner condenser directly behind that location. I possibly could figure out a way for the A/C line to pass thru the inlet flexible duct but don't like the idea. Another possibility for a second inlet is marked by the arrow in the photo below.

It would require cutting out part of one or more of the stock support brackets.

 

[2000StreetRod]

Second Air Inlet

I decided that the location I was considering was feasible even though the air conditioning line would slightly interfere with the flexible duct. I used my Dremel tool and cut off wheels and grinders to slightly reduce the supports in the new hole location. I removed just enough metal to allow room for my chassis punch. Below is a photo after the hole was punched and the flexible ducts installed in the inlets.

My next step will be to cut holes in the base of the air filter enclosure for the cold air ducts. I'm hoping that the flexible hose will endure the temperatures of the engine compartment!

 

[2000StreetRod]

Air Box Mod

The photo below shows the lower section of the stock air filter enclosure after popping out the inlet cone (noise suppressor) and cutting two 1 3/4 inch diameter holes in the side for the two shop vacuum hose cold air inlets.

The new opening nearest the latch is still low enough that it would not be blocked if I were to use the stock type air filter. Currently I'm using a Akimoto Racing cone filter but when I switch to my 90mm Lightning MAF sensor I'l be using a Spectre cone filter.
The photo below shows the lower section of the air filter enclosure installed in its stock location with the cold air hoses installed.

Eventually, I will modify the upper section of the stock air filter enclosure to fully contain the Spectre cone filter. This will reduce the "sucking air" sound that is even louder with the Spectre cone than with the Akimoto cone. Also, almost all of the intake air will be from the front and very little warm air from the engine compartment. Then I will truly have a cold air intake system!