Homeade Ram-air article...

Like all others before me, and most who have come after me, I have been trying to find ways to make my Non-turbo engine perform as well as possible, and get as much power as I can without the added stress of turbocharging. I know that several companies offer a "ram-air" setup, which is like the stock air intake, but essentially tries to scoop air from an area which is of higher pressure(like the grill just below the windshield) or with as little restriction as possible. The cheapest was the Hypermax cowl induction unit, which, I think was actually designed for a turbo application, but was about $70 dollars(U.S.) which seemed like a lot of money to channel air into the airbox. So, being cheap as I am, I decided to make my own setup. I felt that the coolest air is in front of the engine compartment(cool air is more dense than warm) and as the truck plows through the atmosphere, it builds a high pressure "wave" in front of it, so here too would be the best place to scoop air, right through the grill from in front of the truck.

Click here for pic "front"

I fashioned my scoop from a 5" furnace floor duct. To understand how much air one of these scoops, you need only hold one out the drivers window with the opening into the airstream, and the hole facing inward at about 30mph, and you'll appreciate the amount of air that passively moves through this unit. I decided to place mine alongside the radiator facing forward through the grill. This required removal of some of the mounting metal that held the rad in place at the side/top. The amount of metal that was there, was enough to build a tow hitch to pull about 10,000lbs, so I removed about 60% of it with a sawzall, and re-enforced the leftover piece till I was satisfied that there would be no movement of the radiator with this piece removed. The duct fit in there nicely with the help of some sheetmetal screws, and some duct tape(thanks Red/Green)!

Click here for "scoop"

The rest was just plumbing it into the air intake. I used flexible aluminum duct, which I taped into place also with aluminum duct tape.

Click here for "Duct"

I had a few concerns to start with. Obviously I had the possibility of sucking in large bugs, maybe even a small bird. This was easily solved by just putting some 1/2" square screen in behind the grill, but in front of the opening. So far the only things I've found inside were a couple badly mangled dragonflies plastered into the air filter element. I was also concerned about water coming in. Since my truck doesn't know how to swim, I avoid deep water. However, since it rains here quite a bit(I live in the northwest about 100mi north of Seattle) I was worried about water getting in. I did run it wide open in the rain, and when I got home pulled the air cleaner element, and it appeared dry, but just to be sure, I got my wife(bless her) to make up a vinyl cover which just snaps into place on the 4 corners over the grill. The "ramair" effect may be somewhat compromised while this is in place, but the engine still has lots of room to get air from around behind the edges of the cover. The last thing which may be a bit of a problem, is those of you with the air conditioning. You'll see that I ripped mine out long ago, so there's lots of room for the duct, but if you had the air compressor, you'd probably have to do a little more creative routing for the ducting.

Click here for "Cover"

Does it help?
It was difficult to say for sure if the "ram-air" modification made a significant increase in power on it's own merit, because I cut the bowl out of the air cleaner, and put on a 3-3 1/2" exhaust at the same time. With all these mods together, I sure did notice a difference. I did see though, that the vacum gauge on the intake side of the air filter which previous to this mod,would often read as high as 15in. H20 when the filter was getting dirty, was no longer reading at all, even when the filter got quite dirty. I did notice also that the amount of smoke that came from my exhaust was much less, so much so that I was able to turn up the fuel on the injection pump 60deg. and still the engine barely smokes most of the time unless I'm really gettin' on it!(More air + more fuel definately= more power)!! I think this is a very worthwhile job. If you compare the stock intake opening and passages, and look at where it scoops air from(behind the left turn signal light on my truck) it's a wonder the engine runs at all!! I've got some 15,000miles on my engine with mine now, and I'm convinced it makes a big difference in responsiveness, and overall power.