look, if the diameter of the old and new pipes are different sizes and you are still getting the same net result for each, look to adjust the area that the air comes into the pipe. It seems like you have to modify the area inside the fender where the air is coming into, thus forcing more into the pipe. Is the current area where the air coming into the pipe the best area? Does air get trapped in this area and stay stagnant as opposed to being forced into the pipe?
Getting the largest amount of air into the pipe driven by the "wind sheer" entering the fender at the greatest amount of speed would be my goal. After that, then I could think about increasing the diameter of the pipe
just my thinking.

 

Well the results are in I did they got a project on my iOS 6 I have a6 inch lift on 35 I was getting 10 L highway sad but after the gots I did a run 13.6 yeah baby

 

Sorry for those could understand that stupid talk to text don't work too good I have a 2006 screw cab 4 by 4

 

based on the posts in this section, they are reporting the same. Looks like 2-4mpg gain.

 

I was skeptical but yeah I'd have to agree two to four best $18 I ever spent

 

If I used the Spectre duct, what else would I need? Trying to decide what I want to use for this mod. Def doing it though!

 

Great write up!

Well, im really considering doing this mod to my 5.4, i just have couple of questions, when you cut the 2" piece of pvc and put it into the opening does it have to be perfectly tight againts the fender? Do i have to use any kind of sealent or anything like that? I work at farm&ranch supply store, and i get crazy discounts on pretty much everything, so i could probably spend less that 10$ on the coupler and piece of pvc, im just wondering if a 3" coupling would work instead of the pipe, probably not.

Anyways my second question is, is there any cons to this mod? Will it be lean/rich? Thanks again!

 

You want to seal the pipe going into the fender so it sits in there with no movement. Otherwise it will rattle and drive you nuts.

 

Ok, so after i get the pipe to fit perfectly, do i just tap it in the fender maybe 1/4" deep and leave it? (assuming it's flush with the outside) Or do i use some kind of a sealent?


Also, another big question would abs pipe work too? The main difference between abs and pvc is that pvc is used for sewage and abs for water, abs is also a little bit thicker on the outside, which would be more sturdy, however, i imagine that it's much easier to work with pvc than abs. So yeah if someone could tell me if that would work too, thank you

 

I used 3" (inside diameter, 3 1/2" od) black plastic ABS drain pipe, heated it over a gas burner to soften it, shaped it into the slight oval shape of the hole in the wheelwell, and pushed it into place while it was still hot. Tight fit, no rattle. The other end slips perfectly into the accordion section of the stock intake, no clamps necessary.

My truck is not here right now or I'd snap a pic. Sorry!