blwnsmke

I am fixing to build my own intake horn because I have seen many people build theres and it looks good and Im sure it still picks up hp over the stock on.. I just can't quite spend 400 on a cfm when I can build one for cheap.. Well my question is the piping size.. Should I get (2) 3.5" 90 degree elbows and make it all 3.5 inch or do you think I would notice more hp if I were to come off the base with a 3inch pipe and flare it into 4inch and then back into 3inch going into the intercooler boot? Just seems like the cfm and all aftermarket ones are large in the middle and then shrink down when they meet the intercooler boot..

Billm2004

take a look at glacier diesel's intake. the pro flow i think it is. its around $250 i believe. im thinking of getting that one, only cuz they dont recommend the cfm with nitrous, cuz of possible intake backfire and whatnot.

blwnsmke

Looks like its all just 3.5" I was curious if 3.5" would fit into the intercooler boot also..

OldSmokey

Isnt it just 3 inch Im thinking of doing this too

Billm2004

that im not sure of. i havent really tried to do that.

OldSmokey

Here is a link to a post i made earlier

https://www.dieseltruckresource.com/...omemade+intake

blwnsmke

I was thinking of using 3.5" and right before it gets to the intercooler boot downsize to 3" so it will fit into the boot.. Wonder how much of a gain in hp something like this would make over stock and vs say a cfm?

C Schomer

Mine is in my avatar. I used 3.5" (my old 3.5" downpipe). The circumference is 11" - exactly the same as the inside of the flange I made. A little heater and hammering and it fit into the flange. Then a 3" beaded end from an old leftover CAC pipe to fit the rubber boot. I wouldn't do 3 then 4 then 3. Craig

OldSmokey

Craig do you have any bigger pics of yours. Did you use a pipe bender?

C Schomer

I don't know how to post a link but you can do a search on c schomer and go back to mid Jan 08 to my post "MPG is up with the airhorn". Scroll down to #19 - ah64id posted my airhorn for me and #20 is my air filters. I laid out a pattern and cut segments from straight pipe and welded them together. I was a tinner in a past life. Craig

stock600

Good thread guys, i also fixing to build my own. On my poject i will not be using a intercooler, so i plan on comming off the turbo above the valve covers and splitting it with a 3" wye and hitting the manifold with 2 rather than one pipe. Has any one else seen this done, i know Backs does something simular but thier comes from the other diection due to the use of a intercooler. I believe i theory there will be power to be founf doing this, anyone????

OldSmokey

Here is the thread.
https://www.dieseltruckresource.com/...airhorn&page=2