DIY Ram Cold Air Intake on 3rd Gen CTD

[Diesel_Dave]

So I finally got my ram cold air intake all assembled on my Cummins. My design is "new", however, I borrowed heavily from two projects I saw over at Cumminsforum (AH64ID & turborep):
Home Deopt CAI on a 3rd Gen - Dodge Cummins Diesel Forum
How To Fab a Cold Air Intake from the Fog Lamp Hole - Dodge Cummins Diesel Forum

I liked AH64ID's modification of the stock air box with the toilet flange for an inexpensive, DIY cold air intake. I also liked turborep's idea of using the fog lamp hole to get some ram air. What I didn't like about turborep's setup, however, is that it made the fog lamp hole look very non-stock from the outside. I wasn't too crazy about the light dryer vent hose either.

I came up with the idea of using a roofing flange "boot" behind the existing fog lamp hole. These boots are the palstic rubber ones used in construction for when you send a pipe out the roof. It seals between the pipe with rubber and than has a plastic flange that fits underneath the shingles.

So, first off I took off the bumper to make it easier to work on. I suppose it might be possible to do it with the bumper still on the truck, but it's fairly easy to remove and it makes things a whiole lot easier to work on. I had to cut down the platic flange on the boot to get a good flat contact surface all the way around the hole. I then used RTV silicone to seal it against the bumper. Here's a view from the back side of the bumper:

and from the front side with the stock fog lamp hole grill off:

and with the grile back in place:

I did have to shave a little bit of plastic off the back of the grille to prevent it from contacting the boot, however, what I like is that it keeps thing looking pretty much stock.

Inside the airbox, mine looks pretty much just like AH64ID's does:

And here's the 3" PVC "downpipe" that connects the toilet flange to the boot:


I used two 45 deg elbows rather than one 90 deg elbow--that made it much easier to line the angles and offsets up properly. I also removed the stock plastic piece that hangs down in the way. turborep chose to saw a hole in it, but I chose to just take it out. If I ever want to go back to stock it doesn't have a hole sawed in it.

And here's the finished view from the outside:

I may end up getting some black PVC-compatible paint to spray the pipe so it's a little less conspicuous. It's really only visible now if you squat down and look directly through the fog lamp hole grille. Of course, I probably should have just gotten some black PVC pipe, but white is what I had lying around.

[MGB=MPG]

looks good . i also have a CAI exposed to frontal flow down on the chin fin , sure picks up a lot of bugs and road grime , im thinking about putting a low pressure drop prefilter there .
also intend to measure the overpressure encountered using a DIY manometer[U-Tube] .

theroretical overpressure at 55 MPH in freeair is one inch water , my initial measurement showed 2 inH20 at 55 MPH.
i intend to measure overpressure at the duct leading edge , in the pipe , before the engine air filter , after the engine air filter , and in the air box immediately before the carb velocity stack. , both with and w/o the prefilter. unless the pressure drop with the prefilter is outrageous i intend to run with it, i dont like all that road grime gumming up my k&N.

my first attempt used the corrugated alum. duct , the overpressures encountered blew that light weight pipe to bits .different stuff there now.

my inlet shown

[Diesel_Dave]

As far as grime, water, etc., I also got a test plug, that I think I'll keep in the glovebox. If it's wet or dusty I can just pull out the plug and cap off the end. My air filter is also due for a replacement before too long here anyway. I plan on keeping an eye on my filter. If too much junk gets to the filter, I'll just replace it an go back to stock.

[MGB=MPG]

the denser air charge is worth a lot , to me
i have some 1/2 inch thick washable loose woven filter material i use as prefilter on my house cold air returns. , no measurable pressure drop in that application.

[oil pan 4]

I love PVC too.

Ram air on diesels is great, I really missed mine when I started testing turbo intakes.

[slowmover]

I'll be looking forward to your regimen on testing as it should be the definitive statement about whether CAI is a help or no (by default, as others are more interested in peak [or, sustained] power output).

AH64ID is a prominent contributor on any number of well-researched changes on CTD boards, and always worth reading in contemplation of changes.

I decided against any CAI as the engine fan can pull a tremendous amount of dust into the air (vehicle solo), and any off road parking or driving, solo or in tandem with other vehicles, raises far too much dust for me to want to ever introduce more to the air box. Were I to use a CENTRI air pre-cleaner I'd want it above the level of the headlights, maybe recessed in the hood in some manner as with a NACA duct. But underhood plumbing then becomes a problem.

I don't travel off paved roads for any distance, but park the vehicle -- both at home and at work -- on unpaved surfaces.

The factory method of taking incoming air from fender interior panels means that much if not most dust has fallen out . . but fine dust on the air filter is a given.

I have seen where some have weighed the filters before and after as a "method" of trying to determine efficacy versus pressure drop.

This said, I hope you'll pull the flex boots both up and down stream of the turbocharger as a check for dust prior to prolonged testing.

- Are you using the revised MOPAR 4" deep pleated air filter in the otherwise unmodified airbox?

- Will other entry points to the air filter be sealed?

- Is the airbox "pressure drop" gauge still acting (takes little to damage them), and will it be used to help determine air filter service life?

- Will air temps at the filter be monitored?

- What do you think about induced turbulence . . where pressure at one area on the filter panel might be increased? Or [worse] at the edge seal?

- Ever looked at the TAG? Used ahead of the t/c generally, I wonder if it wouldn't have some upstream, not just downstream effects (probably too hard to quantify). Same for DPP Coolhose (see AH64ID and at linked site).

Comments online from those who design compressor housings/installations have favorable opinions about air flow turbulence "correction" (and design laws) such as the TAG (whether or not it is effective for a CTD; the TAG and Coolhose both on my list to try [more restrictive air flow on an '04 compared to factory improved 6.7L intakes]).

- Would you be averse to drilling some water drainage holes in the lower assembly? I have not yet ever seen an OEM cold air intake assembly without such.

Good looking work. Yeah, paint it.

.

[Diesel_Dave]

Originally Posted by slowmover

I'll be looking forward to your regimen on testing as it should be the definitive statement about whether CAI is a help or no (by default, as others are more interested in peak [or, sustained] power output).

Right now my plan is just to keep my normal commuting--no special testing, although this is one mod that should be fairly easy to do A-B-A testing on, as I have the plug that essentially "reverses" the mod.

As far as the benefit goes, I've seen enough scientific data to say that the lower pressure and temps both do give a benefit, the question is how much. I suspect it's fairly small. Based on the data I've seen, I'm guessing 1-2% or less. It's really hard to measure those kind of differences in real-world testing without advanced equiptment. If I did do A-B-A testing, I can hook up my OBDWiz software to monitor the intake temps.

I also suspect that this may be of slightly more benefit to me in terms of mileage than some others because I've blocked off my grille--my charge air cooler can't be as effective, and my underhood temps are higher as well. Anything I can do to get some cooler, fresher air should help. I've also given some thought to putting some heat wrap on the pipe from the air box to the compressor and the pipe from the charge air cooler to the intake to cut down on the re-heat.

Originally Posted by slowmover

I decided against any CAI as the engine fan can pull a tremendous amount of dust into the air (vehicle solo), and any off road parking or driving, solo or in tandem with other vehicles, raises far too much dust for me to want to ever introduce more to the air box. Were I to use a CENTRI air pre-cleaner I'd want it above the level of the headlights, maybe recessed in the hood in some manner as with a NACA duct. But underhood plumbing then becomes a problem.

I don't travel off paved roads for any distance, but park the vehicle -- both at home and at work -- on unpaved surfaces.

The factory method of taking incoming air from fender interior panels means that much if not most dust has fallen out . . but fine dust on the air filter is a given.

I have seen where some have weighed the filters before and after as a "method" of trying to determine efficacy versus pressure drop.

This said, I hope you'll pull the flex boots both up and down stream of the turbocharger as a check for dust prior to prolonged testing.

- Are you using the revised MOPAR 4" deep pleated air filter in the otherwise unmodified airbox?

Given what I know about where you drive, I don't think I'd recommend one for you. Dust, water, bugs, etc. plugging up my air filter is my biggest concern with this mod. I've heard of some people having some issues with this, but nobody can provide me with much info on what type of conditions they were driving in.

Right now I'm still using the air filter that was in the truck when I bought it. I assume it's the MOPAR filter, but I'll have to check. I've heard the WIX filters are pretty good, but I've still got to research what my next filter should be

Originally Posted by slowmover

- Will other entry points to the air filter be sealed?

For now, I've left the existing air box inlet as it was, although, I may see what happens if I block it off. I suspect if I closed it off, I'd have a disadvantage (at least in terms of pressure) when my vehicle speed is low--which it typically is . This is because the engine will now have to suck it up the pipe before the air box. So I left it open. The only way where I see that could be a disatvantage is when the vehicle speed is so high that there's so much ram air that the pre-filter airbox pressure is actually above atmospheric and the flow will go out the stock airboc entrance. Frankly, I think I'd really have to be moving fast for that to happen.

Originally Posted by slowmover

- Is the airbox "pressure drop" gauge still acting (takes little to damage them), and will it be used to help determine air filter service life?

- Will air temps at the filter be monitored?

By "pressure drop sensor", I assume you mean the "Filter Minder", or are you talking about the electronic ECM sensor? I do have a Filter Minder, but I'm not sure if it works--I've never seen it move at all. I may be able to pull the airbox temp with OBDWiz, but I'm not sure.

Originally Posted by slowmover

- What do you think about induced turbulence . . where pressure at one area on the filter panel might be increased? Or [worse] at the edge seal?

- Ever looked at the TAG? Used ahead of the t/c generally, I wonder if it wouldn't have some upstream, not just downstream effects (probably too hard to quantify). Same for DPP Coolhose (see AH64ID and at linked site).

Comments online from those who design compressor housings/installations have favorable opinions about air flow turbulence "correction" (and design laws) such as the TAG (whether or not it is effective for a CTD; the TAG and Coolhose both on my list to try [more restrictive air flow on an '04 compared to factory improved 6.7L intakes]).

- Would you be averse to drilling some water drainage holes in the lower assembly? I have not yet ever seen an OEM cold air intake assembly without such.

Good looking work. Yeah, paint it.

.

I don't expect any turbulence issues. Turbulence is an issue going into the compressor--not into the filter. I think whatever turbulence that goes into the filter will all get "washed out" as it passes through the filter. All the products that you mention are for pre-compressor, not pre-filter (I believe).

As far as water holes go, I'm just going to keep an eye on it and see how it does. There's a ~15" vertical rise from the fog lamp hole up to the filter, so unless there's a lot of water, I wouldn't think much would got all the way up...but I'll have to see. On my setup, it's also continuously "down-hill" towards the bumper, so the water should run out (if it's not being forced upwards). Frankly, I'm not sure how much help the holes do--if there's enough flow to carry the water up to the filter, then it's not going to fall down to exit through the holes.

[slowmover]

Water makes mud of dust is more the thought. Collects. Releases again and again that dust to the intake.

Screening for mud daubers, too, if you have them up there. Look at RV furnace screens for ideas.

The MOPAR filter is outstanding. Don't know who makes it but it is the one to have (unless you want to get tricky and try the Amsoil/Donaldson panel, or the AFE panel; both dry type).

As to "definitive" on CAI, well, that was a strong word. But no one else out there is testing purely for FE. And even if they were, again, none are as sensitive to changes would be my guess. A-B-A almost isn't needed. I agree it may not be large, but know with the heat problem contextualised I understand it.

Yes, couldn't think of name of filter minder. Most any strong alkaline cleaner will "cook" them, so many do not work after a few passes under a car wash wand. They are also a source of potential leaks (uncontrolled air).

Turbulence is a problem to the compressor, and the additional length of the "draw" if the box is sealed might change what the t/c sees under boost (was the thought).

[Diesel_Dave]

Originally Posted by slowmover

Screening for mud daubers, too, if you have them up there. Look at RV furnace screens for ideas.

I'd never heard them called "mud daubers" before, but we have a couple up here--and various other bugs. An idea that I came up with today is to cut out a piece of window screen and attach that to the top of the toilet flange. That won't help with dust, but will keep the bugs out of the filter.

Originally Posted by slowmover

The MOPAR filter is outstanding. Don't know who makes it but it is the one to have (unless you want to get tricky and try the Amsoil/Donaldson panel, or the AFE panel; both dry type).

I've done some research and, so far, have found a dissapointing about of hard data out there. Everybody seems to have their opinion, but I always try to find the hard data. I would have thought that micron ratings and pressure drops at rated flows, would be fairly easy to get a hold of. Unfortunately I haven't found any numbers yet, although I believe the specs are printed on the side of the Mopar filter. I know Fleetgaurd makes a filter too. I'm not sure whether it's the same as the Mopar branded filter (I don't think so). Fleetgaurd is now owned by Cummins--it's now called "Cummins Filtration" rather than Fleetgaurd, so I would think that's a good quality filter as well. I run their Stratapore lube filter which is, IMO, by far the best on the market.

[ron]

I dont know if this translates to Diesel but Ill add it. I installed a ram air intake on my 2003 toyota techoma the first drive I gained 4mpg from 21 to 25 at 65mph the next time the confuser had detected the lean condition and adjusted the fuel ratio.NOTE now when I drive at 35 mph the ram air will hold the speed at 35 with no throttle, nice for in town.