I have been through so many air intake / filter box posts and I still can't figure this out.

Is the restriction of airflow in the air inlet side of the airbox?
Is the restriction of airflow in the air filter media itself?
Is the restriction of airflow in the air tube from the filter box to the turbo inlet?

I know each may be restrictive in its own way, but if the box is drilled out on the bottom, a better stock fitting filter is used and a new inlet tube installed. How far off from the big dollar filter kits is are airflow numbers?

 

All of the above!

 

IF you are talking about a stock intake and filter the restriction lies with the filtration media/filter.

I don't think it flows enough to support a healthy truck.

Put a huge cone type filter at the end of that tube or any combination of tubes and you will feel an instant seat of the pants increase in throttle response.

 

I believe from everything I've read, including responses from Fleetguard engineers, that the greatest single restriction is the air box design itself. The designers used whatever space they had left to shoehorn a box into and got the largest panel filter that would fit into the box. They are both a compromise in my opinion.

The oem filter probably flows well enough for a stock truck (but doesn't filter as good a BHAF for instance). In any attempt to get a better flow, you would want to address the filter and housing a complete unit.

 

sled4fun,

It's the ole where's the potatoe theory. If you fix one place then hte next worst place is the next problem to fix, so Dodgezilla is right the whole thing is the problem. Get yourself a AFE Stage II Pro Gauad 7 intake and you'll see lower EGT's, better spool up on the turbo and lots of folks see MPG gains too.

Mark @ DPPI

 

NO DOUBT ABOUT IT. THE BIGGEST RESTRICTION IS THE AIRBOX.

I put a vacuum gauge in the hole where the filter minder connects.
(its a Stewart Warner part number 82384) It is actually called a air resistance gauge. I ran a vacuum line into the cab so I could see it while driving. My conclusion. There is nothing wrong with the stock filter in a stock or NEAR stock truck. There is however a serious problem with the airbox..

I took a small drill bit, and drilled a bunch (i would guess over a hundred) little holes in the bottom of the air box. If I had it to do all over, I would remove the whole bottom of the box and replace it with a piece of screen.

 

During my discussions with an engineer at Cummins, I was politely told that Dodge made the airbox to fit the truck, not the engine. He then added..."they made it so it would marginally get by on a stock truck with next to no load Why do you think they changed it on the Post January 1/04 trucks?"

Although he could not endorse aftermarket filters, he did say that most anything out there is an improvement but he also felt that the square box for a square box negates some of the benefits we would be trying to acheive.



Scotty

 

While I agree that the box itself is restrictive, I also feel that the media element is a big contender. If you have a filter that flows up to 600 scfm @ 1.5" of H2O vs. a filter that flows 400 scfm @ .5" of H2O, then, IMHO (I could be wrong), the 400 scfm filter would be better. Is my way of thinking wrong? It just seems that, even though the filter is rated at a higher flow, it would be better if the motor didn't have to work as hard to get it. Maybe I'm just talking out my ****!!

 

By drilling several small holes in the bottom as mentioned by Ray ( I do not know how to quote) did this improve throttle response? Would muck get in there during rainy weather? Thanks

 

That's how you quote . You just press the "quote" tab on the bottom of whoever's reply you want to quote. It's right next to the edit tab.

 

Thanks, now I know

Can you help on the other question?

 

Don't really know for sure. I have yet to drill mine. It would seem to make sense...some say it works, some say it doesn't. As far as crap getting in there, I've heard some guys are putting some sort of screen on the bottom of the box to keep the big stuff out and that they've never had a problem with water/mud. But...this is just what I've heard/read.

 

cool, thanks for the info, I think I'm gonna try it, if it works cool, if not than one more reason to trash it for a stage II

 

I drilled a bunch of 1" holes in the bottom of my airbox and it may have helped A TINY BIT but not good enough IMO. I am trying to decide what intake to get. I think I may be leaning towards the Scotty V but I'm really not sure yet.