Air intake for a na

[DRP67207]

I was looking at this thread http://www.vwdiesel.net/forum/index.php?topic=5427.15  and am considering something similar for my truck. 

My question is this: With an intake routed to behind the grill, is there any reason to be worried about rain/snow getting sucked/driven into the intake?  It seems like people are keeping the stock filter element in the intake manifold.  Is this, combined with the bends in the intake piping leading to the manifold, enough to keep out moisture?  Am I just being overly cautious?  Thanks for any thoughts or experience in this matter.

[GEE-BEE]

You can use some CAT flex ducting from a metal flange to the intake

Aircraftspruce.com

http://www.aircraftspruce.com/catalog/appages/ductflanges.php

http://www.aircraftspruce.com/catalog/appages/cat.php

[VWCaddy]

I have a 45 elbow at the front end of the intake with the angle facing down.  The intake tubing runs uphill all the way to the engine which also helps.
Have not had any water issues over the years I ran it:
- http://www.4crawler.com/Diesel/CheapTricks/index.shtml#ColdAirIntake

[8v-of-fury]

While maintaining a stock paper filter, it is almost impervious to water droplets. You'd have to drive through a river in order to suck up enough water to matter.

[R.O.R-2.0]

While maintaining a stock paper filter, it is almost impervious to water droplets. You'd have to drive through a river in order to suck up enough water to matter.

i call BS on this.. here in oregon, it rains hard enough to completely soak a paper filter..

it rains so hard, that you can feel the car losing power.

doesnt rain hard enough to hydro lock the engine going down the road, but it cant be great for a diesel to be sucking up that much water?

[8v-of-fury]

I'm on my phone where does the OP live?

Also if your engine doesn't hydrolock then your paper filter did its job. It didn't let any water passed it. However enough to soak it will prevent air flow, the colder denser air when it rains is actually a ton better for performance.

[R.O.R-2.0]

no, it sucks water thru the filter.. diesels make an aweful lot of vacuum.. the air enters the filter box.. wheres the water gonna go? back out the tube it came in? no..

its going out the tail pipe..

yea, 3.5" of rain in one day, its gonna suck up water, and soak your filter element.

[8v-of-fury]

I think it was either Andrew or Vince that I was talking to on this subject when I made my 3" intake.. They said 1cc of water is enough to raise your compression ratio to like 55:1 and is right on the brim of a bent rod. A water drop could be detrimental.

However a mist or small small drop may be tolerated.

[R.O.R-2.0]

how many times do you see a drop of water that is 1cm x 1cm x 1cm? a CC is just that, a cubic centimeter.

thats quite a bit of water when the combustion chamber is like 26cc's or something like that.

when it passes thru the air filter, its going to be released as a mist anyways. liquid does not pass thru an air filter as a stream, but more of a mist or spray.

[8v-of-fury]

good, so you living in the wettest state, and not having any problems.. The OP will be fine where he is with water problems.

[DRP67207]

Thanks for the discussion.  Yeah, I'm in the Northeast, so usually nowhere near the amounts of rain that you all see in the Northwest, although I am planning a cross-country ramble in this truck (hence the preparations and once over I'm giving her), so she will be seeing an assortment of climates.  I don't want to compromise the intake for a slight boost in performance/efficiency. 

I've seen discussion of hydrolock on gassers with cold air intakes and cone filters down near the bumper, but  seems like a lot of concern about it, but not actually a frequent occurrence.  What is the real danger of a mist of water entering the intake?  What would the effect of this be on the engine?

[R.O.R-2.0]

pull air from beside the grille, or somewhere like that..

not from down low, thats how they suck up water..

[DRP67207]

I'm planning to build a scoop for behind the grill, between the radiator and the passenger side headlight.  Should be okay, I'll post up some pictures and results when I finish it up.

[damac]

Just curious why I don't see any cowl air intake systems on these cars? 

They are popular for my old f250, I am about to install one.  Only thing it says is to unhook during snow.  Maybe the truck has allot more room in the cowl area as if you keep the drains free water could collect and still be below the lower side of the cowl hole.

[mystery3]

Just curious why I don't see any cowl air intake systems on these cars? 

They are popular for my old f250, I am about to install one.  Only thing it says is to unhook during snow.  Maybe the truck has allot more room in the cowl area as if you keep the drains free water could collect and still be below the lower side of the cowl hole.

On mkI cars there is not much room for a large filter up there, never really poked around enough or measured a mkII. I've thought about putting a long narrow ic in the rain tray but I'd have to buy the ic and I already have a couple small squarish ones around.