Engine/Transmission (1998.5 - 2002) Stock air-box intake horn question

[DThiel]

Is the flange supposed to be inside the airbox or not? The flange on my is on the outside.

 

[lsenus]

Inside. Otherwise you're just pulling unfiltered air into the system.

 

[keimmmo]

I assume you are talking about the short oval plastic tube that goes between the air box and the fender. If so, it goes on the outside of the box... between the box and fender. You can eliminate it and will gain a couple of hourse power and maybe a little fuel economy. You will hear the turbo just a little more under certain conditions without it.



I hope this helps.



Steve Keim

 

[Nate]

The flange goes on the inside of the box.



Unfiltered air? Nope... it's on the bottom of the box, that's where the air is sucked to go thru the filter.

 

[lsenus]

Oops, brain cramp. Not unfiltered, but underhood air is what I meant.

 

[Fireman Dave]

I think some of these were installed incorrectly from the factory. Mine was on the outside as well - didn't make sense. I put it back in the correct way. The flange on the one end goes inside the airbox, and the flange on the other end goes inside the hole in the fender well. So the air comes directly from outside the engine compartment and into the airbox with no gaps in between. It takes a little fanagling, but it does work that way. Once it's installed correctly, you can see that's the way it's supposed to be and it then makes sense.

 

[darkhorse]

Is the flange supposed to be inside the airbox or not? The flange on my is on the outside.

I found the tube to be an air restriction. Under hard acceleration I would pull the filter minder down even with a brand new AFE Pro 7 installed. Removing the tube & no more problems. As for the hot air issue, several folks on the TDR did a lot of temperature readings & found under hood temps were just a little above the ambient temp if you are moving forward with any speed.

 

[JERRYKAM]

As an FYI,



I recently installed a DIY cold air intake tube using 4" aluminum flex tube. The tube connects into the air box on the bottom using a flange. All parts were available from Home Depot.



Prior to routing the tube under the right side of the front bumper where conventional wisdom, and a very easy install dictates its placement I performed a couple of tests to determine if there was perhaps a better location that would take advantage of the ram air effect of the vehicles forward speed. There was only one other location that was a candidate and that was just above the front licence bracket between the bumper and the AC evaporator. What I discovered by measuring the pressure at both locations (30 and 60mph ) was that the ram effect pressure at the location above the licence bracket was twice that of the under bumper location.



With a bit of fabrication I assembled a scoop that fits in the opening above the bumper (just above the licence plate). This location provides cold air, at least as cold as its going to get.



To get some idea of the effectiveness of this DIY intake I performed a couple of tests. First with the new bumper intake closed off (all air coming from the factory inlet). Then one with the DIY intake open and the factory opening blocked and finally with both intakes open. Since my seat of the pants dyno could not detect any performance changes I shifted to a bit more objective method by measuring the air pressure (negative or positive) on the down side of the air filter (stock paper filter). I simply pulled the clean air filter indicator and used its port for my measurements. Air temperatures were not measured only pressures. Tests were performed at an altitude of 7000ft



Results:



For each of the test configurations driving at a steady 60mph the turbo intake was seeing essentially a neutral pressure Under these 60mph steady state conditions turbo boost was under 5psi, generally running around 2-3psi.



Next, I ran each test but this time starting at 60mph I excelerated just enough to produce a boost pressure of 10, 20 and 30psi. With these three levels of boost a larger flow of intake air was obviously being drawn in by the turbo. This is where I could see (measure) an improvement



The second configuration (stock air port blocked off) produced the best readings. The stock air filter was a significant obstruction to air flow but the ram air effect produced by the DIY air scoop located in the center above the bumper produced a measurable and repeatable positive effect.



Now with all that said, my measurements were made with a very sensitive instrument and the actual measurements were not dramatic. But never-the-less the improvement was in fact measureable. What the actual practical improvement would be in performance between the two intake locations is certainly up for debate.



If your up to it, try relocating your cold air intake to the above bumper location and see what if any improvement your seat of the pants dyno can measure. Mine can't tell the difference but the project was cheap, interesting and instructive.

 

[Boondocker]

Jerry,



Nice post. One question though, did you do your project on a 2nd gen Ram or your 2006? The 3rd gens have a better air box setup to begin with by virtue of it being forward near the grill rather than back by the firewall and turbo. I don't think your experiment would be so easy on a 2nd gen



Neil

 

[JERRYKAM]

3rd Gen, 2006 2500 Laramie, Auto, 4X4, CTD, 3. 73,

Factory Nav System, Sirius Satelite radio, Bluetooth cell phone connection; TX Temp, EGT, Boost gauges, 75Gal aux fuel tank. Quadzilla DXZCR2S