OK - I've been reading about the "Gotts" approach to a CAI mod long enough that I decided to try it. Here's what I did - and I take no credit at all for any of this, it was just my implementation of the excellent ideas put out by people that came before me.

In the 2004-2008 trucks, the intake snorkel has only a 2" diameter at the end where it goes into the fender well. Other than that, it's a Cold Air Intake - so, the goal is to increase the intake opening.

We start with the intake ducting. Remove the hold down screw (red circle) in the picture below using a 10mm socket and pull the snorkel out of the fender wall (red arrow). Once you do that, you can pull the duct away from the filter box. It will make a lot of noise that sounds like something is breaking - just smile and ignore the bad sounds. You can also ignore the dirty fender wall in this picture - it just shows my truck is actually used and is not a "Garage Queen".



Now that you've got the intake duct out, turn it over and you'll see two rectangular "bumps" at each end of the bellows that look like they might be "release tabs". Some people have said they can pry the parts apart here using a screwdriver. I was not able to do this, but I found they sit over raised areas on the inside tube that act sort of like "tire irons" to separate the bellows from the other parts of the ducting if you twist and pull on the part you want to remove. I separated the bellows from the duct using the circled "bump" in the picture below. (Notice I like to work on the tailgate of my truck). :o



To do this, I put the duct and bellows between my knees and then twisted the snorkel (where I'm holding it with one hand) all the way around, and it comes right off. (I had to use two hands to do this, but in the picture, one hand was holding the camera).



Now that the pieces are apart, compare the 2" flared opening of the snorkel that fits inside the fender with the over 3" opening of the duct at the bellows and you see why the engine might have trouble getting enough air at WOT.



I went to Home Depot and bought a 2 ft length of 3" ABS pipe and a 3" stainless hose clamp. I wanted to make sure my new duct went into the fender as far as the original snorkel, so I marked my new 3" tube with a white line to match the gasket position.



Now we have a complication. The hole in the fender is an oval, about 3 1/8" high by 3 1/2" wide. There's actually a small "lip" inside this oval too and I got rid of that lip with a Dremel grinding wheel. The resultant hole is now closer to 3 1/4" high and 3 1/2" wide. (Again, ignore the dirty fender wall). :o



The hardest part: I had to reshape the end of my new snorkel tube back to the white line to match the 3 1/4 x 3 1/2 oval opening. I used a "Mouse" sander, pictured here with the end of the tube that I shaped.



(Continued in Part 2)

- Jack

 

Here's the finished tube, looking straight down the intake end. The outer surface is cut down so it will just fit into the fender opening and is a 3 1/4" x 3 1/2" oval. The inside opening is a true 3" circular intake.



The new snorkel tube will have to be angled slightly from the rest of the intake to fit into the fender properly. (It needs to enter the fender at close to a right angle), so, the other end of the tube was cut at an angle try to match the truck's tube opening angle. The length of the new snorkel on the long side is 10 5/8". The length of the short side is 10 3/8". (It's about the same length now as the original snorkel). The hose clamp will be used to stabilize things.



I put my new snorkel into the fender (at a right angle) and it goes in right up to the line where I stopped shaping it. It's actually through the second hole in the inside of the fender at this point. It fits quite tightly through the opening, so I'm not worried about it getting "warm" engine air. Then, I slipped the bellows down over it. (Hey, I wiped my fender wall off a bit)!



After the trial fitting, I painted the new snorkel flat black to cover up the ugly scratches and painted the hose clamp too (for "stealth" purposes). So, here we are - the final "All Black" (apologies to the New Zealand Rugby team) version of my homemade CAI:



I compressed the bellows pretty much to give it some room to expand under engine torque and not pull the tube out of the fender wall. I noticed that earlier, when I had slid the bellows down the tube farther, it had pulled the tube out about 1/2 inch after a hard acceleration (because the engine twists away from the fender wall in this state).

Another view:



It's a fairly neat assembly, and even though the airflow curve is not as "smooth" as I'd like, I think it directs the flow fairly well. Best of all, the total cost was under $8.00. ($0.99 for the hose clamp and about $6.50 for the ABS pipe). And, it's something that is completely reversible if desired. The new snorkel can be taken off and the original put back in and no one will be the wiser.

And here's a final view - it looks almost "stock", even though it's anything but stock:




Now, some final thoughts:

Because the cross-sectional area of the snorkel varies with the square of the radius, the new snorkel has an opening that is about 7.07 square inches compared to just 3.14 square inches for the original snorkel. That's over twice the intake capacity!

Since the modification does not change the environment of the MAF sensor above the air filter, it will not be "fooled" and there is no danger of the engine running lean.

There is no "drone" with this CAI.

While some people have recommended disconnecting the battery so the PCM can "relearn" the new system, there's really nothing for it to learn. In fact, here is a quote from Bill Cohron at Power Hungry Performance: "Don't bother with the battery. There's really no reason to mess with it when doing the snorkel mod. All that's really happening is that the modest restriction is being alleviated allowing a little more flow at higher RPM. However, this mod DOES NOT AFFECT the Mass Airflow Sensor and doesn't significantly change AFR like a CAI does. The MAF sensor still accurately reflects the airflow into the engine and the computer handles everything from there."

I hope this writeup can be useful if you decide to try it yourself.

- Jack

 

Sexy hand you got their Mr.Jack!

 

For those of you that are lazy like me you can just remove the tube that run's into the fender well and it add's a noticable increase in power and better throttle response. With this setup my IAT's ran about the same as the outside temperature except when setting still idiling. I also got a jig saw and cut the muffler's off which improved the under hood appearance.

 

LMAO!!! MUFFLERS?! Oh jeez, you brightened my friday!

 

So is that how you get it off? (in-between your legs and wiggle it back and forth?)

 

nice retake just may try this my self this weakend. thanks jack

 

Everytime I try to describe them I can't think of the correct name so I just call them muffler's. Which is sorta what they are. They help to keep intake noise down. Hopefully it will make your saturday and sunday worthwhile also.

 

I think "resonators" might be the correct name.

Here in Arizona, we regularly get above 100 degrees in the Summer. I wanted the actual air inlet as far as possible from the engine compartment.

- Jack

 

Intake silencer is what I always called it.

 

How about "Smooth Airflow Interrupters" or maybe "Power Inhibitors"?

 

If PHP's dyno runs are believable, then they really do very little to inhibit. Bill removed the snorkle on a stock intake and on the dyno, it performed very close to the same level as an aftermarket CAI.

 

That's some nice work!

 

So JandJ, hows the improvement power/throttle response wise? I might try this some weekend when I have free time.

 

Yea i've run a couple 0-60 and quarter mile time's with my edge since installing my aftermarket intake. It's hard to compare the time's since they weren't done on the same day's but the time's ran with the AEM are almost identical to the one's ran with the modified stock intake. The difference is about a tenth of a second quicker with the AEM. I did have a flat spot at 3,500 rpm's before and it's gone now with the AEM. Also the powerband seem's to be a little broader with the AEM. For the cost of an aftermarket intake to alot of people it may not be worth the money. I like the sound of mine and the look's good so I think it's worth buying. Also for clarification these run's were made with the Edge programmer on level 1.