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
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".
Linear Mode
