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Kerndone 10-10-2006 06:19 PM

Write-up for a Hummer cold air intake
Ok, here’s my version of the Hummer cold air intake…I know its been getting more popular and the “unique-ness” of the mod may start taking a hit, but I think it looks great, its functional, and it was cost effective as well. I got the pieces put together over a two week span and then went to town. BTW, this is what I did and I will not take responsibility for anyone not measuring correctly and cutting holes in the wrong spot or causing any other kind of damage to his or her rig. Nor can I speak for the changes of the TJ throughout the years. Mine is finished and I hit a few bumps along the way, but it’s sealed up and it appears to be working just fine. So, with that in mind, here’s a rough estimate and parts breakdown:

-Hummer intake cap: $32 shipped (ebay)
-Buick (3.3L V6) airbox: $10 (u-pull-it yard)
-Plumbing reducer bushing: $4 (Home Depot)
-Plumbing flange: $2 (Home Depot)
-Nuts, bolts, and miscellaneous items: $10 (all stainless hardware from Lowe’s)
-Flexible 3” ricer air tube: $20 (Autozone)
-Paper air filter: $7 (Autozone)

I opted to use a buick airbox as it has been used previously by fellow jeepers. Not to mention I think it gives it a clean look under the hood. The negatives to this route are you will need to remove the airbox to change all the plugs and you will need to “route” the dipstick when checking your oil and your trans fluid. Oh well, I’ll survive. BTW, here’s some reading on that mod…

JU thread 1
JU thread 2

Ok, on to my airbox install; I’ll explain what I did and then rapid fire some pics. I removed the old airbox and cut the intake tube. I used a 3” to 2” rubber bushing to connect the intake to the new box. The problem was I needed to whittle down the i.d. of the busing since the Jeep’s intake tube is roughly 2 5/8. After that, I did a test fitting with the box and got some scrap metal for a bracket.

For the bracket I opened up the bottom end and attached that to the motor mount. I twisted and bent it with some pliers so everything would line up.

The next step was cutting through the firewall. I measured twice and cut once. You can see how close I got to the ground! Like I said, measure TWICE and cut ONCE!

Ok, at this point you can run some flex tubing into the cowl for cooler air and call it a day. If you choose to do so, it will look something like this under the hood.

I wasn’t done yet, but this first part concludes the “Buick cold air intake” portion of the write-up.

Kerndone 10-10-2006 06:19 PM

Alright, so you want to do the Hummer intake…well there are some things in the cowl you will need to take care. WARNING!!!! THIS WILL BE A TIGHT FIT TO GET THE INTAKE TOWARDS THE EDGE. I had to apply some pressure to get the cowl cover attached and screwed in.

Back to the write-up…the A/C/Heater intake is right under the cowl where you need to cut the hole. Now you can just mount the intake closer to the middle, but I think it looks cleaner at the end of the cowl. So you will need to remove this cover and discard it (research tells me that this piece isn’t on A/C equipped TJs until 1999) or do something like I did. So here it goes…

This is the pic of the cover. I wasn’t going to let that stop me, so I measured a few times and cut a hole in the cowl cover quickly with a 4” hole saw.

I then trimmed up the plumbing flange and test fit that in the cowl cover.

I trimmed up the fresh air intake and then test fit the flex tubing as you can see in this next pic.

I then used the dremel to cut trim the black cover so I could re-install that and keep water out of the A/C/Heater unit. I opted to use it since DC designed it and started using it, there must be a reason. To make my “new” cover, I used some aluminum air duct (thanks for the idea Dad) to close it up. I riveted that in place and sealed it with silicone so it would stay water tight. In the next three pics you can see how I trimmed the cover, closed it with the air duct and finally how the flex tube sits next to it.

Kerndone 10-10-2006 06:20 PM

So, I have it all ready to go. I chose to use some nylon spacers, trimmed to account for the bend in the cowl cover, in order to level the plumbing flange. The end of the cowl cover slopes down, so the inside edge needs to be a little further down. I also clearanced the right edge of the flange so the tube would have some space after the bend. To attach the flange to the cowl, I purchased some stainless bolts and 4 stainless acorn nuts. I drilled the holes through the cowl cover, sealed them up with silicone and bolted it all together. Now, to explain myself a bit more, the flange I picked up is 4” O.D. so I needed a small piece of 4” I.D. PVC to connect the Hummer intake cap to the flange. You can see that small section I used in the pic, it’s actually ABS and I decided to leave it black.

In the subsequent pictures, I am just showing the 3” flex tube coming through the flange. I have not added the ABS “collar.”

Ok, I will say this again; the cowl cover does not fit as nice anymore. It’s pretty cramped in the corner since the cover slopes down and the cowl slopes up. No to mention the flex tube needs to make a 90 degree bend in that area. I was able to press the cowl in place with just enough force to make me comfortable with the clearance I have. There is no doubt the flex tubing has deformed a bit and the cowl cover is slight bulged at the corner. This isn’t noticeable, nor does it concern me. I just want everyone to know that there is not any extra room…in fact, IMO there isn’t enough room, but you can make it work with a little effort!

Finally, I trimmed the ABS “collar” to lay flat over the flange and I then drilled a hole through the ABS and the flange, inserted a threaded tee nut from the back and used an allen head screw to prevent anyone from just walking off with it. I haven’t yet installed the hose clap on the intake cap, but I have some time to do that.

Oh, and I measured twice and cut once…check out this clearance (I got a little lucky I think)!

Kerndone 10-10-2006 06:22 PM

Phew, there it is...a pretty complete write-up. Once again, these are the steps I went through to install my version of a Hummer CAI. I choose to call it a CAI rather than a snorkel because I am not a commander of a submarine. However, if I really want, I can run a longer length of ABS and raise the intake cap a couple feet from the hood. Either way, its higher than stock and its colder air for the engine. Feel free to critique this mod and ask any questions you may have. I'll browse through this later and make any corrections as needed. If I did miss something just let me know.

Oh, with the design of the Hummer intake, the change in the direction of the air and maybe even the flexible tubing, there is a new sound when you really get on the throttle. IMO its a "fun" sound and I'd rather hear that than a loud exhaust.


Grubbi 10-10-2006 06:46 PM

That looks like a nice clean install, Good Job!

olds442 10-10-2006 06:53 PM

wow, great great job that looks awesome. i mean really nice job

SecondTJ 10-10-2006 06:55 PM

that looks great! nice job and write up. now only if i had the guts to cut the metal holes

cavtrooper 10-10-2006 07:12 PM

i like this mod!!

GPER 10-11-2006 02:45 AM

I like that one and maybe carry an extention ofr deeper water. Does the hood hit the top when you lay the hood back against the wind shield????:thumbsup:

Kerndone 10-11-2006 08:57 AM


Originally Posted by GPER
Does the hood hit the top when you lay the hood back against the wind shield????:thumbsup:

Nope, that last pic is showing just how close it gets, but it doesn't touch. I measured for a little clearance, but it wasn't supposed to be that close. As long as it didn't hit when I opened the hood all the way, I was happy.

GPER 10-20-2006 01:27 PM

I finished up my plenium to to fit on my carb today.
I have a TJ air box so I'll see if I have enough room for it. Precleaners are hard to find if nothing else I'll go to a CAT dealer. Couldn't find any on E-bay or at Tractor Supply

Muddeprived 10-21-2006 02:09 PM

Hey how wide is that hummer intake cap? is there anything out there we can use instead? I have a 4" pvc cap on my snorkel but it's kinda small. I would like something the size of the cap you used.

GPER 10-21-2006 04:37 PM
This is about all I have found so far I stopped into Tractor Supply and they had nothing. So that leaves my a John Deer dealer or a CAT dealer I haven't found a place to get the Centri's yet.

Kerndone 10-21-2006 09:33 PM


Originally Posted by Muddeprived
Hey how wide is that hummer intake cap? is there anything out there we can use instead? I have a 4" pvc cap on my snorkel but it's kinda small. I would like something the size of the cap you used.

The hummer cap is about 8" in diameter and 2" tall (not including the mounting flange).

Muddeprived 10-22-2006 03:05 AM


Originally Posted by Kerndone
The hummer cap is about 8" in diameter and 2" tall (not including the mounting flange).


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