Howdy everyone. I've enjoyed the wealth of helpful info here, but this is my first post. So here goes...

Recently acquired a '01 4.0L XJ in great condition with about 160k miles on it. I've been going through changing fluids and doing maintenance to get a nice clean slate, and I can tell the previous owner took fairly good care of her (hey they may even be on these forums), but unfortunately it's got a lackluster aftermarket air intake installed. No heat shield or anything, just kinda plopped into the engine bay. See pic below...



So here's my conundrum: As you can see the elbow on the valve from the crankcase is cracked. I ordered a new grommet and elbow to replace, but I want to improve the whole air intake situation. Should I upgrade to a pretty good aftermarket air intake that would, at the very least, be better than this one (as well as come with a hose for the breather so I can lose the crummy little filter) OR try to get a stock air box back in there with a nice filter in it?

If the Jeep had come with the stock air box I'd probably be inclined to keep it and upgrade the filter. Just looking around though, buying a cold air intake from Rough Country or Spectre would only set me back $150 or so and be a pretty easy process. Even if I did manage to pull a stock air box, hardware, breather hose, etc from a junkyard and got a nice filter to put in there it seems like it would be only marginally cheaper than the aftermarket intake at the end of the day, and maybe even more expensive if I had to order all the parts online.

So what do y'all think? My main priorities are just normal engine performance and longevity, as well as MPG, I'm not necessarily looking to mod out everything just yet.

 

http://www.timbukthree4wd.com/

Have you called Timbukthree? They probably have a bunch of stock air intakes lying around. There's also a bunch on Ebay if you can't find one at the Junkyard.

 

That's not a cold air intake. That's a hot air intake. I'd lose it right now.

 

Honestly I doubt the xj cares wether it breaths hot or cold air.

 

Well, do some research on the topic, then.

 

I don't think it would make much of a difference seeing as the intake sets directly on top of the exhaust manifold. Nobody does the cowl intake expecting performance gains.

 

The issue is what temp the intake air starts out at.

 

I got the whole stock setup for mine at the junkyard for less than 30 bucks, so significantly cheaper than the aftermarket setups mentioned. The PO on mine did something similar to what you have, and I didn't really care for it. I don't notice any performance difference and feel a little more comfortable when I splash water up into my engine bay. Also, since I have hood vents, not worried so much about rain with it. I think having the shroud around the filter on the RC or Spectre setup helps a little with the heat going into the intake over what you currently have, but personally don't think it is as good as the stock setup. Just an opinion from someone who has had both.

 

I have a complete factory airbox out of a 96. Let me know if you want it.

 

I personally dont care for flat panel filter's seen to many fall through the box.i feel much better with a filter clamped on a tube.
My Cummins is drawing air from under the hood ramming it through the intercooler then down the intake it might only slightly care that its breathing under hood air but buy how much I dunno shel pull 20mpg and is running semi clean yanking a loud around.

The little 4.0 really doesnt care ease of maintenance and price of mind are all that matters. If the filter box is holding the filter securely then thts perfect.

 

While my jeep have some upgrades, i am not a big fan of changing what was engineered for the engine. That being said, my brother had gifted me a Rough Country cold air intake set up and was never installed until recently that i decided to install and.... oh boy... it makes a difference. Take off is like night and day, not sure how many but i also gain some horse power/performance wise. Now keep in mind, this is not my daily driver, it is a hobby truck and gets used once every couple of weeks so it might have increase gas consumption as well, not sure.
the bad, i disposed of the original filter box and related.

 

save your money for the new head