View Full Version : Air IntakeQuestion

June 1st, 2010, 09:56
I got a 2000 XJ 4.0L, pretty much all stock except for the lift i have on it, a few odds and ends, and a steering box brace. I am looking to start getting some more power out of the good old 4.0L. the first easy step is usually an air intake. I have had experience with air intakes before, and think they are a pretty good place to start.

I been trying to find research on the different brands. All the companies i know promise the world, but really they may not be all that good. And I cannot find any testing done on XJ's; only on wranglers.

I was wondering if their is an air intake out there that will benefit my cherokee and i was hoping i could hear some testamony from real Jeepers and not some magazine of company trying to blow its own horn.

the most promising one looks like the AEM Brute Force. But I am open to any and all ideas.

June 1st, 2010, 12:05
Most all of them are a joke. Take the $150+ dollars you will spend, and got get about $50 worth of supplies and you will see a world of benefit, instead of a pretty sticker.

I would search for the cowl relocation mod. This is the only one that will feasibly give you a cold air setup, and that is if you insulate the components well. It will also give you some protection against a hydrolock due to ingested water. It is for this reason alone that I will not use a cone style filter on an off road vehicle. One forced engine build is plenty.

The 4.0 is not a motor that can easily get power wrung out of it without going internal. You can bore the TB and get bigger injectors for a very slight gain. A new exhaust manifold/high flow cat/straight through style muffler will pick up a slight gain as well.

June 1st, 2010, 14:08
Yep search for homebrew intakes on NAXJA here and you ll find a lot of home made intakes of all shapes and sizes for usually under $50. Some PVC, a hacksaw, a couple of Hesco couplers, your' filter of choice and youll b in business. Ive made 3 of these types before on different vehicles. You wotn seea big power increase or anything but the "seat of the pants" meter can show positive results. The main difference is to rid yourself of that convuleted ductwork. Point is, search around, you can save a lot of $$

June 1st, 2010, 16:18
Do you have the 50 state emissions, i.e., the mini-CATs on the exhaust manifold?

Spend your money on a free-flow CAT-back system--the most bang for your buck. If that doesn't do it for you, you can build your own CAI for around $50.

Before spending any dollars, read this 4.0 Myths article by JP Mag: http://www.jpmagazine.com/techarticles/engine/154_0911_jeep_4_liter_engine_myth_busting_true_lie s/index.html

They aren't trying to sell anything in the article.