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Let it Breath!

Although it may sound like the opener for a wine commercial, it is about the TJ's 4.0L engine.  I was on my way to Death Valley (well, it was the weekend before I was leaving for a DV Jeep trip) and I knew my air filter was in need of replacement.  I had stopped by the local PepBoys and suffered sticker shock when I saw what an off-the-shelf TJ air cleaner was selling for.  Prior to that, I had kicked around the possibility of getting a K&N filter but due to the price, it didn't make it on my "Top 10" list.  After seeing the price of that filter in PepBoys, (and verifying it was not mis-marked), I decided a K&N was certainly the better choice.

So....I guess the story goes like "A funny thing happened on the way to 4x4 shop....".  I had heard some positive comments about the Airaid High Flow filter so I decided to give it a try.  The splash shield that covers the really large filter was one of the things I wanted if I was going with an after-market filter system.   The Airaid comes with one so I decided to give it a try.  I also opted to try the Poweraid spacer that bolts in between the throttle body and the intake manifold.   It claims to create more turbulent air flow, giving a better air-gas mix in the intakes.  I am not completely certain of this....but time will tell.  If I can sneak some gas mileage improvement out with this combination, I'll be happy.  Improved performance and better engine response will be frosting on the cake, as far as I am concerned.

The installation is a no-brainer.  Common hand tools, consisting of a couple of wrenches and small sockets (both SAE and metric) are used, along with a screwdriver.   I think that was all I got out of the toolbox for this project.  There is no splicing, cutting, or wiring involved, so it has to be easy!  Just follow the instructions and you shouldn't go wrong.  In a nutshell, you remove the stock air filter box from the TJ (3 bolts and a hose clamp).  It is replaced with the new filter and splash shield, using the new hardware.  As far as the Poweraid is concerned, remove the 4 bolts that secure the throttle body to the intake manifold.   Remove the old gasket.  Install the supplied gasket, the Poweraid, another supplied gasket, and then the throttle body.  Secure with the new hardware.   Install the 1" tall spacers under the cable bracket with the supplied hardware and you are done.  Check everything over twice to make sure nothing is binding, your cables move freely, etc.

The instructions for both the air cleaner and the Poweraid were adequate to get the job done.  I have a phone call in to their tech support concerning the Poweraid parts.  It includes a couple of bolts and two spacers to relocate the bracket that supports the end of the throttle and cruise control cables.  The odd thing is that my bracket mounts with 3 bolts, not the two that their instructions indicate.  Maybe the one they prototyped only had two?  I left them a message about the problem and I'll comment here after they call me back with a solution.  (always like to see how the customer support side of the world works in these companies).  The nice thing about it is that the company is in Scottsdale, AZ, which is across town from my place in Phoenix.  At least I don't have to worry about long distance charges (no 800 number provided either).

Here are a few pictures, after the install.  I would have snapped some of the components before I put them in but I was at my friend's house and did not take my digital along.  So, you'll have to put up with the "after" shots.


Airaid airfilter system - 1

The splash shield covers the sides and top of the filter and leaves the forward facing rubber end exposed.  An adapter is supplied to properly adapt the large air filter to the smaller stock air tube.  The fit is nice and snug and should provide a good seal.  The rigid adapter serves as an attachment point for two brackets that mount the filter assembly to two of the old airbox mounting holes.


Airaid airfilter system - 2

Another view of the air filter system.  You do not have to drill any new holes, but rather you recycle the ones from the old air box.


Airaid airfilter system - 3

Here is the Poweraid installed under the throttle body. 


Airaid airfilter system - 4

As you can see, there is not much too it.  It just slipped in under the rest of the parts.

Well, that is about it.  Time will tell just how much of an improvement any of this made.  I am certain that these add-ons would do better if I also replaced the exhaust system with a high-flow system as well.  One mod at a time for now!  Gosh...the gears and Detroits took a heavy toll already this year!

April 2000 - The Death Valley trip has come and gone and Moab is just two weeks away.  I checked my mileage on the way going to Death Valley using the first two fill ups.  One was 16.5 MPG and the other was 17.5 MPG.  So....17 MPG average was pretty good as far as I am concerned.   I had the back end of the TJ loaded with the usual stuff and was pulling my heavy duty custom made off-road trailer.  It is a 4'x6' trailer that runs on a pair of Goodyear Wrangler GSAs.  It was loaded heavy for the trip.  I was carrying 200 lbs of gas and 150 lbs of water.  I had about another 50 lbs of fire wood along and then my regular camping equipment, couple of coolers, tents, 20 lb. propane tank....well, you get the picture.  I ran about 55-60 MPH on that part of the trip.  All in all, I think the new air equipment is doing a pretty good job.  I've mentioned my results to others and they were quite impressed with 17 MPG on a Jeep with 4.56 gears and towing a trailer.

May 2000 - Moab has come and gone as well as several local AZ trips and last week's excursion into the Cinders off-road recreation area near Flagstaff, AZ.   Perhaps this last trip at the volcanoes was more of a test than the previous ones.   The major difference.....red-line on the 4.0 was hit on a few occasions while attempting to climb out of the craters.  Much of the driving was done at about 3000 - 4500 RPM.  You could really hear the engine gulping air.  I had never ran here before, so am unable to do a before and after comparison.  However, considering I was not running paddle tires, and I was running my 32" MTs, Lady made quite a showing for herself.  (not exactly the tire of choice for volcanic cinders). 

May 2001 - I had a chance last month to check my mileage while going to/from Moab, Utah.  My wife was with me and we had the back of the TJ packed pretty well....about as much as I would ever carry in it.  I checked the mileage on a stretch of highway in northern AZ....going both directions in hopes of canceling out any elevation changes that might make a difference if checked just one way.  I got 17 MPG going one way and 19 MPG going the other way.  So....18 MPG is the number I'll post here.  Now...considering Lady is turning 35"x12.5" tires with 4.56 gears....I can live with 18 MPG on the highway (speed was about 60~65 MPH).

Note:  The K&N filter has been removed.

My home made K&N filter pre-charger



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