Redundant Emmisions System.

[LibertyOrDeath]

I was looking around and I saw that Liberty's have 2 mini catalytic converters in addition to the main cat. Am I reading this right or is this just a model year issue, if so which years? If my 2006 has those extra cats can I legally remove them?

 

[VTNomad]

Cat's

Legally, you probably can't remove them. So long as you live in a state that doesn't have emissions tests, who's gonna know? Cat's aren't cheap, so I can't imagine them not being on there for a good reason.

I'm not sure exactly what's on our Jeeps, but there are a couple of different types of catalytic converters. There is a 2-wat cat, that converts carbon monoxide to carbon dioxide, and unburnt hydrocarbons to carbon dioxide and water. A 3-wat cat does what a 2-way cat does, but also converts NOx's to N2 and O2. Maybe the main cat is a 2-way, and the "supplemental" cat's are for NOx's.

 

[LibertyOrDeath]

Anybody out there have the ability to decode these. I am not familiar with electronics. I do have a Sawzall with a metal cutting blade.

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[JeepJeepster]

No, the 06 liberty doesnt have 3 cats from what I know. Only the 02(and maybe some 03's) have 3 cats.

Yours has one on each bank with an O2 sensor before and after each. Im not sure why you would want to remove either.

 

[LibertyOrDeath]

Because gas is rapidly approaching $4 per gallon and I would like to squeeze as much mileage out of my Jeep as possible. Since there is a cat on each bank I doubt I will be doing that.

 

[JeepJeepster]

Most stock cats are fairly free flowing so taking them off wont benefit the fines if you get caught. Its a couple grand per cat I believe.

A muffler, intake(drop in K&N or amsoil is fine), and fastman throttle body will help the mpg 'a little,' but will also give you alittle more pep. If you look at it from a performance stand point them the cost of those products equal out since you are getting them for a HP gain and not a mpg gain. It amazes me some people spend $300 on a CAI just to try and boost the mpg a little. It would take so long to save $300 on gas you could just put that $300 towards gas.

 

[05kj6spd]

Use good quality gas, don't be a lead-foot and a good cold air intake will help some.

 

[tjkj2002]

Because gas is rapidly approaching $4 per gallon and I would like to squeeze as much mileage out of my Jeep as possible. Since there is a cat on each bank I doubt I will be doing that.

You take those cat's off and your gas mileage will go down the tubes,you will never get out of "closed loop" programing which is a preset program for a richer running setting till your KJ warms up and the O2 sensors start working(which doesn't happen till they reach 600 degrees).When your O2 sensors start working you go into "open loop",which means the PCM adjusts the fuel/air ratio depending on what the O2 sensors are reading before/after the cat's,which gives better mpg's.Use good fuel,change the fuel filter,change the O2 sensors and your mpg's will stay put(or get better).You bought a Jeep,it's not going to get good mpg's,sorry but if you want better mpg's get something else that is very much less capable then the KJ.Once you atart getting worse mpg's then me then you can start complaining,I get about 10mpg right now,in perfect running condition.

Newer cat's are made by company's like DynoMax so they are pretty free flowing(OEM ones).You want the ultimate free flowing cat's find some Viper cat's,they are boarder line for being legal.


Oh and it's a $2500 fine per cat removed from your vehicle,that's also a federal fine.

 

[LibertyOrDeath]

MPG is a minor issue. I was mainly just trying to find an easy way to recover MPG and power lost due to lift and bigger tires; however, it sounds a lot easier (and potentially cheaper) just to get 4.10 gears and upgrade the exhaust.

 

[tan's2002kjlimited]

You bought a Jeep,it's not going to get good mpg's,sorry but if you want better mpg's get something else that is very much less capable then the KJ.Once you start getting worse mpg's then me then you can start complaining,I get about 10mpg right now,in perfect running condition.

And I whine about 15 MPG. 10, that's what I was getting with a bad O2 sensor.

 

[VTNomad]

MPG's

There is no cheap way to increase mpg's. The 3.7L is pretty efficient as is. The best ways to increase mpg's are to reduce weight, improve aerodynamics and reduce rolling resistance.

Go on a diet, rip out your interior, lower your Jeep, coat it in teflon and put some slicks on the ground, and you'll be good to go.