Hey all,

Looking at getting some more power and betting gas mileage out of the KJ and was wondering what you would do first? K&N Cold Air Intake or replacing the stock muffler with a free flowing one? I will probably do both eventually but want to do one or the other for now. The main thing I'm looking for is more power and possibly better MPG.

Thanks
Ryan

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04 Liberty Sport 4x4;
3.7L V-6
Amsoil Filter
Rusty's 2.5in Lift
Lund Air Deflector
Hella 500 Series Lights (6)
Sirius Sat. Radio; Garmin GPS System
Amer. Racing ATX Chamber w/Teflon; Goodyear Wrangler Silent Armor 265/70/16

It's been tried before and documented in magazine articles. There isn't much to get, if at all, with either or together. We already have a decent system it appears.
Last article I saw was in 4WD & SUV magazine maybe 5 months ago.
Same with the diesels, one company tried to make a kit, but they weren't gaining anything.

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No one knows as much as all of us.

The first thing I did went I bought my '02 Sport 4x4 beside putting in AMSOIL from bumper to bumper had a MagnaFlo
Muffler installed, I then got a K&N stock style Air filter after a year and no noticable improvement in mileage I replaced the K&N with an AMSOIL stock style air filter. After talking to many at L.O.S.T. . As I said no milage improvement but it does sound real Good . Any way don't waste your money on a K&N the Amsoil is superior. and about half the cost. Then if your looking for better gas milage spend the money on synthetic Oil. I've used Amsoil for about 30 years. Yes I am that old.

LEAD FOLLOW or GET OUT of THE WAY

The K&N dirt funnel systems do not draw in any more cold air than a factory system. They draw their air from under hood w/ no provision to draw it in from a cool source. The factory intake/filter flows more than enough for a 3.7L and is the same size as used on larger engines and it draws it from the leading edge of the hood. Search around and you will find a couple people that have added an additional fresh air inlet to the factory air box and they report good results from it.

I didn't notice a huge performance or mileage improvement w/ the Flowmaster mufflers I have installed on all my Jeeps but I do like the sound and they hold up much better in the rocks I wheel so they were worth the expense. The factory pipes are big enough for the 3.7L.

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99 TJ
71 C101
04 KJ
03 SFA KJ Sport
LOST JEEPS So-Cal

Or in otherwords, the stock Liberty is about as good as it gets. Most of those add ons are a waste of money until you start talking about things like: head modifications, cams, headers, superchargers [or turbo / or nitrous] and such... Then different air intakes and mufflers acutally do some good in terms of air flow


The muffler will change the sound - it will not give you a significnat MPG increase

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02 Liberty Limited
Silver Outside & Taupe Inside
Heated Seats, Sunroof & Infinity speakers
USA Spec I-Pod adaptor, Mopar Sub, Garmin GPS
Tow Package, Select-Trac
Rock Rails, Tow Hooks

The stock muffler is very restrictive so you would get a small amount of power MPG gain, BUT with any engine the size we have it will not be that much. If you look at it in terms of dollars -vs- savings in mileage well its not much. Main reason is sound, and Flowmaster, Flo Pros (like I have) are made to be stronger and last longer. To those that want to go to a full cat back system they are just changing out one 2.5 inch tailpipe for another one, a waste of money. Same location, same size pipe, maybe a 10 dollar chrome tip on the end thats it!

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MUDD'S MOTORSPORT'S We do IFS lift installs ,
03 OVERLAND EDITION /Kilby-Skidrow-Mopar-4XGuard skids/ 2.5 inch TOTAL CONTROL JBA coilovers -JBA Arms/MOABS-31 FALKEN WILDPEAK AT3W / 4.10's etc, 04 Kilimanjaro Edition loaded, plus 05 KJ limited