3.7L Performance

[Damotee]

I did a round trip of 183km on the weekend and used just under half a tank. That included a bit of 4 wheeling too. I wish this Jeep had better mileage. Oh well. Better pack a few extra jerries.

 

[Jcdes]

A reflash and exhaust/intake mods is the cheapest way to gain a little bit of power at the expense of MPG... That's the only thing I see that would make a noticeable change. I just do regular tuneups and keep it as stock as possible no mods except the wheels. For going fast I use my very, very, very modded 400hp 91 Rx-7 Turbo LOL...

 

[Damotee]

I have a faulty O2 sensor which would be affecting my mileage. Gotta get onto that..

 

[2002KJLimited]

Future stuff i want to add to complete the setup would be D.U.I SOS coils and a JET chip. I am considering running 89 instead of 87 now because of how much leaner it must be running with the better flow, 30 cents more per gallon sadly.

 

[wheeee32]

Future stuff i want to add to complete the setup would be D.U.I SOS coils and a JET chip. I am considering running 89 instead of 87 now because of how much leaner it must be running with the better flow, 30 cents more per gallon sadly.

Save your money on the gas and the chip. They won't make any noticeable difference in how your KJ performs over time.

 

[rockdart]

Future stuff i want to add to complete the setup would be D.U.I SOS coils and a JET chip. I am considering running 89 instead of 87 now because of how much leaner it must be running with the better flow, 30 cents more per gallon sadly.

I picked up a 6 pack of Duralast IC's for $98 at Autobone. Lifetime warranty. Even got $20 back from a promotion they happened to be running at the time. That $20 got me the 28mm open end wrench that fits my 4Link rods.

 

[Dayspring78]

I've been reading through the posts and I can't get a definitive answer about mufflers/exhaust. I'm going to need a replacement muffler soon. To be honest, I don't care about my Jeep sounding "cool". Trust me, when I was younger I put a Cherry Bomb on a 2.2 4 cylinder Chrysler and Purple Hornies on a 318 in a 1978 W-150 step-side and I outgrew that years ago! Anyways, I can get a Flowmaster Super 44 2.5 I.D/2.5 O.D. as cheap or cheaper than a stock muffler. However, I don't want to lose torque. So, do I go with stock or get the Flowmaster? I'm going to retain the same stock diameter out to the back, too.

 

[wheeee32]

As long as you stick with the stock exhaust pipe diameter, the muffler selection comes down to personal preference. I never cared for the sound of a flowmaster on a KJ. Too droney. Magnaflow makes a good one that has a decent sound but doesn't drone on the highway. Check out videos to get a better idea of the sound you like. There's several floating around on youtube.

 

[tommudd]

I've been reading through the posts and I can't get a definitive answer about mufflers/exhaust. I'm going to need a replacement muffler soon. To be honest, I don't care about my Jeep sounding "cool". Trust me, when I was younger I put a Cherry Bomb on a 2.2 4 cylinder Chrysler and Purple Hornies on a 318 in a 1978 W-150 step-side and I outgrew that years ago! Anyways, I can get a Flowmaster Super 44 2.5 I.D/2.5 O.D. as cheap or cheaper than a stock muffler. However, I don't want to lose torque. So, do I go with stock or get the Flowmaster? I'm going to retain the same stock diameter out to the back, too.

Anything but flowmaster, drone at highway speed is bed, magnaflow all the way

 

[04Liberty]

Anything but flowmaster, drone at highway speed is bed, magnaflow all the way

Or Borla

 

[JasonJ]

Or Borla

Always a great choice, expensive, but a great muffler.

Personally, if all you wanted was OE performance and quietness, the factory muffler lasted 110,000 miles on my KJ before it rusted on the side seam and began leaking, so I'd just go with another OE replacement muffler. It should last another 110,000 miles. Theoretically.

It hasn't come up in this topic, but sometimes you hear owners saying their <insert whatever part here> went bad after 80,000.... 100,000 ... 150,000 miles.. and then ask for what replacement part is an upgrade or better than the one that just failed with regards to longevity. Hilarity ensues.

 

[04Liberty]

Always a great choice, expensive, but a great muffler.

Personally, if all you wanted was OE performance and quietness, the factory muffler lasted 110,000 miles on my KJ before it rusted on the side seam and began leaking, so I'd just go with another OE replacement muffler. It should last another 110,000 miles. Theoretically.

It hasn't come up in this topic, but sometimes you hear owners saying their <insert whatever part here> went bad after 80,000.... 100,000 ... 150,000 miles.. and then ask for what replacement part is an upgrade or better than the one that just failed with regards to longevity. Hilarity ensues.

Normally true, but either time I've gotten a Borla catback (both my Ram and the Jeep) it was a closeout and I paid like $150 for brand new kit.

 

[Adam Roby]

Normally true, but either time I've gotten a Borla catback (both my Ram and the Jeep) it was a closeout and I paid like $150 for brand new kit.

The Magnaflow are crazy expensive... woah... 1/4 the price of the Jeep? Some people have expensive tastes. The Borlas seem reasonably priced at least.

Probably an OE muffler with a glasspack replacing the cat would be fine.

 

[tjkj2002]

The Magnaflow are crazy expensive... woah... 1/4 the price of the Jeep? Some people have expensive tastes. The Borlas seem reasonably priced at least.

Probably an OE muffler with a glasspack replacing the cat would be fine.

My MagnaFlow muffler cost like $50-$60.

 

[tommudd]

The Magnaflow are crazy expensive... woah... 1/4 the price of the Jeep? Some people have expensive tastes. The Borlas seem reasonably priced at least.

Probably an OE muffler with a glasspack replacing the cat would be fine.

???????????
expensive? got mine for like 45 bucks , took 20 minutes to install
Don't need full exhaust just muffler

 

[HoosierJeeper]

Always a great choice, expensive, but a great muffler.

Personally, if all you wanted was OE performance and quietness, the factory muffler lasted 110,000 miles on my KJ before it rusted on the side seam and began leaking, so I'd just go with another OE replacement muffler. It should last another 110,000 miles. Theoretically.

It hasn't come up in this topic, but sometimes you hear owners saying their <insert whatever part here> went bad after 80,000.... 100,000 ... 150,000 miles.. and then ask for what replacement part is an upgrade or better than the one that just failed with regards to longevity. Hilarity ensues.

I'm still on my factory one with 164k...definitely will get a Mopar one when/if the time comes for a new one. Still quiet! It's been bashed up a bit over the years. :gr_grin:

 

[ltd02]

My 02 had a Borla catback dual setup on it when I bought it. Whoever installed it did a good job and it still sounds great even after the almost 100k I've put on it. I priced them a while back and it was over 500 for the kit. I wouldn't have done it but glad the PO did. Doubt it adds any performance but sounds like it does. I think 3.7L performance is an oxymoron. :gr_grin:

 

[Adam Roby]

I only checked one line and it showed a "special" of $603 with regular price of $814... but I just double-checked and that WAS for a cat back system... not just the muffler. My bad... also polished stainless steel...

Magnaflow 15870_Jeep Liberty Performance Exhaust System

 

[2002KJLimited]

I believe CherryBomb has a cat back system. For a full upgrade, look for the the complete midsection, some are a higher quality mandrel bent style. May not create more power, but it may increase efficiency.

 

[2002KJLimited]

For the whole shabang get the JBA Cat4ward shorty headers too. Wrapping or coating them will also lower under hood temps adding to more efficiency.