Performance mods? -
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post #1 of 8 Old 02-21-2010, 03:25 PM Thread Starter
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Performance mods?

I was going to upgrade from my 08 KK to a WK with a V8, but decided not to for various reasons. Now, I'm looking to possibly give my 3.7L a little boost, without going crazy. Judging by my brief look at available upgrades, it appears that a cold air intake system and new muffler (or maybe a completely new exhaust system) can both boost power and improve fuel economy a little bit. I'm also considering a performance computer chip, but those seem to be very hard to find for a V6, and I'm not sure whatever you gain is worth what they cost.

Has anybody here installed any of these mods on their KK? If so, could you tell me if there are truly tangible benefits, and if it's really worth it? Or, if there are other simple and non-expensive tweaks that could be made, I'm all ears. Thanks!

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post #2 of 8 Old 02-27-2010, 06:36 PM
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I have an 08 and i put in a K&N 77 series air intake and also a Cat to Back exhaust system with a flowmaster 40 series muffler. These two alone sound awesome, the muffler over powers the sound of the intake, and give a huge boost in HP. I'm sure dual system would have given more performance. I can't say if this has yielded more gas mpg but it def adds a lot of power. if you accelerate off the line just right you get a lot of power and speed. I also put in new plugs, a transmission cooler and a K&N oil filter (although I think the dealer might have replaced that on me when i last went in)

in total it was prob about 2k worth of upgrades maybe less.
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post #3 of 8 Old 02-27-2010, 07:16 PM Thread Starter
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Thanks for the reply. Since I didn't get any response quickly here, I asked in the KJ forum, and there's been a fair amount of discussion on it. There are, of course, a lot of naysayers. Reading between the lines, I think there's definitely a chance for improvement in performance, but how much improvement can be a matter of perception, as well as other factors. I'm going for a K&N 63-1559 (advertised gain is slightly more than 77 series for this engine), and a Dynomax cat-back system. I've heard Flowmaster and Magnaflow systems on many different vehicles, and I don't care for any of them, too loud or bratty. The Dynomax Ultra Flo gives the nice, low rumble I'm looking for, and it doesn't sound like it's going to add much noise inside the cabin, but rather kick it out the back. I'm a little concerned about the noise added by the air intake, but I guess I'll just have to see what happens. I'm not going to put up with a roaring engine just to gain a few HP, so I can always put the factory intake back on if I don't like it. Such is the beauty of bolt-ons. If I like the upgrades, I might spring for a stage 1 Jet performance chip too. Oh, and I've got a transmission cooler already, because that comes with the trailer tow package. I'm not looking to make a hotrod out of this, just get a little extra boost, hopefully improved fuel economy, and make it sound more powerful.
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post #4 of 8 Old 04-12-2010, 04:22 PM
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I did the intake and went with the Dynomax Ultra Flo. Have to say that the muffler is great. Just like you said, it hardly adds any noise in the cabin, but sounds throaty out the back. Noticed a little HP gain, but no mileage gain.
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post #5 of 8 Old 04-12-2010, 08:38 PM
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It is a wager of dollars vs results. Your KK will never be a race car. Also the 3.7 has plenty of power to get on the highway and push bigger tires or wheel in low what are trying to accomplish. Do not put me down as a Naysayer, because I know how much difference these small upgrades can make to a vehicles performance, I just think you should consider the end result you want before you buy your first upgrade.

Happy Moding!!!

97 TSI ZJ... Getting groceries

2010 COMMANDER!!!! (sweet!)
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post #6 of 8 Old 04-12-2010, 08:52 PM
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Skip the K&N,only allows dirt into your engine and the OEM airbox flows more then the 3.7 could ever use with a good paper filter in it.After a few miles the PCM will over ride any performance gains from a intake and muffler anyways,which at most is maybe 5hp at most(highly doubt it,closer to 2-3hp).

Your driving a 4000lbs brick,your not going to get alot of performance or good mpg's,it's a Jeep thing.

'02 Liberty sitting on 35" tires,HP44,RockJock60,and AtlasII t-case
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post #7 of 8 Old 04-15-2010, 03:22 PM
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Mopar makes a Cat-Back Exhaust System, Dual Rear Exit, Square Tips, 2.5" Pipe, 2009-2010 3.7L Liberty PN #P5155035
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post #8 of 8 Old 11-02-2010, 03:25 PM
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Originally Posted by ivorycruncher View Post
I was going to upgrade from my 08 KK to a WK with a V8, but decided not to for various reasons. Now, I'm looking to possibly give my 3.7L a little boost, without going crazy!
A company in california, installed a 5.7 hemi in a wrangler. There is a kit for it on sale. One can be shoe horned in a liberty.

I would like to try this supercharger. Wish they had dyno test it before and after installation...

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