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Discussion Starter · #1 ·
A couple of months ago I installed a Bank CAI and a better flowing Magnaflow muffler on my 09 JK. I never really saw much increase in MPG but it ran better. I later installed new spark plugs and cleaned throttle body and intake. Same story. Yesterday I got to thinking that maybe I should have done a computer reset by removing the negative cable for a while. I did that and noticed that it might be running a little smoother. Today I went for a long drive. During one 140 mile portion of the trip I averaged 18.5 and this included 60 miles of gravel and off-road. That is way better than I was getting before. I probably have picked up a couple mpg just through this free thing I should have done when I installed the intake and exhaust. The following are a couple of pictures from today:
 

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That is what I have been hearing. You have to change all 3 to get any results out of the jk. Congrats you are not dreaming lol.
 

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Discussion Starter · #3 ·
I sucks that I didn't do this last week before driving 700 miles to Vegas and back. Oh well. I am at least reasonably satisfied for the time being. I will keep the Jeep for a while longer.
 

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Yeah, that's the first thing you do when when changing a can on a sport bike. Unplug the battery for a bit and then reconnect and let the computer do it's thing fuel injection wise. Minor changes, the brain will compensate and improve. Major changes, you need a power commander (bike) or maybe a reflash for a Jeep. Don't mess with V6s' noise wise; never heard a 6 that sounds as sweet as an 8. My stock '12 has enough power for what it is anyway.
 

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Discussion Starter · #6 ·
The wheels are 16" Mickey Thompson Classic II's. The MB's are flatter. I like the old school dish look.
 

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I have experienced this on my son's 93 XJ High Output 4.0 liter.
We put a new Bored Throttle Body from Jeepers&Creepers, a K&N CAI and a Dynomax Cat Back system all at the same time and did not reset the battery just to see what difference it made.
It almost seemed like we did nothing at all to the XJ.
Then we pulled battery and did the headlight/key procedure to reset the CPU.
And after starting it and letting it idle for a few minutes. We took it for a test drive and it seemed like a different vehicle. Massive amounts of throttle response.
This may be the extreme situation. Throttle Body,CAI and Cat Back, but it gives you an idea how these CPU's "learn" their engine tune look-up tables.
 

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I also read on the JK forum(not a plug) that Chrysler "neuters" the Pentastar CPU programming for the first 500 miles so as to minimize the possibility of engine damage during break-in.
Which results in less than stellar mpg for the first 500 miles.
I noticed a big improvement in mpg when my 2012 JK hit the 500 mile mark.
It did not seem to have any more power that I could notice. But I have not been trying to "race" it during break-in. Just vary rpm and some brief full throttles on hiway.
Then from 500-1500 it completes it's data collection.
Others may confirm this.
I have not found additional sources to help confirm it myself.
But I did notice an improved mpg after 500 miles, so there may be some validity to this.
 

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I also read on the JK forum(not a plug) that Chrysler "neuters" the Pentastar CPU programming for the first 500 miles so as to minimize the possibility of engine damage during break-in.
Rumor and conjecture.
 

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My mpg dropped after the new shoe install. I also noticed a drop after removing the air damn.

I do miss the sound of my old v8 with CAI and dual exhaust out of a magnaflow.
 

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Not trying to mimic a V8 soundwise, I have never even had one.

I have heard some sweet sounding V6's though, Infiniti is one example.

The engine sounds meaner than my Wrangler :(

Infinity just has that sweet grumble on acceleration, and doesn't drown cab out or anything, you can just hear it.
 

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New2012JEEP said:
Not trying to mimic a V8 soundwise, I have never even had one.

I have heard some sweet sounding V6's though, Infiniti is one example.

The engine sounds meaner than my Wrangler :(

Infinity just has that sweet grumble on acceleration, and doesn't drown cab out or anything, you can just hear it.
I would like to find a solution to give me just a little grumble.
 

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I would like to find a solution to give me just a little grumble.
I'm wondering if the intake will give me what I am looking for. I have noticed on hondas, with just intake, gave me the growl I love.

Maybe I will hold out and see if anything else comes out for the 2012.
 

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New2012JEEP said:
I'm wondering if the intake will give me what I am looking for. I have noticed on hondas, with just intake, gave me the growl I love.

Maybe I will hold out and see if anything else comes out for the 2012.
Intake? I doubt it. The only thing that should affect sounds noticeably would be a change to the exhaust.
 

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It is the growl (Mouth grrrrr), Not the exhaust tone (Butt Fart) I want. ha
 

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New2012JEEP said:
It is the growl (Mouth grrrrr), Not the exhaust tone (Butt Fart) I want. ha
Nice imagery. Thanks. :)

With a v6 I don't think you can do much for either.
 

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Discussion Starter · #17 ·
I guess this is going to be another sound thread instead of a reminder to reset the computer. Regardless, the sound changes I experienced are ok. The Banks intake is noticeable and pretty loud at WOT. It is a big throaty sound but not bad or good necessarily. The exhaust I have discussed at length before. I started with a Flowmaster. It sounded terrible and had a horrific drone. We then put a 14" resonator mid-pipe, next to the recirculating canister. This helped but it still had the drone and sounded basically like a boy-racer's car. The exhaust shop then swapped out the Flowmaster for a stainless steel, straight-through Magnaflow. This ended up having a good sound. It is better than stock but not great. These V-6's are not going to sound great.

As for what V-6's do produce a good sound, the old Ford 2.8 did have a pretty good sound to it. I had on in a Ranger. I got it sounding good with a set of Hooker long-tube headers and glasspacks plumbed all the way to the back.

Lastly, good sound doesn't always mean great performance. One of the nicest sounding engines I have ever built was a Triumph 1147 installed in a 1966 Herald. I had a full race solid lifter cam installed, long-tube headers, and dual SU carbs installed. It had a formula car sound to it. It really sounded great going through the gears as it ran from 0-60 in 14 or 15 seconds.

This is sort of how the Banks works on my JK. It sounds a lot better than the actual gains. The gains I did experience are that it will hold speed going up a long grade from sea level to 4200 feet without the need for the transmission to shift down. It changed the torque curve just enough to make my Jeep a better rig for me. That is all that counts. It is not what others think or a need for a "look at me go" setup.
 
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