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Discussion Starter #1
Well last wk I installed my 50 series Flowmaster HD and removed the resonator and install a K&N cone filter within the factory air box and remove the snorkel also and its like a custom job thing. I did go a bit crazy last wk on enjoying that way it sounded. Oh i also installed a optima red top battery so of course I had to disconnect the battery. So I put 10 gallons in on sunday on a empty tank and Ive been driving normal and I mean normal so like 55 on cruise. So how long will it take the ECM to learn its new breathing levels. Im showing 11.4 miles to a gallon and before I did everything it was showing 13.4. So how long before it starts to hopefully show the correct gas mileage. ALSO when your gauge says you have ZERO miles before empty do we still have like a gallon or less left.
 

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I think it's about 2 gals left.
 

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I agree it's about 2 gallons
 

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Discussion Starter #4
so why would jeep do this. when is show empty well I guess it should be empty but its not. Crazy. Any info on my mileage issue by any chance
 

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I agree with 2 gallons left. When my light comes on, I hit the odo and know I have 20 miles to go. Roughly.
 

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HEMI Commander. said:
so why would jeep do this. when is show empty well I guess it should be empty but its not. Crazy. Any info on my mileage issue by any chance
People are stupid and will run it to empty if they can - that extra is to try and prevent the dumbass factor.

Thats my theory.
 

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I have not changed out the exhaust but when I put on the CAI, I noticed only a very small increase. I am not convinced that mileage goes up with one. I am convinced you have more power on demand. I am wondering if the same is true on the exhaust. I have seen lots of claims around about what some of these changes are supposed to do as far as MPG but I have seen more that claim it gained little to nothing on that account. I think all would agree that performance goes up quite noticeably.

It would be interesting to know how much work the engine does at steady state cruise to just exhaust itself in a standard system vs a mod. (especially at low rpm) ? I am not certain that a lot of horses are used. Any engineers with an answer out there?
 

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Discussion Starter #8
I thought they did this so that you dont burn out the fuel pump, because running on empty to many times does burn it out.
 

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Discussion Starter #9
well ohio but before the changes I was only getting 13.4 mpg and with the intake, muffler and disconnected the battery and IM driving like miss daisy and it shows 11.4. Does it take time for the ECM to learn the new mods or what.
 

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i think to make use of any mods you have to be able to change the spark and air/fuel mixtures.

that is the only way to maximize your changes. of course no one is tuning for the commander, so you are kind of SOL.

the computer is programmed. it does not learn anything. the transmission is the only part that learns. and it only learns shift points.
 

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I noticed a small MPG increase with the CAI only, and the exhaust took that away. However, the performance and "growl" factor were noticeably increased.

And yes, I think the two gallons is to prevent the "idiot factor" I have, on two occasions, ran the XK out of fuel and it saved my butt.

And yes, it is bad run completely out of fuel. That , in addition to walking to a gas station, is where my butt was saved.
 

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As I recall, less exhaust pressure gives you less torque and less power on the low end and will reduce your mpg. But it will help higher end performance.

That being said, if you do a lot of in town driving or towing, your mpg will suffer. If you do a lot of highway driving, should be better.
 

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I know that after disconnecting the bat the XK will start at the default shift pattern, etc, but it does learn new shift patterns as well as advance the spark timing as much as possible until the preignition knock kicks in. That is why the Hemi wants 89 octane fuel. It adjusts timing for the fuel being used. The higher octane the more advanced the timing can go to get more power before you get the ignition knock. Give it time to adjust.
-JJ
 

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Discussion Starter #16
Im mostly highway or back roads with cruise set at 55. I did notice its now at 12.6 mpg so it seems like its getting better. I wish Superchips would do a programmer for our commanders. Let me to you that my 04 Hemi Ram turned into a whole diff truck with superchips. Shift points and some fuel and air ratio's changed also. Maybe we cant band together and show superchips that there is a need for a programmer for us. Its one of the best mods you can do.
 

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About the running to empty part. I probably ran a good 10-15 miles on the zero miles to empty when emptying the tank for the skid plate install. The tank still had gas in it. How much I don't know.
 

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Discussion Starter #18
Well this past sat I did the zero test. I got a gallon of gas in a gas can just in case and then proceeded to drive and then noticed the gauge state 0 to empty, but then I did stop and let it sit for 10 mins and then start it and it said 1 mile to empty so I got as close to 0 for good test results so I drove it during the day and got to about 19 miles but 1 less so really 18 miles on it and said OK thats good enough for me and went to the gas station and filled it up. SO if anyone gets to that zero to empty thing and you can get 18 to 20 miles more and still have a piece of mind of not getting stuck on a highway or a bad part of town. SO that was my test of the day. GOOD LUCK
 

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I drove my about 40 miles more after the zero to empty mark.
 

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Discussion Starter #20
XKTX said:
I drove my about 40 miles more after the zero to empty mark.


40 miles WOW. Was that Highway because I cant see that being city driving. Well Back to the drawing board. ILL do another test and will do it till it dies on me.
 
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