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Discussion Starter #1
Going to ask this here since it is LS/JK related. I want to know as I do not see any real answers except for the scattering around of answers.

Who all drives there conversions as daily drivers?

What kind of mileage are you getting and with what combinations?

All I know is mine is horrible, getting 10-13 mpg's with that being a combination of city/highway - highway being an 11 mile drive one way on the interstate at 80 mph's.

I just got it dyno'd and all I got was more power (not a bad thing) but it did nothing for my mileage or the fact that I can not hold 6th gear, before or after the tune.

Here lately it has been a head wind of 18-25 mph's and it will not hold 6th on the flats and all most always on the overpasses with the headwind and that is in Kansas, hell it looks like this _______________________________________ almost everywhere you look around here with the occasional overpass.

I am running a 6.0, 6L80E with 4.10's and 35" tires.

So what are all you getting and how is 6th gear?
 

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I don't run an LS conversion so cannot help you there much.However, because I was inspired and entertained by your portrait of Kansas...


_________________________________________
____________/||____||\___________________


..I created an illustration of your overpass that should accompany your detailed rendering of the Kansas landscape real nice.

Welcome to JKOwners and I am sure you'll get some useful advice , on top of the awesome art I've just provided.

:grinpimp:







:jeep2:
 

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I don't drive mine daily, but I was getting 12.8-13 stop and go, in town, AC on with 35's and 4.10's. On the interstate, 75-78mph, AC on with 35's and 4.10's it was almost 15mpg. I'm now on 37's, but it has only dropped by about 1mpg.

There are a lot of factors that contribute to mpg. PM me if you want to discuss.

Edit: 6th gear is easy. It shifts in at anywhere from 55mph on up, depending on throttle percentage. It will hold it all day long.
 

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Discussion Starter #4
Thanks j3ff3ry. That is some awesome artwork. I was unable to create the overpass thanks again:smile2:
 
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Going to ask this here since it is LS/JK related. I want to know as I do not see any real answers except for the scattering around of answers.

Who all drives there conversions as daily drivers?

What kind of mileage are you getting and with what combinations?

All I know is mine is horrible, getting 10-13 mpg's with that being a combination of city/highway - highway being an 11 mile drive one way on the interstate at 80 mph's.

I just got it dyno'd and all I got was more power (not a bad thing) but it did nothing for my mileage or the fact that I can not hold 6th gear, before or after the tune.

Here lately it has been a head wind of 18-25 mph's and it will not hold 6th on the flats and all most always on the overpasses with the headwind and that is in Kansas, hell it looks like this _______________________________________ almost everywhere you look around here with the occasional overpass.

I am running a 6.0, 6L80E with 4.10's and 35" tires.

So what are all you getting and how is 6th gear?

You are still on a stock tune ?
I am running a LS-3 and doing much better than you are but I'm not running a stock tune .
I have seen 17.3 mpg at the best on a long distance run calculated (not on the gauge cluster) , average about 14 mpg if I keep my foot out of it .
I'm also in a 2Dr so I'm a bit lighter , and on 37's and 5.13's .

John at Overland Performance did my tune with EFI-Live and it does hold shifts way better than the stock tune , sixth gear would kick down with the slightest increase in stock form , but now it will hang in there until I get into it about 3/8 throttle .

The difference was 'nite and day .


Right now I'm in the process of axels and changing gear ratios but I don't expect to see any mpg or performance advantages because the tire and wheel weight will increase as well as the weight increases of 60's will negate any mpg increase .


Look into EFI-Live ,I just believe there are more advantages there than the others available on the market .


Also the guy behind the tune needs to have the experience also and John @JohnPShoe has tuned many other members here on JKO with results that speak for themselves .
 
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Going to ask this here since it is LS/JK related. I want to know as I do not see any real answers except for the scattering around of answers.

Who all drives there conversions as daily drivers?

What kind of mileage are you getting and with what combinations?

All I know is mine is horrible, getting 10-13 mpg's with that being a combination of city/highway - highway being an 11 mile drive one way on the interstate at 80 mph's.

I just got it dyno'd and all I got was more power (not a bad thing) but it did nothing for my mileage or the fact that I can not hold 6th gear, before or after the tune.

Here lately it has been a head wind of 18-25 mph's and it will not hold 6th on the flats and all most always on the overpasses with the headwind and that is in Kansas, hell it looks like this _______________________________________ almost everywhere you look around here with the occasional overpass.

I am running a 6.0, 6L80E with 4.10's and 35" tires.

So what are all you getting and how is 6th gear?

Did you ever get HP tuners?
 

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Definately need HPTuners. I have a 6400lb JKUR with 4.88's, D60's, and 40's running a 6.0L/6L80e combo like you and can run down the highway at 1900 rpm in 6th gear all day long. I get 14-18mpg on avg and drive it every single day.
 

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Discussion Starter #10
So it does look like I should be getting better mileage.

Soon as I get a computer that will support the newest version of hptuners I can get this thing dialed in, I hope :|

I've had hptuners for sometime now, still trying to learn what the heck I need to do. Got it dynoed and he cleaned it up and got me some more power but nothing on the mileage and when I went to update hptuners with the latest version I find out my xp will not support it :crying: so that is why I am stuck right now.

Thanks for all the responses and seeing that things can be better.
 

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Discussion Starter #11
Thought I would update as a little tweaking was done to the dyno tune that I have and it may have help at tad, maybe 1 mpg better.

I know this is not really what this area is for but it is about the only avenue I have. Seems like I am starting to have more issues as I go, that may be all related to fuel mileage.

I noticed it a couple times before I had it tuned but now it is more frequent. In 6th gear cruising it feels like I am touching the brakes on and off, which I am not but that is what it feels like. Still drops out of 6th at the slightest increase of pedal and to me it just feels like it is laboring, or it just doesn't feel like a 6.0 should going down the road.

I am wondering if my cats are going bad or are plugged. Is there a way to check without dropping the down pipes and looking inside of them?

Thanks in advance for any help, this is starting to get a bit frustrating.
 

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Can you smell anything like Sulphur at the tail pipe .
If not bang on the cat with a rubber mallet , if it rattles it may be compromised , tail pipe would also show signs of a rich condition .
Without any of those things present there are parameters if your able to see them , like trims on each bank that would show either a large disparity post cat . Exhaust leaks at collector can cause fuel mileage numbers to look low also .

It's not common to have cats to go bad without some abuse , intentional or not . Over rich conditions are hard on cats because of the heat generated . Lean conditions are not as bad , but still .


Exhaust leaks pre-cat can and will cause a rich condition and also reduce fuel economy numbers .

Ability to use a tuner and monitor parameters is important to understand what your engine wants or needs .


Do you have an Areoforce Interceptor or something to see what is going on ?
 

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Discussion Starter #13
Can you smell anything like Sulphur at the tail pipe .
If not bang on the cat with a rubber mallet , if it rattles it may be compromised , tail pipe would also show signs of a rich condition .
Without any of those things present there are parameters if your able to see them , like trims on each bank that would show either a large disparity post cat . Exhaust leaks at collector can cause fuel mileage numbers to look low also .

It's not common to have cats to go bad without some abuse , intentional or not . Over rich conditions are hard on cats because of the heat generated . Lean conditions are not as bad , but still .


Exhaust leaks pre-cat can and will cause a rich condition and also reduce fuel economy numbers .

Ability to use a tuner and monitor parameters is important to understand what your engine wants or needs .


Do you have an Areoforce Interceptor or something to see what is going on ?

Yes, I can smell sulfur when driving on the interstate and accelerating up over an overpass.

I did go out after my last post and beat on the cats with a mallet but couldn't really hear anything. Tailpipe has black residue on it. I know it was running rich before the tune by the logs I took and was seeing all the pulling it was doing on the ltft and stft. Much better now after the tune.

Yes I do have hptuner and still trying to figure it out and understand what I am looking at. I have it down a little bit but not enough to really use it.

I do know that the tuner has turned off the post cat o2's but I still have the cats. I thought I had part numbers for the cats I used but I can not find them.

If this makes sense I understand what needs to be done but it is the use of the hptune that I can not figure out and what all needs to be done.
 

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Not running post cat O2's is pretty common with almost all the swap companies , there is not really any reason to if your not subject to emissions requirements that hold you to the letter (like Cali) .

To see fuel trims while you are driving is in my humble opinion important to help you diagnose weather or not you have a cat problem or not , exhaust leaks at the pre-cat location will cause you to have a rich condition because the mixture will be over-oxygen tricked to show a need for the computer to richen the fuel curve when it's really not required .


To see these you need to either use a laptop or a monitor like I mentioned before , the Areoforce Interceptor .

I find this handy little item easier than a laptop , and it is always there without having to boot it up ,or connect it every time I want to look at parameters .

It can be set up to monitor many other things beyond the things we are talking about here .

Understanding what you have is the first step to a diagnosis .
 

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Discussion Starter #15
I was actually laying under the jeep this morning looking at the cats seeing if I can cut them out and get my mig torch up in there and weld a piece back in.
 

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Discussion Starter #17

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Discussion Starter #19
Why do you need cats, besides inspection if you have it in your state?
I'm guessing that is what he means.

No I do not have inspections, so I would not have to deal with that part of it. That is why I am looking at it. Should have never put them in to begin with.
 

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I'm guessing that is what he means.

No I do not have inspections, so I would not have to deal with that part of it. That is why I am looking at it. Should have never put them in to begin with.
ok just making sure. i won't need cats in arkansas and don't run them on anything
 
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