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Topic: Getting better MPG's...

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Getting better MPG's...
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Well it's no news that gas prices are up. We've talked about in another topic the price of gas affecting our lives. But I figured since this is a Jeep forum that it's time to talk about getting better MPG's out of our Jeeps...

So, I'd like to discuss things that you have (or would like to) do to increase the MPG's in your XJ or MJ. If you've installed a product what were your results (better or worse) and if you've gained MPG's how much.

Things I'd like to discuss would be (and not limted to);

-Exhaust Systems
-Intake Systems
-Plugs/Wires


So those of you who've installed these (or other) products in the past let us know the results you've gotten and if you think that the money spent on a certain product has paid off at the pump.

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threeEs99
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Keeping a good maintainance schedule is most effective. Tire pressure, allignment also.
I did install an aftermarket ignition, plugs, exhaust, and modified air box w/K&N filter. I gained about 38 miles on a tank. Not alot, but it helped. For the daily driven rigs out there, LIGHTEN YOUR LOAD. This means, take out the full size spare, Hi-Lift, and tool bag. This helps too.

-- Edited by threeEs99 at 23:59, 2008-06-28

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aci4369
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threeEs99 wrote:

 LIGHTEN YOUR LOAD. This means, take out the full size spare, Hi-Lift, and tool bag.



x2 I did this and noticed a difference, but I used to carry a full tool box...

Also I put champion spark plugs in and wires and I notice 1 mpg increase, but I don't know how old the one were that I took out. I think that it had been a while, maybe never....



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threeEs99
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I know the manual trans XJ get great mileage, but dose any one know if there is any kind of upgrades for the autos. Maybe so more of the operating power range is used. Some aftermarket companys make "skip shift" harnesses ( for GMs autos). How about Jeep stuff?

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89eliminator
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i have a Rusty's air tube with K&N filter and a flowmaster muffler. Im getting 20mpg highway and around 15-17 tooling around town. Thats a 4.0/AW-4/33s/4.10s on a 145,000 mile motor. And yes i still have my full size spare, rollbar, winch, rock rails...

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89eliminator wrote:
i have a Rusty's air tube with K&N filter and a flowmaster muffler. Im getting 20mpg highway and around 15-17 tooling around town. Thats a 4.0/AW-4/33s/4.10s on a 145,000 mile motor. And yes i still have my full size spare, rollbar, winch, rock rails...
I'm not looking for what you have done and what milage your getting. The variables are WAY to great for us to compare rig to rig.

What I am looking for is info as to what kind of increase you got from a specific part. For instance you said you have a flowmaster muffler. What were you getting prior and than what where you getting after. The difference would be an increase (or decrease) in MPG's. I'm looking for facts on specific items, not all of them together and what your getting now.

The point of this thread was to talk about specific items and how they directly effect the MPG's. I could tell you everything I've done to my rig and what I'm getting in MPG's (it's not good I'll tell you that), but the info really does nobody any good if I can't tell them what has increased and decreased my MPG's.

 



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89eliminator
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i understand.

I put the flowmaster on the day i got the truck so i dont have a before mpg.

The intake i put on later. I had the stock airbox with regular stock filter and was getting 19-20 highway and 14-15 city. I probably got 1mpg tops with the airtube and filter upgrade.

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threeEs99
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Each aftermarket part dose have an increased MPG benifit to a point, but we may be talking only a mile or so if that. Each part works to improve another. Honestly I only upgraded my intake, ignition, & exhaust for performance. Long before the possiabilty of $5.00 a gallon.
My comparison is as a total of parts because I did them all at once. Sorry no seperate MPGs here.



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ChevelleSSLS6
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I gained about 1 to 1.5mpg by taking a dremel tool to the stock airbox...

first remove the air intake stuff, and in some of the newer ones between the top part and the tb-airbox tube there is a restrictor/silencer thing that is best removed.

Next, fire up the dremel and extend the factory air intake hole around the side of the airbox (toward the drivers side fender) and continue with the lines of the airbox (looking at it from the side it'll look like a rectangle with a triangular end where the airbox tapers at the wheelwell). I also replaced the stock paper filter.

I have a 2.5" exhaust with a fm40 and noticed no gains in mpg. This was done BEFORE the intake mod, so the stock was likely adequate for the air that it took in. Perhaps I would have gotten better with a 2.25" exhaust.

I have heard of some guys putting a short piece of exhaust pipe inside the air intake hose (airbox-tb) right in the corrugated section to smooth airflow and it had positive results.

\/edit
I have also decided on keeping my 2" lift.  I'm still debating on wether or not to get 30s or 31s.  I'm not a big fan of the lifted (even a little)+stock tire look.



-- Edited by ChevelleSSLS6 at 08:21, 2008-06-30

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aci4369
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threeEs99 wrote:

Each aftermarket part dose have an increased MPG benifit to a point, but we may be talking only a mile or so if that. Each part works to improve another. Honestly I only upgraded my intake, ignition, & exhaust for performance. Long before the possiabilty of $5.00 a gallon.
My comparison is as a total of parts because I did them all at once. Sorry no seperate MPGs here.


So how much better are you getting now that you did them all at once?



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threeEs99
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Before I was getting about 230 miles on a tank. Now I get around 268 on average.hmm


-- Edited by threeEs99 at 20:25, 2008-06-30

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xjryder
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I have a great set up I have started with spark plugs, wires, flushed coolant and put in a 180 thermostat, header, full exhaust, throttlebody , spacer, cold air intake mid to high 20's per gallon

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mvusse
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I got an 87 MJ, Renix 4.0, AW4 4wd.

When I got the truck I got around 13 mpg around town, 18 on the highway. My thinking was along the lines of "Crud, I might as well be driving the Suburban."

After replacing cap, rotor, plugs and wires as well as fixing my ccv system and replacing air filter it went up to 17 around town, 23-24 on the highway when keeping my speed down to 60-65mph. Turned out one of the plug wires was broken and I was running on 5 cylinders.

That was also with a muffler shop economy exhaust that ranged anywhere from 2.25" to 1.75" and rusted full of holes. It had a 2" front pipe welded to a 2.25" muffler and reduced to a 1.75" rear pipe out the side just before the rear bumper. I just today finished installing a stock 2.25" front pipe, followed by a stock 2.25" muffler, and a 2.25" Thrush glass pack to make it to the next hanger. Finished it off with a 2.5" down turn in front of the rear axle. Cat was already missing when I got the truck. Don't know if the new exhaust will make a difference or not. Only time will tell. That 2.25" front pipe has about 6" of length smashed down halfway to closing the pipe to help clear the front drive shaft. Talk about overdoing it. It probably only needed 1/2" or so!

I am also wanting to get a set of reman Ford Motorsports injectors. Most people have reported improved idle and better performance, some better mileage as well. I think I might be getting about the best mileage that can be expected from this engine, though, so I'm not holding my breath.

Oh, and I'm also running a 195 degree thermostat, but the truck never seems to get anywhere near that on the highway and 41 psi in my tires (rated maximum) when not on the trail.

-- Edited by mvusse at 22:51, 2008-07-27

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xjryder wrote:
mid to high 20's per gallon
I'm not going to call your a liar, however I highly doubt your getting that.

This is why...

With larger tires, unless you've changed your speedo gear your odom. is not reading correctly. This is even more the factor on a 97+ rig with the different speedo gear type setup.

So if you can confirm your running the correct toothed speedo gear for your gear ratio and tire size combo; than we'll talk...

 



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threeEs99
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I was having this great dream of getting mid to high 20's mpg in my jeep when I herd Leads voice saying. WAKE UP IT'LL NEVER HAPPEN.
It was a good dream. LOLbiggrin

-- Edited by threeEs99 at 00:02, 2008-07-28

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