Increase MPG on stock Jk?
12-22-2010, 12:46 PM
#41
ronjenx is correct, taking the ethanol out of gasoline/ethanol blends is a very bad idea just for everyone's information. The main reason is that even if you manage to separate the ethanol out without contaminating the gasoline, ethanol has a high octane (between 116 and 129 depending whether you are talking MON or RON). So when mixed in at ~10% (the standard mix at the pumps these days) the gasoline portion of the blend can be far below the ratings at the pump. So if you take out the stable portion of the 87 octane fuel blend you might end up with pure gasoline that has an octane rating of only 80 or 85. If you then put this fuel in your JK it will cause excessive knocking and likely destroy the engine without even taking into account any contamination. Also I am a fuel scientist and mechanical engineer for everyone's information so this is not general information I have heard, it is scientific fact 
As far as ways to help with stock fuel economy driving style is that biggest improvement you can make to improve fuel economy. Driving and accelerating slower will certainly help decrease fuel consumption.
If you free up the intake and exhaust you -might- gain 1 mpg. But then again your rig will sound more badass at high throttle and high RPMs so you will probably lose anything you gain wanting to hear your engine roar...
Supercharging with the RIPP system would probably help you gain some more MPG but that is a large investment that would likely never pay for itself as far as fuel savings. So you will need to decide on the balance you want to strike, is higher mpg or overall financial savings higher on the list. If financial savings are your goals, there are probably no mods that you can do that would pay for themselves as far as fuel savings over the life of the vehicle.
I can say that I have been looking at the RIPP SC set-up lately because I currently get over 20 mpg on the highway with my 6-speed JK and if the SC allows me to maintain similar fuel economy while having a lot more power on tap if needed, I would definitely love to have one. But since my income is fairly low it will likely be about a year before I can even think of investing in the SC...plenty of time to get more reviews on the gen 2 set-ups.
As far as ways to help with stock fuel economy driving style is that biggest improvement you can make to improve fuel economy. Driving and accelerating slower will certainly help decrease fuel consumption.
If you free up the intake and exhaust you -might- gain 1 mpg. But then again your rig will sound more badass at high throttle and high RPMs so you will probably lose anything you gain wanting to hear your engine roar...
Supercharging with the RIPP system would probably help you gain some more MPG but that is a large investment that would likely never pay for itself as far as fuel savings. So you will need to decide on the balance you want to strike, is higher mpg or overall financial savings higher on the list. If financial savings are your goals, there are probably no mods that you can do that would pay for themselves as far as fuel savings over the life of the vehicle.
I can say that I have been looking at the RIPP SC set-up lately because I currently get over 20 mpg on the highway with my 6-speed JK and if the SC allows me to maintain similar fuel economy while having a lot more power on tap if needed, I would definitely love to have one. But since my income is fairly low it will likely be about a year before I can even think of investing in the SC...plenty of time to get more reviews on the gen 2 set-ups.
12-23-2010, 07:29 AM
#44
JK Enthusiast
My 07 with 33's got 16 all the time. My stock 10 seems to get 19.5 to 20. I just spent a week in my wife's 09 Nissan Pathfinder and it only got 19.6. It's does have more power and better areodynamics,plus is lighter.I would expect better from it. Makes my jeep mileage ok because it's a lot more fun than her ride.
12-23-2010, 07:50 AM
#45
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Ditto on the regular maintenance, oil, filters, tire pressure...
Synthetics should help, or that is the word. I use AMSOIL in all my vehicles (Ram & Harley) (engine/tranny) and they run cooler (the Harley) and gas mileage is better.
Only had my Jeep for 2000 miles so far, so not ready for oil change yet. But did just get back from a round trip to south NC to pick up my son for the holidays and averaged 22.5 mpg @ 65 mph. - 6speed, 3.73, 32" tires -
Not too shabby considering we aren't that aerodynamic...
Have read that RIPP S/C reports an increase of 2 or so mpg... FWIW But 5 grand seems like a steep price to pay only for a mpg increase. Suppose the additional HP and grin would help offset the cost????
Synthetics should help, or that is the word. I use AMSOIL in all my vehicles (Ram & Harley) (engine/tranny) and they run cooler (the Harley) and gas mileage is better.
Only had my Jeep for 2000 miles so far, so not ready for oil change yet. But did just get back from a round trip to south NC to pick up my son for the holidays and averaged 22.5 mpg @ 65 mph. - 6speed, 3.73, 32" tires -
Not too shabby considering we aren't that aerodynamic...
Have read that RIPP S/C reports an increase of 2 or so mpg... FWIW But 5 grand seems like a steep price to pay only for a mpg increase. Suppose the additional HP and grin would help offset the cost????
12-23-2010, 04:07 PM
#46
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Things to do ...
I've wrestled with the same issue for years, not just with my JK either. There is a whole cult devoted to doing things to maximize fuel economy and those people are called hypermilers. Even if you're not a Prius-driving, treehuggin dirt head, I think you'll still find some of the hypermiling sites insightful. And then there are some JK-specific things. Here's a short list of things that I think are worth looking at:
* Hypermiling
http://www.wired.com/cars/energy/new.../hypermilers09
* Programmers
I own a Hypertech Max Energy. It was the only gadget that I thought was remotely legit. Since then I've run quite a few tanks of regular through it and my mileage is about 7% better as a result. They say HP is improved, but I can't feel it if it is. Right now I'm experimenting with the premium fuel programming. No verdict on that yet. I can't comment on anything else.
* Tire pressure
This is a big deal. I left my tire pressure low (~20-25 psi) for several tanks to see the effect and it's substantial. My average mileage dropped from about 18.5 mpg to low 17s.
* Speed
Probably the biggest factor, in my opinion, for good/bad mileage. Go back to the hypermiling bullet above. Google that for hard data on what +/- 10 mph will do to you at highway speeds.
* Supercharger
I'm kind of serious about this. I don't have one on my JK, but a buddy does. He has 35s, an automatic, and a heavy foot. I think he was getting about 12 mpg. Now he's getting about 15-16 I believe (post-SC install). Not sure if his foot has gotten any lighter. He doesn't have an IC either. Even if this is legit, you'll have to put a lot of fuel through your JK before you can justify the price tag!
I hope this helps.
* Hypermiling
http://www.wired.com/cars/energy/new.../hypermilers09
* Programmers
I own a Hypertech Max Energy. It was the only gadget that I thought was remotely legit. Since then I've run quite a few tanks of regular through it and my mileage is about 7% better as a result. They say HP is improved, but I can't feel it if it is. Right now I'm experimenting with the premium fuel programming. No verdict on that yet. I can't comment on anything else.
* Tire pressure
This is a big deal. I left my tire pressure low (~20-25 psi) for several tanks to see the effect and it's substantial. My average mileage dropped from about 18.5 mpg to low 17s.
* Speed
Probably the biggest factor, in my opinion, for good/bad mileage. Go back to the hypermiling bullet above. Google that for hard data on what +/- 10 mph will do to you at highway speeds.
* Supercharger
I'm kind of serious about this. I don't have one on my JK, but a buddy does. He has 35s, an automatic, and a heavy foot. I think he was getting about 12 mpg. Now he's getting about 15-16 I believe (post-SC install). Not sure if his foot has gotten any lighter. He doesn't have an IC either. Even if this is legit, you'll have to put a lot of fuel through your JK before you can justify the price tag!
I hope this helps.
12-23-2010, 07:18 PM
#47
JK Enthusiast
Ok my jeep is a 2010 sport with steel stock wheels and I put on 32" tires. When driving past a speed sign at 90 on the high way the sign says I'm doing 98 km/h, I'm getting like 350 km or less to a tank of gas and I have a flowmaster exhaust and tryed cold air intake and it doesn't help? What are you guys getting to a tank of fuel????
12-23-2010, 07:52 PM
#48
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I have a 2010 sport as well - manual, synthetic oil, soft top. All stock except Hypertech tuning. I've been averaging 300 miles per tank with mixed city/hwy driving. I guess that's about 480 kilometers.
12-25-2010, 10:32 PM
#49
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Generally speaking, I think the higher the PSI the better the mileage...it stands to reason...a well inflated tire will roll with less resistance. I did it for a while...pumped up to almost 40 PSI...However, I did not like the feel of the ride...and went back down to 35 PSI.
And with the 400Ft.lbs. VW-motori diesel engine I dont have to worry about MPG`s, or liters pr. 10km`s as we tend to do our measurings by
