Saving Fuel & Riding In Style
03-28-2011, 05:46 PM
#1
JK Freak
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There are a few scattered posts/threads touching on gears, tires, susspention lift hight and their effect on fuel economy. I started this thread to discuss the best opions for fuel savings. I think that with recent huge increases to fuel costs this should be a popular thread to share ideas.
The idea is to have a Jeep that has the hight and attitude of a heavy duty jeep but at the same time saving every drop of fuel possible. Finding the right ratio!
For example my own delema.
My Jeep:
2009 Jeep Wrangler Rubicon 2 Door
4.5" Lift - tones of extra add ons, steel bumpers, fenders, armour, excetera.
6sp with 4:10 gears and 35" tires. (I dont plan on going bigger than 35")
I hear mixed opinions on weather I should go with 4:88 or 5:13 gears for performance and better fuel economy.
As it stands now my jeep feels like its pulling a trailer at all times and uses way to much fuel. I have steel bumpers and armour so there is extra weight on my jeep. I have installed a CAI and a performace Catback exaust kit and am also considering adding headers for even more bottom end.
What can I do to improve fuel economy without swaping my engine out with something else or droping my height or going to smaller tires?
what gears should I go with? 4:88 or 5:13? proper ratio.
Would headers help with fuel economy or make things worse?
Programmer? A good idea?
The idea is to have a Jeep that has the hight and attitude of a heavy duty jeep but at the same time saving every drop of fuel possible. Finding the right ratio!
For example my own delema.
My Jeep:
2009 Jeep Wrangler Rubicon 2 Door
4.5" Lift - tones of extra add ons, steel bumpers, fenders, armour, excetera.
6sp with 4:10 gears and 35" tires. (I dont plan on going bigger than 35")
I hear mixed opinions on weather I should go with 4:88 or 5:13 gears for performance and better fuel economy.
As it stands now my jeep feels like its pulling a trailer at all times and uses way to much fuel. I have steel bumpers and armour so there is extra weight on my jeep. I have installed a CAI and a performace Catback exaust kit and am also considering adding headers for even more bottom end.
What can I do to improve fuel economy without swaping my engine out with something else or droping my height or going to smaller tires?
what gears should I go with? 4:88 or 5:13? proper ratio.
Would headers help with fuel economy or make things worse?
Programmer? A good idea?
Last edited by Jeep Hound; 03-29-2011 at 05:45 AM.
03-28-2011, 05:53 PM
#2
JK Junkie
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You have a 6-speed, and you are concerned about gas mileage... then 4.88s all the way. I did 5.13s on mine, and those are WAY too low to provide decent MPG.
I am getting about 13 on the highway, and most of that is because I am turning too many RPMS. 4.88s should make up for lost power, but not so much as to cause you to turn the engine at excess RPMs and thusly kill your mileage.
I am getting about 13 on the highway, and most of that is because I am turning too many RPMS. 4.88s should make up for lost power, but not so much as to cause you to turn the engine at excess RPMs and thusly kill your mileage.
03-28-2011, 06:00 PM
#3
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I have a hell of a time not flooring it whenever I get the chance...so for me it's my driving habits that play the largest part in my Jeep's poor fuel economy. Have you tried a programmer? I know some have a fuel saver/economy setting and some people have reported having some (read: like 1-2 mpg ish) success with that. Headers would increase your throughput even more, so yes it would increase your HP, and theoretically you should be able to use less throttle to get the same job done, but we all know that headers sound too damn cool to not floor it.
IMO gearing would be your best bet...but which ratio depends on what you want your jeep to be best at. If you want better crawling, 5.13 would be better for you...if you're on highway more, 4.88's with your 6 speed should be more than enough to regain your lost power and keep you from having to floor it every time you want to move faster than the 89 Hyundai Pony beside you. Even doing all that, the best way to save gas is to use the skinny pedal less, but it's hard to look cool idling up to 70 mph
IMO gearing would be your best bet...but which ratio depends on what you want your jeep to be best at. If you want better crawling, 5.13 would be better for you...if you're on highway more, 4.88's with your 6 speed should be more than enough to regain your lost power and keep you from having to floor it every time you want to move faster than the 89 Hyundai Pony beside you. Even doing all that, the best way to save gas is to use the skinny pedal less, but it's hard to look cool idling up to 70 mph
03-28-2011, 06:10 PM
#4
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When I first bought the JKU in December I was heavy on the gas just see what it would do 
and it sucked gas like a Hummer 
Now I keep the RPM's down when possible. 2000 to 2500 unless necessary. No need to push it...a Jeep at 3500 RPM's is not going to get you there much faster than a Jeep at 2000 RPMs
Just pushed almost 300 miles before the low fuel buzzer went off yesterday. All interstate at 70 MPH for about 18 MPG.
and it sucked gas like a Hummer Now I keep the RPM's down when possible. 2000 to 2500 unless necessary. No need to push it...a Jeep at 3500 RPM's is not going to get you there much faster than a Jeep at 2000 RPMs
Just pushed almost 300 miles before the low fuel buzzer went off yesterday. All interstate at 70 MPH for about 18 MPG.
03-28-2011, 09:57 PM
#5
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You have a 6-speed, and you are concerned about gas mileage... then 4.88s all the way. I did 5.13s on mine, and those are WAY too low to provide decent MPG.
I am getting about 13 on the highway, and most of that is because I am turning too many RPMS. 4.88s should make up for lost power, but not so much as to cause you to turn the engine at excess RPMs and thusly kill your mileage.
I am getting about 13 on the highway, and most of that is because I am turning too many RPMS. 4.88s should make up for lost power, but not so much as to cause you to turn the engine at excess RPMs and thusly kill your mileage.
03-28-2011, 09:59 PM
#6
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When I first bought the JKU in December I was heavy on the gas just see what it would do and it sucked gas like a Hummer
Now I keep the RPM's down when possible. 2000 to 2500 unless necessary. No need to push it...a Jeep at 3500 RPM's is not going to get you there much faster than a Jeep at 2000 RPMs
Just pushed almost 300 miles before the low fuel buzzer went off yesterday. All interstate at 70 MPH for about 18 MPG.
and it sucked gas like a Hummer Now I keep the RPM's down when possible. 2000 to 2500 unless necessary. No need to push it...a Jeep at 3500 RPM's is not going to get you there much faster than a Jeep at 2000 RPMs
Just pushed almost 300 miles before the low fuel buzzer went off yesterday. All interstate at 70 MPH for about 18 MPG.
03-28-2011, 10:48 PM
#7
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Originally Posted by Scott-BC
I have a hell of a time not flooring it whenever I get the chance...so for me it's my driving habits that play the largest part in my Jeep's poor fuel economy. Have you tried a programmer? I know some have a fuel saver/economy setting and some people have reported having some (read: like 1-2 mpg ish) success with that. Headers would increase your throughput even more, so yes it would increase your HP, and theoretically you should be able to use less throttle to get the same job done, but we all know that headers sound too damn cool to not floor it.
IMO gearing would be your best bet...but which ratio depends on what you want your jeep to be best at. If you want better crawling, 5.13 would be better for you...if you're on highway more, 4.88's with your 6 speed should be more than enough to regain your lost power and keep you from having to floor it every time you want to move faster than the 89 Hyundai Pony beside you. Even doing all that, the best way to save gas is to use the skinny pedal less, but it's hard to look cool idling up to 70 mph
IMO gearing would be your best bet...but which ratio depends on what you want your jeep to be best at. If you want better crawling, 5.13 would be better for you...if you're on highway more, 4.88's with your 6 speed should be more than enough to regain your lost power and keep you from having to floor it every time you want to move faster than the 89 Hyundai Pony beside you. Even doing all that, the best way to save gas is to use the skinny pedal less, but it's hard to look cool idling up to 70 mph
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03-28-2011, 11:10 PM
#8
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In just about every one of the other thousand gearing threads, someone will mention the RPM charts in the Drivetrain faq's. Why? Because that is a great place to start. Measure your tires and plug the number in. 2400-2600 @ 70mph is a decent place to be. 2700-2800 you can live with. 3000rpm is a bit high. 2400-2600 would be better mpg's. 3k would be better low end off-road.
Figure out what you were at stock. Compare with where you are now. And then decide where you want to be.
It's not rocket surgery, and there are literally a thousand other threads asking the exact same question, so there is plenty of feedback to look through.
Here is 60-something pages of MPG data:
https://www.jk-forum.com/forums/show...getting/page66
And some HP/Torque curve charts in this one:
https://www.jk-forum.com/forums/show...500-3.8-engine
And I won't bother linking any other 'what gears should I go with' threads:
Figure out what you were at stock. Compare with where you are now. And then decide where you want to be.
It's not rocket surgery, and there are literally a thousand other threads asking the exact same question, so there is plenty of feedback to look through.
Here is 60-something pages of MPG data:
https://www.jk-forum.com/forums/show...getting/page66
And some HP/Torque curve charts in this one:
https://www.jk-forum.com/forums/show...500-3.8-engine
And I won't bother linking any other 'what gears should I go with' threads:
03-29-2011, 05:43 AM
#9
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Originally Posted by nthinuf
In just about every one of the other thousand gearing threads, someone will mention the RPM charts in the Drivetrain faq's. Why? Because that is a great place to start. Measure your tires and plug the number in. 2400-2600 @ 70mph is a decent place to be. 2700-2800 you can live with. 3000rpm is a bit high. 2400-2600 would be better mpg's. 3k would be better low end off-road.
Figure out what you were at stock. Compare with where you are now. And then decide where you want to be.
It's not rocket surgery, and there are literally a thousand other threads asking the exact same question, so there is plenty of feedback to look through.
Here is 60-something pages of MPG data:
https://www.jk-forum.com/forums/show...getting/page66
And some HP/Torque curve charts in this one:
https://www.jk-forum.com/forums/show...500-3.8-engine
And I won't bother linking any other 'what gears should I go with' threads:
Figure out what you were at stock. Compare with where you are now. And then decide where you want to be.
It's not rocket surgery, and there are literally a thousand other threads asking the exact same question, so there is plenty of feedback to look through.
Here is 60-something pages of MPG data:
https://www.jk-forum.com/forums/show...getting/page66
And some HP/Torque curve charts in this one:
https://www.jk-forum.com/forums/show...500-3.8-engine
And I won't bother linking any other 'what gears should I go with' threads:
03-29-2011, 05:53 AM
#10
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I'm told, whenever possible, use cruise control, supposedly it meters the fuel far better than your foot can. Though I'm not sure how hilly it is in Burnaby Joe country, if you're constantly hauling all that weight up and down hills, the cruise control will be all over the place when dealing with a manual transmission.
Not sure the current Loonie per Litre price, but I'm sure it's rough to deal with, your best bet is to be very light on the throttle until they come up with affordable carbon fiber bumpers.
Not sure the current Loonie per Litre price, but I'm sure it's rough to deal with, your best bet is to be very light on the throttle until they come up with affordable carbon fiber bumpers.