Gas Mileage
06-20-2011 | 03:23 AM
#1
Thread Starter
CF Veteran
Joined: May 2011
Posts: 1,201
Likes: 0
From: Somerset,Ky
Year: 1999
Model: Cherokee
Engine: 4.0
Gas Mileage
Well guys, i love my jeep but the thing is only getting like 14-15 mpg... i cant be easy on the skinny pedal lol...
No but really ima get straight to the point haha, what could i possibly do to get better gas mileage? what could i replace? what could i add?
No but really ima get straight to the point haha, what could i possibly do to get better gas mileage? what could i replace? what could i add?
06-20-2011 | 03:54 AM
#2
Registered Users
Joined: Mar 2009
Posts: 4,057
Likes: 0
From: Western NY
Year: 2001
Model: Cherokee
Engine: 4.0 I6
Not much really you can do.. Your driving a brick on wheels.. Keep the maintence up on it and try your best to stay light on the gas pedal. I always got 14-16 mpg on my XJ when I had it.. I expected that from it so I was content. Obviously the less weight in it/on it the better it will do. Also if your running a 33 or bigger and haven't regeared, regearing your jeep will help a bit. Run AT's instead of MT's, All that will help a little bit, but since your getting 14 15 mpg that is normal for a XJ.. Your really not gonna do much better..
06-20-2011 | 10:20 AM
#4
CF Veteran
Joined: Jun 2010
Posts: 2,117
Likes: 3
From: Ohio
Year: 1998
Model: Cherokee
Engine: 4.0 stock
Typically the best way to improve fuel efficiency is to improve driving efficiency.
Mechanical and physical ways to improve efficiency...
Disclaimer: This entire post is opinion based only on personal experience. Take it how you will.
- Hills kill MPG.... if you can find a different route with less of a grade, the engine can work less going up and the engine can be the brake going down.
- Brakes kill MPG.... If you think about it... the braking system essentially converts forward momentum into heat. The forward momentum is generated by engine power which is generated by fuel. So using the brakes essentially wastes fuel. Now this obviously doesn't mean you should never use them... just using them less and using the engine to slow down will increase fuel economy as well as make the overhaul interval for the brake system longer.
- If you drive in town 25-35MPH shifting into 3 instead of D can greatly aid in keeping the engine operating in an efficient RPM while preventing the trans from "hunting" for the right gear. A side benefit in my experience is also it can help reduce the chances of speeding... which saves you a ticket... Also while towing use 3 so you don't overheat the transmission.
Mechanical and physical ways to improve efficiency...
- Removing weight will help. If you carry a bunch of junk around that you do not need all you are doing is paying money to haul it with you.
- Improper calibration of speedometer... this is a big killer of MPG's without being a killer of MPG's. Your calculations depend on an accurate measurement of distance Vs volume of fuel used. If you have larger tires you will travel farther than your odometer said you went. This means your calculations will be off.
- Wind resistance... If you have a big ol' roof rack with a huge spare on top that might look cool but the wind hitting it on the highway essentially makes it a large air brake. streamlining the vehicle will improve MPG.
- This one is obvious... but keeping your vehicle maintained will be one of the largest fuel efficiency factors next to driving habits. Keep the engine tuned up and happy so it is efficient. Use quality parts and products not just the cheapest. Use the proper spark plugs with the proper gap. Use the right weight of motor oil for the conditions you are in. Keep the fluid in the transfer case, trans and diffs changed... remember the T case and diffs do not have filters to change. if you never have done it.... do it!
- Fuel additives.... this is a very touchy subject... while some are legitimate additives that do specific things there is a majority that are snake oil that does absolutely nothing or worse...
- In my experience using a fuel system cleaner is smart. But the ones that claim they clean carbon out of your engine with one use is BS. Simply the fuel system cleaners help to dissolve varnish. If your car has never sat before you will likely never need it. But it is cheap so it isn't going to hurt to use it every so often just in case you fuel up with some older fuel from a mom and pop gas station.
Disclaimer: This entire post is opinion based only on personal experience. Take it how you will.
Last edited by razor02097; 06-20-2011 at 10:24 AM.
06-20-2011 | 10:35 AM
#5
CF Veteran
Joined: Jun 2010
Posts: 2,501
Likes: 4
From: Flint/Asheville
Year: 1995
Model: Cherokee
Engine: 4.0 HO
Get rid of the slush box and swap in a manual. Stock i was at 21-23 mpg (2wd 5sp), now with lift and different gearing (3.07-3.55) i still get 18-19 everywhere, Sometimes i get into the 20's still but rarely. I dont really dive gingerly either and only have 3 mile commute to work
Auto use up alot of the engine's HP and thus uses more fuel. I personally think that the aw4 shifts too high of rpms. I almost never take mine above 2k rpms, then again i have 3.55 gearing with only 235/74r15 tires. Might change when i get 33's
Auto use up alot of the engine's HP and thus uses more fuel. I personally think that the aw4 shifts too high of rpms. I almost never take mine above 2k rpms, then again i have 3.55 gearing with only 235/74r15 tires. Might change when i get 33's
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06-20-2011 | 10:46 AM
#10
CF Veteran
Joined: Jun 2010
Posts: 2,117
Likes: 3
From: Ohio
Year: 1998
Model: Cherokee
Engine: 4.0 stock
I think this article sums it up nicely...
http://www.articleclick.com/Article/...Spacers/918947
After reading many many people having little to no results I decided not to buy one.
http://www.articleclick.com/Article/...Spacers/918947
After reading many many people having little to no results I decided not to buy one.
06-20-2011 | 01:39 PM
#11
Senior Member
Joined: Jun 2011
Posts: 967
Likes: 0
From: Brookfield, WI
Year: 1997
Model: Cherokee
Engine: 4.2L bored out 4.0L I6
high-flow intake + bored out TB+ TB spacer + high-flow performance exhaust = performance gain/mpg increase
any of these separate will yield little to no change
any of these separate will yield little to no change
06-20-2011 | 01:53 PM
#12
CF Veteran
Joined: Jun 2010
Posts: 2,117
Likes: 3
From: Ohio
Year: 1998
Model: Cherokee
Engine: 4.0 stock
For an engine with a carburetor you might see gains but on a multiport fuel injected motor....IMO it's a waste of money. Better to spend it on boring out your TB. Again after I researched it... I decided not to buy it.
http://www.jeepz.com/forum/jeep-perf...ally-work.html
Throttle Body Spacers (Primarily the "Helix" style):
These spacers do not provide any gains in HP at all. They claim to increase TQ and MPG but we tested one and it gained nothing. The Dyno showed no gains in HP or TQ. We also had contacted one of the manufacturers for their comments on them and here's the direct quote (from email):
--------------------------------------------
From: AirAid Info
Subject: Re: AIRAID.COM Contact
Dear Sir, thank you for your inquiry in our products. The spacer makes no HP on the Dyno. It makes all of it's power in torque in the low end. If you haven't noticed any power on the Dyno or the track then it's doing what it's supposed to. You would not see any gains down the 1/4 mile or increases on the Dyno. The idea of the spacer is to improve overall drivability and fuel mileage. In most cases when people install a bolt on part they expect better mileage and power, what happens is they are into the throttle a lot more than before trying to test performance and that's when the decrease in mileage happens.
Sincerely,
<Airaid Technician>
-------------------------------------------
Points to look at:
"The spacer makes no HP on the Dyno. It makes all of it's power in torque in the low end."
"If you haven't noticed any power on the Dyno or the track then it's doing what it's supposed to."
"The idea of the spacer is to improve overall drivability and fuel mileage."
So...it doesn't make any more HP, is not supposed to help in 1/4 mile performance (or on the Dyno), and is mainly for mileage and bottom end Torque. Well, Dyno's show TQ figures and there were no changes, mileage stayed the same, and 1/4 mile performance wasn't affected on the several others who have tried it"
These spacers do not provide any gains in HP at all. They claim to increase TQ and MPG but we tested one and it gained nothing. The Dyno showed no gains in HP or TQ. We also had contacted one of the manufacturers for their comments on them and here's the direct quote (from email):
--------------------------------------------
From: AirAid Info
Subject: Re: AIRAID.COM Contact
Dear Sir, thank you for your inquiry in our products. The spacer makes no HP on the Dyno. It makes all of it's power in torque in the low end. If you haven't noticed any power on the Dyno or the track then it's doing what it's supposed to. You would not see any gains down the 1/4 mile or increases on the Dyno. The idea of the spacer is to improve overall drivability and fuel mileage. In most cases when people install a bolt on part they expect better mileage and power, what happens is they are into the throttle a lot more than before trying to test performance and that's when the decrease in mileage happens.
Sincerely,
<Airaid Technician>
-------------------------------------------
Points to look at:
"The spacer makes no HP on the Dyno. It makes all of it's power in torque in the low end."
"If you haven't noticed any power on the Dyno or the track then it's doing what it's supposed to."
"The idea of the spacer is to improve overall drivability and fuel mileage."
So...it doesn't make any more HP, is not supposed to help in 1/4 mile performance (or on the Dyno), and is mainly for mileage and bottom end Torque. Well, Dyno's show TQ figures and there were no changes, mileage stayed the same, and 1/4 mile performance wasn't affected on the several others who have tried it"
06-20-2011 | 02:12 PM
#13
CF Veteran
Joined: Jun 2010
Posts: 2,501
Likes: 4
From: Flint/Asheville
Year: 1995
Model: Cherokee
Engine: 4.0 HO
Yea the whole TB spacer thing has been beat to death. They work on the premise that they mix the air and fuel better. Since jeeps spray fuel basically right into the combustion chamber, the added volume of air from spacers do nothing to help mix the air/fuel. So basically junk if there isnt a carb bolted on top
06-20-2011 | 03:32 PM
#14
CF Veteran
Joined: Apr 2011
Posts: 1,291
Likes: 0
From: ellington, missouri
Year: 1990
Model: Cherokee
Engine: 4.0l inline 6cyl
completely off topic i guess, but the last time i put 20 bucks in, filled it lil over half, pushed the mileage reset thing. recently refilled and it said 34.2. just wondering if anyone knew what this ment.