The Official "My Gas Mileage *****" Thread

[Phil + Neela]

Here's my current MPG Calculator. I may have a slight affinity for excel...

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I noticed a rather funny trend from the chart. The hotter it got, the worse my gas mileage became. Hard proof that A/C degrades gas milage.

Looking forward to a road trip next week to finally see what my highway MPG will be. Thus far, everything has been mixed city/highway, or just city.

 

[tjkj2002]

Here's my current MPG Calculator. I may have a slight affinity for excel...

You must be registered for see images attach

I noticed a rather funny trend from the chart. The hotter it got, the worse my gas mileage became. Hard proof that A/C degrades gas milage.

Looking forward to a road trip next week to finally see what my highway MPG will be. Thus far, everything has been mixed city/highway, or just city.

AC does lower mpg's but less then a few tenth's of a MPG.Hotter it is the worst mpg's you will get due to hot air is less dense the cool air.

 

[Knightrider03m]

I'm starting to be OK with my mileage. I was getting above EPA sticker when I took my road trip so I"m good.

 

[Phil + Neela]

AC does lower mpg's but less then a few tenth's of a MPG.Hotter it is the worst mpg's you will get due to hot air is less dense the cool air.

Ooooooh, i didn't think of that. Makes sense though.

 

[Slava]

My first fill up was very good. I drove in "my granny" manner, 90% country roads and 10% city - 9.95 liters per 100 kilometers! (23.64 MPG). I have no doubts my MPG will drop when I'll drive as usual but I was curious to see what is the best case scenario :emotions34:

 

[Chuck C]

My '06 Jeep Liberty is a gas drunk

I am going to try some of the mods suggested asap.

Mods:
1.) Cat Back Exhausts are known to help mpg by 1~2 mpg sometimes 3.
2.) K&N filter
3.) High Flow Catalyic Converter
4.) Some people have mentioned with a throttle body spacer does help. (I can't verify this, because I don't have one)
5.) Synthetic Oil supposed to give maybe 1~2 mpg with a good filter.

My high school girlfriend was less of a pig than this Liberty.

Gets the best mileage of all parked in my driveway. I'll keep it if I hit the win for life this month, otherwise, it's time for old reliable again; another accord.

Or, I'll be using the wife's sonata.

 

[Chris_22]

putting a tune on my jeep and using cruise control/discretion on throttle, i managed to gain ~3 mpg. FWIW

 

[Jaber]

I'm on my 3rd fillup since owning the Jeep. Got 17.8MPG with 20% highway, 80% city. 2nd tank was 10% highway, 80% city and got 17.3MPG.

I can live with this

 

[iamweasel]

2nd tank was 10% highway, 80% city and got 17.3MPG.

and 10% free falling? that's good for an extra 3 or 4 mpg at least :happy175:

 

[Jaber]

and 10% free falling? that's good for an extra 3 or 4 mpg at least :happy175:

10% is the mystery section :happy160:

 

[SabaII]

Sitting at 18.2MPG right now. I drive 12miles to and from work with 1mile of that 'city' type driving. The rest is 67mph cruising pretty flat. I do that 5 days a week. Weekends are anyones guess as to how I am driving. I probably do 19 on the highway and 16-17 in town. I am pretty easy on the throttle and use cruise. 3.7l 45rfe on 235-75-16s. If I could get it up a bit I would be happy but I accept where its at now.

 

[redpoint5]

Basic Things:
1.) Check Air Pressure of tires, lower pressure = more rolling resistance.
2.) Check to make sure air filter is clean. Won't help. Clogged air filter is like closing the throttle.

Mods:
1.) Cat Back Exhausts are known to help mpg by 1~2 mpg sometimes 3.
2.) Aftermarket Cold Air Intake or Drop in K&N filter
False. Just the opposite is true. Warm air intakes will very slightly increase fuel mileage and slightly decrease top end power.
3.) High Flow Catalyic Converter
4.) Some people have mentioned with a throttle body spacer does help. (I can't verify this, because I don't have one)
5.) Synthetic Oil supposed to give maybe 1~2 mpg with a good filter.
6.) Some people mention better spark plugs can help Not likely as long as current spark plugs are in good shape.

Hotter it is the worst mpg's you will get due to hot air is less dense the cool air.

The first part is correct, but the second part does not follow. Hot air is less dense, which means less wind resistance. Driving at altitude or in hot weather will increase fuel efficiency since less air must be pushed around.

 

[tjkj2002]

The first part is correct, but the second part does not follow. Hot air is less dense, which means less wind resistance. Driving at altitude or in hot weather will increase fuel efficiency since less air must be pushed around.

Refering to the air coming into the intake,not the air your driving through.

Now to cold of incoming intake air can reduce mpg's but your talking about below freezing temps then,again not talking about the air your driving through.

Cold air is more dense,hot air is less dense and when talking about the air coming into the engine you want denser air.If your engine is sucking in 50 degrees air,that would be 50 degree air entering the combustion chamber,you will make more power and more mpg's then your engine sucking in 150 degree air.


Oh and driving at high altitude decreases mpg's due to less dense air by default due to altitude.Your engine must work harder at 6000' then it does at 2000' which will reduce mpg's/power,known and proven fact.

 

[sevenhelmet]

Less wind resistance at higher temps is technically true, but wind resistance is far from the only factor. Vehicles do get better MPGs at higher temperatures... up to a point. The altitude, humidity, and temperature of the engine and various drivetrain parts come into play as well. Usually 70-80F is the best operating temperature, much above that and the engine works harder to keep itself cool. Also, there is another big reason vehicles don't get better MPG in the summer:

Air Conditioning.

Troy, you beat me to the punch on the altitude discussion.

 

[Ry' N Jen]

Last tank of fuel our Rig got 23.4 mpg!
All Freeway at a constant 75 mph.
No, no EVIC; just good Old fashion math.

 

[sevenhelmet]

I use an iPhone app that tracks my mileage at every fill-up. My best right now is around 22MPG on a weekend road trip, but I am averaging about 19 right now. The EVIC reads slightly optomistic, so I only use it as a trend indicator.

 

[redpoint5]

Refering to the air coming into the intake,not the air your driving through.

Now to cold of incoming intake air can reduce mpg's but your talking about below freezing temps then,again not talking about the air your driving through.

Cold air is more dense,hot air is less dense and when talking about the air coming into the engine you want denser air.If your engine is sucking in 50 degrees air,that would be 50 degree air entering the combustion chamber,you will make more power and more mpg's then your engine sucking in 150 degree air.


Oh and driving at high altitude decreases mpg's due to less dense air by default due to altitude.Your engine must work harder at 6000' then it does at 2000' which will reduce mpg's/power,known and proven fact.

Incorrect. Fuel injected engines routinely get better fuel economy at higher altitude for 2 reasons. The first is that the thinner air is easier to push through, which is very important in a vehicle that gave no consideration to aerodynamics. The second reason is that the throttle must be opened further to produce the same power as at sea-level. A wider-open throttle has less pumping losses. An open throttle allows the engine to breath more freely and the pistons have less vacuum to work against.

Pressing the throttle further doesn't mean the engine is "working harder". The throttle merely controls how much air to restrict to the engine. The ECU then injects an appropriate amount of fuel according to how much oxygen the engine has.

People who are most concerned with fuel economy will install a warm air intake (WAI) to reduce the density of air entering the engine. This reduces peak engine power, but it also forces the driver to open the throttle further for a given amount of power. This is a proven method to improve fuel economy in nearly any vehicle.

Check out this post at ecomodder.com. These guys are serious about getting every last mile out of a tank of gas and they do ABA testing to verify their results.

To sum up this post, if you want more power, install a cold-air intake, drive when it's cold out, and at sea-level. If you want better FUEL ECONOMY, install a warm-air intake, drive when it's warm out, and at elevation.

 

[0240kliberty]

My Libby gets 16.1 highway miles. It's a 02 only mod to mess with that is 235/75-16 tires and soft 8s.

 

[first&lastKJ]

Just checked our 02 with 245/75/16 and 2.5 inch lift after returning from the badlands in Attica In. and got just over 12 mpg. That was pulling a 12 foot trailer with two ATV's on it.

 

[tjkj2002]

Incorrect. Fuel injected engines routinely get better fuel economy at higher altitude for 2 reasons. The first is that the thinner air is easier to push through, which is very important in a vehicle that gave no consideration to aerodynamics. The second reason is that the throttle must be opened further to produce the same power as at sea-level. A wider-open throttle has less pumping losses. An open throttle allows the engine to breath more freely and the pistons have less vacuum to work against.

Pressing the throttle further doesn't mean the engine is "working harder". The throttle merely controls how much air to restrict to the engine. The ECU then injects an appropriate amount of fuel according to how much oxygen the engine has.

People who are most concerned with fuel economy will install a warm air intake (WAI) to reduce the density of air entering the engine. This reduces peak engine power, but it also forces the driver to open the throttle further for a given amount of power. This is a proven method to improve fuel economy in nearly any vehicle.

Check out this post at ecomodder.com. These guys are serious about getting every last mile out of a tank of gas and they do ABA testing to verify their results.

To sum up this post, if you want more power, install a cold-air intake, drive when it's cold out, and at sea-level. If you want better FUEL ECONOMY, install a warm-air intake, drive when it's warm out, and at elevation.

Boy you need to stop thinking everything you read on the internet is true or lay off the wacky weed.

You will get worse mpg's at higher altitude,known fact and has been known for over 70 years.You loose HP and higher altitude,again another known fact for over 70 years,which means your engine must work harder at higher altitude thus worse mpg's.For how much power you loose at high altitude is far greater then the advantage of driving through thinner air.

Where your throttle is has everything to do with how much gas you use as the TPS sends info to the PCM to match fuel flow for throttle position.The KJ already comes with a CAI right from the factory.

Your whole post and everything in it would leave,like myself,any ASE Master Tech rolling on the ground laughing and give most automotive engineers a heart attach.