Gas Mileage FAQ

[Bebop]

Originally Posted by lovely09

Here are some gas mileage tips:

*Drive more efficiently
*Keep your car in shape
*Plan & combining trips
*Choose a more efficient vehicle

[etothen]

So, now that my stock 09 wrx has 15K on it I noticed that the mileage had improved considerably, around 5k my average was 20.5+- in mixed Highway/Canyon driving (I live 4 ½ miles up a canyon and the trip to town is 19mi each way).
Recently I noticed that my average mileage on Trip log A was up to 24.5 over the last 1400 miles, mostly the same route. So I did a quick check of what my mileage was in the canyon (14.5mpg) and found that I must be doing fairly well on the highway. Turns out I am, cruise at 64-65 between lights (4 in 14 miles, it is US 30, Scappoose to Portland OR) and I am getting 31.4, averaged over 10 runs, all in the rain, it has been raining quite a bit here lately.
As I don’t believe I have a magic car or a poorly calibrated odometer I assume this is fairly the norm, but I am still quite surprised, happily so, but surprised.

[pepper06]

I'm not sure how relevant this is to anything that's been said in the past few pages, but it's definitely relevant to gas MPGs.

I did a speech in my communications class a couple days ago on hybrid automobiles vs gasoline, and why hybrids weren't worth the money (at least not yet). I'm sorry this wasn't done with a soobie, but they don't make a hybrid I could compare one of their gas cars to. I found an equation on AOL autos that can find out how much time you have a drive a hybrid car (which costs more than a comparable gas car) until the money you've saved on gas has outweighed the extra price tag on the hybrid. This is really interesting.

Step 1: Take EPA's average miles traveled per year (15000) and divide it by the combined MPG reading for whatever car you choose.

Step 2: Multiply that number by the average gas price (as of a few days ago, it was $2.67/gal). This will yield the car's annual fuel cost.

Step 3: Complete the above equation for both the hybrid and gasoline vehicle.

Step 4: Once you have the annual fuel costs for each car,find the difference between them.

Step 5: Divide the cost difference between each car by the difference in annual fuel costs and you will get the length of time it will take you, driving 15000 miles/year, to make up the extra money paid for a hybrid in gas $.

For the example, I used a 2010 Honda Civic Sedan (about 33 mpg combined) VS a 2010 Honda Civic Hybrid Sedan (about 41 mpg combined).

Gasoline: 15000/33 = 454.54 x 2.67 = $1,213.62
Hybrid: 15000/41 = 365.85 x 2.67 = $976.81
1213.62 - 976.81 = $236.81 difference
Difference in price: $8,145 (according to Honda.com)
8145/236.81 = about 34!

I was like, holy ****! I double checked this, and it holds true. As of now, if you have a 2010 Honda Civic Hybrid, you have to drive 15000 miles a year for 34 years until you've made up that extra $8,145 you paid in saved gas. How about that? I thought that number was more like 6 or 8 years, not 34 years. However, this number (34) will go down considerably if gas goes back up to 4 or 5 bucks a gallon.

But still, I thought that was pretty cool.

Is that Hybrid Worth It?

Originally Posted by pepper06

I'm not sure how relevant this is to anything that's been said in the past few pages, but it's definitely relevant to gas MPGs.

I did a speech in my communications class a couple days ago on hybrid automobiles vs gasoline, and why hybrids weren't worth the money (at least not yet). I'm sorry this wasn't done with a soobie, but they don't make a hybrid I could compare one of their gas cars to. I found an equation on AOL autos that can find out how much time you have a drive a hybrid car (which costs more than a comparable gas car) until the money you've saved on gas has outweighed the extra price tag on the hybrid. This is really interesting.

Step 1: Take EPA's average miles traveled per year (15000) and divide it by the combined MPG reading for whatever car you choose.

Step 2: Multiply that number by the average gas price (as of a few days ago, it was $2.67/gal). This will yield the car's annual fuel cost.

Step 3: Complete the above equation for both the hybrid and gasoline vehicle.

Step 4: Once you have the annual fuel costs for each car,find the difference between them.

Step 5: Divide the cost difference between each car by the difference in annual fuel costs and you will get the length of time it will take you, driving 15000 miles/year, to make up the extra money paid for a hybrid in gas $.

For the example, I used a 2010 Honda Civic Sedan (about 33 mpg combined) VS a 2010 Honda Civic Hybrid Sedan (about 41 mpg combined).

Gasoline: 15000/33 = 454.54 x 2.67 = $1,213.62
Hybrid: 15000/41 = 365.85 x 2.67 = $976.81
1213.62 - 976.81 = $236.81 difference
Difference in price: $8,145 (according to Honda.com)
8145/236.81 = about 34!

I was like, holy ****! I double checked this, and it holds true. As of now, if you have a 2010 Honda Civic Hybrid, you have to drive 15000 miles a year for 34 years until you've made up that extra $8,145 you paid in saved gas. How about that? I thought that number was more like 6 or 8 years, not 34 years. However, this number (34) will go down considerably if gas goes back up to 4 or 5 bucks a gallon.

But still, I thought that was pretty cool.

Is that Hybrid Worth It?

Awesome read. Hybrids are a joke. If you want gas mileage, why not buy a diesel? They laugh at us here in Europe with their 77mpg Lupos.

[Donkey]

Volvo created a hybrid that could get up to 160 mpg's

Fuel-Efficient-Vehicles.org » TOMORROW’s HYBRID From Volvo: “ReCharge C30″

Originally Posted by Donkey

Volvo created a hybrid that could get up to 160 mpg's

Fuel-Efficient-Vehicles.org » TOMORROW’s HYBRID From Volvo: “ReCharge C30″

Nice. Probably has crap for power. Chevy is making the Volt too, which is supposed to get like 200mpg or something crazy. At least the diesels still have a little oomph. The Volt will be out sooner than the Volvo too by about 4 years. Nothing like $40,000 for 73hp though!

[pepper06]

OK, I've got a bit of an issue. I've owned my WRX for a few months now, and the MPGs I've been getting have always been disappointing. I kept telling myself that the more I drove it, the more they would improve because I'd become more familiar with the car. They haven't improved.

So, my question is, is this typical WRX gas mileage? Or is there a problem with my car. As seen in the picture below, I've gotten that many miles out of pretty much a whole tank. 272/16 is pretty much a solid 17 miles per gallon. Is that normal? I really believe I drive pretty responsibly...I've been driving stick since I was 15, and I hardly ever shift too far over 3000 RPMs. Even though I live in Germany and am on the autobahns pretty much every day, I really don't ever exceed 70 MPH (RPMs= 2/300 under 3000). Here are few conditions which could be affecting my car and/or my sense of gas mileage.

1. I stepped up to this from a 1997 Dodge Avenger ES with a 2 liter Mitsubishi Eclipse engine. It got GREAT gas mileage.
2. I've got a short ram intake.
3. It has been frigid lately in Germany. Many days never get above freezing, so the car tends to idle high for a little bit when I first start it in the morning to warm itself up.
4. Because it's cold and snowy, I used the de-froster more than normal.
5. I know for a fact that I have 2 bad O2 sensors...both of which have replacements in the mail somewhere.
6. At that level (in the pic), should my gas light be on?

Am I doing something wrong here? Does my car need to be tuned again (it's got 80k miles)? I'm no Subarologist, so I'm assuming more people on here would know better than me. Thanks for the help!!

[Donkey]

Originally Posted by pepper06

OK, I've got a bit of an issue. I've owned my WRX for a few months now, and the MPGs I've been getting have always been disappointing. I kept telling myself that the more I drove it, the more they would improve because I'd become more familiar with the car. They haven't improved.



1. I stepped up to this from a 1997 Dodge Avenger ES with a 2 liter Mitsubishi Eclipse engine. It got GREAT gas mileage.
You bought a 2.5L forced induction vehicle for gas mileage? Maybe you should trade it in for a Prius.
2. I've got a short ram intake.
3. It has been frigid lately in Germany. Many days never get above freezing, so the car tends to idle high for a little bit when I first start it in the morning to warm itself up.
The colder air is,the denser it is requiring more fuel.
4. Because it's cold and snowy, I used the de-froster more than normal. Doesn't matter
5. I know for a fact that I have 2 bad O2 sensors...both of which have replacements in the mail somewhere.
Jebus........you think that might be the problem? Install the new sensors then whine about the gas milage
6. At that level (in the pic), should my gas light be on?
All cars are different,this is a given

Am I doing something wrong here? Does my car need to be tuned again (it's got 80k miles)? I'm no Subarologist, so I'm assuming more people on here would know better than me. Thanks for the help!!

You want better gas mileage?Read the whole thread, fix the O2 sensors,get a tune,maybe clean the MAF sensor and make sure your running 36 psi all around on the tires and don't buy a forced induction vehicle for gas milage.

[pepper06]

Originally Posted by Donkey

You want better gas mileage?Read the whole thread, fix the O2 sensors,get a tune,maybe clean the MAF sensor and make sure your running 36 psi all around on the tires and don't buy a forced induction vehicle for gas milage.

Haha, I was very aware that I'd experience a decrease in gas mileage, I'm not stupid. I just didn't think it would be so dramatic...I read thru a lot of the thread and it sounded like a lot of people were getting at least above 20 mpg's. That's the only reason I asked.

The cold air thing does make sense though...

Originally Posted by Donkey

and don't buy a forced induction vehicle for gas milage.

Then again Ron, a turbo can help fuel economy, as long as you're not flooring it all the time. It helps atomize the air, so if you're light on the throttle, you should see some good numbers. If anything, I would argue that our cars being AWD sucks as much gas mileage as a turbo does. I have friends with regular NA Impreza's and Legacy's and they aren't seeing any more mileage than I do with a turbo.

The new Cobalt SS turbo gets 35mpg on the highway easily. It's the FWD.

[Donkey]

Originally Posted by Wrinklechops

Then again Ron, a turbo can help fuel economy, as long as you're not flooring it all the time. It helps atomize the air, so if you're light on the throttle, you should see some good numbers. If anything, I would argue that our cars being AWD sucks as much gas mileage as a turbo does. I have friends with regular NA Impreza's and Legacy's and they aren't seeing any more mileage than I do with a turbo.

The new Cobalt SS turbo gets 35mpg on the highway easily. It's the FWD.

Yea AWD eats more gas than FWD or RWD regarless. My purpose in stating that was most people have a heavy right foot and like to drive it like you stole it. I can drive out of boost all day long if I try. Does that always happen? No. I get 26-28 mpg city and 32-34 hwy if I play nice. This is mostly due to a much bigger turbo than stock allowing me to stay out of boost easier. A turbo doesn't exactly help fuel economy any more than just being NA. If your boosting your eating gas and if your not its an exhaust restriction. I guarantee if I tuned your friends NA cars like I tuned my car they would easily see a huge increase in gas mileage. Whats their maintenance like? How about their tire pressure? How about their driving habits? We could easily keep comparing apples to oranges here..........

Stock for stock both the Colbalt and Impreza N/A versions have a higher MPG rating than their turbocharged brothers. According to Chevy's site the SS model gets 30 MPG hwy the N/A version gets 37 hwy. For Subaru the N/A Impreza gets 27 hwy while the WRX gets 25 hwy. Chevy has a 2.0L while the Subaru a 2.5L.

2010 Chevy Cobalt | Chevy Cobalt Coupe | Vehicle Specs

Originally Posted by Donkey

Yea AWD eats more gas than FWD or RWD regarless. My purpose in stating that was most people have a heavy right foot and like to drive it like you stole it. I can drive out of boost all day long if I try. Does that always happen? No. I get 26-28 mpg city and 32-34 hwy if I play nice. This is mostly due to a much bigger turbo than stock allowing me to stay out of boost easier. A turbo doesn't exactly help fuel economy any more than just being NA. If your boosting your eating gas and if your not its an exhaust restriction. I guarantee if I tuned your friends NA cars like I tuned my car they would easily see a huge increase in gas mileage. Whats their maintenance like? How about their tire pressure? How about their driving habits? We could easily keep comparing apples to oranges here..........

Stock for stock both the Colbalt and Impreza N/A versions have a higher MPG rating than their turbocharged brothers. According to Chevy's site the SS model gets 30 MPG hwy the N/A version gets 37 hwy. For Subaru the N/A Impreza gets 27 hwy while the WRX gets 25 hwy. Chevy has a 2.0L while the Subaru a 2.5L.

2010 Chevy Cobalt | Chevy Cobalt Coupe | Vehicle Specs

Ya, that SS is nuts.

My friends NA... one of them takes care of his car and it's a 2008. The other doesn't take care of his 2005.

I lost gas mileage after my "pro-tune", but that was because I was very lean before the tune. I understand stock tunes to be very, very rich, thus gas mileage could benefit from a slight leaning out - right?

I always understood AWD/4WD to have worse fuel mileage due to the drivetrain loss? Or is it the weight? I wonder what happens to the STi fuel economy when you use the DCCD to put all the power distribution to the front or rear?

[Donkey]

Originally Posted by Wrinklechops

I lost gas mileage after my "pro-tune", but that was because I was very lean before the tune. I understand stock tunes to be very, very rich, thus gas mileage could benefit from a slight leaning out - right?.Thats a given.........

I always understood AWD/4WD to have worse fuel mileage due to the drivetrain loss? Or is it the weight?

It's both. Regardless as you can see by the numbers I posted forced induction alone gets worse gas mileage but comparing two different cars is a moot point. The Cobalt had a huge change compared to the Subaru. Not sure where you got 35 hwy for the SS. As for the OP its also a moot point to ask until he gets his car in a better state of tune including two bad O2 sensors or to compare a 2.0L n/a FWD coupe to a AWD 2.5L turbocharged sedan.

[pepper06]

Originally Posted by Donkey

My purpose in stating that was most people have a heavy right foot and like to drive it like you stole it. I can drive out of boost all day long if I try. Does that always happen? No. I get 26-28 mpg city and 32-34 hwy if I play nice. This is mostly due to a much bigger turbo than stock allowing me to stay out of boost easier. A turbo doesn't exactly help fuel economy any more than just being NA.

2010 Chevy Cobalt | Chevy Cobalt Coupe | Vehicle Specs

I guess my real problem right now is just the weather. Germany's winters get pretty hard and it really hardly ever gets over 30 degrees (F). That combined with the AWD and my stock turbo could just being doing a number on my gas. Like I said, I really don't drive too hard unless I really want to. But, I still hear that turbo begin to spool up even when I don't want or need it to.

I hope I didn't come off as too much of a lunatic...lol. As I said before, I stepped up from a 97 Dodge Avenger so I'm totally in the dark when it comes to knowledge of turbos and stuff.

And if my O2 sensors would just get here...

[Donkey]

Originally Posted by pepper06

I guess my real problem right now is just the weather.

Your main problem is the O2 sensors. Second would be the stock tune,third maybe a dirty MAF from your intake and last being weather. I don't think you quite understand how important those sensors are especially if they are indeed damaged or functioning improperly.