20.3 mpg

[AKghandi]

Reset your mpg reading lately? It's computed on average so if you're getting better mpg lately the average is only slightly improving

I reset mpg trip and avg speed every fill up

 

[The Champ]

Because more engine knock produced with the no ethanol fuel(data logged thousands of miles) the MPG loss with 10% ethanol is nowhere close to 3%. a few stations in my area sell both 91E0 and 93E10 from the same pump(different hoses). I filled up at the same pump week after week and compared the two....

I saw only a 0.8MPG improvement once I averaged every fill up with the no ethanol fuel, so it wasn't worth the extra 10-20cents a gallon over the comparable 10% ethanol 93 octane fuel.

First I want to repost what I said:

You do realize that without the ethanol, your mileage will improve by about 3%.

For what it's worth, I live close to several ethanol plants. The MN Corn Growers Association sponsors the "Ethanol Cup Challenge" at our local dirt track which is a $5,000 year end bonus split between the Top 10 drivers that have been running at least 15% ethanol.

I run E10 in my daily drivers because I know that it represents the best cost per mile. I know that from a pollution stand point it's better for the environment.

But I know that there is less energy in a gallon of E10 vs a gallon of E0. It's not much - just about 3% - just like I posted

I don't know what your "average" fuel economy is, but let's say it's 35MPG:

3% of 35 is 1.05 and that's pretty close to .8 - or about 3%.

"Actual results will vary for many reasons," says the fine print below the EPA gas mileage on any new car's Monroney sticker. The sticker then lists a few of them: driving conditions, driving style, vehicle maintenance.

There's one more: ethanol.

These days more than 95 percent of gas sold is E10, said AAA spokesman Michael Green. E10 is 10 percent ethanol and came into use after amendments in 1990 to the Clean Air Act, according to the Department of Energy. All cars are certified to run the stuff; in fact, it's difficult to find ethanol-free gas anymore.

Yet the more efficient ethanol-free blend is what the EPA uses to produce gas mileage figures posted on that new-car sticker.

And there's the problem. Ethanol's lower energy density leads to worse gas mileage, which is why using E85 (85 percent ethanol) in cars that accommodate it is usually a bad idea.

The math carries to E10, which has up to 10 percent ethanol. A gallon of E10 has 96.7 percent of the energy in one gallon of gasoline, according to the DOE's Alternative Fuels Data Center.

That means E10 fractionally lowers real-world gas mileage. How much? Try about 3 percent, said Toyota Senior Energy Researcher Mike McCarthy and Ford powertrain spokesman Paul Seredynski. AAA's Green and the EPA both pegged the E10 loss between 3 and 4 percent. That means a car that sports a 30 mpg EPA combined figure is already hampered from achieving that number. The starting line is really 29 mpg.

Read more at https://www.cars.com/articles/2013/...ry-for-the-worse-ethanol/#Ayflpfl4wxgACB5e.99

 

[AKghandi]

Ok well thanks for that enlightening bit of information.

I dont have ethanol any where near me. So let's get back on track.

 

[spacedout]

I reset mpg trip and avg speed every fill up

So what is your average speed? Its really telling of how much idling you are doing. Summertime with 80% highway my average speed is usually about 42mph or higher. In the Wintertime with 100% city driving and tons of idling I've seen my average speed as low as 15-20mph.

 

[spacedout]

But I know that there is less energy in a gallon of E10 vs a gallon of E0. It's not much - just about 3% - just like I posted.

The energy content of the fuel doesn't always tell the whole story, Exactly why I mentioned Testing done on the Ecoboost F150 gets better MPG on 93E30 than on 91E0. The reason? No ethanol fuel causes more knock events(you can compare 87E0 to 87E10, 91E0 to 91E10 in your sonic or any other modern turbo car to see this) which causes the engine to dial things back when you need the power the most and will effect your MPG.

Even though the EPA testing is done with no ethanol fuel, Daily at 45-70mph I easily beat the EPA highway rating with my sonic with E10 or E15 fuel. According to the energy loss you mention I should not even be able to achieve that MPG. I average 40mpg highway even on 15% ethanol(90 octane fuel).

Last I heard Alaska only has 90 octane no ethanol fuel available, so the OP unfortunately has one of the crappiest fuels available for the turbo sonic. With no ethanol fuel from my fleet testing these cars can get worse MPG. There is a Cenex in Middleton,WI that has two sets of islands, one with and one without ethanol. They offer 87E10, 90E10 and 93E10 on one and 87E0,89E0 and 91E0 on the other.

87 and 89 octane no ethanol could at times cause severe knock events 91 not as often but still could occur. Funny part? 90E10 mid-grade preformed better than the 91E0 at a significant price reduction. Heck even the 87E10 outperformed the 91E0 in controlling engine knock. We tested this on a fleet of (40 drivers)20 Cruze with 1.4T and even tried using different brands of fuel and found the same results. In hot weather or just dealing with heatsoak(city driving) we saw MPG loss across all cars and drivers when using no ethanol fuel of any grade.

So unfortunately that no ethanol fuel the OP is using could be contributing to their low city MPG especially if the outside temperatures are above 80F.

 

[AKghandi]

So what is your average speed? Its really telling of how much idling you are doing. Summertime with 80% highway my average speed is usually about 42mph or higher. In the Wintertime with 100% city driving and tons of idling I've seen my average speed as low as 15-20mph.

I idle only in traffic, and my avg speed ends up being right around 30mph


tried a tank of 87. only put in about 60 miles and my mpg readout was 20.5.. so it went down.
tomorrow I'm going on a road trip, I'll see what kinda mpgs I get on the highway. last highway trip was 36 mpg

 

[Rowdy_Sonic_RS]

That's crazy, I run my car and still get at least 25 with plus fuel.


Sent from my iPhone using Tapatalk

 

[The Champ]

The energy content of the fuel doesn't always tell the whole story, Exactly why I mentioned Testing done on the Ecoboost F150 gets better MPG on 93E30 than on 91E0. The reason? No ethanol fuel causes more knock events(you can compare 87E0 to 87E10, 91E0 to 91E10 in your sonic or any other modern turbo car to see this) which causes the engine to dial things back when you need the power the most and will effect your MPG.

Even though the EPA testing is done with no ethanol fuel, Daily at 45-70mph I easily beat the EPA highway rating with my sonic with E10 or E15 fuel. According to the energy loss you mention I should not even be able to achieve that MPG. I average 40mpg highway even on 15% ethanol(90 octane fuel).

Last I heard Alaska only has 90 octane no ethanol fuel available, so the OP unfortunately has one of the crappiest fuels available for the turbo sonic. With no ethanol fuel from my fleet testing these cars can get worse MPG. There is a Cenex in Middleton,WI that has two sets of islands, one with and one without ethanol. They offer 87E10, 90E10 and 93E10 on one and 87E0,89E0 and 91E0 on the other.

87 and 89 octane no ethanol could at times cause severe knock events 91 not as often but still could occur. Funny part? 90E10 mid-grade preformed better than the 91E0 at a significant price reduction. Heck even the 87E10 outperformed the 91E0 in controlling engine knock. We tested this on a fleet of (40 drivers)20 Cruze with 1.4T and even tried using different brands of fuel and found the same results. In hot weather or just dealing with heatsoak(city driving) we saw MPG loss across all cars and drivers when using no ethanol fuel of any grade.

So unfortunately that no ethanol fuel the OP is using could be contributing to their low city MPG especially if the outside temperatures are above 80F.

I don't understand how the same octane level of fuel would have more or less knock events. That's the whole concept of the octane rating is based on the "Anti Knock Index". 87 is 87 whether it's E10 or E0.

I also beat the EPA estimates on E10. But I've been able to beat the estimates on every car I've owned. Driving style has more to do with fuel mileage than fuel, IMHO. Remember that E0 only provides a 3% boost in fuel mileage - driving style and other factors can have a much bigger impact.

You are correct that all gas in Alaska is E0 - they have an exemption to the Renewable Fuel Standard imposed on the lower 48. But Alaska does have regular, midgrade and premium gas - gasbuddy.com will verify that for you. Or you can watch the youtube by Alaska John where this screen capture is from:

https://www.youtube.com/watch?v=nHugWXA8Bso

 

[ecohauler]

High ethanol fuel can cause pre-ignition (spontaneous combustion before the spark plug fires) even if the octane rating is the same, but I don't believe it will cause knock. The two are similar and treated in some of the same ways. Pre-ignition in this case is caused by a lean condition as the Sonic is not equipped with an alcohol sensor and stoichiometric for ethanol is significantly lower than gasoline.

 

[AKghandi]

didnt end up going on the road trip. but I have put 2 tanks of 87 through it.

still getting 20ish mpg. I even tried to drive more economically.. I'm getting pretty irritated.

 

[dannyg]

Have you tried manually calculating your MPG to confirm the numbers you're seeing on the DIC? Just to make sure it isn't some weird electronic problem...

The 2014 RS manual is rated 27 city / 34 hwy:

2014 Chevrolet Sonic 5 RS

Looks like you're hitting the 34 number on the highway but not the 27 number around town...

 

[AKghandi]

the DIC reads about 2mpg higher. I always calc it manually I divide how many gals I use to fill it by how many miles I drove since I filled it last.

 

[JesusTheAgnostic]

2014 RS 6speed. all stock 30k

So I'm getting pretty terrible mileage I'm averaging 20 mpg I have verified it through a dozen fill-ups.

I do A LOT of city driving, round 100 miles a day. I do drive the car pretty hard but mostly just accelerating, once I'm at the speed I want I just cruze'.

However even driving very gently, or as gently as I can before I feel I am a burden to others on the road, I still only manage 22.mpg

Highway I managed 35mpg

The only things I have done is new tires(235/45/17) and a K&N drop in panel.

Mpg was the same before both changes.

Tires are at correct pressure. They were actually over filled to 42-3 psi, I put them back to 35.

Anyone Have any thoughts? could it really be time for sparkplugs??

I'm no expert but here's what I think the problem is.

1. You have an RS. Not sure if I'm right but I think the transmission is geared differently in the RS so your RPM's are higher at any given speed than everyone else's. Robbing MPG.

2. You drive the car hard... in city. Do I really have to explain this? Sometimes when I drive hard I see my MPG's drop by 3 - 5 after a few pulls (on the highway). I could cruise under the speed limit for about an hour and might average those 3 - 5 back, but it's highly unlikely.

3. Did you get super sticky tires? I know when I put ultimate summer tires, or whatever the category is, my MPG's dropped by an average of 7 - 10.

Here's my recommendation though. Take it to the dealer and tell them you're experiencing ridiculously low MPG's. They might charge you to check it out but they should find if there's a problem with the car. Then if that doesn't work try hypermiling

I solved my "low" MPG problem by installing a BNR tune. My MPG's went from 33 -> 37 ish. Like I said I got ultra performance summer tires. I was at 42 average MPG before the tires.

I see that my post makes me sound kind of like a dick, but I'm not trying to be o:

 

[mitdr774]

Probably the biggest factory with city economy, especially with a small turbo engine, is how the right pedal is used. A couple rips up to speed will decimate your economy average. Idle time will also have a big impact. If you sit at lights a lot and then take off fast when it goes green you will never have decent economy.

 

[nickalltogether]

Probably the biggest factory with city economy, especially with a small turbo engine, is how the right pedal is used. A couple rips up to speed will decimate your economy average. Idle time will also have a big impact. If you sit at lights a lot and then take off fast when it goes green you will never have decent economy.

I agree fully. Sure, a 1.4 doesn't burn much gas, but 14.7psi on a 1.4 effectively makes it a 2.8... kinda like double the displacement.

 

[AKghandi]

well looks like I'll just have to deal with the mpgs for now. once I get a different job where I dont drive 8 hrs a night at 7/10ths it wont be such an issue.

I will be getting a BNR tune in about a month so hopefully that will help.

the tires I got were Uniroyal tiger paw GTZ all seasons.

 

[AKghandi]

I agree fully. Sure, a 1.4 doesn't burn much gas, but 14.7psi on a 1.4 effectively makes it a 2.8... kinda like double the displacement.

If that were true it would be getting better mpgs. My 92 Taurus SHO with the 3.0l v6 would easily pull 20 mpg driven much harder.

 

[T76]

What is seafoam?

 

[nickalltogether]

If that were true it would be getting better mpgs. My 92 Taurus SHO with the 3.0l v6 would easily pull 20 mpg driven much harder.

Sorry, you clearly have all the answers already.

 

[AKghandi]

Sorry, you clearly have all the answers already.

I meant no offense. Just saying something is wrong with my car. If a larger engine in a larger and heavier car that I drove much harder could achieve the same economy