poor mpg?

[Swordsmith]

Running E85 and driving like I enjoy, I get around 22mpg. Driving it reasonably, NOT grandma, but accelerating more gradually, staying near the speed limit, shifting at around 2K whenever I don't actually need the added power for merging, I got 31mpg. Same car, same mods, same road conditions.

Again driving normally, with 87 gasoline, I got 29mpg under the same conditions, and I bet I can get over 40mpg driving it gently. I haven't been in the mood to try that experiment yet, but I did get similar results last fall when the car was new.

Driver behavior seems to be the single biggest factor in mpg, which agrees with everything everyone else has posted here.

Other than that, tire inflation (more pressure= better mpg BUT worse traction), tire type (the stock Hankooks are pretty terrible all around), AC (the compressor costs you about 5 hp and 2-3mpg, worse going slow than going fast), intake (rumor has it an Injen will net you a couple mpg due to warming the incoming air, and cold air intakes may reduce your mpg for the opposite reason), octane of fuel (unverified, but people have reported getting a few more mpg out of higher octane, which compensates for the higher price per gallon) and weather: naturally driving into a headwind is worse, tailwind better, but also cold air worse warm air better, dry weather better, and so on. Even your elevation matters.

Still the thing you can most control is your driving. Why would you leave it at 3500rpm most of the time? Even I don't do that; sure I will go up to 6K while pulling up an onramp, and downshift into fourth when I want to pass... but cruising around at 80 I'm still in sixth, the car only needs around 25hp to keep moving at that speed anyway.

 

[ChevySonic]

That was with 87. I just started 93. Since I've been using it I went up 0.2mpg

 

[ahtoxa]

0.2 is such a small margin, that it could have been influenced by nearly anything, as one cannot drive the same route at the same time each day with 100% consistency of throttle input, traffic, etc.

 

[Macehammer]

Not to mention .2mpg isn't worth the extra gas cost...

 

[Moxie]

That's just it though, you can still speed, have fun and get great economy. Look at some of my scangauge stats from yesterday and today, top speed in the mid 70's, almost 5500 RPM (at WOT I might add), low average speed around 40 MPH and over 36 MPG. I should teach a class on how to do this.

I wish you would teach a class! I clearly have a lot to learn. I get around 28 MPG doing mostly city driving. I tend to accelerate fairly quickly, shifting around 3000-3500 RPM and then get up to high gears and stay at a constant speed at around 1500-2000 RPM. I coast when possible, but never actually put it in neutral unless I'm stopped. For the OP, this is with the 1.4 on 93 octane. I did get better MPG, around 33, when I was breaking in my engine and shifted at lower RPM. I agree driving style has A LOT to do with your MPG.

For those who know, this might be a dumb question, but if I put my clutch in when coasting would that be the same as putting it in neutral? Would that possibly help with MPG? Just thinking that would be safer to quickly engage the engine if necessary..

 

[Moxie]

http://www.sonicownersforum.com/forum/mpg-discussion/7069-video-tips-increasing-mpg-%24%24%24%24.html


Here

Thanks for this link!

 

[Swordsmith]

For those who know, this might be a dumb question, but if I put my clutch in when coasting would that be the same as putting it in neutral? Would that possibly help with MPG? Just thinking that would be safer to quickly engage the engine if necessary..

Clutch in and putting it in neutral accomplish the same thing (unless there's something wrong with your clutch); they disengage the engine from the wheels. There is some discussion, however, indicating that under some circumstances it is actually more productive to leave the car in gear, since in neutral (or clutch in, same thing) the engine is forced to burn a little fuel to keep idling, while in a certain rpm range it will be able to use no fuel at all while in gear.

Seems to me this is only useful when you want or at least don't mind, a little added drag, if coming down a steepish hill or when deliberately slowing, but again, there's some who say that the fuel saved more than makes up for the extra fuel needed to speed back up more often than if you'd been coasting.

For sure clutch in is better than leaving your foot on the throttle to keep speed up.

 

[$ub$onic]

Actually, no. As the 1.8 is designed to run on 87, higher octane fuel being the only variable (no mod, etc) will do absolutely nothing but waste your money. In fact, it is entirely possible to get WORSE mpg in a case like this by running higher octane.

Use 87, save money and report your MPG.

I disagree I ran 93 when my car was stock and it 1-2 more mpg out of it running the exact same way. It also ran slightly smoother. With that being said I do run 87 because of how much I drive

 

[ungawd]

I disagree I ran 93 when my car was stock and it 1-2 more mpg out of it running the exact same way. It also ran slightly smoother. With that being said I do run 87 because of how much I drive

That could be a result of temperature affecting air density. The 1.8 could benefit slightly from a higher octane in that situation as it could read slightly lean on 87.

 

[$ub$onic]

I could see that

 

[HADES20]

Speed makes a huge difference believe me I know

 

[ChevySonic]

If the cost of gas was an issue for me, than I definitely would use 87. But it isn't, so I don't mind spending the extra cash. It's not like its $4+ a gallon by me. But you all make some valid points on how to get some extra mpg. I'm just used to driving fast like I did with my old cobalt ss. I'm just going to lay off the down shifting and coast as much as possible.

 

[bmason01]

Just read all of these. I too have a few questions.

I have the 1.4t M6 LTZ hatchback. I read where it can run fine of 87 octane? Is this true? All of the stations here offer, 87,89, and 93.

Next question. I got about 25mpg on this tank(Calculated-Not going by dash). That's about 90% or more of city driving. I almost ALWAYS shift between 1500-2000 RPM's. I constantly find myself cruising in town, roughg 35-45 mph, in 6th gear. As everyone will, I will got WOT and "power shift" at times, but that's slim to none. Would this mpg be accurate for me?

Another thing, how accurate is the gauge that shows the mpg? I have noticed, this week actually, that the gauge is acting different. Even at a stoplight, at idle. I have see, the gauge constantly do down. It went down to about 17mpg, at one point, just at idle. When I start to drive off, it will slowly work its way up to about 25-29 mpg. IS this normal? It did just start. Before it would never go down while at idle at a light.

And finally, my tire pressure light has been on for a couple of weeks now. I know I need to check the pressure, I honestly just have been too lazy to yet. Will do that tomorrow though, as I am off work. But could this cause that kind of low mpg or the gauge going down?


Sorry for the book, just tried to be as detailed as possible. Thanks for any input or help everyone.

 

[sx sonic]

Bmason01- you can run whatever octane you want in your sonic. The 1.4t's ECM does have a fancy dual map mode that CAN allow for slightly better MPG and power. This is only true if it happens to detect knock on lower octane. I have personally not see any difference in power or MPG between octane grades, and I keep a log of every fill up.

The MPG display (DIC) accuracy does vary slightly between each car. Typically it is 1-3 mpg on the high side.

It will drop at idle when you're not moving, it is an average of fuel used over distance travel. When you're sitting idling you are getting 0 mpg! That will drop your average down. The fewer miles between reseting the DIC the more it will fluctuate, the more miles between resets the longer it will take to go Up or Down mpg wise. If you break it down to its core its fairly basic math, the bigger the pool of existing numbers the longer it will take for new numbers to sway it higher or lower.

Your tire light will not affect DIC operation. However the low tire will negatively affect your MPG. A low tire has larger contact patch plus more deflection. This mean more rolling resistance and worse MPG. Tires below 30psi typically start to have a very progressive and noticable change in tire wear and mpg, both in a bad way.


Check your tire pressures and set them to the recommended pressure, IMHO 38psi is a great compromise for ride, mpg, and avoiding low tire psi from temp flucs. Just don't exceed the max psi listed on the sidewall.


Next keep short shifting like you are and try to avoid unnecesary idling.

 

[Blissmaster13]

To OP, I feel your pain. I bought this car because my 98 Buick 3.8 V6 started taking a dive on me. My Buick got 20 MPG when I drove it "normally." I even had a 2006 Cobalt SS Supercharged 5-speed that averaged 24 MPG when driven "Normally."

Now, I bought this supposedly economical car and I am only averaging 24 MPG when I drive it like I drove my other cars. I have a 1.8 auto and when I drive normally, my shift points are between 2500-3000 RPM, I do about the same 60/40 split that you do.

I already took it to the dealership and they said everything is fine. I am trying the tips and tricks mentioned in this and other threads and am keeping my shift point right at 2000 RPM and half a tank in, I'm averaging 26.5 MPG with 50/50 split.

Needless to say, I am frustrated with the fuel economy that I am receiving. I don't feel that I should have to drive super slow to get on the lowest side of what the car is rated. I want to be able to drive normally like I have done on all my other cars and get decent mileage. I don't expect 35 MPG, but I would at least expect 28 or so with a 60/40 split.

Otherwise, I love the styling and quality of the car, just upset with the gas mileage. And, yes, I know this was kind of a lengthy post. Lol

 

[$ub$onic]

Wow that seems low even for a 1.8 auto

 

[Preloader]

Clutch in and putting it in neutral accomplish the same thing (unless there's something wrong with your clutch); they disengage the engine from the wheels.
since in neutral (or clutch in, same thing)

For sure clutch in is better than leaving your foot on the throttle to keep speed up.

Holding the clutch in and neutral are not the same. Holding the clutch in for extended lengths of time is bad behavior for the life of your clutch. It will overheat/glaze the friction disc, and speed up wear on the pressure plate springs.

It is always better to be in neutral, over holding the clutch in to disengage the engine from the wheels for any length of time.

 

[Isambard]

Holding the clutch in and neutral are not the same. Holding the clutch in for extended lengths of time is bad behavior for the life of your clutch. It will overheat/glaze the friction disc, and speed up wear on the pressure plate springs.

It is always better to be in neutral, over holding the clutch in to disengage the engine from the wheels for any length of time.

Bad for the throw out bearing as well. Not to mention that it tires your leg out

 

[Insanika]

What is considered an "extended period of time"? I get nervous at times waiting for traffic with it in and poised to jump out. Usually I just sit and wait, or coast, or etc in neutral.

 

[Preloader]

At a stop light it's OK. I was just suggestion that its not good behavior to coast for miles with the clutch pressed in.