20.3 mpg

[AKghandi]

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??

 

[minitrucking02]

Not plugs, maybe through some seafoam in the gas, thats what gm uses as their "fuel system cleaning service"
Other than that what type of gas from where?

 

[2014 Blue RS]

Mine runs great. Same year/model. I bought it new over 2 years ago and have done most of the mods mentioned on this forum minus bolt ons (bigger turbo). Below is a pic from yesterday. Could not be happier.

Time to start modding that thing! Or take it to the dealer for a check up.

FYI check engine light is for the catalytic converter I removed.

 

[AKghandi]

Mine runs great. Same year/model. I bought it new over 2 years ago and have done most of the mods mentioned on this forum minus bolt ons (bigger turbo). Below is a pic from yesterday. Could not be happier.

Time to start modding that thing! Or take it to the dealer for a check up.

FYI check engine light is for the catalytic converter I removed.
View attachment 12479

same color too

I'll try some seafoam, dont see how it could make much difference though.

I run 90oct from chevron. its the highest oct we can get here.

also what mods specifically do you have? and which made the most impact on economy?

 

[minitrucking02]

same color too

I'll try some seafoam, dont see how it could make much difference though.

I run 90oct from chevron. its the highest oct we can get here.

Cars are programmed for 87, unless you have mods, intaje exhaust tube etc, dont run higher. Higher octane is hsrder to ignite, causing you to run rich (negatable by how much, but true)

Run 87, like good gas tho. Shell mobil sunocco for at least 3 fillups then run seafoam and resume. No difference, dont waste money on high octane cuz clearly your gas is a thirsty bi***

 

[2014 Blue RS]

Seems weird to only get 20? Great color though! At this point you may as well mod it. At least do the cheap easy ones like the bypass. That doesn't cost anything.

 

[minitrucking02]

Seems weird to only get 20? Great color though! At this point you may as well mod it. At least do the cheap easy ones like the bypass. That doesn't cost anything.

I can honestly say I wish I went pearl or victory. The Onyx just shows everything the car wash sucks at (but they do undercarage and its 19.99 a month and in New England that's pretty awesome).

Anywho, do the 87 fill up for a few weeks and track it. No difference versus 90, try seafoam, track it. Then go back to 90, track it. If no difference, go back to 87 and call it a day.
Or go to the dealer, because that is so much lower than advertised CAFE you might get a lemon law or rebate or something.

 

[minitrucking02]

btw, what mudflaps you rocking

 

[2014 Blue RS]

Loved the pearl but wasn't willing to pay extra for it. I'd get that to the dealer asap to document what's going on.

 

[KnucklestheRS]

This really doesn't sound right. My RS is 90% city/suburb 10% highway. My average is at 34.7 in the car and that has been consistent with at the pump calculations.

My trip to work is only about 30 miles but shorter runs should be worse for MPG's. Do you drive it really hard? I drive like a Grandma most of the time to be honest.

Turbos can destroy gas mileage if your constantly accelerating hard.

 

[spacedout]

What is your average speed? I suspect you also do allot of idling, be it in traffic or just letting the car run, either way you get ZERO MPG anytime you idle because you are burning fuel while not moving.

This all gets averaged into whatever MPG you were already getting, so if your accelerating hard frequently or even just accelerating normally allot you can expect city EPA MPG or lower. My typical average MPG below is about 80% highway, however in the winter time with remote start use daily(multiple times) and allot more city driving I've had fill ups around 20MPG. Though that is pretty bad MPG I remember my old 2.2L ecotec or my 2.5L iron duke getting 13MPG in those same conditions.

AC use also will bring down your MPG below the EPA ratings, Not sure they use it during their testing considering they test indoors in a laboratory. I loose 3-4MPG any day I use the AC vs cracking the windows on my 100-200 mile highway route.

 

[spacedout]

Cars are programmed for 87, unless you have mods

When above 80F outside these engines are much more prone to knock when running 87 octane. Sure the knock sensor dials things back when this occurs, but your MPG will suffer as will the power.

There has been some testing with the cruze 1.4T that shows improved MPG in warm weather when running premium. The test on the website below mirrors my own experience over 4 years with my 2012 cruze and now this summer with my 2015 sonic, in hot weather these engines preform better on premium fuel. To quote the article:

"Instead, the hot weather led to a very noticeable lack of drive-away power and sub-par highway fuel economy. Subsequent discussions with GM powertrain bigwigs and our own Jay Kavanagh revealed that small turbo engines are especially octane sensitive, which means their computers may aggressively dial back the engine calibration in order to ward off knock in high load situations or in very hot weather."

The Ultimate Hot Weather MPG Test - Regular vs. Premium - 2011 Chevrolet Cruze LTZ Long-Term Road Test

Now with that said, not all premium fuel is created equal. Allot of stations in my state only sell crappy 91 octane no ethanol fuel, I find these engines run much better on 93 octane with 10% ethanol. I go out of my way to get this fuel during hot weather months.

 

[AKghandi]

btw, what mudflaps you rocking

Rokblokz.



Thanks for the input guys, I filled up with 90 at a different gas station and the car seemed to run better, and had more power. whats more I managed 21.3 mpg. not much but its something.

Next tank I'll fill it with 87 and see what happens

 

[The Champ]

Now with that said, not all premium fuel is created equal. Allot of stations in my state only sell crappy 91 octane no ethanol fuel, I find these engines run much better on 93 octane with 10% ethanol. I go out of my way to get this fuel during hot weather months.

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

Ethanol is a "cleaner" fuel as far as emissions go, but it has less energy than gasoline, so it reduces fuel mileage.

I go out of my way to buy that "crappy 91 octane no ethanol fuel" for my '64 GTO because of the benefits that it provides a better driving experience for an engine that was originally designed to run on straight gas. E10 will work, but it is more prone to absorb moisture, which is not good for a car that isn't driven year round.

When we built my 462 ci engine - it was built to be able to run on the most readily available "premium" octane available in my area - which is 91. I know a few stations that have 92 in my area - but can't think of a single station with 93 around me (there may be - I just haven't seen them).

If I was inclined to pay $.50 more per gallon to get a 3% improvement in my fuel mileage in my Sonic - I'd buy the "crappy 91 octane no ethanol fuel".

If max octane would improve fuel mileage - run E85 - it's the highest octane (non racing fuel) you can buy. But being 85% ethanol the mileage drop (not improvement) is actually somewhere around 30%.

I actually had some discussions about building my 462 to run on E85 because of the higher octane (which would have allowed me to run higher compression/more advanced tuning to get more power) because I really didn't care about the fuel mileage (and E85 is readily available and much cheaper than "crappy 91 octane no ethanol fuel") - but their were too many negatives involved. Mainly that long storage period where the 85% ethanol would be absorbing moisture.

 

[spacedout]

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

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.

 

[spacedout]

I actually had some discussions about building my 462 to run on E85 because of the higher octane (which would have allowed me to run higher compression/more advanced tuning to get more power) because I really didn't care about the fuel mileage (and E85 is readily available and much cheaper than "crappy 91 octane no ethanol fuel") - but their were too many negatives involved. Mainly that long storage period where the 85% ethanol would be absorbing moisture.

The storage thing is the only reason to not build for ethanol use, any engine that is going into storage for more than a few months should use no ethanol fuel unless you can drain the system easily. I live really close to an ethanol plant and they offer many grade levels including E35, which is comparable to 93octane fuel, but about 30 cents a gallon less than regular. The reason I mention this, I have read some interesting MPG testing done on the Ecoboost ford F-150, and the truck actually gets better MPG on E30 than 91E0.

 

[nickalltogether]

You're probably driving the car harder than you realize, I hate to say. The fact that your highway mpg is still "normal" makes it more apparent.

As far as being a burden to traffic, 90% of people are just oblivious to the world and their driving and just floor it from every stop light. These people will be on your bumper no matter how fast or slow you accelerate.

For what it's worth, my normal driving style is fairly conservative (slow) with shifting at 3000, but if I go even more conservative and shift at 2000 I get noticeably better mpg. If you're taking the car up to 4000 before shifting for example you may be burning a good bit more gas.

 

[carsNskis]

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

 

[ScarabEpic22]

I drive my 13 RS 6MT (the transmission makes a HUGE difference in MPG, especially on the RS) and all city I get 26-28mpg. Highway I'll get 34-35mpg and my usual commute is about 2mi of city then 18mi of highway, right between 29-30mpg. (Bone stock)

I hate to rev the heck outta it around town, but I've found it a necessary evil so I dont get hit pulling out into traffic with the super short 1st gear, usually by the time I'm at 30mph I'm in 4th.

 

[AKghandi]

I drive my 13 RS 6MT (the transmission makes a HUGE difference in MPG, especially on the RS) and all city I get 26-28mpg. Highway I'll get 34-35mpg and my usual commute is about 2mi of city then 18mi of highway, right between 29-30mpg. (Bone stock)

I hate to rev the heck outta it around town, but I've found it a necessary evil so I dont get hit pulling out into traffic with the super short 1st gear, usually by the time I'm at 30mph I'm in 4th.

God I hate first gear. I seriously wish I had an eco trans.


To anyone asking about how hard i drive the car. The answer is sometimes very hard. But I have to, I'm a delivery driver so sometimes i have to beat the poor thing.

That said even driving like a gramma the mileage doesnt improve by more than a few mpg.

my old lifted 91 cherokee on 33x12.5s driven the same way pulled in 16 mpg. My 92 SHO which I drove much harder pulled 22 mpg.. I just cant help but think somethings a miss. Hell even my old 87 subaru gl-10 turbo lifted in the winter in 4x4 all the time pedal to the floor snow drifting managed 25mpg.