20.3 mpg

[VaBumbleBee]

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

Could not agree more, something wrong with your car.

My RS gets on avg. 42 mpg this summer, calculated. My DIC is showing 44.,,

I drive 100 miles a day, mostly up and down country roads, with 10 miles city stop and go driving.

I do usually drive my age, but not always, I don't use the air conditioning, love the wind and heat.

Last winter, I was avg. 39-40 mpg.

Good luck with your car, I'm loving mine and still enjoying driving it after 36,000 mi.

 

[JesusTheAgnostic]

What is seafoam?

It's a product meant for cleaning boat engines. People put it in their cars by spraying it in the intake I believe, and it's supposed to clean the cylinders.

 

[carsNskis]

Seafoam is for older motors, NOT ideal for use in a modern computer controlled motor.

Home brewed versions are made like this... 40-60% Pail Oil: Deisel Fuel, Automatic transmission fluid, or a light motor oil (to increase compression in worn engines)
25-35% Napatha
10-20% IPA AKA: Isopropyl Alcohol (to burn hot and "clean" deposits)

DON'T USE IT

I have a 2014 RS and drive the piss out of it and manage anywhere from 27-29mpg and I'm in Colorado so I average less than flat landers...

Have a Service Center do a diagnostic. All this speculation is wasting your time and money. Find a shop you can trust and get the right answer.

 

[AKghandi]

yeah, with only 30k miles I see no reason to seafoam.

I need to take the car in to the dealer for half a dozen reasons. which is really frustrating.

 

[dannyg]

Could not agree more, something wrong with your car.

Just curious, how does the MPG compare between your 1.8auto and 1.4T manual RS? Thanks.

 

[T76]

It's a product meant for cleaning boat engines. People put it in their cars by spraying it in the intake I believe, and it's supposed to clean the cylinders.

As a former R2800 engine aircraft mech,I would never inject that stuff in an engine.Can you imagine what that does to cylinder walls,piston rings and valve faces.

 

[JesusTheAgnostic]

As a former R2800 engine aircraft mech,I would never inject that stuff in an engine.Can you imagine what that does to cylinder walls,piston rings and valve faces.

As far as I understand it's an old out dated product.

 

[AKghandi]

As far as I understand it's an old out dated product.

It works ok on old out dated cars. but personally I prefer to use it to restore plastic trim. works really well actually.

 

[VaBumbleBee]

Just curious, how does the MPG compare between your 1.8auto and 1.4T manual RS? Thanks.

My gf drives the 1.8 "sweatbee". Her DIC shows 35.6 mpg, of course she always
runs a.c.

Her commute to work is mostly highway on hilly terrain.

I will also add that we both use 93e10 fuel.

 

[rojoes]

I use Seafoam for small engines... I use 1 oz per gallon of Methanol Free Super Unleaded gasoline to stabilize the fuel for lawn mower and snow blower. I don't think it would hurt the car engine adding to gasoline. As far as adding it to air intake to de-carbon an engine isn't necessary for a modern engine. I really think you can do damage doing that anyway.

My 2013 1.8 Auto gets about 27 mpg in urban driving and 35-37 mpg highway speeds. This car rivals the gas mileage of my 2008 Toyota Yaris Automatic , a much smaller car that has only a 4 speed auto transmission rather than the 6 speed Automatic the Sonic has. The Sonic also has a lot more get up and go than the Yaris too.

 

[JesusTheAgnostic]

It works ok on old out dated cars. but personally I prefer to use it to restore plastic trim. works really well actually.

How do use it to restore plastic trim?

 

[AKghandi]

How do use it to restore plastic trim?

Just wipe it on. sometimes you need to do it a few times but it really brings old plastics back to life.. I probably wouldn't use it on newer stuff though.

seafoam contains pure petroleum distillates. Being that plastic is made from petroleum and it dries out over time, it actually brings the plastic back to life.

 

[AKghandi]

so I drove like a gramma for a few hours. managed 27 mpg city. epa ratings should not mean 6th gear at 30mph. It was so boring.

 

[JesusTheAgnostic]

Intereting stuff on the SeaFoam. But yeah, not sure how you got into 6th going 30mph but you're supposed to short shift all day to get near EPA ratings.

I don't know about the RS ratios but I know on my LT I shift at

1 - 2: 10
2 - 3: 15
3 - 4: 25
4 - 5: 32
5 - 6: 42

to maximize fuel economy of course. Before the sticky tires I was averaging 42. If I kept my foot out of it in the city I would get around 37, as is I get around 35.

 

[AKghandi]

Intereting stuff on the SeaFoam. But yeah, not sure how you got into 6th going 30mph but you're supposed to short shift all day to get near EPA ratings.

I don't know about the RS ratios but I know on my LT I shift at

1 - 2: 10
2 - 3: 15
3 - 4: 25
4 - 5: 32
5 - 6: 42

to maximize fuel economy of course. Before the sticky tires I was averaging 42. If I kept my foot out of it in the city I would get around 37, as is I get around 35.

in 6th at 30 I was doing 1500ish rpm. sadly though first gear is so short I cant short shift if I have any hope of pulling into traffic.

 

[JesusTheAgnostic]

in 6th at 30 I was doing 1500ish rpm. sadly though first gear is so short I cant short shift if I have any hope of pulling into traffic.

Oh yeah bro, it's hard to short shift first. Usually I end up shifting at 15mph into second then at 20 and then at 25. It sounds like your 6th gear is more like my 5th gear. Which explains why you get worse fuel economy than me. I installed the ZZP turboback minus the downpipe and the BNR stage 1 kit though so I've been revving her up and down the street lately so my average MPG is around 35.

You could also try just revving the **** out of your car then shifting into the highest gear you could get to. Not sure how well that would work. I assume as long as you apply the throttle gently instead of putting your foot through the floor and then shift into the highest gear possible it might help. I do this sometimes but not often enough to know if it works for increasing mpg. I really like shifting so I tend to go through every gear because I love the feel of the short shifter.

 

[AKghandi]

Oh yeah bro, it's hard to short shift first. Usually I end up shifting at 15mph into second then at 20 and then at 25. It sounds like your 6th gear is more like my 5th gear. Which explains why you get worse fuel economy than me. I installed the ZZP turboback minus the downpipe and the BNR stage 1 kit though so I've been revving her up and down the street lately so my average MPG is around 35.

You could also try just revving the **** out of your car then shifting into the highest gear you could get to. Not sure how well that would work. I assume as long as you apply the throttle gently instead of putting your foot through the floor and then shift into the highest gear possible it might help. I do this sometimes but not often enough to know if it works for increasing mpg. I really like shifting so I tend to go through every gear because I love the feel of the short shifter.

first in my car goes to 25mph. which short shifter you got?

 

[Hemplacrosse4]

I always find it very interesting that some Sonics get very bag MPG, I LOVE my Sonics MPG. I average 37-38 almost every gas tank, when I'm all highway it's easily above 40! I will admit though that I do have the 6 speed and I coast down pretty much every hill possible lol I find it a game really, but for the most part I drive the speed limit roughly 5mph over like every other driver. My only pet peeve is my gosh darn second gear always as a hard time shifting into place. It has been like this since the day I bought it. I took it into my dealer where I bought it and the two times I brought it in they have no idea what I am talking about and say if its anything that's just how it's suppose to be.

 

[eggsalad]

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'm curious. Have you owned any other cars? Did you get significantly below the EPA ratings on those too?

I usually get higher MPG numbers than the window sticker of whatever car I'm driving says. I have friends who can't ever even meet the EPA numbers.

 

[pbkn1p]

I always find it very interesting that some Sonics get very bag MPG, I LOVE my Sonics MPG. I average 37-38 almost every gas tank, when I'm all highway it's easily above 40! I will admit though that I do have the 6 speed and I coast down pretty much every hill possible lol I find it a game really, but for the most part I drive the speed limit roughly 5mph over like every other driver. My only pet peeve is my gosh darn second gear always as a hard time shifting into place. It has been like this since the day I bought it. I took it into my dealer where I bought it and the two times I brought it in they have no idea what I am talking about and say if its anything that's just how it's suppose to be.

Hey. Same thing with mine. I have a 16 RS 6m and I've read on here somewhere to use the finger shifting technique. Instead of grabbing the knob. Just gently shift using your fingers. It took me a while to get it. But now I shift so much better. And I try to do this for 1-4. 5-6 I shift normal.

I've taken my car to the dealer 2 times and both times they sent me away with assurances that nothing is wrong.