Gas Mileage
- Thread starter intimidatorss
- Start date
readytogo!
New member
But that's just it, I don't get better mpg with my tune im like at max mpg at 31.5 average driving very conservatively. I expected to get better mpg like everyone else with mods. That's why I am thinking that my tune was not dialed in correctly despite several datalogs..very dissapointed
readytogo!
New member
I also wanted to ask, a have a slightly unsteady idle(not too bad). I have noticed a few tiny exhaust leaks on my slp catback portion of my exhaust because I haven't gotten it welded yet. would these little exhaust leaks account for the unsteady idle and horrid mpg?
Swordsmith
242hp/252 ft-lbs BNR EFI
I have not seen many mods showing an increase in mpg. For the most part, they supply more power, or just noise. The car is already well set up to give good mpg, the principle mod for that is driver behavior... and the problem with power mods is they tempt you to push the car to enjoy that power, with a corresponding loss of mpg.
Driving the way I normally do I get literally 2/3rds the mpg that I got on a test run, simply driving moderately, accelerating gently, going no more than 5 mph over the speed limit. 50% more miles out of every gallon on that tank... there's no mod I've ever heard of that comes anywhere near that.
The interesting thing about Breezer's post though, is that unlike most folks complaining about lower than expected mpg, it's hard to write his issue up as driver behavior... because he says he's coming from a Focus which he could get 35-40 mpg out of.
Assuming that's the same 90/10 commute, and that both cars are auto transmission, we're looking at a bigger and lower EPA rated car getting better mpg, with what is presumably the same driving style. That eliminates a lot of the "low hanging fruit" in terms of what is wrong, and suggests that the problem lies in the car itself. But since plenty of folks are able to get much better numbers from their Sonic than he is, it actually suggests a problem with his personal Sonic. We've seen some others come in here and come to the same conclusion, there seem to be some "lemon" Sonics out there in the MPG department.
Quick checks: Tire inflation. If they are low, there's an MPG hit. Running them around 40 seems ideal as far as getting the best mileage without becoming dangerous. Spark gap. They often come from the factory with a random assortment of gaps; gap should all be the same, and for the 1.8, .35 seems to be ideal.
He has the 1.8, which gets worse MPG, and an auto, which gets worse MPG, and the transmission on the 1.8 lacks a 6th gear, so he's suffering more due to his relatively high highway speed. I don't know how this compares to the 2008 Focus he was driving, maybe it didn't dislike higher speeds as much?
Driving the way I normally do I get literally 2/3rds the mpg that I got on a test run, simply driving moderately, accelerating gently, going no more than 5 mph over the speed limit. 50% more miles out of every gallon on that tank... there's no mod I've ever heard of that comes anywhere near that.
The interesting thing about Breezer's post though, is that unlike most folks complaining about lower than expected mpg, it's hard to write his issue up as driver behavior... because he says he's coming from a Focus which he could get 35-40 mpg out of.
Assuming that's the same 90/10 commute, and that both cars are auto transmission, we're looking at a bigger and lower EPA rated car getting better mpg, with what is presumably the same driving style. That eliminates a lot of the "low hanging fruit" in terms of what is wrong, and suggests that the problem lies in the car itself. But since plenty of folks are able to get much better numbers from their Sonic than he is, it actually suggests a problem with his personal Sonic. We've seen some others come in here and come to the same conclusion, there seem to be some "lemon" Sonics out there in the MPG department.
Quick checks: Tire inflation. If they are low, there's an MPG hit. Running them around 40 seems ideal as far as getting the best mileage without becoming dangerous. Spark gap. They often come from the factory with a random assortment of gaps; gap should all be the same, and for the 1.8, .35 seems to be ideal.
He has the 1.8, which gets worse MPG, and an auto, which gets worse MPG, and the transmission on the 1.8 lacks a 6th gear, so he's suffering more due to his relatively high highway speed. I don't know how this compares to the 2008 Focus he was driving, maybe it didn't dislike higher speeds as much?
ahtoxa
New member
Coincidence. Oil change alone does not provide such huge mpg increase. I'd be hard-pressed to believe if it even claimed 1 or 2 mpg increase.
There are SO many more variables and frankly, there are even large variables in the seemingly same day-to-day commute, that for the most part, outside of a lab, the results we all get are useless for any kind of statistics. A general picture can be seen with long-term tracking, but what you show is simply too short-term.
sx sonic
New member
Agreed. Unless you're running mud and then clean the engine and switch to oil
.I could claim a 20mpg gain with my mods, I've even got the fuel logs to prove it. No lie 32mpg on a tank with no mods and 55mpg on a full tank with mods, hand calculated and even used the same fuel pump and grade.
Swordsmith
242hp/252 ft-lbs BNR EFI
Then start a "Modding for MPG" thread, because I haven't seen much of anything on that subject here, and what there is seems to be all spread out.
What have you got going, a WAI, blocked over front grill, aero cover for the headlamps area, low resistance tires, deleted side mirrors?
(edit, assumes you don't mean "driver mod" but are somehow using the exact same acceleration, speed, fuel and weather conditions... if that 22mpg jump is attributable solely to car mods, that's hot stuff)
Last edited:
sx sonic
New member
Mods in my build thread, nothing outside of normal power mods.
The reality is that while those numbers are completely true and recorded logically, they are completely out of context. One was my worst log during the winter with more than normal idling and higher commute speeds, the other was my best hypermiling drive during summer..............:..... It is clear that conditions and driving style are responsible for the different mpg results
This is why I keep a log of my fuel economy, each tanks mileage, gallons used, DIC mpg, actual mpg, fuel grade, mods and a note of my commute are recorded.
From there I note trends and averages and then make comparisons. Following this basic scientific method has indicated that my gas mileage has not changed substantially since the addition of any mods or changes in octane. My best, worst, and average mpg have been all within a couple mpg.
My best mpg was with mods, but the engine had cleared its break in period, I had the almost ideal hypermiling conditions, and I'd gotten better at driving effeciently. Certainly worth a few mpg and within standard deviation.
TL;dr My point was if you're not objectively tracking fuel economy after mods the results are worthless. Call it placebo tracking.
ahtoxa
New member
In most cases, modding for MPG is a paradox. The gains seen will take a VERY long time to offset the costs of the mods, because in most cases, once you go past few basic mods, you really need to shell out some money.
Those that take this to extremes, normally spend most attention (and money) into reducing aero drag and optimizing gearing.
Those that take this to extremes, normally spend most attention (and money) into reducing aero drag and optimizing gearing.
readytogo!
New member
like I said before, tired at 38 and check weekly, drive at or below the speed limits, 90/10 highway city, very slow acceleration, nothing in the car but me. trying my hardest and did not gas it even one time in my last tank and only scraped up 31.5
davecerv
New member
I know how you feel! It's been cold over here lately with lots of wind (40F-60F) and I'm struggling to stay at 27mpg. But in regular weather (90F+) I was averaging 30-32mpg per tank. And thats being on the right lane freeway going 58-60mph. I also do all those things to yield "better" mpg. I'm okay with those numbers though. I drive about 2k a month. A full tank seems to always last me six days just like with my old civic I had.
That's just how it is with our 1.8 autos, I still love the car because it looks so damn good
opcorn:
Last edited:
readytogo!
New member
I know how you feel! It's been cold over here lately with lots of wind (40F-60F) and I'm struggling to stay at 27mpg. But in regular weather (90F+) I was averaging 30-32mpg per tank. And thats being on the right lane freeway going 58-60mph. I also do all those things to yield "better" mpg. I'm okay with those numbers though. I drive about 2k a month. A full tank seems to always last me six days just like with my old civic I had.
That's just how it is with our 1.8 autos, I still love the car because it looks so damn good
Yea I mean I am still very happy compared to the numbers in my old truck just disappointed because of other peoples mpg success. And I agree, the car is so unique. Great car
