Optimum Gas Mileage

[DuH-ReL]

Sorry to sound stupid but when you all talk about 87, 91, and 93 is that the octane levels of your fuels over there? The lowest we have over here in the uk is 95 and my d16z runs like a bag of s**t on it! I use 97 to 99 and get over 37mpg at 70mph.

That's correct! And don't feel stupid, lots of us don't know sht about the UK

WTH?!?!? I hope it stays like that or goes lower on Sunday... I move back to Riverside that day and will definitely need to fill up. Oh and the 21 mpg... ALL city driving with lots of VTEC on that tank, haha. I usually get around 23 too. I need to see if the oil change I got today will also make a bump in there too, haha.

It just dropped to USD$2.87 Chevron 93 unleaded premium!!!!

I wish I could figure out how to avg ~30 mpg =/

 

[GETxERxDONE]

I wish I could figure out how to avg ~30 mpg =/

drive on the interstate at about 70-80 mph on cruise in 6th gear until the tank runs out

 

[92civicEGSI]

I got 300 or so on my first gallion which is not that bad cause I drive fast a about 40 miles to work. Actually accelerating fast does not kill my miles what does if I use my ac and drive fast that will kill ur gas mileage. I live in az so you guys probably dont have to worry about the heat like me.

: Turning off the AC is the best way to up your gas mileage. Although, driving with the windows down has a negative effect on drag and can actually bump you down by 5mpg, so man up and take the heat or pick your battles. Don't forget tire pressure guys! Having your tyres incorrectly inflated could easily bump you down another 5 mpg.

 

[92civicEGSI]

I got 300 or so on my first gallion which is not that bad cause I drive fast a about 40 miles to work. Actually accelerating fast does not kill my miles what does if I use my ac and drive fast that will kill ur gas mileage. I live in az so you guys probably dont have to worry about the heat like me.

: Turning off the AC is probably the best way to up your mileage. Although, rolling you windows down has a negative effect on drag and can actually bump you down by 5mpg. So man up and take the heat or pick you battles. Don't forget about tyre pressure guys! Having your tyres improperly inflated can easily bump you down another 5mpg.

 

[GETxERxDONE]

: Turning off the AC is probably the best way to up your mileage. Although, rolling you windows down has a negative effect on drag and can actually bump you down by 5mpg. So man up and take the heat or pick you battles. Don't forget about tyre pressure guys! Having your tyres improperly inflated can easily bump you down another 5mpg.

must not have seen the Mythbusters..i think they did that. and it didnt matter either way

 

[Kaotic_Zeus]

I filled up on costco gas the other day, not sure howi feel about it, and waiting in line to get some of it for the same price ARCO has it, i think i'll fill up at ARCO, because Chevron and Shell around here are too damn pricey, 3.15 a gal for 87 over here, andi fill it up with 89. i get about 300mi a tank, and i Floor it once in a while to redline. i need to stop, it's costing me

I think costco gas isn't good enough, since they must refuel the tanks often because of the amount of people who line up for it, and fueling your tank up after the station was refueled is the WORST IDEA. you're just putting garbage in your tank. I never filled it up at ARCO but it's the same price for gas as costco, and there's no lines either, so f**k costco. i think they sold me Compressed Air last time. =/

 

[bmyers4321]

best way to save gas would be accelerate slower, if you have a manual trans shift at a low rpm maybe around 3000 rpm and dont engine brake put it into neutral and then brake.

 

[Kingjames83]

I got a b16 with a tuned ECU... I'm not really looking for a car thats good on gas but if I was I'd take out my subs... and keep rolling my lightweight rims. some nice injector cleaner.. like lucas or redline. tune up and a clean air filter for our air intakes and CIA

 

[chasingveronica]

Very Poor Mileage with 2007 Civic

I have had my 2007 Civic Ex for 6 weeks now and I am averaging 21 MPG. I generally drive only city, but my 2002 Civic LX averaged 30mpg City. I am seriously upset, as much as I like the superior styling, that I traded in a car for POORER mileage in an age when gas prices are so high.

 

[Dere-Licte]

woah i'm surprised... i thought in the mainland your gas would be a lot cheaper! Over here in hawaii it's still 2.67...


well i was underthe impression that if you stay at fast speeds (higher gears) you save more gas. The lower gears supposedly eats up more gas...

 

[Kaotic_Zeus]

Somethings not right then, you should be getting about the same or better, either you're driving it differently, or somethings probably wrong with the car itself.

 

[Kaotic_Zeus]

woah i'm surprised... i thought in the mainland your gas would be a lot cheaper! Over here in hawaii it's still 2.67...


well i was underthe impression that if you stay at fast speeds (higher gears) you save more gas. The lower gears supposedly eats up more gas...

You stay in the highest gear at lowest RPM for the speed you're going.

 

[mrd]

You stay in the highest gear at lowest RPM for the speed you're going.

Sounds about right. Any used fuel is coming in through the injectors, and those are going to fire only once per cycle. Assuming a fixed amount of fuel is delivered per cycle, you would use twice as much fuel at 3000 RPM as you would at 1500 RPM.

Even if the amount delivered by the injectors isn't constant, they'd need to supply twice the amount per cycle at 1500 RPM to be equivalent to 3000 RPM. So lower RPMs should be more economical. However, I'd posit that running at a lower RPM can put additional strain on the entire drivetrain - though I'm not sure if it's enough to significantly affect today's well-engineered parts.

 

[Sion0x]

21MPG on an EX is wrong...take it in or stop flooring it (if that's the case).

I have a 2 door LX, with exhaust and intake, and I average about 27MPG.

 

[chasingveronica]

i did take it in.
.
Was told there is a 5,000 mile "break in" period. i only do 7,000 miles a year, it's gonna be a LONG year.

 

[Kaotic_Zeus]

this thread is old lol

but anyways, the engine should break in sooner for newer cars.

 

[GETxERxDONE]

who told you that? its more like..600 miles

 

[Killa_CiViC]

must not have seen the Mythbusters..i think they did that. and it didnt matter either way

It didn't matter in the big Ford SUV they were using to test, because the difference comes when you compare the displacement of your engine to the displacement of the a/c compressor.... so with that large V8, the difference between the engine and the compressor is very large, so the percentage of power sapped from the engine is very small.... with a smaller displacement engine like a Honda engine, the difference is less, so the power percentage loss is greater... means you have to get on the gas more to keep going as fast... means you have to use more gas.
I sent them in my arguement about that, and never got a reply. But yes, turning off your a/c in your civic will get you better milage. I drive 120 miles a day, and I've tracked it.

As far as the milage I'm getting... I've tested most other gas brands listed, 92octane or better.... found that I get the best milage (consistent 32mpg) on Exxon supreme, Chevron/Texico super. Worst milage would be Shell, Fina, QT, and on down from there.

This is in an 07 Si Sedan.

 

[mrd]

..the difference comes when you compare the displacement of your engine to the displacement of the a/c compressor..

You shouldn't compare displacements directly, as there is a different amount of work exerted to move through these displacements. Instead, simply compare the power produced by the engine to the power consumed by the compressor.

..means you have to get on the gas more to keep going as fast... means you have to use more gas..

This fails to clarify the difference. Whilst the percentage of the engine's power lost due to the compressor may be greater on a smaller engine, this doesn't necessarily mean the smaller engine uses more gas to run the compressor.

In theory, the compressor should consume the same amount of power on either engine, although there will be differences between compressors for different cabin sizes and different typical RPM ranges. In light of this, to compare gas consumption from the compressor, it would seem best to compare power produced per gas consumed. That is, a more fuel efficient engine will use less gas to run the compressor. Keep in mind this is engine efficiency, not total MPG of a vehicle - that will differ greatly depending on vehicle weight, etc.

..I've tested most other gas brands listed, 92octane or better.... found that I get the best milage (consistent 32mpg) on Exxon supreme, Chevron/Texico super. Worst milage would be Shell, Fina, QT, and on down...

I'd be interested in seeing hard numbers from folks here in their MPG with different octane fuels. It may prove cost-effective to use a more expensive gasoline.

Also, regarding the classic windows-down vs AC question, an important point has been missed: The AC compressor will consume about the same amount of power regardless of your vehicle's speed, but the amount of drag experienced by the vehicle will increase exponentially with speed.

Additionally, opening the windows on a vehicle with poor aerodynamics to begin with, such as a van, introduces less additional drag than doing the same on a vehicle with good aerodynamics, such as an 8th gen civic.

 

[Killa_CiViC]

I think perhaps you didn't grasp the concepts in what I typed.

I will add that aerodynamics doesn't matter nearly as much as you may think. I've tried with my windows down in my 8th gen, my 6th gen, and my 4th gen... result is the same, and I still get better milage with the windows down and the a/c off... on average milage difference, the 8th gen suffers by 2mpg, the 6th gen by 3mpg, and the 4th gen by 6-7mpg with the a/c on and the windows up.

All of my arguement is based on personal observations, and knowledge of how the vehicles systems work.