i have a 2000 civic ex and the most i got in the city was 38 and i shift between 2,500 and 2,800 and the most i got on the highway for 41 so thats not too bad for the ex i am sure i could have done better if i went 60 mph than 70 next time i will try that but i love the gas mileage honda rocks

 

theres no magic answer but TONS of generic ones... tire pressure, air filter, plugs, etc.

driving smoothly is the biggest IMO. especially in town, if you know the light ahead is going to be red when you get there, start coasting, avoid the brakes as much as SAFELY PRACTICAL.

drive slower on the highway. anything over 65 starts really screwing your mileage. but the folks driving 54 mph on the highway are safety hazards...

avoid ac if possible... don't go through the drive through at the bank or fast food..

lose weight from your car... don't carry 50 lbs of crap in the trunk that you never use... remember Force = Mass x Acceleration. We all want more acceleration and have a very limited amount of force, so, reduce the mass.

theres tons of small stupid stuff that doesn't make a big difference, but in combination, it really does start to add up.

i just had a road trip in my 98 ex right before i did a lot of work to it (it was stock for trip) and drove from maryland to texas... i got 38-42.. i was happy with that, but I won't get that in town.

as far as the magical rpms to shift... it depends.. lower rpms use less gas, but lugging the engine puts a lot of unnecessary stress on the pistons, rods, and crank... shifting below 3000 is good... but lets be honest.. most of us posting on a civic forum are here because we like driving our cars...and they're usually the most fun at high rpms..

a lot of aftermarket performance parts can help mileage as well... not much, but they'll help a bit... a free flowing intake and exhaust will reduce pumping losses... you'll see 1-3 mpg (just an estimate, no one fight me on that) if you change all intake and exhaust stuff.. having your car maintained in the biggest thing... also, another benefit of headers is that the knock a few lbs off. back to shaving mass again..

as for you other guys fighting about the mph in second gear, remember that aftermarket wheels and tires can easily change the gear ratios a bit as well.. the moron with 19" rims on his civic has taller gearing and slower acceleration than grandma with the stock 13".

 

haha im not fighting about the mph in 2nd, just sayin that my car WILL do over 60, he probly has an EX is my guess which would mean shorter gearing and that would explain why his goes to about 59

you made a lot of good points in your post that people should pay attention to (and its nice you're honest about driving being more fun at high rpms), but how do aftermarket wheels change gearing? The speedometer reading will be different but that is only cuz the sensor uses wheel diameter to measure speed, the ACTUAL speed you are doing in any given gear shouldnt change as far as i kno unless there is something i am missing. mine are 15" Si rims with the "stock" 195/55/15 tire size, so my speedometer should be reading correctly or really close

 

also, when you're coming to a stop, try and shift to neutral while slowing down as soon as you can, so that you'll still make it to the stop sign, but use less gas.

 

^ only recommended for a manual! with a automatic ive heard that its bad for them due to the internals still spinning. ive heard three things that hurt them, is heat, and bent fins in the converter, and lubrication. i have no proof BUT common sense makes me believe they are very plausible!
i only pop it in neutral with my manual 5speed.

 

as far as the aftermarket wheels changing the gear ratios.... its essentially if the overall tire diameter changes... it really isn't in reference to aftermarket wheels per se...

i don't know what the final gear ratios are on those years of civics, but if you put larger diameter tires on than what came with the car, your car is traveling farther with ever turn of the axle than what the speedo/odometer think it is...

but its not solely up to the wheel... its up to the overall diameter of the tire.

 

yea i meant to say that
lol
definitely not good for an auto

 

I would suggest this;

Maintain good tire pressure
Clear airfilter
Good spark plug wires
Good spark plugs
Good Fuel filter( make sure you don't have the one from factory, lol it might be really dirty)
Clean engine Oil( do your oil changes on time)
Use a fuel injection cleaner once a month or so and make sure you fill with 91 to give your fuel system a good clean then you can go back to 87 on your next fill ups

A/C Ussage;

the rule supposedly is, under 45, windows down, over 45, windows up- A/C on low ( going over 45 actually creates more wind resistance than if you had the A/C on on a low setting)

Weight;

Don't carry stuff around that you don't necessarily need

The more weight you have in the car, the more fuel you use to move it

Driving Habits;

This is obvious...
Don't gun it
Don't brake too much
No take offs
keep RPM's low( don't go 64 mph on 2nd, lol)
Try to shift under 3k ( you can shift a lot sooner than that, its mostly all based on terrain)
Try using neutral as much as possible


Just don't forget to have fun when you're driving your car or you're going to hate doing all of these things just for a few extra miles on the gallon.

ALSO- Remember that bigger tire/rim size affects gas mileage. The more surface area your car covers creates more traction and hooking which in result uses more gas

 

try to shift as soon as you can, or at the lowest rpm. try not to throw heavy mods on it. an aem catback,headers, and cold air intake should do the trick. maybe change the fuel filter, or throw on a fuel regulator. if you are thinking of getting serious good mpg, maybe 60 miles a gallon or more, think about a fuel cell. $1000. i've seen an 8th gen civic getting 84 miles to the gallon. you might want to ask your mechanic or tuner.