2004 Honda Civic Si EP3 - 42.6 mpg
 

Well, I really wouldn't have believed it a couple of years ago. The EPA is 22/28 and I have always gotten 32+. Two tanks ago it averaged just under 40 mpg and this last tank was 42.6. Really surprised since the Si has a low geared tranny. I never used the highway and most trips were short and the motor didn't get the chance to warm up often so there's lots of room for improvement. Psyched!

Changes this past tank:

-High(er) tire psi.

-Very low rpm shifting @ 2/3 throttle (read an article, in here I think, about lugging).

-Premium gas, wanted to try it since the EP3 has higher hp on a dyno with premium.

-Pulse and glide.

This refill I went back to regular and won't change anything else. And, yes, I need to fill out the gas logs, sorry. I do have all my reciepts and mileage.

That's a lot of changes for just one tank. Be sure to let us know if you can continue these great results, and which of those you determine to be the most effective.

:thumbup: That's great with that car.

Thumbs up!!! I have an 02 ep3, and my best tanks were 37 mpg. Its colder now, and mileage is dropping. I know how much work that takes!!! I have yet to get a 40 mpg tank. My tires at 40 psi front, and 44 rear. It rides like a brick.

I feel for you. It's just now starting to get nice here in Tuscon.
Slurp, are you an EPHatch.com member? MetroMPG is going to add a list here that shows mpg by make and model. It would be cool to get 20 or so EPers comparing notes.

AHHH if only my fellow Mazda 6 owners would actually post! (Nobody with a Mazda 6 has posted anything grrr!! So I always have to compare myself to accords and civics !)

That is one aerodynamic looking car. A good alternative to getting a metro (not knocking on metros) or something if the fuel economy like this was easier to achieve. Great numbers!


Don't forget to compare to the Altimas. I don't think there are any other 3rd generation altimas here either.

Yes, I am on EPhatch. but I don't visit much lately...

I guy I work with has a 6. I think its a 2004? Not sure. Iv tried to get him on here, and other mileage related sites. Maybe I will talk to him more. He's been getting low 30's but not trying all that hard.

fellow hatcher here. My best was 38mpg driving 40mph and coasting everywhere, but I hadent tried higher pressure in the tires or EOC or anything. though I was lowered and that helped.
right now I am no longer lowered, I have wider and taller and heavier tires at lower pressures, and a raceheader and I am getting about the EPA milage on it. but I havent been driving it nicely or slowly. so my snowtires will be smaller and lighter and higher pressure, I'll adjust the wing to flatter or middle (doubt it will do much), try to drive 55 on the interstate w/o cruise, drive low RPMS with low throttle so no lugging, and maybe set my intake up to suck hot air instead of cold, and I'll see from there.

as far as premium VS regular gas, its been shown without mods or computer changes to not do anything, though with mods and computer changes can be significant (the VTC changes dynamic compression and the ignition is also changable, so is the changover from 12valve to 16valve I belive)

best thing to do for milage is swap the tranny to an RSX-S or add the TSX 5th gear as a 6th on ours, drops highway RPM significantly.