'04 Civic Si

[Hasbro]

Hi, saw GasSavers mentioned on grassrootsmotorsports.com and joined up. I have an '04 Si. Anyone on here with the same model? The gearing(5th gear is half of the speed) is pretty low for mileage but I am getting around 35-36 mpg overall (rated at 26-28) and never drive on the highway and don't have too many lights to deal with and most speeds are at 40-50 mph. I guess about 1 light per every 2 miles. A lot of short runs.

So far I have:
48 psi tires(currently playing with 55)
gutted interior of 250 lbs.
5-20 Redline oil
Shift at 2k, coast, etc.

Although it hurts mpg, I never use ac and drive with the windows and sunroof open. Will be removing wipers(live in desert) and roof antenna soon. I will need new tires (original 205/55/16s, 37k) in a few thousand miles but want good cornering along with improved mpg (I know, it's a compromise).

Thanks for having me and any suggestions are appreciated.

[kamesama980]

sounds like you're well on your way. Since you've got an SI it's designed to be driven hard. Be careful you don't lug the engine shifting at 2k, hondas aren't overly torquey down low.

[Hasbro]

No, I never lug it but I'm not sure where I should be shifting for FE, actually. I'm torn about keeping it or building a 91 CRX/Civic hatch. It sure is a beautiful chassis and the K is so sweet. And I'm sure I can get 200 more pounds off of it pretty easily. With 250 lbs. off it feels like a different car already. I'm pretty sure I could get 40 mpg around town, which would be a great number for such a nice handling car. Even though it doesn't have the double wishbone front suspension it can still be made to corner like stink, just not like a CRX.

[GasSavers_Red]

Welcome to the site hasbro, any plans of any aero mods? Belly pan and the like?

[Hasbro]

Yes, about a year ago I started working out some plans, then got sidelined for a while. After coming here it has gotten me motivated again. I'm open to suggestions!

Some of my original ideas:

2300 lbs. (-450 total, 250 so far)

larger rear aero?, belly pan, front dam, cut away some of rear bumper for uplift, few other things

plastic rear windows and lighten hatch

remove rear mirrors and install two cameras

remove wipers, sun roof, antenna

lighter wheels/12 lbs., thinner tires/18 lbs (wish Falken Azeni 615s were in the right size) Stock wheels and tires-44 lbs.!!!

remove ac or install smaller?

suspension drop 1.75"- not too firm due to handling with 50+ psi tires

lsd and maybe change final drive ratio.

40-50 mpg?

The weight reduction would put me at 15lbs./bhp. Stock is about 18/1, fully loaded. My goal was to get it to about 12/1 but I could live with 14/1, I guess. I have other toys.

At the time I couldn't find anyone who had done much with the EP3 with regard to FE, just performance. They are relatively rare (about 8,000 in 4 years iirc) and are more sporty than high mpg. Maybe there's someone else out there by now?

[204snic]

Nice EP hatch. I had an 04'EP hatch to. I love the shifter position, but ended trading it in for an 06' SI coupe. I still miss the little hatch, but I got an 07' Honda Fit now. I've been told that if you put the rsx 6-spd tranny into the EP hatch it would make a difinite diff. w/mpg. I believe it was on EPhatch.com. I switched to the 06' because the 04' (I feel) wasn't really SI (engine wise). The vtec wasn't the real vtec that you would feel at 5-5500 rpm. But, it's still an great car to drive around in. Keep us posted w/your mods for better FE.