Hi, Civic Ex owner just found this board...
 

Hello...new here. My daily vehicle is a 98 Civic EX coupe with nearly 200k miles. I average around 35mpg mixed driving, and 37 all interstate with cruise set around 70-73mph.

I am going to start using the methods you guys recommend and hopefully I can knock down some new numbers. I plan on doing some aero mods too. Probably a grill block off, remove mirrors/antenna, and lower the car. Some minor weight reduction will be employed as well.

Any other ideas?

Welcome to ecomodder!

I think that hondaworkshop had good results with his Hot air intake on his 6th generation civic. I had good results with mine, but it's a 5th gen, so not *directly* applicable to your situation.


Oooh, before I forget (or someone else jumps in) get a scangauge or some other feedback device, it'll pay for itself VERY quickly.

If you're strapped for cash or just enjoy a good DIY project you might checkout the Opengauge/MPGuino.

Hi Andrew, thank you for the reply. The car has an aftermarket air intake, but I should probably clean the filter. When I bought it it had the intake, a header, and an aftermarket muffler. I swapped the muffler for an OEM one b/c the aftermarket one was too loud. I also did a tuneup on it about 1000miles ago...new plugs, wires, and a distributer (old one was dead).

I'm wondering if I extend the intake piping down away from the motor if it will help any with receiving cooler air.

I would like to get a scanguage. Can you tell me more about how it will help me? Is it just by seeing your mpg live that it helps you keep your foot off the gas?

Cooler air is generally great for helping to get a little more power. The usefulness of cold air intakes for better gas mileage is debatable.

Essentially a cold air intake gets denser air (more oxygen = more fuel = more power)

A hot air intake does the opposite (less oxygen = less fuel = less power)

With hot air, you have to open the throttle more to get the same amount of power, so you reduce pumping losses in the engine and make it more efficient. (that's the theory anyway) Only way to tell for sure is to try it :thumbup:

I have learned by reading on this website that warmer air is your friend since the engine runs most effectively when warm. But I don't know if this is true in summer also.

EDIT: I guess Andrew was working on his post the same time as I was, his is way more informative though.

Ahhh ok. I was thinking the colder air would allow the motor to use the fuel I was giving it more efficiently but what you're saying is that it will simply use less fuel (computer retard timing possibly?)

What kind of mileage can I reasonably expect to see with a few mods and some conscience driving habits?

Has anyone calculated how big of a difference it makes to lower the vehicle?

I think you can reasonably expect to hit 50mpg with no mods and just driving habit changes (that's assuming you have a manual transmission)

If you have an auto, that changes things a bit. Prolly 45ish.

With mods, the sky is the limit.

As for lowering, it's gonna definitely help.
There was a thread in the aerodynamics forum that refrenced solid numbers for lowering gains, something about an aeromodded Ford Fusion bonneville car.

aah yes, here it is.

Lowering takes off 0.08 Cd (at least on that car)

Wow! I had no idea it could make that big a difference. I am buying some coilovers from a friend so hopefully I can test different heights and see which nets the best numbers. :)

Hey Zach, I joined the boards not too long ago and own a 98 Honda Civic DX and since I read just a few tricks on here i went from getting 42mpg on the interstate to 49mpg. So you could easily bump yours up without much modding. Welcome to the boards!

Hey spitfire, is your car a 5spd? What have you done on the interstate to increase mileage? Mine will get right at 37-38mpg on the interstate with my cruise set to 70mph.

I did get 41mpg on one road trip doing 70mph with the cruise set (with a trunk full of luggage and 1 passenger!). I made the same roadtrip again the next year and only got 37mpg while doing everything else identical. I still can't figure out why I couldn't duplicate it.

^Wind could have been a factor.

Mine is a 5 speed. I do not have cruise control, which can help especially if there are hills because then i can control the RPMs more closely without them rising drastically. I drive about the same as you right around 70mph. I also try to draft semis at a safe distance and just accelerate slower and make more planned decisions to pass and other maneuvers. Coasting on the Interstate is harder as you will lose speed alot quicker than on two lane or residential roads.

I should say I dont get 49 on the interstate that is on two lane highway sorry, but I do get above 40mpg consistently on the Interstate.