New guy with a Honda
 

Hi there. I drive a 2011 Honda Civic LX, five speed stick. It's a good car that usually returns 31 to 32 mpg in my mixed driving, but I've got the tinkering bug. For the moment I've installed a set of the more aerodynamic wheels from the Civic Hybrid, wrapped in some LRR tires. I'm interested in improving my aero to reduce drag, without putting my warranty into jeopardy.

From what I understand the Civic Hybrid has underbody panels that should work on my sedan. Is it a simple installation, or will there be drilling involved?

And what about the Civic Hybrid's little rear spoiler? Is it just for looks or does it actually do something?

Filled up this morning, more out of curiosity than necessity. 33.5 miles per gallon, a decent improvement over my last tank at 31 miles per gallon.

Welcome to ecomodder.

33.5 mpg is OK, but surely there's a bit of room for improvement ;)
EPA numbers being what they are, you should be able to beat the highway spec in all around driving with mild hypermiling techniques.

Driving slower helps - driving faster only burns more fuel.
I've shaved 12 mph from my usual highway speed, yet over my regular 30-mile commute, it hardly changed the time or the average speed for the trip.
The catch is that once on the highway, I no longer slow down from my reduced normal speed, unless I absolutely have to ;)
Day-to-day traffic variations have more effect than the 12mph reduced cruise speed.


Have you already increased the tyre pressure ?
You can safely go up to the sidewall max. pressure, even if Honda recommends lower pressures (for comfort).
The ride will get harder, but it should not get bouncy.


If it's just a small deck-lid spoiler, nothing obtrusive, shaped like the spoiler on the 2012 HF or hybrid, it'll be OK.


If the underside panels fit, they'd help as they do on the hybrid, but may not be cost-efficient depending on their price.
Plenty of people have made their own belly pan using coroplast (which is like plastic cardboard) from left-over election signs etc.

The tires are currently set at 35 PSI. When I get home this evening I'll bring them up to 40 and see how it goes. They're rated for 44, so that'll give me a little leeway for peace of mind.

The driver needs work. I remember doing some tests a long time ago on the highway, looking at the difference in going the posted limit and going 5-9 MPH over. As I recall it made a noticeable difference in my efficiency, and it wouldn't be the most difficult thing in the world to change.

The 2011 Civic Hybrid's rear spoiler (which is what I would use on my own car) is a small lip on the edge of the trunk. Not a huge wing or anything like that. My mentality as far as modifications go is that whatever's on the Civic Hybrid is probably going to be beneficial on my LX. The front air dam is the same on both cars, and it curves around quite a bit to shield the front wheels from airflow. Airdam/deflector in one piece, as it were. I ordered up some rear tire leading edge deflectors that are on the Hybrid that aren't on my car, so we'll see how those go. There are also some trailing edge pieces I could add. Maybe next paycheck.

The big purchase I'm working towards will be completing the car's underbody panels. I'm intending to focus on improving aerodynamics over the next few months and working on my driving skills.

Grill block. Its cheap, easy, and gives good results.

Other than that, seriously look at driving technique. It is completely possible to double your mileage with driving technique alone (albeit a lot of work). Simply being an aware driver following the speed limit and anticipating lights can get you a pretty easy 30% over epa ratings. You'd have to mod the heck out of your car to get a 30% gain.

I've been working on a new route to and from work. It's a bit longer in distance and time, but it consists of long periods of uninterrupted cruising at 50 MPH. There's still a good bit of stop and go don't get me wrong, but I've cut out probably 50% of my bumper to bumper.

Grill block - is this an all the time thing? Anything I can do that won't damage the car (mechanically or, to a certain extent, visually) I'd be interested in trying.

Your 2011 Civic still has a grill that could take temporary blocking with black foam plumbing pipe insulation well. It would not mark paint, be cheap, easy, and painlessly reversible. You might even like the look, which will be fairly stealthy anyway.

Second tank is a bit of a bummer! 33.056 MPG. That's with the new route that features far fewer traffic lights and more sections of uninterrupted cruising, tires at 40 PSI, and driving sedately.

Don't be discouraged. There are many many factors, including temperatures, time of day, crosswinds, minor changes in driving style that none of us would detect but that instrumentation could show were deleterious.

And don't forget the possibility of pump error. It can swing your calculations significantly. Always do your fills with the tank closer to empty, always fill at the same pump, always choose the slowest automatic fill speed, always stop filling at the first click.

Third tank was 31.9 MPG. Maybe it's the cold snap, but it sure hurts my efficiency ego. My car originally came with a front license plate bracket that I removed because A: I think it looked ugly, and B: it isn't required in Georgia. For the grill block, I was thinking of making something out of black plastic roughly the size of a license plate or slightly larger and mounting that to the grill via the bolt holes used to hold the front license plate bracket on. It would be somewhat recessed within the front bumper. Would this have a desirable impact on drag by partially blocking air entering the engine bay, or would this create more drag?