Ecomodding an automatic '04 Civic Sedan

[mpg_numbers_guy]

Still dreaming up ideas for my Civic. Timing belt replacement is scheduled for next week Saturday. Then I can start modding. Did add a full upper grille block that seems to improve coasting, warm up time, and mpg slightly.

Kammback (purple part) would be clear coroplast for visibility. I didn't match it up against the streamlining template so this isn't exactly how it would look.

[California98Civic]

That's a box cavity you are planning in the back, eh?

[mpg_numbers_guy]

Yep. Hoping the box cavity helps the kammback eek out maximum possible mpgs. What do you think of the aerodynamics of the design, especially the box cavity? Should it be enclosed? I know a full boattail is better but that's waayy too impractical.

Interesting to note how I have gone from my first post in this thread determining to make everything look "stock" to now trying to maximize everything possible (of course making the mods 100% reversible).

Lots of rain today but my painters tape upper grille block is still in place, much to my surprise. Need to start locating supplies so I can start modding as soon as the belt is replaced.

[California98Civic]

Originally Posted by mpg_numbers_guy

Yep. Hoping the box cavity helps the kammback eek out maximum possible mpgs. What do you think of the aerodynamics of the design, especially the box cavity? Should it be enclosed? I know a full boattail is better but that's waayy too impractical....

Well I am no authority. But I have seen studies that show box cavities can work. I totally agree about how it seems more practical than a boat tail. Beginning with post #3 in my modding thread for my car I describe show my adandoned effort at a box cavity. The devil is in the details. Something else for you to consider is that a kamm is probably less useful on our Civics because the rear window and deck lid were already optimized quite nicely. It might be konda easy to build a kamm that makes the wake worse, not better on our cars. The box cavity and kamm can work, but it takes precision and luck. Check out my box cavity failure. It should have instructive detail on studies and such you may or may not have already seen : http://ecomodder.com/forum/showthrea...tml#post374866

[mpg_numbers_guy]

I will definitely have to do coastdown/ABA testing if/when I implement this; definitely don't want to add drag to the car. But I read somewhere that the rear of the Civic sedans wasn't that good until 2006 with the release of the 8th gen with it's smoother rear end like MetroMPG had for his winter beater??

I haven't done any tuft testing (will do that before building this) but I live on a dirt road so I've gotten some semblance of an idea how the wind flows - "dirt" on the rear sides of my car tends to travel upwards onto the rear trunk; doesn't this indicate a significantly unaerodynamic rear end?

Yes I saw that post and it's honestly what I'm basing this off of mostly. Your thread has been an inspiration to me; I doubt I'll reach your 60 mpg since yours is a manual and you've done significant mechanical changes to your car, but if I can get 50 or close to that I'll be satisfied.

[California98Civic]

You should totally experiment.

Yes the eigth gen is beautiful. I think the 2006 Civic coupe is one of the best looking cars Honda ever built and I have long wanted one. And the backlight does have a better angle than a sixth gen or seventh gen coupe. But a sixth gen coupe is like 20 or 22 degrees. Your sedan will be a little steeper because the back end of the roof line is higher for rear passengers. But not a lot higher... At least an inch, maybe two inches, but that is all. Producing your own backlight Kamm with optimal compound curves and radiusing will be a challenge requiring experiment and revision. Honda had windtunnels and computers and professional staff. I think one of the reasons EM folks seem to go for th boat tail to succeed is because the greater possibility of big gains in the boat tail over the OEM makes it easier to get to a build that forgives design flaws. A Kamm cannot be as forgiving. Get it wrong and you may see no benefit.

This was prt of my problem with the box cavity, too. And I lost enthusiasm because I just did not have the time needed for testing multiple design mods. I would love to see you experiment. I believe I have the PDF articles I read for the box cavity (no longer freely available, IIRC. Send me a PM if you want them and we can exchange email addresses for the attachment. (That goes for any other EM member too who wants them).

[mpg_numbers_guy]

I want to start trying stuff out now, but I still have to wait a few days...and the weather isn't cooperating either. It's been nasty here since Saturday with snow, ice, and everything. Surprisingly though my upper grille block of painters tape and duct tape is still holding up, and my engine warm up time seems to be reduced 15-25% so that's helping. Unfortunately today's ride wasn't that good - my last three days driving last week averaged 42.0, 42.1 and 41.9, then I didn't drive Saturday and Sunday, and then with today's crappy weather I got 37.6 with one portion being 31.6 mpg (how???????!!!!!!! grrrrrrr lol)...I cannot stand seeing it under 40 anymore lol.

I had a bunch of cardboard from work I was going to bring home to experiment with, but I forgot and left it at work tonight. Not that the weather is currently conducive for that anyway...

Yes the 8th gen Civic sedan was my "dream" first car, however all the ones with decent mileage were $5K or higher, unless I wanted one with 300K+ miles on it or one with a rebuilt title or have to drive 1000 miles just to even look at it. Still very happy with my car though.

Compound curves and radiusing...to be honest I'm not sure how much of that my prototype will have, so I suppose I cannot be to sanguine about it's success. But I'll never know until I try.

Do you think vortex generators will "force" air to reattach to the Kamm if it isn't perfectly angled?

I want to get the Kamm working well now so that when I go down to Virginia for college this fall I have something to attach a temporary boat tail too....there's way too many steep hills to drive anything not perfectly streamlined and still beat 40 MPG...my family's minivan would drop gears for RPMS steady at almost 5000 sometimes to climb those hills, and then destroy the brakes on the way down (yes, I know, I couldn't get the driver to hypermile at all ...not to mention he was trying to go 75 the whole time.. )

Yes, I would definitely be interested in reading those articles! although I'm not exactly sure how the whole messaging feature works on here, until now I haven't been on a forum site in ages (today's generation....lol)

[19bonestock88]

Temperature has a lot to do with MPG... it not only affects aero drag(denser airmass to drive through) but also affects fuel trims(denser airmass needs more fuel to burn at same AFR)... a warm air intake can combat this some, at expense of power

[mpg_numbers_guy]

Originally Posted by 19bonestock88

Temperature has a lot to do with MPG... it not only affects aero drag(denser airmass to drive through) but also affects fuel trims(denser airmass needs more fuel to burn at same AFR)... a warm air intake can combat this some, at expense of power

The temperature wasn't THAT much colder...30s versus 40s/50s (fahrenheit). True, I had wind against me and all that, but even still I've been able to average 37-40 mpg instead of that 31.6...and that was with some intense hypermiling just in desperate attempts just to break into the 30s.

And of course Torque has to stop working this morning so I have no idea what kind of mpgs I'm getting today...guessing somewhere between 37 and 39 though..

[mpg_numbers_guy]

My timing belt replacement is done! This means...ecomodding!

Before taking my Civic in for its overdue timing belt replacement (153K on original belt) I removed my temporary grille block made from blue painters tape covered in silver duct tape, which surprisingly held on fairly well despite snow, ice, and rain over a period of 5 days. After getting my car back I replaced it with one made from duct tape covered cardboard attached with zip ties. Edges and gaps between the cardboard and the car were "sealed" off with duct tape covered painters tape. I considered painting it black, but figured I'd leave it as is since the duct tape closely resembles the color of my car (photo attached).

I also finally decided to go ahead and do wheel covers as well. Front two are mounted and the other two should be mounted in a day or two when I have time. Any guesses as to the materials used? (see attached photos) It should be obvious..

The 112 miles I drove today averaged out to 47.89 mpg (tank average up to this point was 42 mpg), but I can't claim the 14% increase to those mods alone; most if it was probably due to the maintenance I had done on it today, as well as each trip being about 30 miles instead of the 5-15 my trips usually are.

Next steps:
- Install rear wheel covers
- Partial lower grille block and fog light area covering
- Air dam
- Windshield wiper deflector

We'll see when I can get to all of this.

PS: Can one of the admins move this thread over to Ecomodding Central? It seems more appropriate there..TYIA