Streamlining the Civic (2005 Civic EX coupe)
 

I've been doing some work since joining this forum a couple months ago and perusing the information here. I've gone from consistent 37-38mpg tanks to a best of 51.7mpg and 90-day average of 47mpg! Most of my driving is on the highway, with a 45-mile (one-way) commute three days a week through pancake-flat central Illinois, so I've been focusing on aerodynamic modifications for the open road and gliding and coasting around town. I figured I'd start a build thread here to chronicle the mods and my results.

First up: lowering. I've had height-adjustable coilovers on the Civic since last year, so I lowered the ride height a bit more to get rid of as much wheelwell gap as possible:

http://i1047.photobucket.com/albums/...315_113102.jpg

Next up were the mirrors. I was surprised how much removing the side mirrors changed the look of the car. Before:

http://i1047.photobucket.com/albums/...129_153025.jpg

(I ditched the front plate, too). The mirrors were replaced with convex mirrors from Autozone. I didn't trust the 3M tape to hold them to the sail panels, so I used some screws to mechanically attach them:

http://i1047.photobucket.com/albums/...316_163039.jpg

http://i1047.photobucket.com/albums/...316_163020.jpg

The driver side mirror started sagging after a few days, so I epoxied the ball joint at the base of each mirror. On the outside, I cut a closeout panel out of some flashing and reused the rubber moisture barrier from the mirrors and three bolts through the stock mounting holes, with silicon caulk to seal the edge gaps.

http://i1047.photobucket.com/albums/...419_150223.jpg

When I bought the car a couple of years ago, it was riding on the original tires. I was planning on replacing them this spring anyway, so I picked up some LRR Continentals on cheap steel wheels and a set of solid wheel covers.

http://i1047.photobucket.com/albums/...419_150256.jpg

Finally, to finish the front end, grill blocks were in order. After driving around with a temporary (cardboard and duct tape!) full upper grill block and partial (2/3 covered) lower grill block, I decided to use sheet metal to smooth over the whole front and cover the fog light indentations as well.

http://i1047.photobucket.com/albums/...419_150232.jpg

The radiator inlet is now significantly smaller, so I've been keeping a close eye on coolant temperature. It seems fine for now, but if I need to enlarge it when 90-degree temperatures roll around, it should be pretty easy to do with a pair of snips.

http://i1047.photobucket.com/albums/...419_150201.jpg

As it sits now:

http://i1047.photobucket.com/albums/...419_150150.jpg

Next up, I'll turn my attention to the underside and rear end. My goal for the near future is an 845-mile trip to New Jersey this summer for my brother's wedding: I'd like to do it on one tank (13.2 gallons) or as close to that as possible, which will require the car to get ~65mpg. I'm not sure if that will be possible, but, hey--dream big, right?

Looking good! Love those mods.

How much adjustibility do you have with your coil overs, what brand ect.

Thanks! I got the coilovers from AMR Engineering in Seattle; they're a great value for the price (Hypercoil springs, etc.), custom built with user-specified spring rates and valving, and were highly recommended by lots of people on Honda Tech.

64 mpg
 

You'd need to hit fuel starvation at 64 mpg to coast in to your brother'
s place.
I think you'd need at least a couple feet of boat tail behind you to have a fighting chance.Your existing wake is just too big and powerful.You've got to shed some of that load.

Two feet would put me in the neighborhood of 50% of template. Do you think I'd see much more benefit from going further than that?

Looking very much like this one here : http://image.turbomagazine.com/f/900...front_view.jpg

Very nice work. Any plans for wheel skirts?

further
 

*@ 50% with a good cleanup you could push Cd 0.177
*@ 60%,Cd 0.153 (think EV-1 with its tailcone at 183 mph at Ft.Stockton,Tx)
*@ 70%,Cd 0.140
*@ 80%,Cd 0.133
After 80% you're pretty much in 'phantom' tail territory and additional length couldn't get you below Cd 0.13 unless you went after the wheels/tires.
If you attacked those,then might be looking at Cd 0.11 or so.
My truck is at Cd 0.18 at its present length with the quirky rear bed corners.
basjoos is at Cd 0.17 with AeroCivic.
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If you execute a tail mod staying close to the 'template',you could start at 50% and then later, if you got hungry for more savings,you could just extend it some more.'Plug-and play.';)

very clean.
I would go w/ black.
The red w/ dark tint is just beggin for black!!

I was going to agree with you on this, but I think the car looks great as is.
Looks very much like the Bonneville race car.
Also, the aluminum sets off the wheels quote well.

The car looks great, though I would install a shelf spoiler to the car.
( which is just what was on that Bonneville car ! )

One thing I would black out would be the area where the mirror was.
I think it draws too much attention from the police.

Unless the rest of your car is so heavily aeromodded that the police don't notice the lack of external rear view mirrors. In all of my traffic stops, the cops have never mentioned the lack of external rear view mirrors on my car (although it meets SC auto regs as long as I don't have the center rear view mirror's view blocked by cargo).

looks good!

I feel the mirror finish is too "blingy", especially since the car is already red. The ride height and bonneville caps look great though. If mirror removal is legal in your state don't sweat it unless the aesthetics bug you. I put black electrical tape over my mirror deletes.

I made sure to check that before removing them...Washington (where the car is registered for now) requires a driver's exterior mirror, but Illinois (where I'm in school and where it will be registered once the tabs expire) only requires "a mirror so located as to reflect to the driver a view of the highway for a distance of at least 200 feet to the rear of such motor vehicle." Funny this comes up now, too, as just last night I was pulled over because one of my tail lights was out--the officer noticed the mirrors, I'm sure, and didn't say anything!

Awesome. I'm the opposite- they're legal where registered in MN but at college in MI they're illegal. I've been pulled over in both states and neither mentioned the mirrors (though one was at night).

It looks like you have some non-eco mods on the car, too (coils, grille, head and tail lights) so I'm wondering if you race it or if it's just for street fun. My Rabbit's got coils and I definitely didn't buy them for fuel economy! ;)

Yup--I've had fun autocrossing the car. Now I work weekends, though, and since its primary function is as a commuter I've decided to take it in a different (and more economical) direction.

I've been reading all the boattail threads I can find on here, and the idea is really growing on me (especially with those potential Cd values Aerohead posted!). I'm thinking of a 36"-38" extension past the rear bumper (~60% of template), moving the license plate and stock taillight housings to the end of the taper, and building the tail out of foam blocks and fiberglass (using 3-wheeler's method). I have to be able to see out the rear to have a legal mirror situation, so I'm thinking of using a piece of Lexan doubling as a hatch for trunk access, and removing the trunklid since it would be superfluous. This would also allow me to use the trunk edges as mounting points, in addition to a support on the bumper and perhaps in the taillight holes.

rearview mirror
 

At the 'angles' associated with the 'Template' your LEXAN might produce refraction and internal reflections significant enough to obliterate the rear view.
If you have any clear plastic laying around you might prop it against the back of the car at the anticipated angle and look through the rearview to check your rearward vision.
Should it be a problem,you can always do a small,vertical, 'step' backlight which is inset into the rear slope.It doesn't have to be very large and the recessed area around it will simply capture a vortex of which the outer flow will just skip over.Many supercars and competition race cars have used this when running proper K-Form rooflines.

Thanks for pointing that out! I'm going to take it one step further, and tell me if I'm off base here. What would happen if I ditch the Lexan entirely and leave the rear window and trunk lid uncovered, with the tail coming up the sides to the roof and then everything past the trunklid built up to the template? Essentially, a larger cutout inset in the slope? Is there a maximum size where that will start to impact the airflow?

Subscribed. I like that red body + sheet aluminum / stainless look.

impact
 

I kinda did that with the CRX.
*I extended the C-pillars along the 'template' curvature on each side of the hatch.
*At the top,I had a cantilever wing projecting out about a foot along the 'T' curve.
*Then I had a low wing which extended back to intercept the 'T' curve which morphed into the boat tail.
Leaves captured inside the 'void' would dance around,impelled by the vortex,with outer flow glancing off the vortex.

Before I embark on the tail, I figured it would be good to get some more fiberglass experience since I have very little (I built a sub box once, but that's about it). So, I found some inspiration in this thread and started chopping up my stock mirrors. I basically followed the same process, with the exception of having to glass in the plastic bit that holds the attachment bolts as it's a separate piece from the mirror housing in my car. Bondoed and sanded:

http://i1047.photobucket.com/albums/...507_193142.jpg

Painted and on the car:

http://i1047.photobucket.com/albums/...508_161307.jpg

http://i1047.photobucket.com/albums/...508_161255.jpg

Next up, I'm going to glass and paint the upper grill to match, and then do the lower bumper. Then I think I'll be ready to tackle a full tail.

any further progress?

Actually, yes--I pulled the bumper cover and grill off yesterday, removed the galvanized steel flashing, and covered them in expanding foam which I let set overnight. I'm about to cut/sand them down and fiberglass over them, then sand/Bondo and paint. Pics to follow!

And done! After removing the flashing, I filled the grill and lower fascia opening with expanding foam:

http://i1047.photobucket.com/albums/...528_093954.jpg

http://i1047.photobucket.com/albums/...528_093945.jpg

Cut off the excess with a kitchen knife:

http://i1047.photobucket.com/albums/...528_102855.jpg

http://i1047.photobucket.com/albums/...528_105417.jpg

Then fiberglassed:

http://i1047.photobucket.com/albums/...528_171909.jpg

After our hottest weekend of the year last week (97--and it's only in the 50s today), I noticed my temperature creeping up when the AC was running. So I made the radiator inlet slightly larger than what I had in the sheet metal:

http://i1047.photobucket.com/albums/...528_172016.jpg

Sanding:

http://i1047.photobucket.com/albums/...529_112251.jpg

Lots of sanding:

http://i1047.photobucket.com/albums/...529_140350.jpg

Painted:

http://i1047.photobucket.com/albums/...531_214151.jpg

And on the car!

http://i1047.photobucket.com/albums/...601_141336.jpg

I adhered to the 10-foot rule; it looks pretty good...from 10 feet away. If I have more time in the future I can go back and clean up some spots, but overall I'm happy with it for how much time I put in. And it looks much less conspicuous than the galvanized steel!

Dang Dog..Really great work!! Great pics too. Thanks a bunch for sharing.

Excellent.

Fantastic job. But why black? Why not make it red like the rest of the body? Just wondering, looks really good.

I can answer that..... you never get a perfect match when you try to go factory color.

The black is PERFECT!!!!!!

Nice job Vman. How do you see out your side mirrors. Seems like there may be some safety issues. When I had an Illinois drivers license I was required to have outside mirrors. It is a fairly common restriction.

Do you have narrow mirrors in your flattish panels?

I went with black for a few reasons--black was readily available, whereas factory matching color would have had to be ordered, and I thought it might look weird with the negative space of the stock grill and foglight hole covers turned red. I wasn't planning on extending the black that far out the sides, but I got carried away sanding.:p Plus, the black will match my eventual tail.

Nope, just some interior convex mirrors from Autozone. I can see just as well as with the stock mirrors, and Illinois only requires one mirror(!), "so located as to reflect to the driver a view of the highway for a distance of at least 200 feet to the rear of such motor vehicle." So, blocking the rear window would make the interior mirrors no-go, but as it sits it's legal (but not in Washington, where it's registered until the tabs expire later this year).

Very nice work! Thank you for sharing :)

Looks good, did you do anything to the bumper to get the glass to adhere better? I almost did this back in 09, but the civic that did the foam/fiberglass bumper back then, he had problems with it cracking off of the bumper. The polyester resin doesnt stick to plastic very well. In the audio world, a lot of times, we'll drill a bunch of small holes through the plastic to get it to adhere better.

Actually, I used epoxy resin, which I understand has better adhesion properties than polyester resin to non-porous surfaces like plastics. I haven't had any problems so far (knock on wood).

You should be fine then, its rare people at home use epoxy resin. Not only should it adhere better, but its a little more flexible, so it should give a little more before breaking, in case anything hits it.

Well, I haven't had time to build my tail, and I'm leaving Wednesday for New Jersey. I did get coroplast full pans on the front and rear of the car (with aluminum under the downpipe and catalytic converter in front after the plastic started melting!) and a couple panels in the middle to cover up the center tunnel. I'm also experimenting with 6 vortex generators on the rear window, after tuft testing without them, with 10, and then removing 4--they're keeping the flow attached now, but if they're having an effect on fuel economy, it's not significant enough to tell. I may try and fab up a temporary coroplast-and-tape box cavity tomorrow if I have time....

Looks slick, have a good trip!

Any pictures of the belly pan?

I'm considering it on my '01 Civic, but not sure if it's worth the hassle.

Once the weather warms up a little I can take some. I'm also planning on re-working the middle of the car with flat bar and more coroplast to make a smoother, full pan.

Wow, looks nice, time to photoshop my xA to see how it would look like that