Streamlining the Civic (2005 Civic EX coupe)

[Vman455]

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:



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



(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:





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.



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.



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.



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.



As it sits now:



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?

[Sporty Modder]

Looking good! Love those mods.

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

[Vman455]

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.

[aerohead]

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?

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.

[Vman455]

Originally Posted by aerohead

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?

[Cd]

Looking very much like this one here :

[TOOSTUBBORN2FAIL]

Very nice work. Any plans for wheel skirts?

[aerohead]

Originally Posted by Vman455

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?

*@ 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.'

[mcrews]

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

[Cd]

Originally Posted by mcrews

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 ! )