My 95 Civic Needs an Aero Makeover

[Pawtuckett]

I've hit something like a "writer's block" when it comes to planning out exactly what aero mods I would like to do to my car. I know that the area that will reap the most rewards is the rear of the car. I already plan on doing wheel spats and a full undertray. What I need help deciding is how to attack the rear and front of the car.

For the rear, I'd like to do a full boattail, but I don't know what points I should use for attachment, the angles, what materials to use for the frame, etc. I have no problem cutting or welding on my car. I am even thinking of removing the rear glass and trunk lid to reduce weight once I get the boattail done (or to create an opening for mounting points in the interior). The boattail doesn't need to be removable. I have a large sheet of coroplast that I think I want to use for the outside. I'll attach my template photos so y'all can let me know if I'm lining it up right. Also, I don't know if the angles are the same when tapering the rear end horizontally as they are vertically. Do the gains of a boattail make it worthwhile to do or would a kammback suffice with much less effort?



Now, for the front end, I've got an airdam on there right now (work-in-progress, as evidenced by the duct tape mounting job) that has made a noticeable difference when coasting, but I don't know what design I should use for the front end that will help direct air over the car instead of under it. I don't know if a more rounded shape, or even a parabolic shape, would be noticeably better. Sorry if this didn't make much sense. I'm about to help my kiddo pack to go see his grandma, so I'm trying to type this out as quickly as possible. Thanks in advance for all the advice/input/criticism/props/etc.

[HydroJim]

If you're not afraid to do it, remove/cut whatever you have to in order to make a good mounting surface. Coroplast is light, but I don't think it will be water tight, so you might want to consider a different material. the coroplast never turns out looking too good also. it's cheap and light and that's why ecomodders use it. I'd look into fiberglass for your tail.

[Pawtuckett]

Originally Posted by HydroJim

If you're not afraid to do it, remove/cut whatever you have to in order to make a good mounting surface. Coroplast is light, but I don't think it will be water tight, so you might want to consider a different material. the coroplast never turns out looking too good also. it's cheap and light and that's why ecomodders use it. I'd look into fiberglass for your tail.

Agreed on the glass. The only time I ever glassed anything, it looked terrible and was bulky as heck, lol. I'd be willing to try again, though. Would you suggest something like a wire mesh to support the glass structure?

[Pawtuckett]

Would an aluminum-skinned boat tail be feasible, cost-wise?

[HydroJim]

aluminum would work. cost wise, that depends on you. I think it would be hard to make it look very good. I'd say look around the forum for fiberglassing tips. It takes a lot of work to make it look good, but it's worth the time.

This is all if you want the tail to be sealed. if you just leave the original car pieces in place, you can make your tail out of coroplast similar to mine.

[Pawtuckett]

Does anyone have any suggestions for the front end shape?

[Sven7]

Front end looks good- just make sure those corners on either side are rounded off so you don't risk detaching the airflow.

As far as making a boat tail, it depends on your quality/appearance standards. I spent probably $500 making an aluminum framed, coroplast skinned tail for the Anal Probe. 3-Wheeler built an OEM-looking Insight tail you'll want to check out. Also peruse threads by Jethro Bodine (Mk2 Jetta), basjoos (Aero Civic EG) and Weather Spotter (Matrix).

Seems a blue foam buck covered in foam is a good approach. You can put a lexan rear window on if you use simple curvature over that area.

Make sure you figure out a good way to transition from the belly pan (you'll need one) to the bottom of the boat tail. My Civic hatch has a convenient rear tow hook for possible mounting; perhaps your sedan does as well.

Anyway, read some threads and see how they planned it. There's a ton of information to absorb.

[aerohead]

Originally Posted by Pawtuckett

Does anyone have any suggestions for the front end shape?

If you're determined to alter the CIVICs nose you might consider copying basjoos' AeroCivic.It would be off-the-shelf technology with a proven track record.It's doubtful that you could improve on it.

[aerohead]

Originally Posted by Pawtuckett

Would an aluminum-skinned boat tail be feasible, cost-wise?

Aluminum,even salvaged from a metal recycling center can be pricey.
And to shape it for maximum drag reduction would require many,many,many hours/weeks/months with an English wheel,planisher,tree stump,leather shot bag,rawhide mallet,and assortment of body dollies.And there are many different grades of aluminum,and not all would be compatible to forming.
And you'd need a gas welding outfit to properly anneal the metal between stretching and bumping so as not to rupture it.
Straight,single-curve panels could be done (like Chevy VOLT).You'd have to figure out how to bond them together.Flush,bucking rivets can't always be reached from behind.Cherry makes flush pop-rivets for aircraft applications.You'd have to seal every rivet head.And you'd want to look at price.
Fiberglass is going to be hard to beat.

[j12piprius]

Originally Posted by Pawtuckett

Now, for the front end, I've got an airdam on there right now (work-in-progress, as evidenced by the duct tape mounting job) that has made a noticeable difference when coasting, but I don't know what design I should use for the front end that will help direct air over the car instead of under it. I don't know if a more rounded shape, or even a parabolic shape, would be noticeably better.

Do you still have the same design, and how is that working for you?