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The boattail I built last fall on my 92 Civic was so effective, FE-wise, that I decided to make it a permanent addition to my car, replacing the Coroplast and clear vinyl boattail with one made of aluminum sheet and Lexan. I recycled most of the original aluminum bar framework in the new boattail and the new boatttail has the same proportions as the old one. I extended the car's cargo area into the boattail, so now with the back seats down, I have 6-1/2 feet of load floor (4-1/2" of cargo space behind the back seats when I'm carrying 4 people). I also installed a functioning hatch (the stock hatch was covered by the original boattail).

I had the Civic off the road for over a week while installing the mods, during which time I drove our Honda Odyssey and Ford F150. When I first took the modified Civic out for a drive after a week's worth of getting used to driving "normal" vehicles, I was impressed by how differently it drove than your typical vehicle. Most cars slow down fairly quickly when the power is cut, especially at highway speeds, but the aerocivic only very slowly loses speed when power is cut. It makes a normal car feel like driving around with the parking brake lightly engaged.

http://img.photobucket.com/albums/v417/MikeMariettaSC/80MPG%20Honda%20Civic/BoatRebuild15.jpg
http://img.photobucket.com/albums/v417/MikeMariettaSC/80MPG%20Honda%20Civic/BoatRebuild11.jpg
http://img.photobucket.com/albums/v417/MikeMariettaSC/80MPG%20Honda%20Civic/BoatRebuild17.jpg
http://img.photobucket.com/albums/v417/MikeMariettaSC/80MPG%20Honda%20Civic/BoatRebuild13.jpg

This may sound silly, but the car looks beautiful, basjoos. I hope folks can take what you've gained through experimentation with aerodynamics and directly apply it to making vehicles slip through the air more efficiently.

I'm very impressed bas' !! Looks great !

All I can say is, "Wow!"

Excellent work... any idea what the net weight impact was?

I'll bet the Cd would be pretty good going backwards as well!

One word: WINGS

And btw, great work! :D I'd love to see a wind tunnel test on that beast one day.

Excellent work... any idea what the net weight impact was?

I'll bet the Cd would be pretty good going backwards as well!

Probably not much change in weight from stock. I lost the steel tailgate and rear glass and gained some aluminum sheet/rod and Lexan sheet. The handling hasn't changed at all.

that looks really good, the biggest flaw with the old tail I saw was how it covered the hatch, and this one takes care of that!

(if I didnt love being able to park anywhere in my yaris I would consider doing something like that) I bet it was fun making to create

omg i want one! how much you think you spent on materials just making the body? aerodynamic sexy

VERY cool, Basjoos!! That's very professional looking -- I was just sitting here imagining the rest of the car looking that clean?? With a good paint job that would be AWESOME. :thumbs_up:

By the way, I'm still on board if you decide to start selling aero-modded cars!!!!

Wow Basjoos, just Wow... that really looks good. My hat is off to you.

I'm impressed by the results and the effort.

I'm bad about not finishing projects, so kudos for getting it done!

Good job. Much better than your old one. Now if you could find a way to integrate the rear wheel covers and still be able to change the tires, the back end would be perfect.

Excellent job! Well done. So now, whats next...

Wow. That is fan-freakin'-tastic. Awesome job.

Super!!!!!

omg i want one! how much you think you spent on materials just making the body? aerodynamic sexy

The boattail upgrade cost about $200 in materials. Prior to this, all of my aero mods had costed $210.

Excellent job! Well done. So now, whats next...

Convert the front skirts and nosepiece from coroplast to aluminum, then a new paint job.

That is a great project car you've built.

I wonder if aerodynamically you would gain/lose by having the rear section formed down to a ground effects height above the ground rather than rising?

Overall net might be a loss with my idea due to added weight involved?

I think it would be a loss, but not because of added weight. One of the ideas on making aerodynamic vehicles is the smooth the flow of air transitioning in the back of the car. Making everything come to a point is what's commonly called the teardrop shape. Making it come to the ground would limit the ability of the car to effectively smooth the underbody flow with the air coming over the top.

It looks really cool, especially from the back. How did you make the rear hatch? Also is it Lexan? Thanks.

The glazing is Lexan and is attached to a frame attached to the hinges used by the original hatch.

How much mpg did you gain with the boattail?

About 6mpg.

So realistically I could get > 50 mpg in my 93 Hatch with no body work, right?

Hi 93Hatch:

___Which 93 Civic do you own and yes, it should be possible to hit 50 mpg with a little work on your side of the fence if that auto is capable …

___Good Luck

___Wayne

Yes. You'll have to work a little harder with the auto, but it's within reach. Mine's a manual, but it's heavier than the early 90's models, and it's the heavier 4-door. I consider it a bad day if I'm as low as 50.

Edit: and I have the bigger 1.6L engine, to your 1.5.

Get a SuperMID (a scangauge-like device for OBD1 (pre-1996) vehicles) so you can get a real-time display of what mileage your car is actually getting as you drive down the road so you can fine tune your hypermiling techniques. They are $150 from Yoshi, who makes them (he's a CleanMPG member, you can PM him) .

Get a SuperMID (a scangauge-like device for OBD1 (pre-1996) vehicles) so you can get a real-time display of what mileage your car is actually getting as you drive down the road so you can fine tune your hypermiling techniques. They are $150 from Yoshi, who makes them (he's a CleanMPG member, you can PM him) .

I assume that the SuperMID will not work on my 2000 Accord? It would be nice to get a scan tool that would work on either vehicle.

Basjoos - Have you done any aero work to the undercarriage? For some reason I was thinking about this on my ride to work today ("I wonder if that guy with the funky civic has undercarriage panels?")... Anyway, if not, you could probably pick up 2-4 mpg.

I have smooth underbody panelling that covers the entire underside of the car except for a small gap around the muffler (with a fairing behind the flat back of the muffler). Also wheel spoilers ahead of the front and rear wheels, double side skirts between the front and rear wheels (outer side skirt even with the outer edge of the tires, inner side skirt even with the inner edge of the tires), and a mini-boattail behind each rear wheel. The effect of aero mods is accummulative, the contribution of each mod may be small, but the sum of all of the mods together is substantial.

Great project!

Two questions...

1) Do you have problems passing state vehicle inspections with your aero-mods?

2) Are you going to aero-mod that RV? (Only half joking)

Bas, any chance of getting pictures of the underbody work?

I'm thinking about working some panels up for the Insight, as well as blocking the upper air dam with a carved foam block (or similar).

The Insight has fairly good underbody work but the whole exhaust is exposed in the center channel - I imagine this is for cooling purposes, but there's no way that exhaust gets that hot.

jzed - Fortunately my state dropped state vehicle inspections in the early 90's. That RV mainly serves as a guest cottage and is rarely driven, so I haven't had much incentive to aero mod it yet.

shifty 35 - Since it has low ground clearance, it is difficult to take a good photograph of the bottom of my car, but those that I do have are posted on my photobucket site:

http://smg.photobucket.com/albums/v417/MikeMariettaSC/80MPG%20Honda%20Civic/

wow bit too out there for me but the rear really reminds me of a auburn boattail speedster. i like your new hatch design. your structure for the rear looks quite strong.

I guess when the Aptera becomes a common sight on the highways, the appearance of my car won't come across as quite so unconventional.

http://img.photobucket.com/albums/v417/MikeMariettaSC/80MPG%20Honda%20Civic/Above5.jpg
http://img.photobucket.com/albums/v417/MikeMariettaSC/80MPG%20Honda%20Civic/Above2.jpg
http://img.photobucket.com/albums/v417/MikeMariettaSC/80MPG%20Honda%20Civic/Above1.jpg

i had to look up what an Aptera was. looks nice, same day they will be more common. btw what was your underbody skin and how did u deal w/ it around the engine/axles? also did u do a warm air intake? sry for all the noob questions

The underbody is made of coroplast, with aluminum flashing nearIt covers the entire underside of the car except for where it flairs into the exposed underside of the muffler. the exhaust system. I didn't build a warm air intake, but the grill block effectively increases the intake air temp.

There's nothing new or avent garde about the design of my car, most of its aero is 70 year old technology. This Maybach was running the Autobahn back in 1939.
http://img.photobucket.com/albums/v417/MikeMariettaSC/80MPG%20Honda%20Civic/sw38-ds03.jpg
http://img.photobucket.com/albums/v417/MikeMariettaSC/80MPG%20Honda%20Civic/sw38-ds04-1.jpg
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http://img.photobucket.com/albums/v417/MikeMariettaSC/80MPG%20Honda%20Civic/sw38-ds02.jpg

max props when i have my grandmother and father emailing me pics of your car sayin "this guy gets over 70mpg, u do something similiar" lol