Civic hatchback aerodynamics

[Silveredwings]

I think it has to be outside the plastic, so he's located it as much out of the slipstream as possible to remain legal (prob had to locate a light for it too).

[kwtorbe]

Originally Posted by Bunger

I've used Dzus fasteners in the past for hoods, bumpers, front ends, etc... should be great for what you need.

Reading this forum this is exactly what I was thinking. I installed a fiberglass 6-pack hood on my '70 cuda using Dzus clips. They work great and you can get them from your local race store.

[BeeUU]

Great work, kicks the #$%#$ out of anything I have done. I will have to use your photos to soften my wife's response to future areo mods on my car.

Thanks for leading the way basjoos.

[itjstagame]

Originally Posted by Mighty Mira

If the wind is nearly parallel to the path of the car (or dead calm), then the air only gets moved out of the way once, out of the way of the first wheel. Now that I understand the effects of crosswinds, I am reluctant to try side skirts, because they will slow you down with a crosswind.

I didn't realize the side skirts were only for the movement of air around the tire, if so, wouldn't it be better to just expand on the wheel spoiler concept? That is, have a spoiler in front of the tire to move air down and around the tire better than just hitting the wall of rubber, and have the same thing afterward to help the air join better instead of just having a massive negative pressure region behind the tire (same concept as the tail on a smaller scale).

Also awesome project, I can't wait to get a daily commuter beater to do this to. Does anyone have any good sites to look up local laws? Because some of these mods seem quite over the top and I'm not sure how much of a stickler NYS is.

[Bill in Houston]

Originally Posted by itjstagame

That is, have a spoiler in front of the tire to move air down and around the tire better than just hitting the wall of rubber, and have the same thing afterward to help the air join better instead of just having a massive negative pressure region behind the tire (same concept as the tail on a smaller scale).

I think that the difficulty comes in trying to allow the "wheel spoiler" to move up and down with the suspension, and turn from side to side.

[basjoos]

Some people were asking questions recently about installing grill blocks on 92-95 Civics. I've had this grill block installed since last Nov, and it hasn't shown any signs of overheating dispite 105F summer temps here in SC and steep climbs up into the NC mountains. The grill block is a rounded nosepiece that replaces the flat surfaces of the original grill/bumper and I use the slot at the front of the hood as my air intake. The radiator in this car sticks a few inches above the lip of the hood opening with a gap in front of it, so the air enters the hood slot, hits the top of the radiator and curls down into the space between the front of the radiator and the original grill openings. I removed the rubber gasket that normally seals the slot at the front of the hood and caulked the part of the hood slot that sits in front of the AC radiator (which doesn't stick up). Air for the AC radiator runs down through some widened holes in the area around the hood release. This mod caused a noticable improvement in coasting (this was in my pre-SuperMID days so I have no hard and fast numbers) and cut the size of the A pillar rain swirl vortex to 1/3 of its original size (= less aero drag). Since this radiator intake is invisible to most people's eye, I've gotten more questions as to whether my car is an electric vehicle since I installed it (often asked after I coast silently, ICE-off, to a stop).

[basjoos]

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. Used pop rivets to mount most of the aluminum sheet. 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.

As time allows, I plan to replace the coroplast on the front wheel skirts and nosepiece with Al sheet. The underpanelling, side skirts and wheel spoilers will remain as coroplast since coroplast's flexibility allows it to better withstand contact with road debris than the rigid aluminum.

Following are steps in the construction process:

[AmmoCatcher]

How'd you get the Lexan to bend without breaking/crazing? I'm wanting to do something similar with my del Sol and haven't got the nerve up to do it yet.

[jwxr7]

that looks really good . Space age looking, and kind of airstream travel trailer crossed with airplane before paint. That makes me want to upgrade to a full boatail soon . Does your middle upper brake light still shine thru good? I know in michigan that could get a car pulled over. We don't need any more excuses to get pulled over.

[SVOboy]

Wow! That's amazing dude! I can't wait to see what you do when you replace the rest of the stuff.