Aero differences between my LX Civic and the Hybrid...mod inspiration?

[KJSatz]

One day on the freeway a Civic Hybrid passed me in my LX Civic. We were both the latest bodystyle, 06-08. I noticed that it looked slightly different, though. Now I checked Honda's website, and they have two photos from the same angle of a non-hybrid (it's the EX but whatever) and the hybrid.

Non-hybrid
http://automobiles.honda.com/images/...y/gal_lg12.jpg

Hybrid
http://automobiles.honda.com/images/...y/gal_lg10.jpg

The differences are the antenna and something on the very back of the trunk. I am wondering if anyone can identify if/why these features are aerodynamically superior, and if either of those ideas could be applied to my Civic. Thanks!

[MetroMPG]

The wheels and deck lid spoiler are the main aero differences I can see.

Both features are superior vs. the "regular" car.

Honda Canada in fact added that spoiler to all "regular" 5-speed Civics for '08 as one of several measures to marginally improve the car's fuel economy to earn a government efficiency rebate.

Source: CTV.ca

[KJSatz]

Oh and of course the wheels! My LX has pretty flat hub caps (plastic covers on steel wheels, unlike that photo of the EX), though they certainly aren't the hybrid wheels.

That story about Honda Canada is very interesting!

Does the external antenna on the hybrid make a difference? I think I remember seeing an image on these forums similar to that but with a lot of smaller fin type things alongside it. Vortex generator? I don't think I'm making sense.

[Tourigjm]

the hybrid has bigger side mirrors, and it also looks like it has a lower front lip. The external antenna on the hybrid probly does act like a vortex generator, however ther's only one adn it wouldn't have a huge impact on the cars aero.

as far as that deck spoiler... id rather see something that extends back from the top of the trunk than that little lip for aero. airflow's probly turbulent at that point anyway, the spoiler would probly just increase drag.

[MechEngVT]

If Honda bothered to design and place this item on the Hybrid you can bet it wasn't because it increased drag.

The deck lid spoiler could very well reduce drag if the flow on the normal car separates somewhere up the deck lid. The lip spoiler will help the flow stay attached (not laminar, "attached" turbulent flow) and may even generate a vortex (sharp edges are better at this than rounded ones) to reduce wake area behind the trunk.

The mirrors on the hybrid aren't just larger they're shaped differently. I'm curious as to why the mirrors on the hybrid would be larger but the shape looks like it makes sense. Most of the "aero" mirrors on high-end cars these days (BMWs) have a design more similar to the HCH than the EX where the leading face of the mirror has a split line with a downward-facing angle below and an upward-facing angle above, and the split line on the HCH/BMW is about 60-70% above the bottom edge of the mirror. On the Civic EX it looks like the split line is dead center to below-center.

Good eye re: lower front lip Tourigjm...I looked at the photos before reading the thread and noticed that myself. Not only a lower lip on the hybrid but looks like it flares further out to the side of the car in front of the tire.

[ALS]

If I owned an EX I would install the rear spoiler and Hybrid wheels to squeeze out a few MPG on the highway mileage. The front wheel spoilers and mirrors would help a little but I feel the other two upgrades would give you the best bang for the budget. The more I look at the pictures the front spoiler looks the same and instead it looks like there are small individual tire spoilers installed in front of the wheels.