5th generation civic hatchback - improving aerodynamics

[MetroMPG]

Originally Posted by AndrewJ

images downsized sir.

Thanks. There's likely a function to automatically resize giant ones, even if they're hosted offsite (by dynamically setting width="" in the html). I'll have a look and see, as I'm sure this will come up often.

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That air dam is GIANT! I'll be very interested to see how it compares on your "calibrated" hills. I'll also be very surprised to hear that you didn't scrape it .

Sounds like you're going to be using the same methods Coyote X did to determine which bumper style was best for his car - comparing terminal coasting velocities on an often used descent.

I'm envious - "testing season" has been finished here for over a month due to the weather.

[MetroMPG]

PS: smooth wheel covers?

[AndrewJ]

Originally Posted by MetroMPG

That air dam is GIANT! I'll also be very surprised to hear that you didn't scrape it .

Oh, belive me it scrapes! Eventually it won't be quite so giant as it will be ground down.


Terminal velocity coasting results are in and they're interesting.

So my testing hill starts at about a 3% grade for 1/2 mile then goes to a 6% grade for another 1/2 mile. I usually start by killing the engine at the top going 55mph. By the end of the 3% grade section I've usually slowed to 50mph. Terminal velocity at the end of the 6% grade section is just shy of 65mph.

Today I did the same run with the airdam on and got a surprising result. The terminal velocity at the bottom of the hill was 67mph. But the interesting part was that on the 3% grade section I did not slow down from 55mph.

I think the airdam is a keeper. I'll have some tinkering to do in the next few days to get the final form down.

[MetroMPG]

Any chance of an A-B-A? How many screws on that puppy?

[AndrewJ]

I might do an A-B-A on Tuesday or Wednesday. It's only got 4 screws in it at this point, not counting the 3 license plate screws (there were 4 but one was so rusted it snapped off)
I'll probably do some A-B-A with the wheel skirts then too. Maybe front wheel skirts if I can get motivated to get them done by that time.

[MetroMPG]

That would be very cool.

So here's the other big question... do you feel self-conscious driving it?

It took quite a while to forget about my car's skirts. Lots of people noticed, and I even got a few quick rolled-down-window Q&A's. And that's just with rear skirts!

[AndrewJ]

People seem to take notice of the airdam much more than the skirts. I think it's because the airdam is frickin' loud when it scrapes, that and it's a huge white expanse of plastic. I think it gets the attention of the younger guys b/c of it's almost "racer" appearance.

About a week ago I got the first comment about the skirts from an old guy in a store that I frequently work in. I was passing him in the stock room and he stops me "Is that you're little white car out there?" me: "the civic? yeah." him: "those wheel covers are really neat looking!"

I can't help thinking that they're much more likely to be appreciated by the older crowd, those that grew up around all the Cadillacs, Buicks, Oldsmobiles, etc that had rear wheel skirts from the factory.

[AndrewJ]

So I finally got some motivation to do some more work on the car today.

I took off the airdam and shortened it about 2" so hopefully that will resolve the scraping issues I've been having.
I also took the opportunity to add some front wheel spoilers to the airdam.

Here it is all trimmed up with the wheel spoilers, off the car of course.




And here it is on the car.




And one detail shot of the wheel spoiler.




I also deleted both side mirrors, but it was very much dark when I got them done, so pictures will have to wait until tomorrow.

[MetroMPG]

Nice to see you working on refinements.

Originally Posted by AndrewJ

I might do an A-B-A on Tuesday or Wednesday.

Any news there? (Clearly I'm a sucker for the data.)

If not, I'll settle for qualified subjective observations .

[AndrewJ]

No, still no A-B-A but I'll try to squeeze in some testing on my next day off. I think my data gathering is moving at a Forkenswift pace.