5th generation civic hatchback - improving aerodynamics

[AndrewJ]

Yeah Daox, I did (kinda) do a "stock" coastdown test in post #32 I only got in one pair of runs, so two data sets, but it showed 0.33, the same Cd Honda claims. I thought about doing another set of "stock" coastdowns today, but I couldn't bring myself to do it. It's pretty nerve-fraying going out on a public highway and doing a series of these tests.
Not to mention it KILLS your mileage for that tank.

And Ben, I'll gladly do test your plugs out if you just send me the proper testing equipment.
:cough: SuperMID :cough:

[SVOboy]

O rly? I was always under the impression it was .25, I suckz.

[tdicandy05]

AndrewJ - Thanks great idea on the hub caps. When the weather warms, I'll have to think about changing my TDI's wheels - don't like the current ones.
Hope to up the car's mpg's too. Drove the Honda VX for 13years - it was a great car - it could get 70mpg!
Kristina

[bennelson]

What is the exact diameter of those pizza pans? They look factory installed!

Are those lightweight/rustproof aluminum, or sheet steel?

[AndrewJ]

The pizza pans are 14" aluminum pans that I got from Cash & Carry (a restaurant supply place) and they pretty much perfectly fit the 13" wheel covers, actually they're about 1/4" smaller, but they work.

[AndrewJ]

OK, we're gonna get all web2.0 with this $h!t, yo. (you know, interactivity or something)
I'm gonna be conducting a poll to determine my next mod. But, since I don't want to start a new poll thread just for that, you have to PM me with your choice. I'll tally and post the results.

Here's the situation.
I'm going to San Fran in a few weeks, driving 275 miles each way, and I REALLY want to make it there and back on one tank of gas. That means hitting at least 57 mpg the whole way, something I have yet to do.

So I'll be looking to do one major aero improvement before then to boost my highway mpg (hopefully into the +57mpg range). And I think I may only have enough ABS plastic left to make one of the two mods that I want to...

Here's were all of you fine folks come in. You'll be making the decision for me as to what mod I make.

Front wheel skirts or a Kammback?

The front wheel skirts would strongly resemble those on basjoos's car, and the Kammback would strongly resemble Darin's prototype.

So, let the battle begin! (and thanks for the help!)

Oh, and feel free to post with your vote and/or reasoning.

[AndrewJ]

OK folks, so far I have two votes in.

basjoos voted for the Kammback (along the lines of MightyMiras) , though his post got lost in the crash.

And I have one from diesel john voting for a splitter on the front airdam.

While I agree that a splitter may be beneficial, I don't think that it falls into the category of "low-hanging fruit" at this point, and that's what I'm shooting for with my dwindling supply of ABS.

I'm inclined to go the Kammback route because it seems the wake of my car would be one of the biggest contributors to drag at this point, but the other biggest contributor to drag is the front wheels (~13% if you believe the Volvo graph).
So, what do the rest of you think???

[Daox]

I'd have to agree with basjoos. His boattail was the most effective aero mod. A kamm back isn't quite as good, but I think will do more than skirts.

[MetroMPG]

My post was also eaten by the great ForkenSwift/Digg Event (TM) of 2008.

I wrote a lengthy, incisive and elegant argument (trust me) for going the Kammback route as well.

[AndrewJ]

Originally Posted by MetroMPG

the great ForkenSwift/Digg Event (TM) of 2008.

Damn, and I was hoping to trademark it first!

Well, it looks like the Kammbacks are walking away with it! Time to go do some preliminary measurements. And to figure out how to get that darn lip spoiler off the top of the hatchback glass. Chilton manual, here I come!