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Old 04-09-2008, 09:22 AM   #11 (permalink)
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There are two major sources of CdA numbers that I've been using. Neither is ideal from the point of view of authentication. They are:

http://www.mayfco.com/tbls.htm
http://en.wikipedia.org/wiki/Automob...g_coefficients

The problem is that I believe a lot of the wiki info came from the mayfield (mayfco) numbers, so they're not an independent confirmation. Second, many of the mayfco numbers are estimates, but they don't say which ones, nor do they say which part (Cd, A) is estimated.

In addition to the above, I have occasionally found, for newer cars, CdA numbers from Car and Driver (their full reviews often have them), manufacturer websites occasionally have Cd numbers and you have to estimate the area (I am finding that .85 of WxH seems to give a decent number). I haven't been looking at newer cars much because for my application they weigh too darn much. Seems like for every year after 1995, the same exact car model puts on about 200 lbs.

Do you know of other sources for this info?

--Steve

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Old 04-09-2008, 10:09 AM   #12 (permalink)
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Old 04-09-2008, 10:53 AM   #13 (permalink)
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I don't really have any other sources. There was a real recent post about carfolio.com to get some info from. It seems alright. I was hoping you had compiled a spreadsheet with a bunch of small compacts and could just paste them into the post. I'd have to double check, but I believe in Hucho's book he recommends height times width times .81.
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Old 04-09-2008, 01:07 PM   #14 (permalink)
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Yeah, I looked at carfolio.com -- lots of the data was missing (random check), so I haven't bothered looking there any more. I also don't know where they got their data from, so I don't know whether to rely on it or not.

Re the .85 factor, I've heard of .8 and .81; I picked .85 since it seemed to match the EV1 and Insight numbers. I think it would depend on how rounded (side to side) the body is and cars vary quite a bit in that (the Prius is darn near rectangular!). For my uses, the .85 is likely "worst case" which is what I'm designing to. If whatever vehicle I end up with turns out to be a little better, that's a welcome "plus".

As far as my "spreadsheet"--it's just numbers on of paper--I've mostly started from lightweight vehicles and tried to add CdAs as I could find them. Maybe this will help:

Since weight is important to me, and weight (at least curb weight) is fairly easy to find, I looked at a *vast* array of vehicles and discovered that American mfrs don't make light cars. So I ruled all those out--basically I was looking for 2,000 lbs (900 kg) curb weight or less. The other set of cars I ruled out were sports cars--no room for batteries and, usually, their CdAs are horrible because despite the low "A", they have crappy Cds (usually). There are exceptions--'93 Mazda RX-7 is listed at 5.61 but its curb weight is 2600 lbs. The '95 Mitsubishi eclipse GSX and GS-T are listed at 5.92. I also wanted a car that was popular so I'd be able to get parts, etc. so that ruled out a lot of foreign cars -- even the Insight didn't sell that well, so that, too, might be iffy (from my point of view).

What's left (for me) is a set of light cars with horrible CdAs: Tercel only weighs about 1800 lbs but the CdA is listed in the low 7s. Geos are light, too, but are about 6.8 or so (for those that I could find)--the problem there is the payload capacity (in lbs) isn't that great. Some Subarus aren't too bad; something called the SVX has a CdA of about 6.0 for the '92, but I haven't (yet) found the weight--also don't know what it looks like. Honda Civics are pretty bad: '94 DX is 7.22 for example (don't know what body type) and they seem weigh up in the 2200 lb region.

The problem with compiling a list is that there are so many considerations, I wouldn't know how to sort it for someone else--that and the fact that the CdAs really aren't available for most cars. I mean, do you cut it off at a CdA of 7? 6.5? How about year: go back as far as 1990? 1980? (I know, you were hoping for whatever I *did* have, but I kinda got going there )

My best advice is 1) decide what mfrs you're willing to consider, 2) consider what CdAs you're willing to live with. Then go to mayfco and click on the boxes for those mfrs. There are so few cars listed you can see at at a glance what, if anything, matches your criteria. After that, it's just slogging, model by model looking at various car sites for whatever scraps of info you can find. What I've found so far is darn few cars are under 6; most are in the mid-6s to mid-7s.

If you have specific criteria in mind, I could look through my notes (about 20 pages worth) and see if I notice anything (assuming I have the relevant info) that would be of use to you.


--Steve
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Old 04-09-2008, 03:35 PM   #15 (permalink)
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Hey Steve, welcome to EM. If you are still hunting for an Insight, your best bet would be to just physically go to the local Honda wrecking yards and check it out for yourself. The yard I got mine from didn't even know it was an Insight, they had it listed in their stock as a Civic coupe so you can't really rely on them to know what they have got.

The Suby SVX isn't a bad looking car, it is a V6 though

And it weighs 3600lbx

Last edited by Red; 04-09-2008 at 03:39 PM.. Reason: added SVR weight
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Old 04-09-2008, 03:54 PM   #16 (permalink)
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Thanks Red,

I read your build thread with great interest. I'll have a go at a local junk yard, as you suggest--probably this weekend. Thanks for the photo of the SVX. It is heavy, as you say; what counts, of course, is how heavy it is after I get rid of the ICE-related stuff and the V6 sounds like it would reduce the weight by quite a bit (though I'm not enough of a car guy to guess at how much). Still, starting with 3600 lbs, I'd have to remove 1600 lbs of stuff to get down to a glider of 2000. That sounds like more than the ICE stuff is likely to weigh, and even at 2000, I'm still way over what a Tercel glider would weigh (not that I'm in love with Tercels, but they *are* light).

--Steve

P.S. Somehow I missed it, but now I see from your profile you're in my neck of the woods. I'm mid-Peninsula and the yards I know about are mostly in San Jose. Where did you find your Insight, if you don't mind sharing?

Last edited by SteveP; 04-09-2008 at 04:28 PM.. Reason: Added the PS
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Old 04-09-2008, 11:15 PM   #17 (permalink)
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Thanks, its been a fun experience. Cool cool, I'm over on the other side of the bridge in the Easy Bay.

It would take some major gutting to get the SVX down to 2000lbs. Its a kind of luxo-sport so most of the weight could just be tied up in sound deadening and creature comforts. But it a 3.3 V6 with a 4spd Auto tied into an AWD system, so if you were to gut the drive train entirely you might get close. I can only use Heeps drive line as a comparison but the engine, transmission and transfer case alone weigh in at ~700-800lbs, so the Suby could be possible.

I found my Insight at Action Auto Wreckers in San Jose. SJ seems to be the best place for Hondas from what I've seen. There are a couple of yards up in Hayward that are ok, and there is a ton up in Sacramento. Never looked for any Japanese parts up north, but if you are looking for anything domestic, Sac has some of the biggest yards.
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Old 04-10-2008, 11:05 AM   #18 (permalink)
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Quote:
Originally Posted by Red View Post
I found my Insight at Action Auto Wreckers in San Jose. SJ seems to be the best place for Hondas from what I've seen. There are a couple of yards up in Hayward that are ok, and there is a ton up in Sacramento. Never looked for any Japanese parts up north, but if you are looking for anything domestic, Sac has some of the biggest yards.
Very useful info, thanks! It's funny about Action Auto Wreckers--their ad in the Yellow Pages says "All American Cars and Trucks" so I had crossed them off my list when thinking about Japanese parts! Glad you set me straight on that one.

--Steve
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Old 04-11-2008, 12:51 AM   #19 (permalink)
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Nah they have 3 yards, a Honda Mazda, GM, Chrysler all within walking distance of each other.
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Old 04-13-2008, 12:04 PM   #20 (permalink)
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Thanks H4MM3R....

Red: visited the auto wrecker--you got a *great* deal on your Insight...all the stuff I saw there looked like a train had hit it (head on). Nothing I'd consider for a project car. Back to Craigslist...or maybe Sacramento for a look-see....sigh.....

--Steve

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