5th generation civic hatchback - improving aerodynamics

[AndrewJ]

Ok, looks like I gotta re-hijack my thread for a little bit

With my recent relocation so stiflingly hot Missouri, and a subsequent lack of internet access, hence by absence here, I started a little project to keep me busy.

Step 1: Strip everything off the back of the car and throw it in a pile on the garage floor.





Step 2: Get a bunch of 1" x 1/8" steel bar-stock from your local hardware store. (Aluminum would be better, but when you're using 30' of the stuff that could get really pricey.) Once you've got your bar-stock, get all creative with it.











Step 3:
Proceed to get out the arc-welder and stick everything together with really crappy welds.











Step 4:
Get a little piece of plywood to stick on the end to hold the new taillights and license plate and such.









Now all I have left to do really is get the sheet-metal, attach it, and then figure out some way of putting on a bit of plexiglass.

More pics to follow as progress and internet-access allow...

[AndrewJ]

Oh, and about the alternator use:
Yeah, I'm trying to put in my fuel-log the approximate percentage of time that the alternator is unbelted.

And about technique vs. mods:
My mods have definately helped out a lot, but as a percentage, technique is more important. Without doing any P&G or EOC (just watching the 'Guino) I was able to pull 63mpg passing through Wyoming at about 65mph. That could have been MUCH worse without watching the 'Guino.

I've let my wife drive a few times (I belive I noted that in my fuel log) and she (the non-hypermiler) got abysmal mileage, somewhere south of 50mpg.


And a note about cx/vx's and P&G:
P&G has never worked for me. Not once. It seems everyone has their theory as to why this is so, tall tranny ratios, Honda engine magic, etc...
All I know is that my car likes constant throttle at light loads, but not too light of a load. I discovered a month or so ago that my "target" speed for best MPG has been too low.
55mph just won't cut it. On the highway my mileage is best when my speed is between 60-65mph depending on the wind direction. Unless I'm driving into a strong headwind, 65mph is my new "target" speed. I'd have never known if not for the MPGuino.

[KJSatz]

One good place for window-age might be in the plywood stern. The license plate will cover some of it up, sure, but that should be an easy way to add visibility. Is it hard to make a window in sheet metal?

Out of curiosity, how do you plan on attaching the sheet metal to the steel frame? More welding? Rivets? Bolts?

It looks pretty BA.

[rcpmac]

How to really build a body panel.
Here are the steps. There is a link below with pics of a guy's project.

This panel would be constructed out of foam core panels and fiberglass/epoxy resin.

Build a mold-
consisting of plywood cross sections in the same plane as the plywood end piece that you currently have moving toward the hatch about every foot and ending with the shape that would provide contact to the body. Call them bulkheads.

Attach battens of flexible pine strips from bulkhead to bulkhead to rough out the shape. Gaps and spaces are fine.

This is your mold. It will need to be undersized because the next step is to-

Attach strips of foam to the mold. 1" thick is probably fine. Use a heat gun to bend it. Screw it to the mold if necessary to hold it. Glue / fill the foam to make a continuous form and fair it out with tools. Remove the screws.

Fiberglass the foam form using standard glassing techniques.
Dissemble the wood mold that is inside. Of course you were clever enough to allow for easy disassembly when you built it.

Smooth out the inside and glass the inside after embedding wiring and structural attaching flanges in the foam.

This will be strong light and look as professional as you want.

Here is a link to a guy building a boat using a similar technique but with a vacuum infusion system that takes some work to set up. Vacuum bagging on the other hand is similar and can yield excellent results- google it.

Scroll down to "2002" and check out pics. He used female moulds to form this hull.

http://www.fram.nl/

[Stuey]

AndrewJ,

I recently (Yesterday) used Lexan to make some covers for the lower grille on my car (Acura EL) and they're crystal clear for the most part. The stuff's pretty similar to plexiglass so I'm sure you can use the same technique as I did, just a heat gun and some work gloves will let you curve the edges if you want to smooth it out into the sheet metal. (the stuff gets really hot though, felt like my fingers were on fire most of the time even with the gloves on so try to find some thick gloves).

Hopefully it will stay fairly clear with sun exposure, etc...

I wouldnt suggest trying to curve the entire sheet though to make a curved window by hand... you'd be better off maybe shoving the thing in the oven at a low temp to uniformly warm it up, and have it rest on a curved surface that matches the curve you want.

This was my first time working with Lexan other that watching the guy at my local machine shop use some with a heat gun (that's where i got it) so I'm no expert on the stuff or whether the oven is a good idea. Anyone have any thoughts?

I agree with KJSatz, car looks pretty BA, can't wait to see how it turns out!

[landscaper52]

just saw your airdam...I just put a basic one on my Ford Ranger last weekend...seems to be improving gas mileage immensely...however, it took a few days of abuse from all the guys I work with who all drive trucks, and now consider me some kind of eco hippie freak...I don't give a dam!!! I'll post pics soon

[MetroMPG]

Welcome to the site, landscaper52. If you do get some pics, post them in a new thread. I'm sure there are others who would like to see what you've done.

[AndrewJ]

Well, the boattails been done for over a week now, guess it's time to get some pics posted up of the finished product.

It's pretty amazing how much the boattail has helped with coastdown times. I'll look down at the speedo after a good 10-15 seconds of coasting on level ground and I *might* have dropped 5mph (from 65 to 60) on a bad day.

Mileage seems to have been improved at least 10%. I'm now able to consistently hit 55mpg burning 87 octane E10 gasoline. I'm positive that I'd be reliably in the 75mpg range with "real" gasoline.


















I scavenged the key mechanism out of the hatches "tailgate" and with a little copious modification it made a serviceable lock for the new rear window.

[MetroMPG]

Andrew! Wow.

No wonder you've been so quiet lately - you've been a-fabricatin'.

Any tuft testing, hmm?

[SVOboy]

God among men!