DaGnoma gets a cap
 

I got bored today, and the weather was beautiful. So here's the result. Matches my aero mockup pretty durn well. Plenty of shaping left, but the weather is supposed to be nice tomorrow as well. :thumbup:

Fantastic Job! You did great to resist the urge to drop the shape to the top of the tailgate. It is a common misconception that you want the back to be as small as possible, but in fact, you just need to follow the template which you've done wonderfully.

I'm sure the first thing you'll notice is that at highway speeds, your truck will feel much more stable, it'll seem like you put arrow fletches in place on the back of your truck. It will be quieter as well. Then you'll notice, hopefully, a 2 mpg gain in FE if you drive at 50 & better a lot. If yer just kickin around town, there may not be much gain.

Looking forward to hearing how it performs.

Again...Great Job!!!!

I'll tell ya, a 4" angle grinder makes quick work of shaping foam and makes much less dust than a belt grinder. Although I will use a little random orbit sander for finish sanding.

I'm going to add a strip of Lexan in the gap at the rear for a thin little rear window. I won't be able to see very far behind me, perhaps 10ft, but it will help considerably when hooking a trailer.

Also, I'm wiring it up for hi-mount brake and dome/cargo lights. I'll just tap into the trailer harness and run a quick-connect plug up through the drain hole at the rear of the bed.

Perfect li'l brake light for $8:
Red 24 LED Car Vehicle Third Brake Stop Tail Light Lamp Bar DC 12V : Amazon.com : Automotive

Dome light for $13, should be bright enough for what I need. I can always add a few more if I need more light:
Amazon.com: LED Bar Light - Heavy Duty, Water resistant 12 Volt DC LED courtesy convenience lamp, 4" length: Home Improvement

And the trailer plug. I'll just cut this in half, use one part to wire the cap, and use the other part to tap into the existing wiring.
Anytime Tools 240" (20 Ft.) 4 Wire Pin Flat TRAILER LIGHT EXTENSION CORD 4 way Plug - Amazon.com

Very nice. I'd love to see more pictures, taken in daylight, including the inside frame.

Ask and ye shall receive:

25 new pics for ya...
Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - SCNTN's Album: DaGnoma Cap

Now I need to get all this glue off the truck... ugh!

http://ecomodder.com/forum/member-sc...80-512x384.jpg

http://ecomodder.com/forum/member-sc...80-512x384.jpg

Took it on a quick trip "around the block", and it didn't blow off! :thumbup:

Noticeably better coasting at highway speeds. It is a bit windy today, so it was hard to really determine any increase in FE. Not to mention the section of highway near my home is rather hilly. I'll know more on Monday with my first commute and nice flat roads...

I did stop to fill up (and grab a Powerball ticket). I live in the rural South, so needless to say I got plenty of attention from the boys with the stars and bars flying on their 4x4 Chevy's. So, my standard response for now when nagged about the truck is "35 mpg AND it can tow 6500 lbs". That appears to pretty much shut them up. :D

First commute yesterday... and the trip average was 30.4 MPG, even with rain on the morning route. Lately, with the cold weather and my new calibrated ScanGauge giving more accurate results, I've been averaging about 25-26 combined. So it looks like I've picked up about 4-5 MPG, or 20% FE increase! Not bad for a couple sheets of foam and some sanding. ;) Now I'm hoping that summer will get here soon, and with a belly pan I might just see 35 MPG!

What is your engine and transmission?

That looks really good if you decide to make it permanent then cover with plastic and pressure sensitive tape then begin covering it with impregnated fiberglass cloth. you would have some money tied up in it but it would be longer lived.

Vortec 4.3L v6, NV3500 5-speed, GU4 3.08 rear axle

That's the plan. Although I think I'm going to go with a few skim-coats of exterior wood glue over nylon tent fabric, then primer and paint.

I still have several areas to finish the detail on, mainly the forward and rear ends of the cap. I have to remove the cap from the truck to work on those areas, and I plan to post some more pics as that work progresses. I have to source a 2x6ft chunk of Lexan to build some windows out of. I may have to make a split-window design, since I haven't been able to find a piece longer than 4ft here locally.

Try a sign shop. I was able to get a 4x8 sheet of lexan near me from a shop that builds commercial signs.

$130 for a 4x8 sheet of 3/16" Lexan. Wow! Guess I'll have smaller windows than I had planned...

Don't count out vehicle sunroof glass at the parts yard. You'll have to do a lot of research to see what might work. Don't even think about cutting it as it is tempered glass and it will shatter. ;)

I was checking out the Maxima's glass sunroof piece. It might work fer yer aero cap as well. ;)
http://www.weblogsinc.com/common/ima...0724735660.JPG
http://www.jbcarpages.com/nissan/max...20%2810%29.jpg

Mounting it might be a little more difficult depending on yer skill set. ;)

Great minds think alike. For the forward window, I'll just grab the back glass from another S10/Sonoma. A few bone yards around here quoted me $40 if I pull it. I'll just mount the window in the same orientation as the existing back glass, and it should line right up. For the rear glass, I'll have to do some digging and find something that will match. I have a 2x2 piece of Lexan in the attic that would do the trick if I add a center divider. That might be my only reasonable option.

Excellent project and very promising results. Keep up the great work!

Two updates...

I solved the rear window issue for $40 - I found a deal on a rear backup camera with a 5" LCD. It mounts perfectly under the rear lip, and I added a quick connect fitting so that it pops off with the cap. Also, I picked up the lights and wiring, and was going to tackle that this weekend. However...

We had some thunderstorms on Wednesday, and apparently my lightweight design was a little too light. We had wind gusts of about 70mph, and one of them spun up directly rearward of the truck. The cap was blown up and over the truck, landed on the hood, destroyed my bug deflector, gouged the paint, and banged up the cap a bit. I now have a hole about the size of a soccer ball on the driver's side of the cap... I'd post pics but at this moment I'm too heartbroken.

That storm damage sucks! Hopefully insurance will help. (fingers crossed)

Unfortunately, my deductible on comp is $500, but thankfully the damage looks to be less than that. The hood doesn't appear to be dented, just scratched, so I'll be fine with one of those touch-up paint pens for now. I had been contemplating removing the bug deflector anyhow... but now I can't do any ABA testing with/without it installed. ;)

Remarkable fuel mileage even before the cap was put on.

My 4.3L S-10 4x4 gets only about half that, best seen is about 20 mpg hwy.

Ouch about the thunderstorm, sorry to be reading of it.

i realize this is a bit of an old thread, but its the first time ive been able to find anyone who built an aero cap specifically on an s10. how did your mpg gains fair? how well did it hold up to daily driving? how come you had the center of the cap taper down from the height of the sides?

Yeah a blast from the past! MPG gains were great for the short time I had the cap. I was able to squeak out close to 36 MPG highway cruising at 60. My average commute was around 32 MPG, 40 miles each way with about 70% highway miles. I've since given the truck to my nephew, and all he cares about is shredding tires. lol
I tapered the back of the cap just to extend the trailing edge without creating a hazard to people walking near it. It was just an extension though, it didn't curve downward or anything. Plus, I thought it looked better. ;)

the part i was talking about with the curve/taper was in the center from the roof line to the tailgate. im fairly new to this site and im not sure how to take one of your pics and point out what im talking about.

Gotcha. Take a look at the fifth picture at the beginning of this thread - the aero profile overlay. Search for that aero template on the site here and you should find plenty of info. It's better to have a gradual curve like that than a straight line for "attached airflow".

http://ecomodder.com/forum/member-ca...-cap-003ss.jpg

here we go. this is the curve i was talking about

its tagged under my album cause its so far the only way i know how to attach pics. i hope you dont mind, as i intend to use your pics as a reference for the cap i intend to build

Nope, it's flat. Look at the album I put of pics taken during the daylight hours. I think the shape of the tail end of the cap is creating a bit of an illusion.

Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - SCNTN's Album: DaGnoma Cap

The Chevy Astro that I had, had the same engine and a 4L60E automatic. I was getting 27-28 mpg in a far worse aero package than your S10. I would say your mileage results are very parallel to my results considering how my truck was brick shaped and yours is more sleek. (especially with the aero cap) I would have liked to have seen the results of your finished belly pan with the aero cap as I always thought my van would have gained 2-4 mpg from a belly pan. I say this as I had all kinds of junk hanging under mine....

aahhh ok, i see what you mean. thanks for clearing that up

You might put a placeholder in that empty Godaddy iframe.