DaGnoma gets a cap

[SCNTN]

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.

[ChazInMT]

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!!!!

[SCNTN]

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

[mackerel]

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

[SCNTN]

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!

[SCNTN]

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

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.

[SCNTN]

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!

[kach22i]

What is your engine and transmission?

[justme1969]

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.

[SCNTN]

Originally Posted by kach22i

What is your engine and transmission?

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

Originally Posted by justme1969

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.

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.