EcoModder Forum F150 aerocap design and construction

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 01-24-2013, 09:06 AM #11 (permalink) Master EcoModder   Join Date: Oct 2009 Location: Fort Worth, Texas Posts: 2,212 2004 CTD - '04 DODGE RAM 2500 SLT Team Cummins 90 day: 19.36 mpg (US) Thanks: 1,214 Thanked 625 Times in 476 Posts Good start, Dave! __________________ 2004.0 DODGE Ram QC/LB 2500 2WD/NV-5600 305/555 ISB. 7,940-lb. Stock. 200,000 miles/5000-hrs @ 40-mph average. 1990 35' Silver Streak TT 7,900-lb. 11-cpm solo & 19-cpm towing; 21-mpg average past 54k-miles Sold: 1983 Silver Streak 3411
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Quote:
 Originally Posted by plasticuser From the baseline of 17 mpg, at 68mph that's 4 gallons/hr. That means 58.8 gallons of air would be consumed in an hour at a fuel:air ratio of 1:14.7, or a gallon a minute. That sounds like a lot less than I'd imagined, so I suspect my math is wrong? Anyone in the know want to weigh in?
Fuel air ratio is figured by weight. That 4 gallons of gasoline weighs about 24 lbs, so 24 X 14.7 = 353 lbs of air. Next you need the density of air, which comes from a pschrometric chart (Google is your friend to find one). Air density depends on temperature, humidity, barometric pressure, and altitude. Psychrometric charts assume the altitude is at sea level, and standard barometric pressure.

Air density can range from over 15 cubic feet per lb (hot and humid) down to less than 12 cubic feet per lb (cold). Air at 70 deg F and 50% RH has density 13.5 cubic feet per lb.

Next, multiply 353 lbs X 13.5 cubic feet per lb = 4763 cubic feet per hour = 79 cubic feet per minute. And that's your air flow.
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The vacuum gauge plus wheel covers helped increase summer 2015 mileage to 38.5 MPG, while summer 2016 mileage was 38.6 MPG without the wheel covers. Drove 33,021 miles 2016-2018 at 35.00 MPG.

 01-26-2013, 07:50 PM #14 (permalink) EcoModding Lurker   Join Date: Jun 2011 Location: Austin, TX Posts: 74 Annette - '04 Ford F150 FX4 Penelope - '08 Mazda CX-7 Sport 90 day: 23.47 mpg (US) Thanks: 10 Thanked 27 Times in 15 Posts Ah, so thinking volume was a mistake, weight is correct. Thanks for explaining it to me. I didn't have good testing conditions today. I do know that up to now my base MPG is 17. With the fan delete and the restriction removed, but no other mods, I have been getting 19.9mpg in mixed driving with a few red lights, town, some 55 and a good 65 run. I'm hoping with the aerocap and a few other changes, I'll be up around 24-25 mpg, which means the F150 4x4 would be beating out the CX-7 for economy Of course, I'll be working on the CX-7 too, so... If I can get that over 30mpg I'll be happy.
 01-27-2013, 05:14 PM #15 (permalink) EcoModding Lurker   Join Date: Jun 2011 Location: Austin, TX Posts: 74 Annette - '04 Ford F150 FX4 Penelope - '08 Mazda CX-7 Sport 90 day: 23.47 mpg (US) Thanks: 10 Thanked 27 Times in 15 Posts Under body panel. I have decided the method and materials I'll use to build and attach my under body tray. I will use tape and expanding foam to make a template/mould, then make a set of fiberglass panels that will be installed from the rear to the front, overlapping. This will make for the most lightweight and easy to install/remove system, at moderate cost/effort. I know how to work around the exhaust, and am comfortable with that side. I also plan to leave toom for suspension travel causing the driveshaft to move lower when the suspension unloads into a dip. Where I am unsure is the differential. Will enclosing it or putting it out of airflow cause it to get significantly hotter? What is a normal temperature for an F150 differential after some freeway driving? I will use my infrared thermometer to collect trip temperature data after longer drives for the next few weeks and report back, but any insight would be helpful.

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BZP T-100 (2010) - '98 Toyota T-100 ext cab - 3.4L/auto SR5
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Quote:
 Originally Posted by plasticuser Where I am unsure is the differential. Will enclosing it or putting it out of airflow cause it to get significantly hotter? What is a normal temperature for an F150 differential after some freeway driving? I will use my infrared thermometer to collect trip temperature data after longer drives for the next few weeks and report back, but any insight would be helpful.
Yer differential will git warmer in temp when it's enclosed with a belly pan. Temperature will depend on the loading (towing/bed load). Best thing to do is run a thermometer probe on the differential and measure yer temps and git a baseline before you install yer belly pans. After you install yer belly pans, you'll be able to tell how warm yer differential will git up to and if you'll be comfortable with those temps or not. Just don't go blind and not use some sort of continuous temp monitoring setup.
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 01-28-2013, 09:37 AM #17 (permalink) Master EcoModder   Join Date: Oct 2009 Location: Fort Worth, Texas Posts: 2,212 2004 CTD - '04 DODGE RAM 2500 SLT Team Cummins 90 day: 19.36 mpg (US) Thanks: 1,214 Thanked 625 Times in 476 Posts Something that came up recently with my pickup. At 7,900-lbs, and two destroyed tires, I had to order a rollback wrecker. We had to find attachment points to winch the thing up the bed. So, be sure to keep this in mind with any bellypan. __________________ 2004.0 DODGE Ram QC/LB 2500 2WD/NV-5600 305/555 ISB. 7,940-lb. Stock. 200,000 miles/5000-hrs @ 40-mph average. 1990 35' Silver Streak TT 7,900-lb. 11-cpm solo & 19-cpm towing; 21-mpg average past 54k-miles Sold: 1983 Silver Streak 3411
 01-28-2013, 02:33 PM #18 (permalink) EcoModding Lurker   Join Date: Jun 2011 Location: Austin, TX Posts: 74 Annette - '04 Ford F150 FX4 Penelope - '08 Mazda CX-7 Sport 90 day: 23.47 mpg (US) Thanks: 10 Thanked 27 Times in 15 Posts *nods* I can see how that would be a problem. Also, getting under there if it was dropped the height of the tires would be an issue too. I will look at the rear attachment points and make a plan. Good call. Thank you. That's a nice Airstream you have there. Single axle at that length, is it a 50's pre-torsion axle one? __________________
 01-28-2013, 07:18 PM #19 (permalink) Batman Junior     Join Date: Nov 2007 Location: 1000 Islands, Ontario, Canada Posts: 20,890 Blackfly - '98 Geo Metro Team Metro Last 3: 70.09 mpg (US) MPGiata - '90 Mazda Miata Last 3: 51.27 mpg (US) Winter beater Metro - '00 Chevrolet Metro 90 day: 70.38 mpg (US) Thanks: 2,735 Thanked 5,613 Times in 2,886 Posts Late to the party, but subscribed and watching with interest. And thumbs up for the "open source" and willingness to share approach. Plans to A-B-A test the cap when it's finished? __________________ Latest mods test: 15 mods = 15% MPG improvement: A-B test, 2007 Honda Civic 1.8L, 5-speed Ecodriving test: Manual vs. automatic transmission MPG showdown: Nissan Micra 1.6L EcoModder has launched a forum for the efficient new Mitsubishi Mirage www.MetroMPG.com - fuel efficiency info for Geo Metro owners www.ForkenSwift.com - electric car conversion on a beer budget
 01-28-2013, 08:28 PM #20 (permalink) Bring on the turd polish!     Join Date: Feb 2010 Location: maine Posts: 45 Pablo - '86 Toyota Pickup 1 Ton, 22RE, W56 trans, 4.300 diff. Pickups 90 day: 25.68 mpg (US) Red Brighton - '98 Subaru Legacy Wagon Brighton 90 day: 32.3 mpg (US) Rust Victim - '00 Toyota Tacoma SR5, 2WD, 5 speed manual, 2.4l, Extracab. Last 3: 29.68 mpg (US) Thanks: 8 Thanked 17 Times in 10 Posts I'm still designing a cap for Pablo's bed. It's a 7' x 5 1/2' flatbed with stake pockets. I'm also going to need full side skirts. It's just a little cold out there to get it done tonight. I drew the horizontal line 4' straight level back from the front of the cap, then angled it down to end 8" above bed level 12" back from the back end of the bed. Then I did a spline curve from the front to the midpoint of each of the lines, and then to the back end of the sloped line. I think this will give me room for a decent side door. The sides will slope so that it's 45" wide (cab top width) in front and 48" wide in back. That will involve torturing the ply on the sides slightly, but it's within doable limits. My plan is to cut two templates out of scrap and bend a properly trimmed 4x8 sheet over them, set the side pieces in place and mark them to that curve on their angles, and then put it together with some interior framing. I'm imagining a large hatch in the roof piece to make loading easy, but I haven't worked out those details. As I said, there'd also be a side door. __________________ Last edited by mackerel; 01-28-2013 at 08:49 PM..
 The Following User Says Thank You to mackerel For This Useful Post: aerohead (07-10-2013)

 Tags aerocap, f150