• Can You Get Additional 4 MPG in a Ram 1500 EcoDiesel with Custom Aerodynamics? (Video)

    ram 1500 ecodiesel pickup truck topper aero best mpg efficiency
    Ram 1500 EcoDiesel with custom aero for better MPG

    Is it possible to considerably improve your truck’s fuel efficiency? If you ask Mark, the answer is a resounding – Yes! Mark spent a little over $200 and a lot of research and testing time to come up with his version of a customized aerodynamic package for his 2014 Ram 1500 EcoDiesel.

    Mark’s truck is a QuadCab 4×4 with an EPA highway rating of 27 MPG (19/27/22 MPG city/highway/combined). He does a lot of cross-country highway driving, and he recorded real-world highway fuel economy between 28-29 MPG. This is already very respectable for a full-size truck with a 4WD system. It was not enough for Mark.

    He added underbody “belly pans” and skid plates to smooth out the airflow under the truck. Next was a custom-made bed topper that Mark built out of foam and plywood. The teardrop shape extends about a foot and a half past the tailgate.

    Mark is reporting real-world highway efficiency between 31-32 MPG after his modifications. We were not able to verify this on our 100-mile highway loop, but Mark’s results are thought provoking to say the least. Ram already offers an air suspension system that lowers the truck at highway speeds for better aerodynamic. Why don’t truck manufacturers offer more aerodynamic devices underneath the truck? Does this add too much development and manufacturing cost? Does it complicate service or safety of the truck? We look forward to more aerodynamic advances from mainstream manufacturers.

    Learn all about Mark’s truck in the video below.

    Andre Smirnov
    Andre Smirnov
    Andre Smirnov is an Automotive Enthusiast, Producer, Reviewer, Videographer, Writer, Software Engineer, Husband, Father, and Friend.

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    48 thoughts on “Can You Get Additional 4 MPG in a Ram 1500 EcoDiesel with Custom Aerodynamics? (Video)

    1. I think it’s neat to see innovation at work by an owner such as Mark. I’m wondering two things: has he considered putting on wheel skirts to address the drag caused in the wheel wells and secondly, has he had any problems with state inspections due to reduced visibility out of the back window?

      1. C Barry – – –

        I fully agree. Great innovation, Mark, — and great diligence: all that testing and patience!
        Thanks for featuring this, Roman.

        I’ll bet Mark has not done everything he could do yet, and no doubt the wheel wells could be addressed easily, especially the rear ones.

        Don’t think rear visibility is going to be a legal issue, since if you tow a tall trailer or put a camper cap on a truck, you are pretty much confined to what side mirrors give you anyway.

        But he “covered” the big one: Bed drag! 32 MPG!! Wow….


        1. Rear visibility is not ever a problem, just put a camera rear view mirror. Like the ones on many GM vehicles(you can buy them third party).

          And you don’t have to build this contraption. Just slap a 14 foot tin boat on the top (with a boat cover on it, and the truck shell of course).

          Thats a much easier way to get an extra 5 mpg all day long, and you don’t have to sacrifice bed room. Really, try it.

          1. What about side views when looking out the rear window. How about blind spot lane changes when you need to look over your shoulder. I stood up 8 bags of insulation in my truck a few months ago, this would have been a no go situation for that and it adds weight driving in town which reduces my payload. Even at 200Lbs, if you only have 1500Lbs of payload you are down to 1300, so you lose 2000Lbs of trailering capacity. Manufacturers will never do this for too many reasons. Just be an aftermarket niche product.

      1. Daniel – – –

        With haul/tow ratings, were you thinking the aero may push the back end down? At low speed, the haul thing may not be affected much, because the added weight could not be more than 100lbs.

        But the under-pan, under the engine bay, may hurt cooling. Maybe a louvered hood could help compensate?


      1. Dan – – –

        Although it wasn’t “officially” verified by the famous TFL “98-Mile Loop”, these 4-MPG gain results are believable and not out of range with what could be expected.

        Mark did go after the Big One: bed drag, the major bugaboo of pickup aerodynamics. He essentially turned the rear of the truck into a “Kammback”**, a design perfected by Wuniblad Kamm in the 1930’s; — and currently mimicked today by the Toyota Prius.

        And, of course, part of Roman’s motive was to stimulate thought for truck makers on how to incorporate better aero on pickups generally, WITHOUT diminishing their functionality.

        Ironically, some aftermarket manufacturers are beginning to move down that road anyway. The November issue of “Petersen’s 4Wheel& Off-Road”, page 58, show Metalcloak’s new full underbody armor, — which ALSO helps aero, AND is made to disassemble very easily for undercarriage servicing. (Melalcloak.com)

        ** https://en.wikipedia.org/wiki/Kammback


      1. Brewhaha – – –

        B: “Why not just buy a civic?”

        Huh! Gasp! Shudder!
        Shut, yo’ mouth, boy.
        We don’t cotton no heresy in these here parts…(^_^)..


            1. Then what would you buy that has similar capabilities and efficiency?

              4X4, 6 passenger seating, 30 MPG diesel (or lets say 25 MPG gas), 6.5’x4’x2′ cargo capacity…

              I think if he was looking for a full size truck with the best aero/fuel efficiency available (especially in 2014) he made the correct choice.

    2. Great video on Mark’s modz ;}>

      You mentioned the possibility of getting an ecodiesel for a long term test. That would be great.

      If you do get one,maybe do the ike again,along with the mpg loop.

      Than when you have about 20k miles on it,do it again and see what the difference is between new and broken in.

      Also,of course,the long term reliability.Very important since your high altitude,and off roading etc.

      Fun times ahead for TflTruck!!

      1. I did forget one thing that I am interested in,on the possible long term ecodiesel,if they will give you one,air suspension. I am very interested to know how that holds up with all the different types of terrain you will take it on.Thanks…

    3. Nice review TFL. Bringing on real world reviews is nice to see. I think it is good innovation but I have to challenge it. We didnt hear what the added weight was? Two sheets of plywood, how heavy?, plus you can double that weight with nuts, bolts, bracing, weather stripping, shocks, styrofoam, glue, paint and other parts and the skid plates. Surely you now by fact lose mpg in town under acceleration to carry that weight and your combined mpg may stay the same. You also worsen your center of gravity, create visual problems and possibly add more drag. I say possibly worsen your drag because the mpg is not proven by a relevant source. Adding weight to any vehicle will increase its speed downhill, was this accounted for. Also depending on head winds and tailwinds his speed can be affected when he tested it on the downhill.

      Also manufactures test the tail winds behind the vehicle once it goes over the windshield it may be best to have nothing there as more surface area creates drag

      The cost of this is way over 200 in parts. Plus my time is worth at least 30/hr. I would be well over 2000 grand by the time I finished building this plus the skid plates. No way you can get your money back on this especially based on combined mpg, then add a trailer and whatever new turbulence created by this design may affect the trailer, so you may worsen mpg when pulling a trailer.

      Great innovation and thinking at work, but like I said I am challenging it and need more facts here before I say great job. Boat tailing always creates less drag just check ballistics on boat tailed bullets vs non boat tailed so the idea here looks relevant but it is definately not without problems and lacks proof for sure. After building this I would definately be bias with my numbers and how I drive it before and after so these numbers dont sound very fact based to me. Run it on the same day with and without the cap on the 98 mile loop and in the new around town loop that TFL said they were going to bring us and I bet the results would be very different.

      1. $2k???
        I don’t know how much thin plywood goes for in your neck of the woods,but it’s pretty cheap down here.So is the foam,and the glue.

        And if you didn’t catch it,Mark is on Fuelly,so his increases are documented.

        Why is it some on here just have to try and denigrate what people do,or buy?

        1. Lohchief, How much do the tools cost to make this? I should have added that too. Well over 2 grand for the average Joe. I am not degrading Mark. I challenged it, grow some? I encourage the innovation but nothing new comes without a challenge

          Just remember Lohchief, as a word of advice. The less you respond to negative comments the better and simpler your life will be, simpler meaning you just agree to everything regardless of its potential problems or benefits. You can take that one of two ways and that depends on how much diesel you have in your tank.

          1. Just agree,or not respond huh? Yeah,and let it go the way of putc? NO. And if you don’t already own the basic tools needed to be creative,then I feel bad for you.

            Lemme see here,a nice guy shows what he is experimenting with to make his fullsize 4×4 pickup more fuel efficient, and a lot of you guys here start cutting him,and his work down? Why???

            Does it make you feel superior? I applaud the man for having tried some stuff on his ride,and I applaud Roman for taking his time to show us.

            I’ll bet some of you would complain if you were hung with a new rope,because it’s scratchy.

            1. Lohchief, everything you said about my posts is false. You need an intervention on reality vs storytelling, and yes I would want a comfortable rope in my final minute.

    4. I agree with each and every negative comments so far! And as for my comment, here goes: why would anyone buy a beautiful pickup and then turn it into an ugly contraption of parts to save a little money on fuel. Just buy a smaller, older vehicle or make a concerted effort to drive less miles based on better daily trip planning.

    5. I don’t want to knock the guy, but what a goof. I doubt he will ever see a return on his investment for time and materials. Also, a regular old fiberglass topper would probably give him half the gains and not look so ridiculously.

      Want more? Get lightweight 17s and low rolling resistance tires.

      Normal looking truck, 31 of the 32 mpg, if not the same mileage.

      1. Rambro, Daniel, Dan Bush, and Hi-Fi – – –

        Guess I’ll have to challenge (some of) your challenges!

        1) Added weight? It’s essentially laminated Luan plywood, sandwiching foam. No biggy. He kept it light weight on purpose. Estimate 100-120 lbs., with the attachment hardware. Ask Roman to get the weight specs from Mark.

        2) Worse city mileage? I doubt that even + 200 lbs would affect that number with an EcoDiesel. It would be just like carrying another passenger. Again ask Roman to ask Mark.

        3) Added weight increased downhill speed? Yes, good point, — but that MIGHT be approximately an MV=MV thing — for a real rolling vehicle with air resistance **. Increase in velocity from even 200 lbs. more might be 200/4000 = 5%, ignoring other influences. If he got 60 MPH empty, and simply tossed a 200-lb. sack in the bed (without the so-called “contraption”), he might get 60*1.05 = 63 MPH. So, yes, he would need to “calibrate” this experiment with a dead weight in the bed, and subtract that weight effect for the aero effect. Again good observation, Rambro.

        4) Wind effect? Yes, but Florida is known for its painfully calm days, — with temps at 95 deg F and humidity at 95 %! Not happy. Also, I would assume he would have chosen a day that met those conditions, and not be foolish enough to ignore the influence of a tailwind with the “contraption” mounted!

        5) Manufacturer’s Test / Tail winds? It so NOT optimum to have nothing there, or the Kammback effect would not work: https://en.wikipedia.org/wiki/Kammback
        And it also explains when having at least a tonneau cover gets better in MPG than an open bed.

        6) Cost? You can’t count his labor! This is an experiment and “labor of love”. Go to a car show: look at all the restored vehicles that guys are selling for $15K-$25 K, — after putting $50K of “labor” into them!

        7) R: “Run it on the same day with and without the cap on the 98 mile loop and in the new around town loop that TFL said they were going to bring us ….”
        Yes, good point, Rambro: that is absolutely what needs to be done.

        8) DB: “…why would anyone buy a beautiful pickup and then turn it into an ugly contraption of parts to save a little money on fuel.”
        The “ugly contraption” is reversible! It’s not a permanent part of the truck. BTW: I agree that it is not the most esthetic thing, but neither is a Toyota Prius, — and people actually buy those “ugly contraptions”, whose ugliness IS part of the vehicle! (^_^)…

        9) HF: “I don’t want to knock the guy, but what a goof.”
        Hey, if you want to encourage innovation, you can’t condemn those who try. So let’s not issue disparaging comments, OK? There is nothing “goofy” about this experiment: it has a good concept; good background research; good (and inexpensive) execution; and the ability to have results that can be measured.
        As an experimental scientist, I can guarantee that I’ve done things that weren’t nearly so “clean”…

        So, in my view, Mark needs to be praised! I want to see more “Marks” do vehicle experiments, — since many big vehicle corporations often have trouble “thinking outside the box.” The vehicle roadway (no pun) of the 20th century is littered with good but “failed” attempts that got discouraged or intentionally “torpedoed” by naysayers or worse (e.g., Tucker, Studebaker, Packard, Rickenbacker, Duesenberg, Corvair, and others). And innovation that DID succeed came from the “Gee, what-if-we-do-this-silly-thing” attitude (e.g., fuel injection, disc brakes, automatic transmissions, and so on).

        ** It wouldn’t be for an object sliding down a frictionless ramp with no air-resistance: they would all make it down at the same time.


        1. Good Night Bernie! I will agree with most of that, just dont know where you get your weight estimate from? We need better estimates than ” He kept it light”How so? What is the plywood thickness? I also seen 2×4’s for framing, what do the skid plates weigh?

          But I really agree with the encouragement to try via the “love of the trade”. But that is subjective. In Marks case That can prove true. For me, I dont care so building this would be a labor, which would require an added expense of a lot of beer and rum. But I can at least appreciate the video. To me a truck has more benefits to offer me than mpg, I have other “loves”, like acceleration, ground clearance, load levelling, comfort, sound, agility, etc, etc, etc. We already know how to get better mpg and better power, adding aero dynamics needs to be left to the guys who designed the new 3rd Gen Tacoma. Lower coeficient than all their competion with the best ground clearance and approach angles in the business.

          1. The plywood he used was 5mm thick. Mark said it in the video.

            And the foam he used only,at most,weighs under 10 lbs I’ll bet.Those 2×4’s?

            Looked like they were cut and trimmed and no longer 2×4’s.

            But I’ll bet that if his truck was all electric, and did the same thing,you’d be praising him for his work.

            1. Lohchief, never said anything about electric and I praisex him for the innovation and he created what was already done which shows he had a good plan. However, if it was electric he would surely be ahead with the mpg’s.

        2. Bernie
          So when are we going to see you build or buy one of these “ugly contraptions” on your new ram truck? I’ll bet never! Come on Bernie be honest. You may think prius is “ugly”, but I’ll tell you. I think a prius is “beautiful” compared to this “ugly” addition to Mark’s truck.

          1. Dan – – –

            Actually, I had a brown 1974 Dodge D100 Club Cab, on which, when brand new, I built a 4’x8′ wooden camper on the back, painted a dull red.
            It had a flat front end, protruding up over the level of the cab. It had cute little pop-up side windows and a leaky homemade skylight.

            It was ugly. No, I take it back: it was hideous.
            Too tall to be garaged.
            Car washes were out.
            It cost me about 2 MPG.
            My wife refused to drive it.
            The police on the Garden State Parkway pulled me over for being a “commercial” vehicle (I had to explain other wise).
            My kid required me to drop him off 2 blocks from school: his friends called it the “Geek Truck”.

            But then, when it was time for somebody to need help moving, gee, it suddenly became the most popular thing in town! (^_^ )…

            But with the new Ram 2500 Diesel, you’re right: no camper or aero experiment. I get 23 MPG with the tonneau over the bed, — more than enough for a 7500-lb. vehicle. Besides, the truck is too high to climb in the back without a little ladder, — and I am too old now. But, as I’ve just told you, bad esthetics doesn’t bother me one iota if I get good function in return, — even at the cost of ridicule.


            1. Bernie
              So I repeat my question. When are you going to add a similar,not to pretty, but functional contraption to your newaa ram 2500. You can’t have it both ways. Just be honest, you will not be adding this to your new truck,period! We all did all kinds of band-aid things to our vehicles (which were pieces of junk already) when we were young. But later in life, when we were more financially sound and had new, beautiful vehicles we stopped just throwing things together.

      2. HIFI, from driving a truck with a truck cap to one place, removing it the same day and driving it on the same tank of gas, the truck cap hurt fuel economy by 3 mpg. I suppose it could be different between designs but truck caps seem to hinder economy. Likely from the excessive drag in the rear.

        1. Truck caps are notoriously heavy for what they claim to do. The cheap and lightweight roll up tonneau covers are much better, but don’t always last that long. If you’re buying either in hopes of offsetting the cost in fuel savings, not gonna happen. Tonneaus gives the + of dry and locked bed storage, so that’s why I have one.

        2. Jimmy Johns – – –

          JJ: ” I suppose it could be different between designs but truck caps seem to hinder economy.”

          Yup. The “Eagle” cap, rising slightly above the level of the cab on my ’96 Ram, costs me about 1.5 MPG’s. But the smooth ARE cap (level with the cab), on my 2010 Nissan Frontier, gets me more than 2 MPG. (That Frontier, with VQ40 engine and 6-speed MT, is EPA-rated at 15/19. I average 22 MPG.)


          1. Bernie. The ARE flat top with curved back glass is the cap I was referring to. Removing it gained me 3 mpg better. But it is a 4×4 truck that is pretty tall. It may have played a part in it. My bosses truck experienced similar results but he is like me. Don’t care to much about fuel economy and he wants a cap. As a side note. My class A buss style motorhome gets the same fuel economy towing my car or not. That is an extra 3500 lbs or more. I contribute most of it on once your rolling it is easier to maintain fuel economy and the flat front end has enough resistance to kill economy and maybe the air smooths out along the car to reduce drag and thus compensates for the extra 2 ton.

            However I give much Kudos to this guy in trying something and seeing his gains. The only way for us to improve is by breaking the mold.

    6. Myth busters years ago took a taurus and tried to increase fuel economy. They did a base line test and they showed having dimples like a golf ball increased economy dramatically. It is amazing what can be done for efficiency by creating less drag. The side effects is usually how it looks.

      1. Dodge did that with one of their NASCAR rigs back in the late 60s or early 70s, when NASCAR was real. They put a dimpled landau roof in one of their cars, and it seemed to work (higher speeds) until the air speeds at near 200mph ripped the fabric part of the roof off.

        Sometime back in the mid-90s, the science journal “Nature” published an article by a couple researchers. They used various configurations (treatments) in pipe walls where the water flowed through, and they would measure the water velocity to determine the best “anti-friction” treatments.

        I forget all of the treatments, but smooth surface was one of the worst. The best was a surface that had random protrusions coming off of it. Apparently, when water (or air) flows along a surface, it slows down right next to the surface and creates small vortices. These vortices tend to roll up and snowball (like rolling up a rug) until they are so large that they break free of the surface and fly into the mainstream and disrupt the laminar flow. By placing protrusions on the surface, those protrusions would break up the vortices at a much smaller stage, thus increasing laminar flow velocities.

        What is interesting is that they tried both uniform protrusions and random protrusions. The uniform ones had little benefit, while the random ones provided very significant benefits (from 7 – 15%, IIRC….i read it over 20 years ago). The biggest issue would be in trying to manufacture random protrusions on a surface. That may become more of a reality with advances in large 3D printing.

      1. Pip – – –

        P: “The reflective tape is also a dead giveaway he is going well under the speed limit.”

        Yeah. Either that, or he just travels a lot and has become paranoid (like me) of tailgaters, and other subhuman life forms who don’t watch where they are going, or don’t leave adequate braking distances, etc. In fact, I have a little orange, flashing LED fixture that mounts in the hitch receiver when I am driving more slowly at night under load. It’s amazing the dodo birds who have no concept for the physics of stopping or maneuvering a motor vehicle at speed nowadays (^_^)…


    7. Good job to Mark and keep up the innovating. Look to the hypermiling forums for inspiration. There were some folks on those forums that designed bed caps that sloped from the top of the cab down to the tailgate, sometimes straight and sometimes bulbous.

      Look at vehicles like Prius and Insight to see what tricks they use. Here is a link to get you started: http://www.caranddriver.com/features/drag-queens-aerodynamics-compared-comparison-test-drag-queens-performance-data-and-complete-specs-page-7

      Anything you can do to reduce air under the vehicle will help. A larger (lower) custom airdam, smooth underbody panels, and fliw-directing strakes can all help. AllPar.com has an article on aerodynamic testing of the NASCAR RAM that is definitely worth a read.

      There is a lot more that can be done to trucks to make them aerodynamic, but some of it has to start at the initial design stage of the vehicle. I have some ideas, but I am not going to give them away here.

    8. I think the point of the article is that the guy is experimenting to get better fuel economy and that perhaps there are means to increase fuel economy. Taken in that light I think this is pretty neat. He in no way is producing a “production” product here meant to be marketed, so no, it’s not intended to be pretty. It’s and experiment (a prototype if you will).
      There is no question that pick trucks could improve in the area of aerodynamics and likely will as fuel economy standards become more extreme.

    9. Neat little video. I don’t see anything wrong with what he did the American spirit always improves life and save money. Though I’m curious what his set speed was on the highway ?

      All he had to do buy a cheap aluminum bote turn up side down with stern up against the cab and probably have the same affect. Just make sure you take the out bourd motor off😉. Just a thought.

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