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Dave Fields

Enclosed trailer modification question

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Dave- I share the pain. I get 10 with my f250 diesel and a flat front trailer. I have thought of this off and on for a while. Even checked out the company who makes the fiberglass bubbles for trailers and big rigs. They start at $750 FOB CA so not reasonable for me.

I have considered cutting a 55 gallon drum in half and mounting, a wood frame with sheet metal cover, and other ideas. Just haven't done one yet- I will watch this conversation now.

I tried the wing on the truck cap and saw no difference in mileage. I put it over the rear wheels and I see most wings on the cab roof or more forward on the cap. Not sure if position was my enemy on my attempt. It is also a small wing compared to the big SST curved wings I have seen.

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Jim- I tried that too. Hardly ever get over 70 anyways when towing (maybe downhill) but did try 60-ish (about 5 less than usual) for a while. I didn't like getting run over by all the big rigs and moving the trailer around so often and my mpg hardly changed to maybe 10.25.

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I see alot of domes added to straight trucks & trailers, you might try a truck junkyard they might have one to sell cheaper than $750.00.

FWIW I have a 98 Dodge & grossed out @ 16,500 & get 12.5 with a 20" V-nose

Bob

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Maybe your diesel is having issues. We regularly get 13-14 mpg with our Dodge diesel pick-em-up towing a 24' enclosed trailer with a 6500# vehicle aboard.

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My diesel was having an issue I never realized. Shortly after getting it (used) I had the tranny flushed and put in Lucas additive. My mileage not towing has always been around 14-15, 10 towing.

Last summer I had the tranny done again at 60K more miles and left out the Lucas since the shop guy was saying how he hates all additves, they don't work, etc. I then drove the truck to Maine (not towing). The three tanks of fuel went from 16 to 16.8 to 17.9 mpg on tht trip and I was running 75 most of the trip! I am amazed at how much better it is shifting as well. Last fall I towed a short trip (100 miles each way) and was disappointed my tow mpg was still only 10 (under 70mph).

I will continue to track this this towing season but would still like to improve the aerodynamics of the trailer. That "brick" back there is never good! It seems the Dodges always get better mileage from the Cummins, I just like the Ford and the 7.3 Navistar better. I know a few Dodges getting 22-25 not towing and in your range or slightly more (15-16) towing.

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Maybe your diesel is having issues. We regularly get 13-14 mpg with our Dodge diesel pick-em-up towing a 24' enclosed trailer with a 6500# vehicle aboard.

Same here with an 04 2500 dodge diesel. 24' flat face trailer, 5000# car @ 65 MPH. 21/22 MPG with no trailer.............Bob

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Students of aerodynamics will tell you that having a tappered tail is actually more effective than a tappered front. Obviously this is not a practical means of trailer construction but if you look at 18 wheelers you'll start to see tapper screens hanging off the back of the trailers which is being used on some long haulers for improved mileage. Perhaps someone can make their fortune selling such a device for enclosed trailers, though yo'd have to workout the highway saftey aspect, (tail lights & such).

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Students of aerodynamics will tell you that having a tappered tail is actually more effective than a tappered front.

That's right,all you have to do is try drafting behind a tanker versus a box trailer & you can feel the difference.

But I have both flat front & v-nose & I'll take the v-nose as much as I can.I can really feel the difference.

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I have an enclosed trailer, with a flat front. Is there a reasonable and easy way to modify the front to get better mileage? I am down to 10 with my Dodge diesel pulling.

Dave: This is just my opinion but unless you are one that puts on many miles towing it is hardly wirth the effort/cost to start modifying a trailer. Watch your

speed and check tires often for air presure on truck and trailer and that should get you the best MPG with what you got. Larry

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The guys with the older tall cars that require a tall trailer might benefit from a Turbo Wing but most people won't see enough difference to ever pay for the wing, I have a 2002 F350 Dually 7.3 diesel, I have a 36' 5th wheel and a 24' enclosed tag, both trailers are just standard height. I see no difference in fuel mileage doesn't matter which trailer I pull. Get's 11.5 to 12.5 MPG, I put a wing on top of the cab, it keeps the front of the trailer clean so it must be kicking the air over the top but it didn't make any noticable difference in the fuel mileage. I think the changes that have been made in the diesel fuel by the Fed gov have cut the fuel mileage more than anything, Ten years ago I was getting 13 to 14 MPG but not anymore.

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I just sold a 96 dodge diesel 2500 with 260000 miles I always took my truck to a good mech And always got 25 mpg .Towing a 30 ft goose I would get 16 to 18 mpg . Stay away from dealers they don't know but to change parts . My guy says most des iels come from the dealers out of time. I use good quality fuel additives. Just bought a 2001 3500 get 21mpg with out the trailer .Haven't got it to the shop yet.

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Rear end gear ratio - trailer weight - head wind speed - grade of pull - speed of travel affect m.p.g.

Sorry - but a wing on the roof of your tow vehicle does nothing for fuel economy - if anything it reduces it by adding additional drag.

That fact has been independently tested ......

A V nose and a flat font will get the same m.p.g.

Adding drag reduction to the REAR of a trailer will increase m.p.g.

Jim

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Adding drag reduction to the REAR of a trailer will increase m.p.g.

Jim

As an aerospace engineer, I can confirm this. The most aerodynamic shape for subsonic speeds (if you're worried about supersonic speeds, that's one HECK of a tow vehicle!) is a raindrop. Rounded at the front, tapered at the rear.

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