Camper Shell Impact on MPG

[Gomav]

Hello,

I built a camper shell and lost 8.4 on MPG, from 49.8 down to 41.4, running 64 miles at 55 MPH. This is a lot more than I expected, I guess hybrid is far more sensitive on MPG. The shell is only 40 lbs, but 8 inches taller than the cab top. I wonder what if I make it 4 inches shorter?

Before I do the surgery (not reversable), I would like to know how about your shells? The LEER 180 and ARE MX are about 4 inches taller than the cab.

Thanks!

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[kingarthur10]

Going about 65-70mph, adding a roof top tent and Leitner ACS rack dropped me from ~41mpg to 34mpg. The rack and tent both extend well above the top of the Maverick and adds about another vertical foot of frontal area.

 

[tom_tucker]

Hello,

I built a camper shell and lost 8.4 on MPG, from 49.8 down to 41.4, running 64 miles at 55 MPH. This is a lot more than I expected, I guess hybrid is far more sensitive on MPG. The shell is only 40 lbs, but 8 inches taller than the cab top. I wonder what if I make it 4 inches shorter?

Before I do the surgery (not reversable), I would like to know how about your shells? The LEER 180 and ARE MX are about 4 inches taller than the cab.

Thanks!

I seem to recall estimating 2-3 mpg loss after installing just the ARE MX, but that was over a year ago. It's heavy, but fairly aerodynamic, IMO. All sides of the MX are angled inward and roof/corners are rounded. I also have clear tape over the entire cap gap so it's seamless. Even with all the highway I'm doing, I'm still right around the EPA 37 mpg combined, truck says 39 but lies by about 2 mpg.

Maybe someone has real and more recent data. Sounds to me like it's more of a theory question. Drag and friction and crap that I don't know about. To me, the mid rise looks proportional to the dimensions of the Maverick.

 

[Raymundo76]

Hello,

I built a camper shell and lost 8.4 on MPG, from 49.8 down to 41.4, running 64 miles at 55 MPH. This is a lot more than I expected, I guess hybrid is far more sensitive on MPG. The shell is only 40 lbs, but 8 inches taller than the cab top. I wonder what if I make it 4 inches shorter?

Before I do the surgery (not reversable), I would like to know how about your shells? The LEER 180 and ARE MX are about 4 inches taller than the cab.

Thanks!

I have the ARE MX. At about 140 lbs did not anticipate much loss. Around town did not notice much change. I do not generally exceed 65 MPH; Only noticed about 1 or 2 MPG loss. My last road trip to AZ high country got ~ 42 MPG round trip. In the past , shells on my 2 Nissan Frontiers with less aerodynamic shells did not have a significant MPG loss.

 

[Master Blaster]

The stock Mav has a Cd of .56, which is about the same terrible drag as any other truck. If you increase the vertical height of the truck, you will raise the Cd to (say) .75 or more, drastically affecting your mileage. The energy required to push the vehicle down the road is directly related to Cd x frontal area x speed squared. You are increasing the Cd, the frontal area and driving fast, and that's going to hurt your fuel usage a lot. Its more noticeable on a relatively efficient drivetrain than it is on one with a lot of other losses. If you want a camper, at least make it more aerodynamic by allowing the top to drop to the cab height. The other issue is losses caused by increased weight increasing the load on the tires. There are good reasons why most trailers are made out of balsa wood, and caps are made of thin sheets of fibregrass to keep the weight down.

 

[Raymundo76]

The stock Mav has a Cd of .56, which is about the same terrible drag as any other truck. If you increase the vertical height of the truck, you will raise the Cd to (say) .75 or more, drastically affecting your mileage. The energy required to push the vehicle down the road is directly related to Cd x frontal area x speed squared. You are increasing the Cd, the frontal area and driving fast, and that's going to hurt your fuel usage a lot. Its more noticeable on a relatively efficient drivetrain than it is on one with a lot of other losses. If you want a camper, at least make it more aerodynamic by allowing the top to drop to the cab height. The other issue is losses caused by increased weight increasing the load on the tires. There are good reasons why most trailers are made out of balsa wood, and caps are made of thin sheets of fibregrass to keep the weight down.

 

[Raymundo76]

I find the ARE MX to be aerodynamic for a taller camper. The reason I chose the MX was for camping. The camper that was even with the truck top did not allow me enough head room to sit up in the bed. So I decided to go with the higher camper knowing that at higher speeds there would be MPG loss. Since the bulk of my driving is around town at lower speeds I am comfortable with that decision. The major issue I had with this camper was it's very high cost. Since it was made in the USA, and considering all issue the MX was a good choice for my needs.

 

[Hot Runr Guy]

@Gomav, any chance you can add a wind deflector on the front of your cap, over the cab?

HRG

 

[Glen Baker LLC]

Hello,

I built a camper shell and lost 8.4 on MPG, from 49.8 down to 41.4, running 64 miles at 55 MPH. This is a lot more than I expected, I guess hybrid is far more sensitive on MPG. The shell is only 40 lbs, but 8 inches taller than the cab top. I wonder what if I make it 4 inches shorter?

Before I do the surgery (not reversable), I would like to know how about your shells? The LEER 180 and ARE MX are about 4 inches taller than the cab.

Thanks!

Do you have a picture of your camper top?
Someone may have some suggestions

 

[Gomav]

@Gomav, any chance you can add a wind deflector on the front of your cap, over the cab?

HRG

Do you have a picture of your camper top?
Someone may have some suggestions

I already have added a simple 45-degree wind fairing. Here is a picture:

 

[Maverickman74]

My Tremor managed 32 when hypermiling with the MX topper. But with a lot of off-road and generally not conducive to mpg roads I average 19mpg. When we reset it after we get off our road it will pull around 25-26mpg on the rest of the island. Speeds are an equal MX between 30 and 60 mph.

 

[TheSEARCH]

You need to angle that part that sticks above cab. I have a 16 foot kayak up on my roof most of the time. The faster you go the MORE it hurts mpg. Under 45 mph hardly much at all.

 

[Glen Baker LLC]

That should help some.

 

[MakinDoForNow]

I already have added a simple 45-degree wind fairing. Here is a picture:

Look at the top of your truck. The ridges front to back are there to create turbulence ending at the bevel just above the vertical rear window. The turbulence will help reduce the suction of the vertical window at speed. You might try a 60° fairing sticking about 3/4" above top corner to 1.25" below top corner with 3/4" clearance to divert the air to reduce suction. Possibly a short wing with a trailing saw tooth edge ending close to rear vertical of your camper. Maybe only four or five halves of golf balls glued to roof of camper near trailing edge will help. Maybe drill hole through golf balls and just screw them to roof of camper?

 

[Old Fart]

Drag was the reason I didn't go mid rise or high rise cap because the camper is like towing a brick, 20-26 mpg with the hybrid. Regular avg is 38 summer, 40-43 when the Air-conditioning isn't blasting. (Hwy/city). I've since closed the frontal area that helps with the mileage b

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