MPGs After Belly Skids?

[Roofus]

After getting my NVM skids on and giving it a fresh fill up and a week of driving I’ve seen a drop in MPG from about 17.5 down to 14.7. Wow! Seems like a big loss just adding 80lbs, but I guess aerodynamics could be having an effect?

Just curious what others are seeing after getting their belly skids on?

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[Fordified1]

Seems odd. And wouldn’t belly skids help aerodynamics instead of hurt?

 

[HoosierDaddy]

If the belly skids create a smoother surface down there, you'd get better mileage.
If they are aerodynamically all fubar'd, it'll go down.

I suspect there are other things at work here besides adding 80lbs of belly skids.

 

[GTTom]

If the belly skids create a smoother surface down there, you'd get better mileage.
If they are aerodynamically all fubar'd, it'll go down.

I suspect there are other things at work here besides adding 80lbs of belly skids.

Agree ^

Adding 80 lbs is like just taking my dog for a ride. He doesn't hurt my milage. Either aerodynamics is worse or other things at play. Maybe check your mileage for longer period of time or a whole tank then compare.

 

[Tilzbow]

I added full set of JCR skids, a JCR bumper, a winch and a roof rack and my mileage wasn't affected at all. The total weight addition, compared to stock, was 208# which is about the weight of a passenger. The weight did create alignment issues though but those were adjusted by my local 4x shop as soon as I noticed tire wear.

I doubt the MPG has anything to do with the skids.

 

[Roofus]

Agree ^

Adding 80 lbs is like just taking my dog for a ride. He doesn't hurt my milage. Either aerodynamics is worse or other things at play. Maybe check your mileage for longer period of time or a whole tank then compare.

Yeah, exactly. My wife weighs 105 (don’t tell her I told you). So that was my first thought as well. The skids should have been no worse than having another passenger in the truck. And the skids create a very smooth surface.

Here’s what’s even more crazy to me. I put all of the boxes for this stuff in my truck and drove 8hrs to my other property so I’d have a garage to work in. I got 17.5 all the way home. So it’s like when I carried the weight in storage it was fine. When I bolted it on it must have gotten much heavier.

Other than skids I also installed 74Weld steering stage 1, e-swaybar disconnect, and Icon tie rods. I don’t understand how in the world any of that would be affecting mpg.

 

[Fordified1]

Bad tank of fuel?

 

[‘21OBX]

Yeah, exactly. My wife weighs 105 (don’t tell her I told you). So that was my first thought as well. The skids should have been no worse than having another passenger in the truck. And the skids create a very smooth surface.

Here’s what’s even more crazy to me. I put all of the boxes for this stuff in my truck and drove 8hrs to my other property so I’d have a garage to work in. I got 17.5 all the way home. So it’s like when I carried the weight in storage it was fine. When I bolted it on it must have gotten much heavier.

Other than skids I also installed 74Weld steering stage 1, e-swaybar disconnect, and Icon tie rods. I don’t understand how in the world any of that would be affecting mpg.

Alignment off just a touch could eat some mpg, Is it up hill one way?

 

[Fordified1]

Alignment off just a touch could eat some mpg, Is it up hill one way?

Lol no both ways. But alignment change seems plausible.

 

[Roofus]

I added full set of JCR skids, a JCR bumper, a winch and a roof rack and my mileage wasn't affected at all. The total weight addition, compared to stock, was 208# which is about the weight of a passenger. The weight did create alignment issues though but those were adjusted by my local 4x shop as soon as I noticed tire wear.

I doubt the MPG has anything to do with the skids.

I'm working with similar additions. Full NVM belly skids, rear diff skid, shock skids, tailgate reinforcement w/35, RC hidden winch mount and winch, and trailrax half rack. I mean at worst we're talking a few hundred pounds.

 

[Roofus]

Alignment off just a touch could eat some mpg, Is it up hill one way?

Okay, that's a flag for me for sure. I took it to Ford for an alignment the day after we got the suspension/skids done. And then the next day on the drive home at interstate speeds I was complaining that they did a piss poor job bc it was noticeably pulling to the right if I took my hands off the wheels.

So the problem might be that I'm dragging some rubber down the road, huh? Unfortunately, I can't take it back to the dealer that did the alignment bc I work out of state and that dealer is near my permanent residence and I won't be back for two months. I'll ask the local guys for a good recommendation around here.

Anywho, good flag! Thanks!

 

[indio22]

A general rule of thumb is adding 100lbs of weight relates to a 1% reduction in mpg. Of course, the type of driving will impact the mpg, as weight mainly will penalize on acceleration, rather than steady-state driving.

Using the above, if you added 80lbs of skid plate weight, and had previously been getting 17.5mpg, you might be looking at a 0.15 or so reduction in mpg. Clearly your 3 mpg reduction is way above that mark.

Theoretically if a skid plate messed up airflow (such as exit flow from the engine compartment/wheel wells or what not), there could be a negative mpg impact. But I'd be surprise to see a 3mpg impact.

 

[Fmuguira]

I don’t think there’s apples to apples on comparison. Do a few more tanks of fuel, try to replicate the driving conditions, then if still 3 mpg less start the hunt for “what the he_l” happened !!!

 

[userdude]

I put 19lbs heavier tires on my 2.3L BL Sas (replacing stock GY's) and lost 2-3 mpg easily. From what I can tell, most of the loss is at lower town speed, e.g. using the turbos more and longer to get to a speed.

 

[ksdon]

Well, when you are stuck on a rock and spinning tires, you will be getting Zero MPG.

Many vehicles have a carpet type mat attached undernearth to supposedly help air flow. Maybe skid plates also help. But either way, a skid plate on the trail is important enough to have even if it reduces MPG.

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