[n9emz]

I'm puzzled and here's a curiosity for y'all to clue me in on. It's real world info after calculations from my weekend anny run compared to lot of previous towing mileage info. Towrig is 2WD 1995 F-250, 5.8L, E4OD, 3.55 rear at 5,400-lbs curb weight with driver and both tanks full. 15.3 mpg.

First, here's the rig, trailer, towrig configuration with a 1,280-lb equipment trailer. 7.5 mpg loaded:

This configuration is with the same trailrig loaded even heavier with parts, tools, etc. on my 2,100-lb steel flatdeck and the addition of the butt-ugly aluminum Fatty RV topper I shacked in over the weekend....10.2 mpg average to and from the event.

Did the POS topper break up the airflow? Is a good quality trailer that much easier to pull than a kitbuilt equipment trailer of half the weight? Did a fairy sprinkle my rig with fairy dust? WTF?

 

[drnut]

It would have to be the topper only explaniation... or it was all down hill to and from..

 

[demonranger]

I'm going to guess on that the fueling up for the higher trip was a little bit shy of a full tank giving you an extra mpg then the topper even though it's fugly is going to help the aerodynamics more than the open bed hitting the rig on the trailer full smack again. Now you're wheeling rig is essentially drafting and not catching much wind resistance b/c the topper is catching most of the wind and what the topper is catching is far less than the trail rig would w/o the topper.

But as a scientist I have to say that once doesn't make it so it could be a freak chance you must repeat to confirm.

 

[Travis Waldher]

also depends on how shitty the first trailer towed.

I can't imagine the aluminum cap made that much difference alone.

 

[BionicCruiser]

i still have to figure out the exact #s, but this year towing my same load, same trailer to Moab, i got noticably better mileage by keeping my boost down under 5 psi. the real point is, i kept my foot out of the gas pedal and mileage improved. could you have taken it a bit easier/slower? that combined w/ the topper may make the difference. just a thought.

 

[n9emz]

I forgot to add....I gas up after loading and always "pack" my tanks. Once I get on the interstate I use cruise control, ride with the windows up and AC on. Yep, there have to be some variables involved and I'll know for sure over a longer haul. However, I have noticed improved mileage since I began towing with the heavier steel flatdeck. The old utility trailer seemed to pull easy and straight, but I have noticed a big difference with the present, heavier trailer. Acceleration is slower with it, but it seems to roll out easier and once I get it up to speed it seems to maintain momentum better than the lighter trailer.

Can you understand that this is worrisome to me....seems that no good fortune comes without a hidden price.

 

[JAG]

Thats great, i was pretty depressed while i was figuring up mileage on the 460 gasser I towed with this weekend, got about 4 with the motor tugging about 25000 LBS of truck/trailer and load with the air on.

 

[TEX]

I'd say it's just a 1-time thing. If you did 10,000 miles at 7.5 & 10,000 miles at 10+, then you have enough data to draw a conclusion. Too many other factors (not fulling filling a tank, wind, speed, etc) to throw off the mileage for one trip.

TEX

 

[yager]

someone slipped some acetone in your tank

 

[VortecYJ]

Dumb question, but were you in overdrive or just Drive for either of the trips? I had a lifted Grand Cherokee that I drove 100 miles in OD without a load (stock 3.55 gears, so the trans was constantly hunting for gears), then drove back with OD shut off pulling two snowmobiles in an enclosed trailer. I got almost the exact same milage for both trips unloaded, then loaded- completely flat both ways (Iowa).

 

[Cap'n Ron]

someone slipped some acetone in your tank

This reminded me...

When I was a kid in the late 70's we had a family friend, Tom who was an early adoptor of the little Datsun B210 cars in the fuel crunch days. He and his neighbor commuted from new Jersey to NYC everyday and Tom kept hounding his neighbor to get rid of his land-yacht Plymouth Fury. This went on for a year with Tom espousing the virtues of high fuel mileage, reliability and all that. His neighbor finally broke down and bought a Datsun and began commuting with it. Every night at around 1:00am, Tom would get up, sneak over to his neighbor's driveway and pour 1 gallon of gas into the tank. This went on for about a month when they had Tom and his family over for dinner. Tom gets around to asking..."So...how's the Datsun working out for you?" He hesitates...and says, "Y'now...I don't know why I didn't buy one of these years ago...that things gets 94 MILES TO THE GALLON!!!!"

 

[n9emz]

Update.....after a few more days of tooling around in the towrig with the topper still on, I'm observing a definite improvement in mileage and overall performance. Previously, it's always seemed like it took forever for my gas gauge to fall below the full mark after a fill-up, and then the gas needle seemed to swing inversely proportionate to the speedo needle. A trip in to work and back would consume a quarter of a tank. Now, it's a little less than 3/16 of a tank, and where the tranny would drop out of OD on hills, it's sticking in OD now. Same driving habits, same routes....same everything, except for that ugly-ass topper that looks to me like it would add wind resistance.

I never seriously considered the tailgate drag arguments but maybe there is some significance where a longbed standard cab pickup is concerned. Anyhow, thanks for burning some brainfat with me about this issue.

 

[TEX]

I had a lifted Grand Cherokee that I drove 100 miles in OD without a load (stock 3.55 gears, so the trans was constantly hunting for gears), then drove back with OD shut off pulling two snowmobiles in an enclosed trailer. I got almost the exact same milage for both trips unloaded, then loaded- completely flat both ways (Iowa).

Just one more reason I tell guys with 1/2 ton or smaller rigs not to EVER tow in Overdrive. Just no benefit to it.

TEX