Loaded my '00 V10 CC with stuff for school and drove the 130 miles up to school. Normally a quarter tank of gas gets me about 75 miles, a quarter tank on this trip got me about 100-105 miles. That's roughly a 30% increase. I didn't do anything differently on the fill up, and my driving was a little worse than normal. There was heavy traffic and rain, so lots of slowing down and speeding up, as opposed to the normal cruise set at 67 the whole way.

Not complaining by any means, I'm just curious as to whether that's normal? I had a grill in the front of the bed, couch along the right side, then the rest of the space filled with firewood.



I'm thinking that having that space occupied allowed the air to flow over the truck instead of getting trapped in the bed, creating a low pressure zone.

I also replaced all four brake rotors this week, so maybe that could factor in as well? Nothing in my search really answered my question, so maybe some of you have had a similar experience?

 

I guess the first thing is that measuring fuel mileage based on 1/4 tank on the gauge is not going to work well at all, you'd be hard pressed to find a less accurate way to do it. Second, with an empty bed the air flows over the pocket and doesn't create more drag. That load might reduce drag by a fraction of a percent, but not enough to notice or measure. Your improved mileage is down to driving slower in the rain and traffic.

 

That makes sense. I normally just use my gauge to roughly estimate my fuel mileage, and get a more accurate measurement when I fill up. I just haven't filled the tank yet. But there was a noticeable difference on my estimate, so I figured I'd ask.

 

How was the wind on this trip? It's virtually impossible for that alone to be responsible for any kind of fuel efficiency increase, typically the opposite is true. More weight without adding wind resistance will still increase the rolling resistance of your tires. But the stuff in the bed would increase your wind resistance instead of decreasing it, so it certainly did you no favors in this regard.

 

I'm more impressed with your school items (grill, couch, firewood) than your mpg increase!

 

I don't think the wind was too bad this time. I figured when I left that I'd see a decrease, but then again, Some wood, couch and grill shouldn't weigh all that much, 200-300# maybe. Its certainly not pulling a 15,000# trailer.

I guess, slower speeds and not so much wind is probably where the increase came from.

Matt, gotta have the essentials... Living off campus does have its benefits!