After removing and fixing the rear bumper a couple of weeks ago I left off the rear mud flaps and this weekend had a chance to do about a 150 mile highway run, the mud flap removal was the only change, tire pressures, etc were kept the same as previous trips. Previous mileage on the same highway, same speeds, same vehicle weight, same time of day, etc has always been about 9.7 L/100 kms (24 US mpg) as read on the trip calculator, this run read 9.0 L/100 kms (26 US mpg).

A 2 mpg improvement at highway speed seems like a lot for just removing the rear mud flaps but that was from the in-dash trip recorder reading. One thing I did notice though was that previously when driving through rain there would always be about a 3 foot side water spray coming from the rear side of the back wheels, this time there was no side spray.

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I have noticed to that the more I put on top of my pathfinder the more gas I use, right now i have a roof rack with 4 hella's my spare tire and my axe and shovel mounted up there, boy do I get sucky gas mileage!

Greybrick wrote:A 2 mpg improvement at highway speed seems like a lot for just removing the rear mud flaps but that was the trip reading. One thing I did notice though was that previously when driving through rain there would always be about a 3 foot side water spray coming from the rear side of the back wheels, this time there was no side spray.

2mpg does seem like a lot. Did you leave the flaps off intentionally? Sounds like a number of the roads you frequent are as full of muck as the ones I take, which makes me wonder why you left them off. They are definitely as plastic & cheap as a mudflap could be, but they do their intended job well.

Back to the mileage. First question is what is your overall mpg since day 1? Also, have you ever verified that your vehicle is even registering the exact speed and mileage? As focused as you seem to be, I can't believe you wouldn't have verified this by now. If I drive from Park City down to Salt Lake City, I can essentially coast the entire way. I'm sure my mpg would be awesome, but the only thing that matters (to me) is the overall mpg for the tank, compounded with the overall mpg of the vehicle since delivery.

NVSteve wrote:2mpg does seem like a lot. Did you leave the flaps off intentionally? Sounds like a number of the roads you frequent are as full of muck as the ones I take, which makes me wonder why you left them off. They are definitely as plastic & cheap as a mudflap could be, but they do their intended job well.

Thanks Steve, the flaps were left off intentionally to check this aspect of mpg improvement. As I don't see the rear flaps as doing much work other than keeping mud from filling the rear bumper, keeping the spare tire clean and keeping rocks from chipping up the underside of the rear plastic bumper, they'll be staying off as I seldom go on unpaved roads.

NVSteve wrote:Back to the mileage. First question is what is your overall mpg since day 1? Also, have you ever verified that your vehicle is even registering the exact speed and mileage? As focused as you seem to be, I can't believe you wouldn't have verified this by now. If I drive from Park City down to Salt Lake City, I can essentially coast the entire way. I'm sure my mpg would be awesome, but the only thing that matters (to me) is the overall mpg for the tank, compounded with the overall mpg of the vehicle since delivery.

Sorry, as far as I can tell this dashboard recorder doesn't give overall (L/100) or mpgs since the vehicle was first purchased, this one has the model 'S' poverty pack with the read-out just inside the bottom of the odometer which seems to give singular event mpgs every time it's reset. My local driving conditions are fairly varied so I'm not sure if checking mileage against liters put in the tank would give acurate info, when I do another long trip then I'll post some better long distance and hopefully more accurate info.

Any L/100 (mpg's) reported as provided by the trip recorder are based on there and back return trips so should be fairly accurate if the trip recorder is accurate, return trips should compensate for both elevation gains or losses as well as wind variation. I have no reason to think that the trip recorder is seriously inaccurate or deficient as a couple of months ago I did a +/- 500 km trip which is about 300 miles, which showed to use just over 1/2 tank of gasoline, as I recall that was a night trip that gave the best previous mpg of 9.4 L/100 kms, 25 mpgs number.

What is your current average or best highway section mpg's, Thanks

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Greybrick wrote: Thanks Steve, the flaps were left off intentionally to check this aspect of mpg improvement. As I don't see the rear flaps as doing much work other than keeping mud from filling the rear bumper, keeping the spare tire clean and keeping rocks from chipping up the underside of the rear plastic bumper, they'll be staying off as I seldom go on unpaved roads.

I have construction going on at both entry points to my office, so I've been driving through the resulting dirt for months now. I remembered this thread as I was walking out to drive home yesterday & noticed that I had mud and dirt splattered all over the rear/rear sides & front sides. I'd hate to think how bad things would be w/out the flaps. I was giving some consideration to replacing them with a self-made rubber flap, or some kind of light poly material (there's a post floating around here with such). But, that was only if I had installed the oversized tires, which I never did. Still, if you don't need them, by all means don't use them. True happiness for me will be the day we can purchase a new vehicle & specify exactly what should be included, down to the type of bolts used.

Sorry, as far as I can tell this dashboard recorder doesn't give overall (L/100) or mpgs since the vehicle was first purchased

I was actually wondering if you kept a written record of it since I don't think any of us never reset the overall MPG readout.

My local driving conditions are fairly varied so I'm not sure if checking mileage against liters put in the tank would give acurate info, when I do another long trip then I'll post some better long distance and hopefully more accurate info.

That would help. My driving consists of everything between fillups, yet I know that my mileage calculations are absolutely correct, based on distance driven and gallons consumed.

I have no reason to think that the trip recorder is seriously inaccurate or deficient as a couple of months ago I did a +/- 500 km trip which is about 300 miles, which showed to use just over 1/2 tank of gasoline, as I recall that was a night trip that gave the best previous mpg of 9.4 L/100 kms, 25 mpgs number.

Yeah, I remember you posting about that one. I don't buy it (the readout, not you). Let me preface that by saying that my fuel gauge is pretty much a joke. The upper half of the gauge (1/2 tank to full) gives me lots of miles, whereas the bottom half of the gauge acts like someone poked a hole in my tank. The way you make your mileage sound, one would presume you could get just under 600 miles per tank. No way is that going to happen. That's why I've been trying to persuade you to get your speedo readings verified as a first step. Something is obviously going on, and it isn't the lack of elevation or slow driving. Nobody anywhere has reported mpg figures like that on a Pathfinder. Does it not seem odd to you that you are the only person who has posted hybrid-like mpg readings? Unless somehow the factory messed up and installed a 4 cylinder in yours.

What is your current average or best highway section mpg's

My current overall mpg is about 17.3. The time between fillups (every 2 weeks) is 50% highway, 50% city. The city portion of that is mostly just sitting idle at lights, and probably 2 days per week the highway portion is mostly idle in traffic. Anytime I leave town, it involves long enough distances that I have to at least fill up twice, so I have a very solid idea of what my mpg is/can be on the highway. The best so far was close to 21 mpg with a fully loaded rear & 2 16' kayaks on top, cruising the freeway at about 85mph. I've also noticed that I tend to get really good mileage if I'm driving in the mountains. The Pathie just doesn't suck that much fuel when climbing, and the downgrades certainly help as well. I also don't drive below 4300' more than a couple of times a year. I'll be at over 12,000 ft in a couple of weeks (*if* the fire outside Yosemite is still burning, that is), so it should be interesting to see how it does at the upper end of the US elevation scale.

Greybrick wrote:
What is your current average or best highway section mpg's, Thanks

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2 mpg does sound like a lot for mud flap removal. Too many variables to account for to make this gain dependable.

BTW, on my trip up the US east coast, I averaged around 22-23mpg. Reset every tank, not total trip average. If I was trailing another vehicle (especially a semi) by 100ft or so, that number could easily jump to 26-27mph. I could get in behind a large SUV (Yukon, Expedition, etc) at around 50 feet, and get close to 30mpg @ 80mph. I-95 gets very boring so analyzing that sort of data easily turns into a game