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Old 09-13-2018, 12:04 PM   #1
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MPG testing

I am not new to fuelly, as I used the app before but suddenly stopped. However, I am using a different vehicle, just pure highway driving on the Florida Turnpike for a good 230+miles. Although I am doing lots of highway driving, I am practicing proper fuel efficient techniques: Using Cruise Control @ posted speed limit (70 MPH), A/C @ speed 3 or even lower, not doing WOT, yet I am not getting the advertised MPG of 33 HWY that Nissan claim's. Florida HWY Patrol gave me a go ahead to drive at the minimum speed on the turnpike which 55 MPH. Also I will be using Fuelly, some excel spreadsheets, etc., to make sure I am getting accurate MPGs for this SUV.
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Old 09-13-2018, 10:48 PM   #2
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Hi there. Check your tyre pressures and make sure they are at least the manufacturer's recommended figure. I set my cold tyre pressures 3 psig over the recommended value.
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Old 09-14-2018, 07:05 AM   #3
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The EPA tests are based upon drive cycles from the 1950's. The test equipment when testing started couldn't handle the highway speeds we drive today.

The highway test speed maxes out at 60mph, and the supplemental high speed one goes up to 80mph. The average speed for both is under 49mph. The highway rating represents country roads and older highways more than our modern interstates, freeways, and turn pikes. Then the aerodynamics of SUVs means they will see worse fuel economy at higher speeds.

https://www.fueleconomy.gov/feg/fe_test_schedules.shtml
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Old 09-14-2018, 07:38 AM   #4
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Originally Posted by trollbait View Post
The EPA tests are based upon drive cycles from the 1950's. The test equipment when testing started couldn't handle the highway speeds we drive today.

The highway test speed maxes out at 60mph, and the supplemental high speed one goes up to 80mph. The average speed for both is under 49mph. The highway rating represents country roads and older highways more than our modern interstates, freeways, and turn pikes. Then the aerodynamics of SUVs means they will see worse fuel economy at higher speeds.

https://www.fueleconomy.gov/feg/fe_test_schedules.shtml
Well, isn't that false advertising then? I am trying to prove a point to EPA, Nissan USA, and probably USDOT, which I might eventually bring a law-suit because we (the consumers) expect to get everything for what we paid for regardless make, model, and trim, but we are being deceived by the big guys.

I also resetted every fuel computer trip on my Rogue so I can start taking data, and keep doing it for roughly an year.
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Old 09-14-2018, 09:00 AM   #5
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Originally Posted by JockoT View Post
Hi there. Check your tyre pressures and make sure they are at least the manufacturer's recommended figure. I set my cold tyre pressures 3 psig over the recommended value.
I just got new tires and changed my trans fluid 4 weeks ago, and the dealer put anywhere between 0-3 PSI more than the recommended cold tire PSI value.
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Old 09-14-2018, 09:40 AM   #6
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New tyres kills fuel efficiency. I put two new tyres on last year, and immediately saw a 10 - 12% drop in mpg. Tyres are at their best, mpg wise, just before they need changed.
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Old 09-14-2018, 11:31 AM   #7
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Yeah, new tires are bad. For the EPA test, the tires have at least 3000 miles worth of wear on them. Rules limit them to 4000 miles.

The point of the tests is to allow a like to like comparison of different models, not provide you with what it will get on the road. There are too variables in the real world to account for that. Changes in temperature will change the fuel consumption, as will using the air conditioning.

The EPA does put the closest to real world on the window sticker. Check Fuelly's database, the average for most models is really close to the EPA combined figure.
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Old 09-14-2018, 04:16 PM   #8
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Originally Posted by datechboss101 View Post
Well, isn't that false advertising.....
People in the know, know what trollbait just told you. So you want to sue, just because you don't know? Hey, maybe you'll succeed. A bunch of leadfooters, who couldn't get 30MPG in their Elantras, sued Hyundai about over-reporting MPG... & they won. Meanwhile, we bought one auto Elantra & one manual Elantra. Both have gotten 45+MPG highs, despite having reduced EPA ratings of 38MPG. Instead of suing people, just drive bigger diameter tires at higher pressures, accelerate slow, drive slow & take care of your gas pedal.
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Old 09-14-2018, 07:28 PM   #9
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I just had a painful 5 1/2 hour drive and achieved 41 MPG average and have 70% gas remaining. To achieve this, grandma mode had to be activated, which was Cruise control set at 60 MPH and ECO mode turned on. And boy, I got two numbers, since I turned off the van two times. The first number was 40.4 MPG, and the second one was 41.6 MPG. And this was over a 254 mile drive.

I saw my tire pressures were 33 and 32, which the two tires that had 32 was under inflated by 1 psi. I also had the live MPG screen on display so I can see the live data.

So I am not sure how EPA achieved 33 as HWY, since I had a painful drive today, since it took me more than 1 hour extra than it usually takes on this route (I use the turnpike for roughly 240 miles). I am going to do my tests for a year and evaluate my results, to see whether or not its worth to bring a lawsuit upon Nissan & EPA for false advertising.

However, just doing some research on average highway speeds in the country, most speed limits are between 65 to 70 MPH, not 50-55 MPH, so EPA needs to redo their speeds.
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Old 09-15-2018, 07:29 AM   #10
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For the EPA to do so would require an act of Congress, and would be a major undertaking to actually change the test cycles for the city and highway tests to match how car's are driven today. More than advertizing is tied to those tests results; CAFE and emissions are measured from them. Emissions is why the testing started. The fuel economy measurement was just a by-product.

Chance the actual tests, and the targets for CAFE and emissions need to be adjusted.

Bump up the tire pressure some. I run at least max sidewall.
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