# Miles Per Gallon



## Titanwannabee (Sep 14, 2006)

Hey guys, just thought you might be interested. I have been tracking this since I bought the truck. I do about half highway, half city driving. '06 Nismo CC stock with a vinal tonnea cover. The vertical lines represent when I did an oil change. Castrol 5w30 and Fram Filter. Does anyone else seem to notice a mpg drop immediately after doing an oil change? Altogether, pretty impressed. Let's here how yours compares.

Daniel


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## Titanwannabee (Sep 14, 2006)

sorry guys.. anyone got any idea how to post a picture? 
- nevermind.. figured it out


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## littlefish (Jul 1, 2006)

I noticed there was the start of a dpwnward trend just below 6K miles. That is just before an oil change. How do you explain the decrease in mileage from 21.5 to 18.25 just before the oil change at 3K miles? This mileage trend may not be related to changing your oil, but could be related to outside ambient temps, running the AC Compressor to have the defroster remove moisture on cold mornings, how long it takes to warm up the engine on cold mornings (colder temps require longer warm-up times), thereby using more fuel to richen the mixture during that warm-up time, and the specific gas you were burning at the time. Number of short trips versus long trips. As outside temps turn cooler, the refineries vary the blends for easier cold starting versus the blends for summertime use. If you do not buy your fuel from the same station, that could also be a variation. There could be lots of variables. I would be hesitant to lay the blame on the oil change. However, I am impressed by the 21.5 mpg you were getting. One of the things I noticed in Houston is the stations were mandated to run 10% methanol. My mileage dropped about 5%. Now they are running at least 10% (mandated) and some brands 15%. Best of luck...Littlefish


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## Z_Rated (Apr 29, 2006)

Give me some time and I can try to give comparison data since I too have been tracking since new ('05 K/C). My first thought is time of year. Piqued my interest. Z


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## jerryp58 (Jan 6, 2005)

FWIW...










BTW, I'm using the "corrected" MPG based on my high miles (~2%) before my tire size change and my low miles (~3%) after.

I can't see an oil change related effect here, but there as so many variables and I think there always will be (the truck aging and all of the repair/maintenance parts changed out along the way, not to mention weather and general driving/traffic conditions).

Click here for excruciating MPG details... hey it's a 4x1 4-cyl, what else have I got but MPG


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## peasly23 (Feb 6, 2007)

I just bought an 07 Frontier NISMO KC 4x4 and my MPG is like freaking 11 - 12 mpg!! I am at about 700 miles and change and it's winter time, but COME ON!!! How long is it till it's supposed to get better?


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## Titanwannabee (Sep 14, 2006)

well, Peasly23, That's kindof why I started this post. As you can see by my first couple trackings, I was getting like 16, but it drastically improved at around 1000 so give it a little while longer, but keep all the other aspects that you mentioned


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## Titanwannabee (Sep 14, 2006)

Another thing is that I noticed that Nissan de-rated the hp ratings for the 4.0's in the Frontier from 06 to 07. I don't know why but I wonder if that has anything to do with Gas mileage.


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## Z_Rated (Apr 29, 2006)

No, new standardized rating system in place.


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## Z_Rated (Apr 29, 2006)

Okay, after comparing my data I found something interesting... after each oil change (7) mpg went down and next tankful went back up to about where it was prior, no matter what the mpg was. Makes me want to check my other and old vehicle logs (still have). Don't know when that will be though. Sorry it took so long, Z

'05 Nismo K/C 4x4
17.X MPG Average


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## BTF/PTM (Oct 19, 2006)

peasly23 said:


> I just bought an 07 Frontier NISMO KC 4x4 and my MPG is like freaking 11 - 12 mpg!! I am at about 700 miles and change and it's winter time, but COME ON!!! How long is it till it's supposed to get better?


You've got 4x4; lots of extra parts that the engine has to move while it's rolling = eats more fuel. Could also be wheel slippage if you do a lot of snow driving (not sure where you live, it doesn't snow here).

This is just a guess, but does anyone else think that a slight drop in mileage right after an oil change could be due to the increased viscosity of the new oil?


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## Centurion (Sep 5, 2002)

BTF/PTM said:


> This is just a guess, but does anyone else think that a slight drop in mileage right after an oil change could be due to the increased viscosity of the new oil?



Could be, but also they (mileage experts) recommend oil changes for better MPG's so that the engine doesn't have to fight its way through thick and sludgy oil.


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## BTF/PTM (Oct 19, 2006)

Centurion said:


> Could be, but also they (mileage experts) recommend oil changes for better MPG's so that the engine doesn't have to fight its way through thick and sludgy oil.


True enough. That's actually a very interesting contradiction...I've heard that oil gets thick and sludgy as it gets dirty (as you mentioned) just as many times as I've heard that the viscosity of engine oil breaks down as the oil gets used. I suppose both may happen...hmm, I smell an experiment in the near future


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## jerryp58 (Jan 6, 2005)

BTF/PTM said:


> True enough. That's actually a very interesting contradiction...I've heard that oil gets thick and sludgy as it gets dirty (as you mentioned) just as many times as I've heard that the viscosity of engine oil breaks down as the oil gets used. I suppose both may happen...hmm, I smell an experiment in the near future


Isn't one of the advantages of synthetic supposed to be that it maintains it's viscosity rating longer than conventional?


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## BTF/PTM (Oct 19, 2006)

jerryp58 said:


> Isn't one of the advantages of synthetic supposed to be that it maintains it's viscosity rating longer than conventional?


I believe so. I used to use synthetic oil in my car for 9,000 miles, I'd just change out the oil filter every 3,000 and top off the oil. I cannot say with any certainty whether the synthetic oil was any better than standard oil, though. It's amazing what we'll do if we're told it's true by some magazine or "expert".


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## littlefish (Jul 1, 2006)

There is a lot of Snake Oil and Slick Salesmen out there. I heard something the other day, that when mileage runs are done, Honda used synthetic auto transmission fluid in place of motor oil. Very low viscosity for a tight motor, good lubrication, almost sounds like it might work. Seems like this might kind of slew the testing for better gas mileage, does it not? Can anyone verify this rumor? Best of Luck...Littlefish


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## Centurion (Sep 5, 2002)

They use _motor oil _ 5W-20 in Hondas. How those motors survive in highway desert conditions is incredible.


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## Tboneroks (Nov 17, 2005)

i've got a little over 36000 on my truck and still averaging right at 20mpg for the whole two years since i've had it...


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## BTF/PTM (Oct 19, 2006)

Centurion said:


> They use _motor oil _ 5W-20 in Hondas. How those motors survive in highway desert conditions is incredible.


Hondas have grossly overdesigned cooling systems, far more radiator and water pump volume than they need. That's how they put up with very thin oil and high RPM. My little 91 CRX (man i miss that car) never got above a third of the temp guage, even when I'd drive across the desert to Vegas.


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