Never thought I would say this bout oil

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*Background info on my current vehicle/driving habits... 2016 Honda Accord Sport i4, bought it brand new with 6 miles on the odo. I change the oil and filter every 10k miles, just hit 70k and just changed it again for the 7th time. I have a 130 mile round trip commute to work, mostly interstate and hardly ever stop and go.

I used to always chuckle when I would hear someone say that their car ran better on one brand of oil vs another, or was quieter, or more efficient etc... Well I may have just experienced this for myself. I know my car pretty well, and its fuel mileage has always been pretty consistent, averaging 33-35 mpg per tank. Out of the 7 oil changes I've done on this car, only 3 of them weren't with Mobil one AFE. Changes 1-3 were with AFE, change #4 was with Valvoline synthetic, changes 5 & 6 were with Pennzoil Platinum and #7 I went back to AFE...all 0w-20. Thru those 2 OCI's with PP (20k miles worth) I noticed a decrease in my fuel mileage, dropping to 30mpg average per tank with a few tanks a couple of ticks lower. Doesn't sound like a lot, but I really noticed it on the total miles I was able to get out of a tank. I'm kinda OCD and like to log all my fill ups so I can track these things for whatever reason. I chalked it up to the car getting older, changes in the weather and I also got a new set of tires and changed the CVT fluid in that time period. The oil never crossed my mind. So I was coming up on 70k miles and it was time for another oil change so I hit up the local wally world and all they had in stock was the AFE so I went with that. And I [censored] you not, I noticed an immediate increase in my fuel mileage after the first full tank of gas. 1000 miles in and my average is back up to 34-35mpg per tank. Didn't change anything else but the oil. So I guess I'm sticking with the AFE.
 
That doesn't make any sense. Oil would not cause a 10%+ fuel economy drop. It's likely coincidental.
 
You are only 10% into your current OCI. It may be premature. Based on your mileage you are probably changing the oil every 3-4 months. In LA, what kinda of drastic weather changes do you experience.
 
Changing gas brands, ethanol %'s, etc can play factors too. E85, E15, E5, Non-Ethanol. Top Tier, non top tier. Even weather can play an important roll in gas mileage.
Are you filling up at the same gas station? Using whatevers closest?
 
Originally Posted by OILJUNKIE
What percentage is you OLM reading at 10,000 miles?


15%

Originally Posted by NO2
That doesn't make any sense. Oil would not cause a 10%+ fuel economy drop. It's likely coincidental.


Maybe, I'll keep an eye on it. Nothing else has changed other than oil brand. Still drive the same route and in the same manner. I work shift work and the times i'm on the road is almost zero traffic.

Originally Posted by Talent_Keyhole
You are only 10% into your current OCI. It may be premature. Based on your mileage you are probably changing the oil every 3-4 months. In LA, what kinda of drastic weather changes do you experience.


Yeah pretty much every 4 months, except when I'm on a turnaround and working 13 on and 1 off for 60 days straight. Like In the month of january I only had 3 days off the whole month, so just in that one month I did over 3k miles. In south Louisiana we only really have 2 seasons, hot with high humidity, and less hot with high humidity.
 
Last edited:
Originally Posted by GumbyJarvis
Changing gas brands, ethanol %'s, etc can play factors too. E85, E15, E5, Non-Ethanol. Top Tier, non top tier. Even weather can play an important roll in gas mileage.
Are you filling up at the same gas station? Using whatevers closest?


I use the same 2 stations, either a exxon or a shell cause of the fuel perks. Non ethanol is too expensive around here. This car is pretty much 95% work and back.
 
I'm guessing that there was a new set of tires somewhere along the way to 70K.
Tire pressure also contributes to good fuel mileage if kept up to or above the recommendations.

My 2¢
 
I went thru my logs and here is the data from the same time period from the last 2 years of May & June to the data from this year. 2017 was with AFE for sure, the 2018 data i'm thinking had the end of a AFE run and the first half of a Valvoline run.

fill up #, date, odo, gallons put in, mpg, price per gallon

46 6/29/17 448.00 12.936 34.63 1.999
45 6/23/17 438.00 12.804 34.21 1.999
44 6/10/17 460.00 12.981 35.44 2.099
43 6/4/17 476.00 13.350 35.66 2.199
42 5/27/17 430.00 12.628 34.05 2.059
41 5/21/17 516.00 14.566 35.42 2.049
40 5/14/17 473.00 14.067 33.62 2.079
39 5/8/17 501.00 14.141 35.43 2.059
38 5/1/17 490.00 14.291 34.29 2.099

87 6/30/18 495.00 14.097 35.11 2.459
86 6/12/18 495.00 13.331 37.13 2.479
85 6/3/18 502.00 14.000 35.86 2.459
84 5/27/18 504.00 14.431 34.92 2.529
83 5/19/18 499.00 14.385 34.69 2.499
82 5/5/18 492.00 13.989 35.17 2.359

150 6/23/19 520.00 14.766 35.22 2.209
149 6/16/19 439.00 12.388 35.44 2.159
148 6/11/19 438.00 12.804 34.21 2.199
147 5/31/19 423.00 13.753 30.76 2.349
146 5/25/19 440.00 13.881 31.70 2.459
145 5/21/19 471.00 14.673 32.10 2.499
144 5/14/19 422.00 15.027 28.08 2.899
143 5/10/19 475.00 14.607 32.52 2.899
142 5/6/19 473.00 14.488 32.65 2.899

Can you tell when I changed the oil at the end of May?
 
Originally Posted by dwendt44
I'm guessing that there was a new set of tires somewhere along the way to 70K.
Tire pressure also contributes to good fuel mileage if kept up to or above the recommendations.

My 2¢


Yup, I changed the CVT oil @ 50k and did the tires @ 60k. I keep'em at 35psi and rotate every time I change the oil. And I do the air filter (oem) when the maint minder says to, which I believe was 3 times so far.
 
Maybe a prankster is siphoning and adding gas just to mess with your calibrated/ocd nature. Add a quart every day for 3 months. Siphon a quart every day for 3 months and sit back and watch the concern and premature aging that happens to you?
 
What I can tell is that you have fallen victim to the typical noob approach to mathematical statistics. This is a perfect example of the perfect storm; too little understanding of statistics combined with too little data causing one to draw inaccurate conclusions.

To know how your fuel mileage would truly track with oil brand, you'll need 30 samples of your full-tank fill ups with brand X, then another 30 with brand Y. You have to know not only the average, but the variation with each product. You only have 9 sets (2017), 6 sets (2018), and 9 sets (2019). That's well short of the 30 needed for each. Without accurate knowledge of the standard deviation (variation) you cannot understand how much overlap there is. This is not unlike the concept I try to educate folks about in the UOA normalcy study I wrote.

Your data shows many things that would cause concern to a person practicing good statistics:
- there is far too little data to understand variation properly; a prime violation of any statistical process analysis
- there's a large amount of disparity in how many miles are exhibited between the max and min data collection points (2018 shows only 12 mile spread in total miles per sample, but 2017 and 2019 are up near 100; this means you didn't drive near-identical cycles per fill-up for all tests)
- your resolution of stated values violates the mantra of reporting within your gauge accuracy; a magnitude of 10:1 (one decimal place) is acceptable (if you measure to the tenth of a value, then you can only report to the whole number ... etc)
- you have no calorimeter data for the fuel loads; this is paramount to knowing an input that should be corrected for. while you cannot control it, you have to correct for it and without knowing it's value, your assumptions are based on false presumptions. If you use E10 gas, it does not mean it always has 10% ethanol. It only means it has a max limit of 10% ethanol. Therefore the fuel can vary from 0% to 10% ethanol and you have no idea of the true BTU energy in the fuel.
- you don't show any data for accounting for tire wear. A tire's circumference will wear away, altering the true distance for any measured cycle relative to the indicated miles driven; up to 4% of tire circumference can be easily accounted for with only 1/2" of tread wear.

In fact, that last point is critical in knowing. Do the math ...
Using a tire that starts out at 27" in diameter, and degrades 1" in circumference (1/2" wear in depth is radius; 2x for diameter), you'll loose about 4% in tire circumference. (I am ignoring the compression of weight on the tire radius). Doesn't seem like a lot, does it? OK, then take your average miles per fill up and subtract 4% of miles. In this case, we'll presume your fill up shows 470 miles traveled. But the REAL miles traveled will vary greatly. Examples:
1) new tire indicates 470.00 miles traveled; actual driven is 470.00 miles divided by 13.00 gallons = 36.2 mpg
2) worn tire indicates 470.00 miles traveled; actual driven is 451.00 miles divided by that same 13.00 gallons = 34.7 mpg
This represents the variation of using a tire from new condition down to 1/2" tread depth worn away. IF NOTHING ELSE CHANGED, YOUR MILEAGE WOULD VARY BY 1.5 MPG OVER TIME !!! Your indicated distance covered would make your mpg shift over time. Because your data is spread out over three years, we have zero idea of what condition the tires were in for any given fill-up.

My point is that there are so many inputs that you cannot accurately define your mpg down to a whole number, let alone hundredths; you've got too much missing info in terms of both magnitude and resolution. You cannot claim that you know what your true economy is using one brand of motor oil relative to another. Your data is incomplete and your methodology ignores very important key inputs that need to be understood.
 
Originally Posted by NO2
That doesn't make any sense. Oil would not cause a 10%+ fuel economy drop. It's likely coincidental.


Well, he said it was the M1 AFE, so... Take the ball and run with it..
 
Originally Posted by dnewton3
What I can tell is that you have fallen victim to the typical noob approach to mathematical statistics. This is a perfect example of the perfect storm; too little understanding of statistics combined with too little data causing one to draw inaccurate conclusions.

To know how your fuel mileage would truly track with oil brand, you'll need 30 samples of your full-tank fill ups with brand X, then another 30 with brand Y. You have to know not only the average, but the variation with each product. You only have 9 sets (2017), 6 sets (2018), and 9 sets (2019). That's well short of the 30 needed for each. Without accurate knowledge of the standard deviation (variation) you cannot understand how much overlap there is. This is not unlike the concept I try to educate folks about in the UOA normalcy study I wrote.

Your data shows many things that would cause concern to a person practicing good statistics:
- there is far too little data to understand variation properly; a prime violation of any statistical process analysis
- there's a large amount of disparity in how many miles are exhibited between the max and min data collection points (2018 shows only 12 mile spread in total miles per sample, but 2017 and 2019 are up near 100; this means you didn't drive near-identical cycles per fill-up for all tests)
- your resolution of stated values violates the mantra of reporting within your gauge accuracy; a magnitude of 10:1 (one decimal place) is acceptable (if you measure to the tenth of a value, then you can only report to the whole number ... etc)
- you have no calorimeter data for the fuel loads; this is paramount to knowing an input that should be corrected for. while you cannot control it, you have to correct for it and without knowing it's value, your assumptions are based on false presumptions. If you use E10 gas, it does not mean it always has 10% ethanol. It only means it has a max limit of 10% ethanol. Therefore the fuel can vary from 0% to 10% ethanol and you have no idea of the true BTU energy in the fuel.
- you don't show any data for accounting for tire wear. A tire's circumference will wear away, altering the true distance for any measured cycle relative to the indicated miles driven; up to 4% of tire circumference can be easily accounted for with only 1/2" of tread wear.

In fact, that last point is critical in knowing. Do the math ...
Using a tire that starts out at 27" in diameter, and degrades 1" in circumference (1/2" wear in depth is radius; 2x for diameter), you'll loose about 4% in tire circumference. (I am ignoring the compression of weight on the tire radius). Doesn't seem like a lot, does it? OK, then take your average miles per fill up and subtract 4% of miles. In this case, we'll presume your fill up shows 470 miles traveled. But the REAL miles traveled will vary greatly. Examples:
1) new tire indicates 470.00 miles traveled; actual driven is 470.00 miles divided by 13.00 gallons = 36.2 mpg
2) worn tire indicates 470.00 miles traveled; actual driven is 451.00 miles divided by that same 13.00 gallons = 34.7 mpg
This represents the variation of using a tire from new condition down to 1/2" tread depth worn away. IF NOTHING ELSE CHANGED, YOUR MILEAGE WOULD VARY BY 1.5 MPG OVER TIME !!! Your indicated distance covered would make your mpg shift over time. Because your data is spread out over three years, we have zero idea of what condition the tires were in for any given fill-up.

My point is that there are so many inputs that you cannot accurately define your mpg down to a whole number, let alone hundredths; you've got too much missing info in terms of both magnitude and resolution. You cannot claim that you know what your true economy is using one brand of motor oil relative to another. Your data is incomplete and your methodology ignores very important key inputs that need to be understood.




It says on the bottle "Make your fuel economy Great Again". All your statistical mumbo jumbo is fake news!
 
Originally Posted by E150GT
I don't know about fuel economy but I know when I switched my old.mazda 3 to mobil 1 the engine was louder.

My 09 altima as well. I tried 10-30 HM as opposed to anything 5-30 to slow down consumption and it used more oil and the engine was noticeably louder. At 3700 miles or so I drained it and refilled with PP 10-30, not high mileage and consumption is next to none through the 1st 1k and the car is so much quieter. I have nothing against Exxon but my Nissan doesn't like the stuff.
 
The things I've noticed that effect fuel economy are few, but weather is a big one with me. The colder it is, the worse my fuel economy gets. And if I use my heated seats or steering wheel, I can really see a difference...I can't average "good" fuel economy with those things on. AC too.

As far as oil goes...all I've noticed is some oils quiet the engine better than others, and some burn less oil than others. That's about it
 
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