Just changed the Castrol Edge 0w-20 in my truck with about 7,000 miles on it and replaced it with the same. I rotated the tires and filled them up too, they were all about 4 psi low. After driving on the new oil for a few days, my mpg already went up 1 mpg, which isn't much. But I was just curious if I attribute this to the new oil or to the tires being inflated more?
7,000 miles on Castrol Edge
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My vote goes to the 4 psi of air going to the tires.
Originally Posted By: demarpaint
My vote goes to the 4 psi of air going to the tires.
That's what I was guessing too, but if it was the oil it makes me wonder.
My vote goes to the 4 psi of air going to the tires.
That's what I was guessing too, but if it was the oil it makes me wonder.
tires
In your case 0.65 mpg improvement was due to the tires and the remaining 0.35 mpg improvement was due to the new oil. Kira
There's no way to measure a 1 MPG gain or loss in real-world driving and attribute it to any single cause, especially when the poster admits to changing multiple variables.
Even if nothing was deliberately changed it's still in the noise. The fuel itself can vary that much in energy density tank-to-tank at the same station.
Even if nothing was deliberately changed it's still in the noise. The fuel itself can vary that much in energy density tank-to-tank at the same station.
I would squeeze another 40 psi in those tires and raise up the mpg 10 more.
Tires, especially since you used the same oil.
I am re evaluating what I posted earlier. 1 mpg can't be attributed to the tires or the oil. It could be a factor but there are so many other factors as well. For instance, I never get the same MPG every time I get gas. It's usually different by 1-2 mpg. Way too many factors....
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Originally Posted By: stower17
I am re evaluating what I posted earlier. 1 mpg can't be attributed to the tires or the oil. It could be a factor but there are so many other factors as well. For instance, I never get the same MPG every time I get gas. It's usually different by 1-2 mpg. Way too many factors....
Whether you can measure it accurately or not at the gas pump, low tire pressure does cause greater drag from rolling resistance. The effect is there from tires, and 4 psi can give you about 1% to 3% ballpark range of decreased MPG.
I am re evaluating what I posted earlier. 1 mpg can't be attributed to the tires or the oil. It could be a factor but there are so many other factors as well. For instance, I never get the same MPG every time I get gas. It's usually different by 1-2 mpg. Way too many factors....
Whether you can measure it accurately or not at the gas pump, low tire pressure does cause greater drag from rolling resistance. The effect is there from tires, and 4 psi can give you about 1% to 3% ballpark range of decreased MPG.
In this instance had many others have said the increase is due to your tires. I have seen increases in my mpg with new oil of over 1 mpg. I have run my car on the exact same stretch of road on route 5 where it is perfectly straight and flat for 2.8 miles in the country averaging 64mph. New oil = 29.3 to 29.9 mpg. Old oil with 5k miles = 28.1 to 28.8. I have done this well about 30 times. The only time I had numbers that were WAY off was when there was a significant headwind and tailwind. 31.7 and 27.3. All of the other times the numbers are so consistent that it is significant in my opinion. If something is that repeatable ( over two dozen times plus) then there may well be something to it. I have used this stretch of road as a testing ground just for the fact it's straight, flat, and no other traffic around or coming onto the highway. Yes of course the air temp, road temp and some slight wind can have some effect. But the striking similar numbers time after time have given me a range to expect. Which it has panned out that way.
But again in your case the tires are far more likely to be the cause in this increase.
But again in your case the tires are far more likely to be the cause in this increase.
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In my focus; the edge that's SM, I am pleased with it so far. Pushing this run to 9,000, then putting the SN edge in. I average 36.8 as my driving is mostly highway. We'll see if the snow tires hurt mileage
Thanks for all the replies!
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