what caused my 3 mpg increase?

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at 90k i did 3 things as maintance on the 2011 crv new tires valve adjustment oil change with pup 5 -20 . last one was 5-30 castrol mangnatec i was getting about 19.5 mpg according to the computer before these things were done. now i get about 22.5 .3 mpg more. i am wondering which of these 3 things caused the mpg increase. or is it a combo of all three?
 
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JC1

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Maybe the old tires were under inflated? Could be a a combo of all three or did you change your driving style or you did more hwy miles as well?
 
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I would say the oil would be the least effective on fuel economy. Tires would be my guess. Maybe your old tires were not inflated properly?
 

WhyMe

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Originally Posted By: JC1
Maybe the old tires were under inflated? Could be a a combo of all three or did you change your driving style or you did more hwy miles as well?
nope drive the same. i check it over 3 fill ups. i check the tires all the time. i am curious if its the oil as i beleve pennzoil states there will be a mileage increase when using it
 
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Over what number of tanks have you seen this improvement in observed fuel mileage? I can't see the things that you've done yielding a 15% improvement in fuel economy. I suspect that you're observing a fluke that will revert to the mean.
 

JHZR2

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Same tire size? Bet you got less resistive tires, running thinner oil, and are breatihing/running more efficient due to the valves.
 

WhyMe

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same tire size rt 43 general. i just filled up at costco and am at 22.7 over 20 miles 50/50.i get gas at the same costco allthe time.
 

gathermewool

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New tires typically give me worse gas mileage (squirmier tread). How much did you have to adjust the valves. The amount of adjustment needed is a pretty important detail to leave out, don't you think???
 
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Leaving differences of rolling resistance between two different makes of tire aside, rolling resistance increases with tread depth so new tires seem unlikely to have contributed to the improvement in MPG, quite the opposite. Not sure what you mean by valve adjustment but on old engines without hydraulic lifters changing the valve clearances makes small but real changes to valve timing, lift and most important for low rev efficiency - overlap.
 

WhyMe

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Originally Posted By: gathermewool
New tires typically give me worse gas mileage (squirmier tread). How much did you have to adjust the valves. The amount of adjustment needed is a pretty important detail to leave out, don't you think???
a few of the intake were tight and a few exhaust loose. pretty common on this engine. i just set them to the mid of specs
 
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Tailwinds? Only kidding. Valve adjustment = better Possibility of new rubber being "brighter" = possibly better Maybe your Costco is getting gas with less ethanol = possibly better Keep on measuring. I do "hard" mileage tallies every month. I start and end each month with a fill-up. Total miles for the month divided by gallons. I understand that the electronic gadgets in our cars is real groovy now-a-days but I still won't fully trust 'em. A low pressure system came through which gave me a tailwind on both legs of a round trip. My 27-28 highway mpg became 35.
 
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Originally Posted By: CharlieBauer
I noticed an mpg increase when going from nearly worn out summer tires to new all seasons.
Brain [censored]. I meant to say an mpg decrease!
 
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