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Summer fuel, most will notice an uptick in fuel economy right now. Warmer weather helps some too, cold air=more dense. More air=more fuel, as the computer adjusts fuel trim. Also shorter warmups in warmer weather.
Changed oil from 0W20 to 5W30 and ...
- Thread starter GraybeardQ60
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It's funny, I just made the switch on my current vehicle as well, and have not noticed a single drop in fuel economy. And I've also done it with a few vehicles and the past, and I've never had any sort of drop in fuel economy. Then again I'm only going from a 0W20 to a 5W30.
Because to even measure it (if there is any difference) would require a lab/testing facility and a dyno.
I won't debate the mpg increase, there are plenty of possible reasons why. I'll just say a smart move IMO switching to 5W30, and leave it at that. 
Also, the aerodynamics in colder weather is a factor as it's harder to push through the more dense, cooler air.
Royal Purple to Motul...hmmm.
Which Motul 5w30? EcoNergy or specific or ??
I am up 2.7mpg LTA also. Going from 5W20 to a 10W30 over a month ago; Same brand oil.
But:
a) Summer gas
b) Higher Tire pressure - I didn't adjust them - they did it themselves
c) Shorter warmup period
d) Warmer inlet air (less pumping losses)
I will say I ran Motul EcoNergy 5w30 back when it was a very lightweight oil before a reformulation.
My then Suzuki Aerio Wagon - through the brutal Winter - started and then ran during warm-up like the car was already fully warm. Pretty amazing.
On your second point, not so sure.
First and third absolutely
Zee09
$200 Site Donor 2023
My buddy got 60 quarts of 5w-30 on sale at TS. the other day and put it in his trunk and his mpgs went way down
That Suzuki in my post was a hot hatch at a bargain price. 155HP and a 5 speed made it fun.My buddy got 60 quarts of 5w-30 on sale at TS. the other day and put it in his trunk and his mpgs went way down
Yes it looked like a bagel toaster on "wittle weels" but ... ...
... HOT HATCH !
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No because I did not have enough cans to store all of the gas I saved.....
CAFE lies!
there's a lot of possibilities. sometimes people report that just an oil change alone seems to be more fuel saving. another possibility can be but there's speculation that the fueling is changing, you might also have used the pump after somebody who used a higher octane or non-ethanol used it previously. some but not all of it can be speculation or the seat of your pants feeling. they're changing to 5W-30 really did improve your fuel economy it could quite possibly be that it's keeping a better seal and you're not consuming as much. driving habits could change, the wind direction. I refuse to doubt anyone for seeing a increase in fuel mileage but there are many variables that go into it. I will congratulate you if you found a way to make your car more fuel economic. I do feel that motul is probably a high efficiency low hths oil so there's some thoughts on that. I'm sure interested and would be willing to listen to your observations, thoughts and beliefs. it's been said but a lot of Honda cars run good on a high Moly content oil but I don't know for myself. just do the best you can at keeping records and see if anything changed from your tire pressure too
