MPG GAIN with conventional oil vs synthetic!

[mechtech2]

The new oil is thinner, or has additives that you particular engine likes!

 

[Blue99]

Oh, I fully believe you acheived a .5 mpg gain on the Valvoline 5W-20, as you would with any friction modified GF-4 oil that has actually passed the GF-4 fuel economy test.

Just because the formulation uses synthetic base oils, this does not automatically guarantee "top shelf" fuel economy.

Remember, when M1 EP was initially launched, it did not meet GF-4 and by ExxonMobil's admission, it could not pass the fuel economy test, which is run against a PAO reference oil.

 

[PT1]

Bottom line: Valvoline is just that good.

 

[rpn453]

Quote:

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Yes, HTHS numbers appear to correlate with fuel mileage. Rather than the sloppy SAE scale, I think HTHS is a better indicator of how thick or thin an oil is.

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Given the consistent driving patterns and mileage records, I'm going with this theory. Normally I'd think it's a coincidence when people report mileage improvements after an oil change.

At 65-70 mph, the viscosity of the oil right at the bearings probably approaches that of the HTHS viscosity. The "energy conserving" tests are probably aimed more at low-speed driving, just like the EPA fuel economy tests, and don't account for higher oil temperatures as much.

 

[Auto-Union]

Audi and Castrol tested Syntec SLX 0w-30 and got a 3% gain in mpg over 15w-40, which had the same HT/HS.

 

[JHZR2]

I'd consider the right adds appealing to the metalurgy of your engine, and operating temperatures/viscoisties being just right to operate perfectlty...

If you have the latest spec oils, youre using an oil that is designed to enhance fuel economy in many applications.

JMH

 

[double vanos]

In my mind GRPIII based oils are not synthetic.....but they are the finest conventional oil money can buy.

 

[06VtecV6]

I went from 23 to 23.5 or so to a 25 mpg average going to Motorcraft. Amazing oil and it does exactly what it says on the bottle "Helps improve gas mileage"

And I was coming off a pretty good oil in its own right in the DC75k. I guess the MC just went in there and tore stuff up after the DC gingerly broke her in with kid gloves!

I love GRP II (+) and GRP III mixes better but that's *all* my car has seen as she's a full synthetic virgin.

 

[Titan]

I haven't change ANYTHING on my car, which I've driven 25000 miles in the past 6 months, and the MPG varies from 28-33.5...95% Highway. The past month, the MPG has increased steadily from just below 30 to about 32. Gas quality related? Perhaps. Temperature related...most probably. Wind direction related...definitely. My worst MPG was into a stiff cold wind out in Kansas....best was away from that same stiff wind.

I'm not saying some oil gives better efficiency, I'm just saying it's not accurate to state the level of efficiency on just one or two tankfuls....too many other variables.

 

[Pablo]

An oil with a lower viscosity (within working limits) will theoretically give better MPG.

An oil with a lower HTHS (within working limits) will theoretically give better MPG.

Given the same HTHS, the oil with the lower working viscosity will theoretically give better MPG.

Given the same HTHS and same working viscosity, the oil with better friction properties (lower via additives and base oils) will theoretically give better MPG.

 

[Bryanccfshr]

Accurate description Pablo.

 

[Pablo]

Thanks - it's generally true - but with MPG claims...well YMMV!!!