Is synthetic oil really improve MPG?

[wolf_06]

Just got a chevy cruze and of course I need to follow the dexos1 specification for warranty.

It mention in the dexos1 description that full synthetic improve fuel economy.
How true is this?

I run AC Delco semi-synthetic, should I run full syn? would it be a bit better on gas?

What do you guys think?

 

[Hyde244]

The thickness of the oil is the "biggest" factor to fuel economy, not synthetic vs. conventional. Even then, oil thickness is nowhere near as large a driving habits in gas mileage.

Just buy dexos1, and you are set.

 

[Donald]

Yes, but in theory only. If might help also if you considered the viscosity of a dino 10W30 and a synthetic 10W30 at say 5000 miles.

 

[ChemicallyChargd]

Yes, synthetic oil is more sloppy than conventional, it's also more resistant to oxidation/heat breakdown, it's better at doin oils job transferring heat from hot spots to cold spots. Synthetic won't form as much waxes and will always flow better than a comparable dino oil on cold starts. It's really too cheap to not use, M1 5qt jug of synthetic @ wal mart is only like $25, w/ a good filter maybe $35 total if you do it yourself, I'm sure there's even cheaper synthetic, but u get wut u pay for. In the tranny, there's no single upgrade you can do that will be better than using a synthetic, and you'll get longer service life out of it, amsoil offers a both universal ATF for most vehicles, and a low-viscosity version for fuel efficiency and several vehicles that require the low-viscosity (mercon SP). Also remember the 3000 mile OCI came from the 60's and today is a downright waste of perfectly good oil that can't be replaced environmentally, any oil that meets latest specs can go 5000 easy, easy, oil molecules never wear out, ever, only the additives get used up, which is why you change it. I go 10,000 and oil analysis shows my wear metals are nearly non existent (amsoil SS 0w-30@12,000mi--iron-11, copper-2, alum-4, lead-0, tin-2, cst viscosity @100C-10.9, oil actually got a little thicker) analysis via Blackstone.
-srv

 

[Rolla07]

Originally Posted By: Hyde244
The thickness of the oil is the "biggest" factor to fuel economy, not synthetic vs. conventional. Even then, oil thickness is nowhere near as large a driving habits in gas mileage.

Just buy dexos1, and you are set.


+1

I switched to syn and noticed no noticeable difference. You can measure your mileage and try full syn for a couple oci's and see if any difference, but i doubt it.

 

[ChemicallyChargd]

I had run a 30wt for the first 164,000no, I just made the switch to amsoil's SS 0w-20 instead of my usual 0w-30, like so many I was convinced after reading the best article I've read on oil. Dr. Haas' "motor oil 101" which can be found here on this site. I'm 500 miles in and so far I'm quite impressed, my mpg went up (measured via ScangaugeE) the engine doesn't feel drugged when I go up higher in the power band(above 4k). If oil analysis shows no higher wear or other warnings, which I'm very confident it wont, then I'm sold on the 20 and will run it as long as available. I was slightly concerned oil consumption may rise a little but so far no noticeable change,(it was only burning 1qt over 10,000 to begin w/).

 

[Doog]

Run synthetic if you:

1. Plan to keep the car to 200,000 miles or more
2. want a clean engine
3. want to pick up an additional 1/2 mpg
4. have female drivers who sit and idle for hours during an OCI picking up kids etc. that throws your ordinary OCI into severe service level.

 

[Smokescreen]

I can say give comparing same weight conventional vs synthetic that without question that synthetic oil does not increase fuel economy given operating temperature are relatively warm 10C to 40C, colder temperatures I haven't and probably will not try.

I have been running synthetic for over 100K miles and have recently switched to conventional and there has been no change. Deep down I was really hoping that there would be in favor of syn after all this distance and money...but there just isn't any to be had. Driving style terrain everything being equal (yes, it is true, my commute is that boring and predictable hence I drive a Corolla...and 95% highway so there is little if no variation.

If you fall in the category of relatively warm climate, want to keep your car's engine clean forever..use conventional synthetic will make no difference. Sorry Doog, its just not true. Severe service just shorten the interval...conventionals are pretty much semi-synthetic anyway.

If you have a female drive that sits there idling away, she needs to be educated, or else have the keys taken away.

 

[Durango]

Originally Posted By: wolf_06
Just got a chevy cruze and of course I need to follow the dexos1 specification for warranty.

It mention in the dexos1 description that full synthetic improve fuel economy.
How true is this?

I run AC Delco semi-synthetic, should I run full syn? would it be a bit better on gas?

What do you guys think?


wolf_06,

I run full synthtic in both my car/truck cuz now a days oils have changed allot and the frequency of the OCI's are much longer than the old every 3K services. In my Impala I go strictly by the OLM monitor and it tell me to have my oil changed about every 6 months based on my driving habits. I just want a little extra insurance due to this.

Since your Cruz is new your mileage will improve allot once you get some miles on it odometer so for now don't worry about it too much until for first OCI. The main thing is not to void your warranty.

Durango

 

[sciphi]

If the semi-syn is a lot cheaper than the full syn where you are in Canada, I'd run the semi-syn. The naturally aspirated 1.8l in your Cruze LS does just fine on semi-syn dexos1 oil. UOA's have shown it to be easy on oil.

Now if you picked up a Cruze LT/Eco/LTZ with the turbocharged 1.4l engine, I'd be telling you to use full synthetic dexos1 and dump it at 7500 miles. Those engines are markedly harder on oil than the 1.8, and need the extra protection of a full synthetic oil.

 

[Quattro Pete]

Originally Posted By: ChemicallyChargd
Yes, synthetic oil is more sloppy than conventional,

Slippery?

 

[99Saturn]

sciphi - Just curious, on the semi synthetic UOA's you've seen for the 1.8l, is the miles run in the 7,500/OLM at 0% range or is it getting dumped early?

 

[FZ1]

Originally Posted By: Smokescreen
I can say give comparing same weight conventional vs synthetic that without question that synthetic oil does not increase fuel economy given operating temperature are relatively warm 10C to 40C, colder temperatures I haven't and probably will not try.

I have been running synthetic for over 100K miles and have recently switched to conventional and there has been no change. Deep down I was really hoping that there would be in favor of syn after all this distance and money...but there just isn't any to be had. Driving style terrain everything being equal (yes, it is true, my commute is that boring and predictable hence I drive a Corolla...and 95% highway so there is little if no variation.

If you fall in the category of relatively warm climate, want to keep your car's engine clean forever..use conventional synthetic will make no difference. Sorry Doog, its just not true. Severe service just shorten the interval...conventionals are pretty much semi-synthetic anyway.

If you have a female drive that sits there idling away, she needs to be educated, or else have the keys taken away.

Not true,for you. That's all that you can,accurately,state. Some of us notice a slight increase in mpg.

 

[dave1251]

Originally Posted By: FZ1
Originally Posted By: Smokescreen
I can say give comparing same weight conventional vs synthetic that without question that synthetic oil does not increase fuel economy given operating temperature are relatively warm 10C to 40C, colder temperatures I haven't and probably will not try.

I have been running synthetic for over 100K miles and have recently switched to conventional and there has been no change. Deep down I was really hoping that there would be in favor of syn after all this distance and money...but there just isn't any to be had. Driving style terrain everything being equal (yes, it is true, my commute is that boring and predictable hence I drive a Corolla...and 95% highway so there is little if no variation.

If you fall in the category of relatively warm climate, want to keep your car's engine clean forever..use conventional synthetic will make no difference. Sorry Doog, its just not true. Severe service just shorten the interval...conventionals are pretty much semi-synthetic anyway.

If you have a female drive that sits there idling away, she needs to be educated, or else have the keys taken away.

Not true,for you. That's all that you can,accurately,state. Some of us notice a slight increase in mpg.


The truth is it not verifiable and that goes to at least 1995 when their was a very measurable performance difference between synthetic and conventional compared to today. The study from Ford and Honda engineer's found that grade and FM additives such as moly had a much greater determining factor in MPG performance than synthetic vs conventional.

www.fueleconomy.gov/feg/.../OwnerRelatedFuelEconomyImprovements.pdf.

I am sure a professional that makes their living at studying lubricants and the relationship lubricants has in a IC engine can explain how this makes sense not simply synthetic is "superior" at lubricating.

 

[Clevy]

During the warmer summer months I doubt very much that a fuel consumption difference would be measurable when comparing oils of the same grade,conventional or synthetic.
Winter and extremely cold temps is where a difference might be noticeable. I think that there would be more of a noticeable consumption difference depending on the levels of friction modifiers in the oil,not whether its conventional or synthetic.
Truth be known my hemi gets its best mileage with pyb vs any other oil I've used in it. I ad mos2 to everything too though.

 

[Capa]

Originally Posted By: dave1251


The truth is it not verifiable and that goes to at least 1995 when their was a very measurable performance difference between synthetic and conventional compared to today. The study from Ford and Honda engineer's found that grade and FM additives such as moly had a much greater determining factor in MPG performance than synthetic vs conventional


Bingo! Moly, the FM additives, viscocity index, etc. all contribute to slightly superior MPG. Generally, synthetics tend to have more FM additives, moly (or the superior tri-nuclear type), and sometimes a significant better viscocity index than conventional oils and all of these contribute to improved mileage.

I currently have Mobil AFE 0W-20 in one of my vehicles and they claim up to a 2% boost of MPG and so the gains are never going to be significant. I'm still waiting for someone to sue Mobil to have that claim removed from their bottle like when Castrol called Royal Purple's bluff and they were forced to remove their increased horsepower and better MPG claims from their bottles. Not going to happen with Mobil!

 

[SteveSRT8]

And no matter what the differences between synth and dino are much smaller than they used to be!

 

[BillyTheKid]

Plain and simple answer, in the real world its HIGHLY unlikely you will see a different. Keeping or adding the proper air pressure in tires will net more of a gain. Real world testing is not consistent enough every single day to give you a real reading. You are not on cruise control on the same roads each tank full day after day, month after month.

 

[Tzu]

I switched over to synthetic when both of our vehicles were about 120,000 miles. Today, they each average 230,000 miles. I have noticed no measureable increase in mpgs. I changed over only to reduce some noise in my GM 5.3. I recently switched back to coventional and (to my ears), I cannot tell a difference in sound, idle smoothness or fuel economy. I might run a syn. blend during winter and go back to dino in spring. That's my 2 cents.

 

[FZ1]

Originally Posted By: dave1251
Originally Posted By: FZ1
Originally Posted By: Smokescreen
I can say give comparing same weight conventional vs synthetic that without question that synthetic oil does not increase fuel economy given operating temperature are relatively warm 10C to 40C, colder temperatures I haven't and probably will not try.

I have been running synthetic for over 100K miles and have recently switched to conventional and there has been no change. Deep down I was really hoping that there would be in favor of syn after all this distance and money...but there just isn't any to be had. Driving style terrain everything being equal (yes, it is true, my commute is that boring and predictable hence I drive a Corolla...and 95% highway so there is little if no variation.

If you fall in the category of relatively warm climate, want to keep your car's engine clean forever..use conventional synthetic will make no difference. Sorry Doog, its just not true. Severe service just shorten the interval...conventionals are pretty much semi-synthetic anyway.

If you have a female drive that sits there idling away, she needs to be educated, or else have the keys taken away.

Not true,for you. That's all that you can,accurately,state. Some of us notice a slight increase in mpg.


The truth is it not verifiable and that goes to at least 1995 when their was a very measurable performance difference between synthetic and conventional compared to today. The study from Ford and Honda engineer's found that grade and FM additives such as moly had a much greater determining factor in MPG performance than synthetic vs conventional.

www.fueleconomy.gov/feg/.../OwnerRelatedFuelEconomyImprovements.pdf.

I am sure a professional that makes their living at studying lubricants and the relationship lubricants has in a IC engine can explain how this makes sense not simply synthetic is "superior" at lubricating.
My point is;a Specific Result is a Specific Result. I agree that newer,higher,oil standards may cause the difference be small to non measureable. Your mpg may vary. Lol.