Fresh oil= Better mileage?

[friendly_jacek]

Originally Posted By: fdcg27

It appears that FMs are required to make the really light oils suitable for use.
I would therefore expect that any 20 grade would have a healthy dose of FMs, and any starburst oil would as well.
I didn't look far enough to tell you how long these additives last.


I remember reading a SAE paper that dealt with the issue of loss of FM quality of oils formulated with Mo by oxidation.

Here is the link to abstract: http://papers.sae.org/971694

 

[Kira]

Hello, A relative visited a testing facility which had a room full of engines running 24 hours a day. They were testing for oil companies. I can't believe there isn't a huge body of data regarding fresh vs. old oil.
A Chevy Volt with a golf ball finish is EXACTLY the car I've been waiting for. Kira

 

[Solarent]

Oil changes that relate to improved fuel economy relate to various reasons:

-1-over time the viscosity of the oil changes and sometimes it can effect fuel economy
-2-contaminants in oil sometimes can cause blockages that prevent oil from alleviating frictional losses from various important components
-3-new oil filters have better flow capabilities (this is a big generalization)
-4-as said by everyone else when you start taking better care of your car (oil changes, car washes etc) you usually change some of your driving habits - even briefly allowing for fleeting improvements in economy.

this doesn't happen with everybody.

 

[Quest]

placebo effect.

The feel-good factor is playing mind jokes + fresh oil change == feel good.

Kinda like folks feeling better after a nice shower..

*grin*

Q.

 

[Jim Allen]

I think you dug pretty deep into the obscure to come up with this some items on this list.

Originally Posted By: Solarent
Oil changes that relate to improved fuel economy relate to various reasons:

-1-over time the viscosity of the oil changes and sometimes it can effect fuel economy

* True. The oil usually thins first, which could have a beneficial effect on fuel economy. It may thicken later if oxidative byproducts or insolubles (soot in diesels) build upand that might lead to a fractional loss of mpg.

-2-contaminants in oil sometimes can cause blockages that prevent oil from alleviating frictional losses from various important components

* How so? Any significant loss of oil flow, and thus a significant increase in frictional HP loss, and the engine dies in short order.

-3-new oil filters have better flow capabilities (this is a big generalization)

* Even a completely plugged and bypassed oil filter couldn't cause enough restriction to change fuel economy in any owner noticeable way.

-4-as said by everyone else when you start taking better care of your car (oil changes, car washes etc) you usually change some of your driving habits - even briefly allowing for fleeting improvements in economy. this doesn't happen with everybody.

* Some subjective truth to this.

 

[Solarent]

Originally Posted By: Jim Allen
In theory, and likely in reality, there is slightly better MPG with fresh oil vs oil for the reasons given. It's got to be a fractional gain at best, given how narrow the mpg margins are with viscosity changes... which would probably have more effect on mpg.

What I am more certain of is that whatever differences there are, they cannot be determined accurately using normal DIY methods (e.g. gallons used, miles driven, ordinary pump fuel) because there are too many variables and inaccuracies. We've spelled those variable out before in other discussions, so I won't belabor them again. Most of you know what they are.


I am in 100% agreement with this statement. I do want to qualify points 2 & 3 in my original post so you can see where I am coming from:

#2 Contaminants - just as oxidative by-products with regards to viscosity changes can effect mpg, so to can some contaminants. I agree with your statement that any significant loss of flow can quickly cause engine death; but temporary blockages and contaminants can cause intermittent failures and thus frictional losses in some engine components without killing the whole thing. I should stress that this is not going to hugely alter your mpg but it can SOMETIMES have a small impact

#3 Filters - like I said originally this is a big generalization and as you stated an owner probably wouldn't notice a significant difference in a dirty or plugged filter vs a new one.

In offering up this information I just wanted to provide some basic principles that can actually effect fuel economy. As mentioned by someone else above the Sequence VID test for the SN Fuel Economy endorsement allows for a general decrease in fuel economy improvement as the oil ages and these issues are some of what gets focused on in terms of cause/effect to ensure an oil meets those qualifications.

I would never try to quantify a mpg increase based on new oil vs used oil based on DIY methods but the OP asked if it was possible on to get better mileage on new oil and the short answer is yes, and these are some of the reasons.



On a personal note, Jim, thank you for your input on my post. That's why I finally joined BITOG after about a year of just casual browsing, I hope that my posts can contribute positively to the bitoger dialogues.

 

[Jim Allen]

Solarent: Glad you're here. Anything that steers us away from "my brand's better than yours" stuff is most welcome in my book.

That said, please allow me to tear your liver out... ( : < )

RE #2- You Said- "Contaminants - just as oxidative by-products with regards to viscosity changes can effect mpg, so to can some contaminants. I agree with your statement that any significant loss of flow can quickly cause engine death; but temporary blockages and contaminants can cause intermittent failures and thus frictional losses in some engine components without killing the whole thing. I should stress that this is not going to hugely alter your mpg but it can SOMETIMES have a small impact."

You are picking at microscopic hypothetical nits here, my friend. There is a very sharp line between "enough oil" and "not enough oil." I doubt there are any studies on this but based on what I know at present, the point at which friction increases enough to make a difference in fuel economy is exactly the same point an engine's death warrant is signed.

#3- You said, "- like I said originally this is a big generalization and as you stated an owner probably wouldn't notice a significant difference in a dirty or plugged filter vs a new one."

You are forgetting one very important aspect of lube flow in the engine: The filter is nowhere near the major restriction in the lube system. Those restrictions are downstream of the filter. Within the world of the filter, I think you'd need to look at the PSID and bypass pressures of the filter and look at how much power is lost at the oil pump potentially adding 10-15 PSI to the normal load (10-15 PSI is a common filter bypass setting) from an extremely plugged filter. Most engines don't develop enough contaminants in one or two OCIs to significantly load a filter, let along put it into bypass. If 10 psi added .5 hp loss to a 150 hp engine (and that's a WAG... I have no idea really), how much mpg loss would that translate to? I submit an insignificant amount, if at all measurable by any means beyond the most pedantic.

 

[Solarent]

Jim
You make very good points; again I was only trying to point out that when it comes to fuel economy improving oil that these are some of the considerations.

Let's also not forget that there are many power transfer points between the engine and the rubber to the road so to speak that you can have fuel economy positives and negatives all along the way. So really engine oil is just one of a list of many that relates to fuel economy (albeit an important one.)

all that said: anyone know where I can get a new liver? it appears I may be missing mine.....

ps...here's an article on the subject

 

[Jim Allen]

A good article referenced that's been in my files for a while too. Fitch relates extra friction to extra wear and worn parts (especially rings, valves cams, etc) will definitely effect fuel economy over time. THis is why I now have a bypass filter on my truck... in which I will likely be buried.

 

[Astro14]

There are so many variables in MPG that street or commuter driving results are almost meaningless. Temperature, traffic flow, wind direction and speed, acceleration rate, top speed - all affect mileage, it's hard to control or account for all those things...

That said, I always notice a slight increase in MPG (which I check on every fill-up...yep, I am that retentive...) after an oil change.

But I figure it's due to the 12 OZ of fuel injector cleaner I add at the same time. I have, in effect, added 0.1 gallons of unaccounted for fuel...so, the MPG goes up just a hair...now, if I added 3 or 4 cans of FI cleaner, I bet I could get a measurable bump in MPG!

 

[Jeff_in_VABch]

Originally Posted By: cchase
Originally Posted By: Jim Allen
Originally Posted By: OtisBlkR1
Originally Posted By: MetalSlug
dirty car have no effect on gas miles. Those guy at mythbuster did the test and it make no different between clean and dirty car.


Mythbusters also tested the theory of no tailgate on pickups and said it makes no difference if the tailgate was up or down.. I CALL B.S. on the same roads daily there is a small but notable improvement in mpg with the gate down at highwayspeeds . and mythbusters can talk all they want, a car with a good smooth wax applied V.S. a never washed rough to the touch finish ? country boy logic says smooth things cut air easier, even if its only 1/1,000 of a mpg difference i have to believe there is a small gain to be had.. mythbusters logic bull-#@#!


Incorrect. Mythbusters said MPG was slightly better with tailgate up. The EPA and others say the same thing. If you search the web, you will find a great wind tunnel test that proves it and actually shows how it works. Country boy logic, otherwise know as WAG-ing, doesn't trump real logic.


I noticed a substantial decrease in fuel mileage when I had the tailgate down on my truck (on the order of 0.5 to 1 mpg loss) over the same driving routines.


Same here, loss in MPG with tailgate down.

 

[tonycarguy]

if people wanted to do something simple to gain MPG, just remove useless junk from the car and go on a diet. I see some cars packed with junk, plus the driver has a 2nd spare tire in the driver's seat if you know what I mean. I think to myself, if they got rid of the junk and lost 125 lbs, they'd probably gain 5+ mpg.

 

[fpracha]

Originally Posted By: Jim Allen
A good article referenced that's been in my files for a while too. Fitch relates extra friction to extra wear and worn parts (especially rings, valves cams, etc) will definitely effect fuel economy over time. THis is why I now have a bypass filter on my truck... in which I will likely be buried.

Quite true and it would be most appropriate to change the topic of this post to "Cleaner Oil= Better mileage, all else being equal".