Fresh oil= Better mileage?

[08_SHELBY]

Originally Posted By: BobFout
Originally Posted By: Popinski
Originally Posted By: needsducktape
Read: Also people feel like their cars perform better right after a car wash.


I'm guilty of this. It feels like my car has better acceleration after a wash and wax.


Mine does too. More aerodynamic!


A few years back some Indy 500 teams stopped using decals on the cars and painted the sponsors names on the car then clear coated over them to prevent excess drag. Also there is a pit crew member during practice and qualification days that just keeps the car spotless. Clean must be faster! Penske started this tradition here at Indy now they all do it.

 

[ammolab]

The way some oils shear down a grade or two...

M1 15W-50 went to a 30wt in my BMW Bike...

You should be getting better mileage on the OLD oil.

 

[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.

 

[WMSmotorhead]

Back on the main topic, I will say my work car idles better when the oil is fresh... the MPG difference is minimal, but I would believe that a heavily used oil may fall out of MFG spec, and thus lead to degraded performance. The goal is to change it before it starts to degrade too much.

 

[mongo161]

IMO....I guess that is where TAN helps in an oil analysis. When the TBN and TAN numbers meet and become equal, that must be the optimal time for an OCI.


Originally Posted By: WMSmotorhead
Back on the main topic, I will say my work car idles better when the oil is fresh... the MPG difference is minimal, but I would believe that a heavily used oil may fall out of MFG spec, and thus lead to degraded performance. The goal is to change it before it starts to degrade too much.

 

[Jim Allen]

If better MPG is ncpticable after an oil change (using the "stone knives and bearskins" methods we commonly use), then going from 5W30 to 5W20 should produce very significant increases. But it doesn't seem to.

 

[fdcg27]

Originally Posted By: Jim Allen
If better MPG is ncpticable after an oil change (using the "stone knives and bearskins" methods we commonly use), then going from 5W30 to 5W20 should produce very significant increases. But it doesn't seem to.


I don't know.
In the one application in which I tried 5W-20, all I saw was a small increase in consumption over a 4K OCI.
I think there is more involved than merely comparing grade and HTHS.
I thought that a fifty grade would kill the little four's fuel economy.
I just wanted to use the oil from my stash and be done with it.
Imagine my surprise when this oil actually yielded consistently lower fuel consumption than the car had on a 15W-40 HDEO.
As of today, I'm 3K into the run of M1 15W-50, and fuel economy has averaged >30mpg, which I have not seen before.
I don't think I imagined this.

 

[OtisBlkR1]

Originally Posted By: needsducktape
Read: Also people feel like their cars perform better right after a car wash.


ROTFLMAO........

 

[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-#@#!

 

[surfstar]

REAL numbers - 150 tanks of gas worth and no provable difference: Old BITOG thread

"Some people have anecdotally stated that "my MPG decreases as my oil gets more miles on it", and I would prefer to have numbers to put with the claims. Luckily I got numbers, tons and tons of numbers. I went back over my MPG data from 120k – 180k miles, as the numbers have the least variables, including the same set of tires for that time. I then looked at my oil change dates/mileage and put them together and looked at the MPG related to how many miles were on the oil. The first set was interesting:

Miles on Oil / Average MPG / count
0000-1500 / 33.93 / 42
1500-3000 / 33.81 / 48
3000-5000 / 33.65 / 60

The MPG does seem to decrease as the miles on the oil increase. So I broke it down farther and got this:

Miles on Oil / Average MPG / count
0000-1000 / 33.93 / 27
1000-2000 / 33.91 / 30
2000-3000 / 33.76 / 33
3000-4000 / 33.67 / 29
4000-5000 / 33.74 / 29
5000-6000 / 32.11 / 2

Unfortunately you can’t give credit to the 32.11MPG average for 5-6k miles, as there are only 2 data points, which is not nearly enough to allow for variance. It almost appears as though MPG DOES decrease with more miles on the oil. Although the variance between them is so small that it is not significant statistically.
Other points:
Oil was M1 10w30 for all but two OCI, which was a mix of M1 10w30 and EP 5w30.
Yes I do like playing with data sets.
And yes I do have a lot of spare time at work. Here’s to BITOG"

Another post of mine from that thread:

"The data was for 150 tanks of gas, so thats pretty extensive and although there is the .2-.3 decreasing trend, you have to look at the standard deviations of these averages, which are all over 1.0. So although the averages look like they might decline, the raw MPG data ranges from 31-36."

 

[TFB1]

Well Castrol has recently been advertising their oils maintain max HP output longer than other brands... If this is truly the case, would mean(at least to me)that there is less internal friction which would translate to a increase in mileage...

 

[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.

 

[A_Harman]

There actually is some validity to the proposition that fuel economy improves immediately after an oil change, but degrades during an OCI, and it is actually specified in the ILSAC GF-5 oil standards.

To receive the fuel-economy endorsement an oil must pass the Sequence VID test and show the following performance:

Xw20 oils: Fuel Economy Improvement 2.6% min., and 1.2% after 100 hours aging.
Xw30 oils: 1.9% min FEI, and 0.9% after 100 hours aging.
10w30 oils: 1.5% min FEI, and 0.6% after 100 hours aging.

Going from the above standards, it seems that ~1-1.4% loss in fuel economy can be expected over 4-5000 miles after an oil change. The initial fuel economy improvement would depend on the oil grade before the change. I believe that the reference oil that is used as baseline in ILSAC testing is a 10w40. Therefore it would be expected that any 20 or 30-grade would give an improvement.

 

[bruckus]

When I started this posting I figured everyone would think I was nuts. I am glad that there are some believers. I check my mileage on my vehicles every tank. I do believe that there is a mileage increase with fresh oil. Now to take this to the next level. My 2001 civic with 285,000 miles has an increase in mileage when there is fresh oil but also uses less oil when it is fresh. I use synthetic , usually different varieties depending whats on sale. I change about every 7500 miles. I have to add about 1/4 qt for the first 3000 miles but then need to add the rest of the qt somewhere within the change interval. Does one tend to use more oil as it gets older or does this just prove I am nuttier than originally thought. Thanks.

 

[fdcg27]

You may well see increased consumption later in an OCI as a result of loss of viscosity due to shearing as well as fuel dilution.
The only car I have had in some years that shows real consumption is the old BMW, and your observation may hold true for it, although after only 14K miles in my hands, I'm not sure.

 

[Mr Nice]

Originally Posted By: ammolab
The way some oils shear down a grade or two...
M1 15W-50 went to a 30wt in my BMW Bike...
You should be getting better mileage on the OLD oil.


Thats exactly what I was about to say.

 

[TFB1]

Originally Posted By: LT4 Vette
Originally Posted By: ammolab
The way some oils shear down a grade or two...
M1 15W-50 went to a 30wt in my BMW Bike...
You should be getting better mileage on the OLD oil.


Thats exactly what I was about to say.



Likely not if the anti-wear additive pack is depleted...

 

[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.

 

[saltyroads]

I got a 1996 Cadillac fleetwood running m1 syn. Its about due for an oil change so I'll keep an eye on the mpg it uses with the scanguage II. I drive 104 miles /day round trip to school and back. Its got 133k miles on it right now. I've rebuilt the trans, new sparkplugs, pcv, tps sensor, changed out the egr and smog pump (which is electric so no drag on the motor) so the car is running in top shape.

I've had the average as high as 25.8mpg and low as 20 mpg

 

[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.