Just wondering. I see a lot of anecdotal evidence, but is there any hard data from carefully-controlled tests?
Troy
Troy
Does Synthetic Oil increase MPGs?
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If there was, the US automakers would be using it as factory fill for the EPA mileage tests. They don't.
Patman
Staff member
I've never noticed any significant increase in MPG on any of my cars when switching over from dino to synthetic.
JHZR2
Staff member
In my 83 MB 300D-turbo, I used dino exclusively, and averaged around 26.5, with a vide range going from around 25-29mpg. After switching to delvac 1, doing the same type of driving as ever, I had a very tight MPG range, always between 28.6 and 28.9. With dino once or twice I hit over 30 mpg, but rarely, with delvac, I couldnt do 30, but it was always in that tight range, no matter what.
My trips were always the same and long, and I always drove the same style.
In my BMW, using 15w-50 (which is a reccomended viscosity) M1, I could never get above 27 MPG, whereas with a dino 15w-40, I can easily average 30 MPG.
I think it depends upon the vehicle, some it helps, others it may not. I think viscosity used also makes a difference, as the 50 wt in the 4cyl BMW was just too much viscous drag (although a reccomended viscoity.
JMH
My trips were always the same and long, and I always drove the same style.
In my BMW, using 15w-50 (which is a reccomended viscosity) M1, I could never get above 27 MPG, whereas with a dino 15w-40, I can easily average 30 MPG.
I think it depends upon the vehicle, some it helps, others it may not. I think viscosity used also makes a difference, as the 50 wt in the 4cyl BMW was just too much viscous drag (although a reccomended viscoity.
JMH
All things being equal...ie. brand and viscosity, my answer would be yes. But, not by a milestone....maybe .5-1mpg...more if tranny and diff. were also synth.. Kinda like increasing tire psi. if you will. The molecules are more uniform with less (or no) impurities to inhibit flow and lubrication should result in a lowered overall coefficient of friction (my guess) in addition to better flow rates when cold.
Howdy,
My 2002 vw will give an average MPG for up to 99 hours of operation, so I think it gives a true picture of my economy. That said, when I switched from 5w30 Castrol GTX to Amsoil 5w30 ASL my milage went from 26.4 MPG to 26.8 MPG. the car also took longer to heat up. My avg. MPH was the same for both readings.
Joe
My 2002 vw will give an average MPG for up to 99 hours of operation, so I think it gives a true picture of my economy. That said, when I switched from 5w30 Castrol GTX to Amsoil 5w30 ASL my milage went from 26.4 MPG to 26.8 MPG. the car also took longer to heat up. My avg. MPH was the same for both readings.
Joe
Think for a moment. Is there any metal to metal contact when using any oil dino or synthetic. NO! So friction is not it. It's better sealing of the piston rings because synthetics has some additive that makes them seal better. I felt this extra power right away after pouring in Royal Purple 15w40 after of my breakin Delo 400. This was right after I backed out of the driveway and hit the throttle the first time. Another evidence of this better sealing is less blowby. My oil is staying clean way longer. Almost have 4000 miles on it and it still very light brown on the dipstick. Oil clings to my dipstick like a blob of thick film.
I'm getting at least 1.5 mpg more with sythetics because of this extra power.
Leo
[ May 22, 2003, 11:08 PM: Message edited by: pedaltothemetal ]
I'm getting at least 1.5 mpg more with sythetics because of this extra power.
Leo
[ May 22, 2003, 11:08 PM: Message edited by: pedaltothemetal ]
Here's a useful link about increasing MPG. The following devices actually worked:
Accessory Drive Modifiers. These devices reduce power to specific auto accessories. The EPA has evaluated: Morse Constant Speed Accessory Drive**; P.A.S.S. Kit**; PASS Master Vehicle Air Conditioner**.
Driving Habit Modifiers. These are lights or sound devices to tell the driver to reduce acceleration or to shift gears. The EPA has evaluated: AUTOTHERM**; IDALERT**.
Kamei Spoilers**;
http://www.ftc.gov/bcp/conline/pubs/autos/gasave.htm
* Indicated a very small improvement in fuel economy but with an increase in exhaust emissions. According to Federal regulations, installation of this device could be considered illegal tampering.
** Indicated a very small improvement in fuel economy without an increase in exhaust emissions. However, cost-effectiveness must be determined by the consumer for a particular application.
Accessory Drive Modifiers. These devices reduce power to specific auto accessories. The EPA has evaluated: Morse Constant Speed Accessory Drive**; P.A.S.S. Kit**; PASS Master Vehicle Air Conditioner**.
Driving Habit Modifiers. These are lights or sound devices to tell the driver to reduce acceleration or to shift gears. The EPA has evaluated: AUTOTHERM**; IDALERT**.
Kamei Spoilers**;
http://www.ftc.gov/bcp/conline/pubs/autos/gasave.htm
* Indicated a very small improvement in fuel economy but with an increase in exhaust emissions. According to Federal regulations, installation of this device could be considered illegal tampering.
** Indicated a very small improvement in fuel economy without an increase in exhaust emissions. However, cost-effectiveness must be determined by the consumer for a particular application.
Any lubricant that reduces friction will add to fuel economy. That fuel economy will depend on many factors. One person stated that after switching to synthetic oil his vehicle took longer to warm up. I have just the opposite experience. My truck warms up within a few minutes and when I start my truck in -30° F I am able to drive away within seconds because my oil pressure was there instantaneously. I am not letting it idle in the driveway because its so cold I can't move it. If the oil in the engine is flowing better its reducing the drag on the engine and that can only have positive affects on fuel economy.
Yes synthetics have been proving to increase mileage. Is it going to jump 5 mpg, no that's un-realistic. But over a 100,000 span, there will be noticeable gain. That is providing you can drive the same way constantly, have no one else hotrod your car (teenagers etc).
[ May 23, 2003, 08:20 AM: Message edited by: Mike ]
Yes synthetics have been proving to increase mileage. Is it going to jump 5 mpg, no that's un-realistic. But over a 100,000 span, there will be noticeable gain. That is providing you can drive the same way constantly, have no one else hotrod your car (teenagers etc).
[ May 23, 2003, 08:20 AM: Message edited by: Mike ]
I believe that synthetics do increase engine effeciency. In more ways than one.
1st is the friction reduction part that will reduce heat, and increase mpgs. about 3-5% is the average.
2nd, is the higher film strenght that allows the rings and such to form a tighter seal, increaseing combustion effeciency.
3rd, is less wear on internal components, so over time, the engine will be more efficient over it's life span than a similar engine run with conventional oil.
4th. Becuase synthetics are better under stress and high heat, you can use a lighter wieghted lube for the same application that you would use a heavier conventional, thus reducing friction.
5th. Cold temperature performance. CCV Index is much better for synthetics overall, so your engine will have to work less when it is first started, thus gaining mpgs.
note: when I say cold, I don't mean extreme cold, even starting at temps in the 50-60's there should be a significant difference in efficiency with a synthetic(also an additive with Moly, will also help for the non-synthetic users).
Well this is my opinion, Let the flaming begin.
1st is the friction reduction part that will reduce heat, and increase mpgs. about 3-5% is the average.
2nd, is the higher film strenght that allows the rings and such to form a tighter seal, increaseing combustion effeciency.
3rd, is less wear on internal components, so over time, the engine will be more efficient over it's life span than a similar engine run with conventional oil.
4th. Becuase synthetics are better under stress and high heat, you can use a lighter wieghted lube for the same application that you would use a heavier conventional, thus reducing friction.
5th. Cold temperature performance. CCV Index is much better for synthetics overall, so your engine will have to work less when it is first started, thus gaining mpgs.
note: when I say cold, I don't mean extreme cold, even starting at temps in the 50-60's there should be a significant difference in efficiency with a synthetic(also an additive with Moly, will also help for the non-synthetic users).
Well this is my opinion, Let the flaming begin.
If this were the case wouldn't you have 0 engine wear metals? There must be some metal to metal.
Higher film strenght of a synthetic will support reduced wear metals.
I wish I could find the reference, but there was a controlled study done where synthetic and conventional oils were compared re fuel efficiency. The conclusion was that the difference (which favored most of the synthetic oils that were tested) could be explained entirely by the lower viscosity of the synthetics. This makes perfect sense because viscosity is just a function of frictional coefficient of the finished oil. As msparks pointed out, many synthetics are blended at the low end of the SAE weight range. This works fine because of the shear stability of the synthetic base stock components.
This is not to suggest that there are not other ways to improve the fuel efficiency of an oil (i.e. friction modifiers), but they are not properties of the base oil.
Just for the sake of arguement, I have never seen convincing UOA data showing that the INITIAL rate of engine wear is lower using synthetic vs good conventional oils. Of course, lots of data show that synthetic oils protect or hold up longer.
This is not to suggest that there are not other ways to improve the fuel efficiency of an oil (i.e. friction modifiers), but they are not properties of the base oil.
Just for the sake of arguement, I have never seen convincing UOA data showing that the INITIAL rate of engine wear is lower using synthetic vs good conventional oils. Of course, lots of data show that synthetic oils protect or hold up longer.
Hmm, wonder where I've heard that before?
[ May 23, 2003, 11:47 AM: Message edited by: BOBISTHEOILGUY ]
Just a few PARTS IN A MILLION in wear metals. I still can't believe this amount will increase mileage measureably. Better sealing of the cylinders during combustion due to the higher film strength, yes.
I only feel extra power at part throttle. At full throttle, I can't feel it because I have so much hp and torque. Although it will likly be measured on a dyno.
These are my seat of the pants observations!
Leo
[ May 23, 2003, 03:18 PM: Message edited by: pedaltothemetal ]
Honestly, I didn't notice any change in MPG when I used synthetic in the past.
I have used synthetic oils off and on since the late 70's. Never seen an increase in gas mileage. What I did see back in about 1979 I had a Datsun 280Z and I switched from Quaker State Deluxe to Amsoil was that with Quaker State I used one quart of oil in 3000 miles. With Amsoil I got 6000 miles before using a quart. Go figure.
Les
Les
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