Better fuel mileage with synthetic?

[Garak]

Originally Posted By: Merkava_4
So the only advantage of synthetic is longer OCI's ?


Well, that may not be the only advantage, but I'd say the fuel economy benefits of synthetic are minimal. They may exist and be statistically significant, but only to those who have the facilities to test such things. The only way you or I might notice is if we had a vehicle speced for an xw-20 weight, and we were running 20w-50 dino and switched to 0w-20 synthetic. But, the grade is making a bigger change than the base stock.

Look at it this way. North American manufacturers have switched to lighter oils, and have been doing so for a lot of years already. That's been driven primarily be fuel economy requirements. If switching to synthetic provided a greater gain than, say, going to a grade or so lighter, they would have done that already.

 

[Eddie]

Subaru 2001 Std engine. Switched from Mobil 5000 to Mobil 1 5w30. I kept carefull records of fuel mileage for one complete year or ~ 7,500 miles. I cakculated the mpg and SD for both oils. The Synthetic oil improved my fuel mileage by 1.03 mpg. I conclude that switching to synthetic oil will probably improve your fuel mileage but, you will never recover the extra oil cost even if you double you OCI.

 

[lexus114]

And if you think about it, it really doesnt make any sense? If its less friction and all, then why doesnt fuel millage improve?

 

[Jeff_in_VABch]

There is little way synthetic vs. conventional would make a difference in fuel economy as the oil managed friction is low to begin with. There is not much way mechanically in an engine a fluid could reduce friction.

Even changing oil weights only results in relatively small differences in output power not easily measured, and not attributed to friction.

When a performance engine is built, the breakaway and rotational torque is measured in order to see what internal friction is present on a 360 degree rotation. Almost all of this drag is caused by the ring packs and the quality and type of bore finish. I dont see the oil making much of a difference in this friction.

 

[lexus114]

Originally Posted By: Jeff_in_VABch
There is little way synthetic vs. conventional would make a difference in fuel economy as the oil managed friction is low to begin with. There is not much way mechanically in an engine a fluid could reduce friction.

Even changing oil weights only results in relatively small differences in output power not easily measured, and not attributed to friction.

When a performance engine is built, the breakaway and rotational torque is measured in order to see what internal friction is present on a 360 degree rotation. Almost all of this drag is caused by the ring packs and the quality and type of bore finish. I dont see the oil making much of a difference in this friction.




Wow....okay. good information then.

 

[mechtech2]

Nope.
[As is expected]

 

[Solarent]

Originally Posted By: Jeff_in_VABch
There is little way synthetic vs. conventional would make a difference in fuel economy as the oil managed friction is low to begin with. There is not much way mechanically in an engine a fluid could reduce friction.


I disagree. One of the main purposes of the oil IS to reduce friction and while I see your point that the FEI contribution of oils is minimal in comparison to what can be done with better engine design. However in some cases the improvements in new oil technology allows these engine designs to accomplish their goals.With tighter tolerances and smaller sumps there is a lot of gain from using new oil technology.

Here is a video where some manufacturers extol the importance of the Sequence VID test which measures fuel economy improvement for the RESOURCE CONSERVING certification that can come with SN oils.

With regards to the merits of "synthetic vs conventional" I believe that comes back to the discussion that we have every week on the merits of synthetic and the arguments for and against Group III base oils. The fact is that when you buy bottle of something that says SYNTHETIC that means you are getting base oils that is Gr III or higher.

ANY OIL that meets the Sequence VID requirements demonstrate a FEI over baseline oils. That means there are conventional oils and synthetic oils that can improve fuel economy, albeit by a small amount. So the benefits of using synthetic oils can't be measured by looking at just one thing (FEI, Sheer stability, Low temp performance) Its a package deal and you need to decide if your engine needs it.

 

[Solarent]

I also should point out that additive technology has come a long way in the last 25 years and a conventional oil with a good additive package will out perform a synthetic with a poor additive package IMO.

However most synthetic oil producers also rely on quality additive packages to allow them to do things like produce and recommend lower viscosity oils.

 

[troyb43]

In my OPE, I have observed a longer run time on a tank of fuel, and on various pieces of it. I have never really checked the difference in my automobiles

 

[lexus114]

I almost forgot this, but the ONLY time my fuel millage went up (at all) was on a run of German Castrol. It went from 18.5 to 19.8 or somewhere around there. But my cold performance on it was more than I could deal with.

 

[icruse]

Originally Posted By: Jeff_in_VABch
There is not much way mechanically in an engine a fluid could reduce friction.


When a performance engine is built, the breakaway and rotational torque is measured in order to see what internal friction is present on a 360 degree rotation. Almost all of this drag is caused by the ring packs and the quality and type of bore finish. I dont see the oil making much of a difference in this friction.


I looked at your credentials, and they are far above mine on this issue, but just wondering then why did Joe Gibbs racing team come up with their own oil for their racing engines?

Good Day,
Steven

 

[SS1970chrysler]

Nope. I tried it for 5 years on a 78 LTD. Only benefit seemed to be easier starting in winter.

 

[Boss302fan]

I think over a full 5K+ OCI, you will see some MPG improvement, how much is anyones guess...

 

[Jeff_in_VABch]

Originally Posted By: icruse
Originally Posted By: Jeff_in_VABch


...just wondering then why did Joe Gibbs racing team come up with their own oil for their racing engines?

Good Day,
Steven


Racing oils are pretty specialized and the teams actually have the money to test them on the engine dyno in real time. I would bet they have changed oil (racing engines are dry sump)with engines under constant load in real time to measure actual changes in power produced. That is in addition to tuning the oil pump output to the desired flow and pressure for the viscosity of oil specified by the builder.

A dry sump racing engine runs oil temperatures much higher than street engines. The oil capacity is also much higher.

The use of low tension oil rings and crankcase vacuum evacuation systems allows very low rotational friction (additional 50 HP) with full oil control even if using low viscosity oils.

Racing oils have few to no detergents to reduce detonation. This also reportedly increases lubricity. Racing oil has up to 3,000 ppm of zinc & phosphorus, more than a non-race oil.

Todays racing engines are more high tech than ever and the teams have the money to sit around and experiment in a controlled manner with oil or anything else thay want. It only makes sense they would use an oil that tested well on the dyno for the specific engine.

 

[Jeff_in_VABch]

Originally Posted By: SS1970chrysler
Nope. I tried it for 5 years on a 78 LTD. Only benefit seemed to be easier starting in winter.


I had a 77 LTD 400-2V with a C-6 and 3.00 gears. Man that thing ran good. There was never a lick of tread on the right rear.

 

[Scoot_4_20]

Nope

 

[4x4chevydude]

not unless you are switching from a 15w40 converntional to a 0w20 synthetic...then you may see a difference.

 

[OilGuy2]

Originally Posted By: Merkava_4
You guys that have switched from conventional to synthetic, has your fuel mileage improved at all?


Yes, definitely. Have a 2008 Nissan Sentra SER which has the same 4 cylinder 2.5 liter DOHC that is put into the Nissan Altima 2.5S. EPA is for 24 city and 30 highway. We were close to those numbers for the first few months until I changed out the factory fill and replaced with Mobil 1 5W-30 Extended Performance with a Mobil 1-110 filter and a 300 ml can of LubroMoly. The gas mileage increased to 26-27 city and 32-33 highway and has gone higher since then as the motor and car "loosens up". Currently, we get 28 mpg city and typically 34 highway but on longer trips of 50 miles or more, we've gotten a whopping 36+ mpg. The car has its own on board computer that calculates gas mileage and predicts how far you can drive until the next refuel. Highly recommend...great tool.

We are extremely pleased with this car which has a CVT transmission that Nissan warrants for 120,000 miles. There are no shift points because the transmission computer will optimally and seamlessly select between 62 different ratios. The car has paddle shifters and I have used them from time to time but you have to be a cyborg driver to best the overall shifting the CVT makes for itself. The engine hits maximum torque at just 2800 rpm so it takes very little throttle (electric, as well as the power steering) to make the car move out fast. There is absolutely no "shift" we can feel, unless I use the paddle shifters which reduces the shifting to just 6 ratios!

Current mileage for the existing tank, about 8/12ths used (LCD fuel tank indicates in 1/12th increments...nice) is 28.2 mpg. We live in Worcester MA. There are a ton of lights, lots of traffic and steep hills everywhere. We live at 1000 ft elevation, BTW, on a very steep hill. We can see Boston's skyline (40 miles away) from our yard.

Car now has 35,000 miles and is currently at 14,000 miles of a 15,000 mile Mobil Extended Performance fill and its running and economizing better than ever. There is no question that the Mobil 1 and LubroMoly have both had a hand in the ease of starting and the fuel mileage.

Also helping is the change in late 2010 to Continental Extreme Contact DWS 225X45X17 radials. They have 2-ply polyester sidewalls and a real, perpendicular true radial construction, along with 2-polymide(kevlar) and 2-nylon belts on the tread. I keep them at their 51 psi maximum and the true radial construction soaks up the bumps while handling is to die for and rolling resistance is as low as it can go. Great tires for wet and snow. Last winter had record snowfall here and we always made it to where we were going without a problem.

The improvements in fuel mileage may be subtle, but it was 10% initially and now exceeds EPA by 16% city and 20% highway.

Dino? Oh, you mean oil heat, right?

 

[Unleashedbeast]

Originally Posted By: JOD
Originally Posted By: Unleashedbeast
Not one lubricant discussed in this thread uses true synthetic base stocks. Group III does not count.
1. I'm not sure how you can say that, unless you have some inside information that no one else does--most manufacturers don't disclose the base stocks they use


Indeed I do, and would love to share.

As of last year, the only Mobil 1 formulations that DID NOT contain any percentage of group III base stocks were....

Mobil 1 0W-30, 0W-40, 5W-40, 5W-50, and 15W-50

Mobil 1 EP 5W-20, 5W-30, and 10W-30

I would also like to add that OilGuy2 made an excellent post above mine and outlined the benefits of a true synthetic formulation. Efficiency will be gained by using them.

Take that to the bank group II and III lovers.

 

[fdcg27]

I'd like to think so, but I've also run conventional oils in cars normally run on syns and seen really good fuel economy.
I think that there may be some small gain in fuel economy with syn oils, but that is more a guess than anything I can back up with more than thirty years of fuel consumption numbers for each tank on a variety of cars.
Even a tiny gain would justify paying more for syn (although I always pay less after MIRs), since we all spend many times more for fuel than we do for oil.