Synthetic Oil vs. Real Oil

<div class='quotetop'>QUOTE(Hokie-Dave\";p=\"78365)</div>

Right you are. The VW gasolene motors "only" have 2 year or 30,000km / 18,000mi oil change intervals. VW and Castrol got together and put a lot of work into developing a superior oil with much longer change intervals:

http://www.vw.co.uk/services/servicing/lon..._service_regime

Make sure you click on the hyperlink provided at "To find out more about Longlife servicing and Castrol SLX Longlife II" which will open a pdf explaining it.

To be competitive other oil makers also had to develop long-life motor oils that met VW specs:

http://www.mobil.com/UK-English/Lubes/PDS/...ulaLD_0W-30.asp

Of course, a car maker in North America can't tell you what brand of motor oil to use as it would violate the Magnuson Moss Warranty Act. Thanks to the interference of the API, we have now raised several generations of drivers on the belief that all motor oils, from a 88 cent a quart mystery oil to a full synthetic, are all exactly the same.

Thanks to the API we have also raised several generations of drivers on the bulls*** that oil changes every 3 months or 3,000 miles are necessary. That's really good marketing for API-affiliated companies.

Consider that only 10 years ago, an API certified oil had the following specs to earn a "passing" grade: engine test run 40 hours, oil was allowed to thicken 500% in service, the test engineer could add 7 quarts during the test, and the oil was allowed to have a 35% volatility.

The oil company sets these specs, with little input from the car maker. So to save the motor, I suppose you had *better* change the oil frequently.

Contrast that to ACEA specs, which you can look up at:

http://www.acea.be

Their current automotive motor oils typically have the following specs: engine test is run minimum 200 hours, no make-up oil is allowed, maximum thickening 80%, volatility under 15%, no sludge, etc.

Full synthetic motor oils easily meet the above specs. A minimum API rated motor oil most definitely will *not* come close to meeting those specs.

I find it ironic that folks here who invest in something like a VW, BMW, MB, etc, will balk at spending $10 a quart for a yearly oil change at the dealer, but will drive to Qwicker Lube While You Waite (I changed the name to avoid a costly lawsuit!) to have mysterious oil put in. Then they bitch and moan about a sludged-up motor.

After all, they've been told that *all* motor oil is the same. And if you can't trust bulls*** marketing departments and powerful government PAC's, who *can* you trust?

:roll:

 

http://neptune.spacebears.com/cars/stories...s/oil-life.html

This is a good read and an ongoing test on the subject being discussed here. It disagrees only slightly with what Jay said and pretty clearly shows that Mobil1 is superior to Amsoil. Though it's not exactly scientific, I did use it to make my decision on choice of synthetic.

 

Dave:

Mobil recently revamped their entire line of Mobil 1 products. Let's face it, the only car out there that specifically calls for a synthetic 0W-20 is the Honda Insight. That viscosity of Mobil 1 will continue to be available at Honda dealerships for that reason - though I bet no longer at Autozone prices.

A lot of Ford and Honda owners just didn't understand that a 0W-20 and a 5W-20 are virtually identical at operating temp. The real advantage to a 0W-20 is slow city driving and especially cold starts. Mobil recently introduced their Mobil 1 5W-20:

http://www.mobil1.com/USA-English/MotorOil...il_1_5W-20.aspx

With a pour point of "only" -47 C, their new Mobil 1 5W-20 isn't anywhere near the cold winter oil the 0W-20 used to be. So sorry to say you had better stock up on the 0W-20 while you still can.

Oddly enough, their 0W-30 still sells good and is readily available in the United States. In a harsh climate where the 0W-30 shines - like Canada - Mobil 1 0W-30 is almost impossible to find. I have to drive into Minnesota to get it.

 

Ray:

I disagree the results are not scientific. They were pretty careful to run UOA (Used Oil Analysis) at defined intervals to track insolubles and TBN. So it's pretty clear a good synthetic can be counted on for at least 10,000 miles.

With a fresh TBN of 10, Mobil 1 is surprising for a passenger car motor oil. Usually, you have to purchase HD diesel motor oil, like a 15W-40, to get TBN's that high or higher. Very impressive!

Jay

 

Jay-
My statement referred to the comparison being made without controlling driving conditions, age of engine, or make-up oil amounts. They only used one vehicle and one type of vehicle so they really limited the number of conclusions that can be safely drawn.

The two conclusions that I felt safe to draw from their test was that Mobil1 was an awesome investment at less than five bucks a quart and that Amsoil wasn't as good at twice the price.

Oh, and that my oil and filter change intervals will increase to 8000 miles starting at 36,000 miles without the slightest concern. They got a bump in performance from all the make-up oil so you've gotta round down on their results.

 

It was the "spacebears" site that interested me in extended oil change intervals in the Prius (a classic model in my case). I ran Mobil1 5W30 synthetic for 7k miles, changed the filter, and had Blackstone analyze sample. Topped off that oil, and after a total of 13k miles sent another sample for analysis.

I have previously posted all the results to yahoo prius technical stuff, but will repeat it here if desired. Briefly, the oil additive chemistry survived well, viscosity did not increase, and TBN fell finally to 2.2. Those familiar with used oil analyses should realize that Blackstone uses a TBN technique where values above 1 are considered "not dead yet".

I did change the oil (and filter) soon after, mostly because I had the impression that my fuel economy was falling. Also, I did not stray far from Toyota's recommended oil filter change interval 7.5k miles for my model in the US.

The wear metals and ash did not accumulate, which says more about the engine than anything else. I will not hesitate in the future using synthetic oils in this way, but would not extend the filter too much without info about filtering effectiveness and pressure drop.

This experiment was conducted between 57 and 70k on the odometer. More Prius oil analyses would be most welcome, especially earlier in the engine's life.

PS: a good hint to look for 0W20 at Honda.

 

Jayman,
Thanks for the info. If Mobil-1 has started making the 5W-20, I'll just go with that since that is what Mazda recommends for the vehicle anyways. I did like the 0W-20 which Mobil stated was a good substitute for the 5W-20 Ford and Honda Motors. I will go to Autozone and see if they still have 0W-20 on the shelves and stock up, but I doubt it. I usually had to really look at a few places, most were usually out of stock of it because they didn't stock much. I really don't think I'll go to Honda and try to get it since they will probably be asking $10/qt for the stuff.

 

If the insolubles were high, then the filter had to be changed. Otherwise I would have drained off just enough for a UOA.

Though to be safe and still help the environment, it's a lot better to change the oil filter and lose less than a quart of oil vs changing the oil and filter.

Please do, or at least PM the results to me. I've very interested in how "hard" this motor is on oil.

Was that with the "old" Mobil 1 or the "new" SuperSyn Mobil 1? Mobil changed the additive chemistries quite a bit: phosphorous levels to help prolong the life of the catalytic converter, higher TBN for longer use, etc.

If the viscosity was still comparable to virgin oil, and the additive chemistry was still present, there shouldn't have been any effect on fuel economy. You'll notice a decrease in fuel economy if the oil thickens in service and/or the additives become depleted.

A well-engineered motor with modern automated assembly techniques, combined with a good synthetic oil, prove that long oil change intervals are possible.

But I bet they won't be selling it at Autozone prices though. It will probably be labelled Honda Insight Motor Oil 0W-20 and cost $10 a quart. I can buy Mobil 1 0W-30 for less than half that, so it will be hard to justify getting 0W-20 at Honda.

I managed to stock up on several cases of 0W-20 last year when I heard the rumor of Mobil discontinuing it. In my experience, it's an outstanding winter oil in my old Ford truck, which is my plow vehicle at the hobby farm.

I've noticed that Canadian Tire still stocks it. They only recently started carrying it at $7.69 a litre, which is comparable in price to the other Mobil 1 grades they carry. I had better get some more before it disappears.

 

Ray:

That's the problem, there is a huge lack of qualified and controlled test cases out there. Unless you count all that Amsoil "proven" test results.

Not.

It's all we have to go on. I would love to see a major manufacturer like Toyota or GM run a controlled test with major synthetic brands (Mobil 1, Castrol SynTec, etc) to see which one performs the best for extended drains.

For example: in Europe such tests have already been done. VW requires Castrol LongLife SLX II 0W-30. Many BMW, Opel, and Mercedes models require an oil that meets "approved" Long Life testing regimes, such as Mobil 1 0W-40 - They prefer the Mobil 1 0W-40 but any synthetic meeting BMW LL-01, MB 229.5, GM LL-A-024, etc may be used.

I doubt we'll see such a test ever done here. Frequent and unnecessary oil changes are a gold mine for profit-driven service centers and those Qwickie Lube While You Waite places. If they could convince us to change the oil every 2 months or 2,000 miles, they would.

 

no mileage increase with synthetic

I noticed no difference in mileage when I switched to synthetic oil. I'm still glad I did for other reasons: getting a bit further off the fossil fuel grid and better long term protection espcially with 5k between changes. Somehow, it felt better to use synthetic oil. I wish we had synthetic gasoline made here, but that will have to wait until Bush is gone.
B

 

OK I am attaching an .xls spreadsheet to this, so first try to limit the confusion. Rows are the reported variables. Columns are different analyses. First 2 are virgin oil, then an average, then my 7k and 13k data, expected = all Prius data that Blackstone had as of the more recent, then 3 other Prius who have shared their results, then an overall Prius avg, then 7 from Toyota Echo engines that I have "collected" from "BobIsTheOilGuy".

Some graphs below to help me visualize how TBN appears to have an exponential decay.

The reason I looked for Echo data is that it is a very similar block but not operated in the intermittent mode. Comparing either group's data with other oil analyses (refer back to spacebears) and see that these engines are simply not shedding metal (yet). But please do not conclude that we understand engine wear - I hope that many other people go through this effort and expense with their Prius and share the results.

Responding to Jayman's specifics, first, was I clear that I sampled the oil at 7k, and changed it after the 13k analysis? My insol went from 0.3% at 7K to 0.4% at 13k. By generally accepted standards such are NOT high enough to call for a new filter but again, I am not ready to extend the filter schedule.

I used the "old" Mobil1 synthetic 5W30, not supersyn. In fact I have an entire case of the former, which should last me about 50k miles! All offers of even swaps for 0W20 will be considered.

The oil characteristics after 13k should not have affected mpg - yes I am in formal agreement with this statement. And yet, my mpg was down, and it did recover with the subsequent oil change. After 73k Prius miles I am familiar with the uncertainty of short-term mpgs. I am not able to further justify that oil change decision. To anyone who chooses to go longer, please do the analyses as well.

 

Thanks that's *exactly* the sort of data I was looking for. I will also consider UOA to see if I can add to the database.

From what I understand, Mobil 1 SuperSyn has different levels of Moly, Boron, and Phosphorous, primarily to help catalytic converter life. Also, API SM requires different add treatments to meet new requirements.

That's why the "new" Extended Life Mobil 1 no longer carries an API certification. They couldn't formulate an extended life oil to meet SM specs.

Your Fe and Al levels are low and probably safe. The TBN also appears safe, especially when you consider that regular motor oil has a VOA TBN of under 5.

Overall it appears the 1.5 litre motor is easy on motor oil. I would expect a far higher moisture level in my Prius due to the extreme cold temps here in winter.

For that reason alone, whatever oil I chose I'm stuck with oil and filter changes every 6 months. I find Oct and Apr to be the best times to change the oil, you have fresh oil for winter and once it warms up you get all that moisture and crap out.

 

Re: no mileage increase with synthetic

Bob:

The Germans had "synthetic" gasolene during WW II and you can purchase synthetic gasolene in South Africa. It's made from coal.

I'm not sure if there is any environmental benefit to the process though.

As far as potential fuel economy benefits from synthetic motor oil, remember that most conventional 5W-30 motor oils have an operating viscosity of around 12 cSt at 100 C. Mobil 1 5W-30 is rated around 10 cSt at 100 C, the somewhat lighter rating may be reflected in slight fuel economy gains.

Since a regular 5W-30 will shear down a bit, it makes sense to run a stable synthetic oil that is thinner to begin with. I'm tempted to try Mobil 1 0W-20 to see if a very thin motor oil might boost MPG by 5% or higher.

Of course, if anybody at the dealer asks, I'm running Mobil 1 5W-30.

 

Interesting results from that test with a synthetic HD 5W-40. You can always tell a HD diesel motor oil as it has a s*** load of Moly in it. It appears to have held up very well, but I wonder where the increase in fuel came from? Idle time? Leaky injector? Frequent cold starts?