Testing/experimentation IS the empirical route! Look up the meaning of empirical...
I'd do something similar, but I'd run at least 200K miles and preferably longer. Almost anything will last 100K these days and I'm not even intested in engines that won't go at least 200K!
You'd also have to put extensive data recorders on each car to find out the driving conditions each experienced so you could try to normalize the data.
This would be a great experiment. When do you plan to start it? :-)
Matt
With a sample size of 200, all conditions average out.
Ya, I miss that part.
Here in Louisiana, I have no excuse for not being out working. :(
No, I'm afraid my quality assurance days are over. And I'm glad of it! :-)
Ah! So I WAS right!
Not necessarily. And it would be hard to cover the full range of driving conditions encountered in the USA with only 100 cars with each type of oil. However, let me know when you plan to start the test and I'll drive one of the cars for you ... no charge! :-)
Matt
It comes from ONE source and it's blended to a standard specification. The lab test I saw indicated that it was comparable to other synthetic oils on the market. Your comments are just idle speculation with no basis in fact. Fear mongering doesn't help anyone.
If you search on "synthetic", you'll see that both Specialty and Warren are listed for SuperTech synthetic oils. I'm not sure if one is the manufacturer and the other is the distributor or what, but the dates on the MSDS's overlap.
I checked the MCN archives and the test appears to have been done in
2000, which is before the latests API specs came out and before Supertech Synthetic was available. While it might be worthwhile as a comparative study, it doesn't tell us much about current products.I know that and that's what I meant when I said it doesn't matter. ANY oil will protect your car long term if it's changed at recommended intervals and you use a decent filter. I don't care how much or how little you spend on oil, as long as you use an API certified oil, it will do the job. API specs are very exacting and effectively limit the amount of variation that's possible in oils. That's the whole point of the certification.
If the argument was completely bogus, what's the point? Exaggeration like that is deliberately misleading. I can make up all kinds of "what if" scenarios too. For example, what if the actual difference in wear rate was 0.1%, which is probably closer to the truth?
Only in your world of exaggerated wear rates.
No kidding.
That I can agree with.
Then it's an apples to oranges comparison and it's largely pointless.
Sorry, I meant anecdotal.
OK, it was a typo. So shoot me.
Fine, but we all know how unreliable anecdotal data can be.
Fair enough, but there are limits to how far you can stretch this before the results are meaningless. Comparing different engines under different loads, then trying to draw correlations between continuous running and frequent stops/starts seems pretty far-fetched. Results from such a test could might indicate that a more definitive test may be worthwhile, but in and of themselves they'd be largely meaningless.
Brian Nystrom wrote in news:TAzQf.2$hc.1@trndny03:
The height of bars can also be deceiving due to the choice of origin: If the vertical axis of the graph starts at 10 and goes to 15, the bar for 11 will be half the size of the bar for 12.
Not that I know anything about oil, but I do teach how to lie with statistics.
Sinan
Matt Whiting wrote in news:VHJQf.7154$ snipped-for-privacy@news1.epix.net:
If the engines are otherwise identical, you would not need a lot more than, say, 15 tested with each kind of oil to detect a difference that is practically as well as statistically significant.
On the other hand, if we are setting up a test of engine lifetimes on different oils, the experiment may have to be run for a long time.
Sinan
Thanks for the clear example. That's what I was trying to get across.
Again, I ask to see the mysterious data you keep referring to, but can't seem to produce a reference to. I provided a clear reference to the source of the data that I saw that is in direct conflict with your claims that all oils are created equal.
Matt
And you accuse me of fear mongering for not wanting to use an oil where the source can't even be determined? :-)
Matt
2000 sounds about right. I knew it was a few years ago. I'd be happy to have more current data, but I've been unable to find any.
No, the point of most certifications, and I believe API falls into this category, is to provide MINIMUM standards. It doesn't prevent a manufacturer from going ABOVE the standards and many manufacturers do this. Sure, many will skirt just above the minimums, but the MCN test showed that many of the reputable names, Mobil being one, have products that are well above the minimum requirements. So, certification doesn't limit variability, it just places a lower limit on the variability range. The upper end is generally not limited by specification.
No, in any difference of wear rate. If the rate of wear is different AT ALL, then the amount of wear between two oils will be completely dependent on the mileage driven.
Yes, my data is just as good as yours claiming that Supertech is a good oil. :-)
So now you agree that better oils are better for your engine? I thought you were saying that all oils were essentially equal and thus buying a better oil was a waste of money.
Matt
Yes, I agree that it is very difficult and that is the reason that I believe it has never been done. A test worth doing would cost literally multiple millions of dollars and just isn't worth it to anyone.
Matt
I saw the data. I own the "How to Lie with Statistics" book that was required reading in my statistics class at Penn State a couple of decades ago. The MCN data was extremely well done.
It is funny how some of you like to throw stones at data that you are too cheap to spend a few bucks to get a copy of and actually see for yourself. You must be a statistician...
Matt
He's not saying at all what you were saying. I'm surprised you can't tell the difference. You are talking about a difference in the data and whether that difference is of significance. He's talking simply about the presentation of that data.
I now understand why you have such a hard time following my arguments. If you can't tell this difference, then the concepts I'm explaining won't be understandable either, so I'll stop wasting my time now. :-)
Matt
Matt Whiting wrote in news:V71Sf.7272$ snipped-for-privacy@news1.epix.net:
On the other hand, my comment was not specifically about the data, but only about the fact that without knowing the scale of the vertical axis, the heights of the bars in bar graph do not convey meaningful information.
Frankly, I do not know anything about oil, and I don't much care. As such, I am unwilling to invest any time or money in researching the article.
That should make it obvious that I am an economist who occasionally teaches statistics.
Sinan
Nice try, but Sinan points out exactly what I was saying before. A difference of "2X" is meaningless without context. Depending on the context it can be a big difference, or completely insignificant. Do you know what the context of the data in the study you referred to is? For that matter, do you even know what parameters were measured? Was it frictional resistance? Viscocity vs. temperature? Levels of chemicals as in the above analysis? Something else. Your claim of "twice as good" is meaningless unless we also know "compared to what?"
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.