Check out this oil test that was done for an Austrailian car magazine, its quite an eye opener. See how your favorite oil compared.

http://www.animegame.com/cars/Oil%20Tests.pdf

That's probably the dumbest test I've ever seen. Hopefully a lube expert will chime in with all the gory details, but I know enough to say that their "testing" is completely worthless.

That's probably the dumbest test I've ever seen. Hopefully a lube expert will chime in with all the gory details, but I know enough to say that their "testing" is completely worthless.

Your comment says a lot more about you, than it does about the test. I think YOU need to do a little more reading/research yourself. This is a test of keeping metal from contacting metal. Geez, how could that be a stupid test? That's the primary thing, but of course not the only thing, that gearheads care about regarding motor oil. If we read between the lines here, I guess your favorite oil must have looked bad, huh? Chill dude.

That's probably the dumbest test I've ever seen. Hopefully a lube expert will chime in with all the gory details, but I know enough to say that their "testing" is completely worthless.

Explanation?

I've always ran Valvoline oils in all my engines (exept diesel, gets Rotella). I don't run valvoline because of any adds, tests or other input. I run Valvoline because it has never dissapointed me in over 20 year of using it. This is from stock 4, 6 and 8 cylinder engines all the way to hi-performance engines. I'm personally not a big fan of synthetic oils. I change my oil religously in all my cars, and frankly I cringe at the thought of running the same oil/filter for 5,000, 7,500 or even 10,000 miles as some of the synthetic oil manufacturers would have you believe. When I was bracket racing my car full time I would change the oil every 25-35 passes as the oil spends little time at full operating temperature.

My $0.02 :D

Intersting - text ( of the actual test parameters) was a little blurred when magnified, but I understood the results. I have been looking into this a lot lately as I want to switch to Synthetic for the high temp stability which I think will cure my post extended run lower than desired hot oil pressure. Short of pulling the motor out and changing out the pan for something with a lot more capacity, a swap to synthetic appears to be a good choice. From what I have gathered, I have it down to either Royal Purple, Red Line or AMSOIL for the switch with the first two being easier for me to get a hold of.

PENRITE - wonder if that's the same as the US brand PITPEN (I think?? - label look similiar).

Intersting - text ( of the actual test parameters) was a little blurred when magnified, but I understood the results. I have been looking into this a lot lately as I want to switch to Synthetic for the high temp stability which I think will cure my post extended run lower than desired hot oil pressure. Short of pulling the motor out and changing out the pan for something with a lot more capacity, a swap to synthetic appears to be a good choice. From what I have gathered, I have it down to either Royal Purple, Red Line or AMSOIL for the switch with the first two being easier for me to get a hold of.

PENRITE - wonder if that's the same as the US brand PITPEN (I think?? - label look similiar).

Actually Redline showed rather poorly on this test. Would be interesting if someone could come up with this test data on AMSOIL.

I'm personally not a big fan of synthetic oils. I change my oil religously in all my cars, and frankly I cringe at the thought of running the same oil/filter for 5,000, 7,500 or even 10,000 miles as some of the synthetic oil manufacturers would have you believe. When I was bracket racing my car full time I would change the oil every 25-35 passes as the oil spends little time at full operating temperature.

Why would you cringe? The old 3,000 Mile range was set back in the early years of the automobile industy, where tolerences were horrific, and some engines didn't even use filters. The mileage was set by the oil companies, we now see most auto manufacturers ranging from 5K -7.5K on oil changes. Newer oils have superior qualities compared to older additives. Last question, Why are you not a big fan of synthetics, I personally have only a synthetic in one car, I just don't want to spend the money but have nothing against them.

Your comment says a lot more about you, than it does about the test. I think YOU need to do a little more reading/research yourself. This is a test of keeping metal from contacting metal. Geez, how could that be a stupid test? That's the primary thing, but of course not the only thing, that gearheads care about regarding motor oil. If we read between the lines here, I guess your favorite oil must have looked bad, huh? Chill dude.

Well, again, I'm not a lubrication expert, but this test only tests shear strength which is hardly an issue in an engine. If there was actual metal-to-metal contact between the crank/rods and bearings the engine would self destruct in seconds. How about the things that actually matter in a quality oil:

* Stability at high temperature
* Ability to neutralize acidic by-products of combustion
* Ability to "cling" to metal to avoid dry-startup and corrosion in case the engine sits.
* Ability to suspend carbon and other thrash to avoid clogging of passages

Why would you cringe? The old 3,000 Mile range was set back in the early years of the automobile industy, where tolerences were horrific, and some engines didn't even use filters. The mileage was set by the oil companies, we now see most auto manufacturers ranging from 5K -7.5K on oil changes. Newer oils have superior qualities compared to older additives. Last question, Why are you not a big fan of synthetics, I personally have only a synthetic in one car, I just don't want to spend the money but have nothing against them.

Rod, I guess I'm just set in my ways when it comes to oil :) I've had vehicles go this long for 257,000 miles using the same process I've used for 20+ years. Maybe my way of thinking is outdated, but as I've said I've never had an oil related issue and I've been driving and servicing my own vehicles since 1982. As far as synthetic oil, It doesn't make sense to me as my oil change intervals are more frequent than would be necessary to see a cost benefit from using synthetic. On top of that, the few times I've used synthetic oil I have on more than one occassion developed oil leaks where I didn't have them with regular oil. I've also tried other oil additives (read gimmicks). Are you old enough to remember when "Slick 50" was all the rage? I'm not saying synthetic oil fails into the gimmick category, but just that regular dino oil meets and exceeds my personal needs. Again, this is just my own experience and opinion.

Pretty hard to argue with the results of this test as it was done. How much this relates to actual use in an engine, I really don't know. If you read all the way to the bottom they said they will be doing more extensive testing in actual engines next.

As far as metal to metal contact, I would think anything with needle bearings in it would qualify for that. As in; roller lifters and rocker arms. As well as flat tappet cams, pistons, rings etc. Properly clearanced and lubricated main/rod bearings are not much of an issue these days, no matter what kind of oil you use.

Hmmm. always did like Pennzoil. It "felt" like a reliable brand. Royal Purple is the king of the hill , eh?

At $30 qt?

Sorry, I'll stick with my poor old tired Valvoline.

If you really wanted to run some synthetic keep in mind that oil filters have by-passes and get dirty just as quick with synthetic as with dino oil. So, buy the good stuff, but change the filter and add a quart every 3000 or so. keeps the filter clean and freshens up the additive package.

That test may well be valid on it's own, but I don't see what it's got to do with conditions in an automotive engine. Not even flat tappet cams are loaded like that.

I think it was $30 a gallon

Im going to go with synthetic only for the advantage of stability at higher oil temps. Ended up buying Lucas Synthetic today. Will know if it was worth it in about 2 weeks.

i couldn't open the link- slow dial up connection and a deep hatred for pdf files conspire to keep me away- but i don't think i'd put too much stock in an oil test on a website that sells individual frames from japanese cartoons.

That test may well be valid on it's own, but I don't see what it's got to do with conditions in an automotive engine. Not even flat tappet cams are loaded like that.


The whole point of the test was simply to show how the oils compared to each other, in a precisely controlled and repeatable manner. They never stated it was exactly the same as in an engine. So yes, the precise test method was "different" than in an engine, but the concept is the "same" as in an engine, particularly, but not limited to, cold start-up. Geez guys, it baffles me how you can take some excellent oil test data, and turn it into pointless info. If you want to ignore it, perhaps because your favorite oil didn't show up very well, that's up to you. But for me, I'd like to know how oils compare, so that I can make an informed decision as to what oil to run. Without a test like this, its largely guess work, marketing hype, and personal preference based on no absolute engine failures in the past. That is hardly a scientific method for arriving at the BEST technical solution to your lubrication needs. I don't know about you, but I have a ton of money in my 540, and I'd like to give it the best chance possible to live. I'm running solid roller lifters, which have a reputation for failing in nasty big blocks, so the oil I run could have a definite impact on how well they hold up. The needles in those lifters are not caged, so their sides rub against each other in OPPOSITE directions as they roll. And the load is very high due to the stiff valve springs we run in these things, not to mention that the rpm can be quite high the way we rev them. This is just one more example of how that rubbing/shearing concept with the needles, is the same as the test. So, it is quite obvious, if you look at things objectively, that the test is indeed valid to what we run. It is often difficult to come by real test data, so we should make full use of it when it comes along.

How about the things that actually matter in a quality oil:

* Stability at high temperature
* Ability to neutralize acidic by-products of combustion
* Ability to "cling" to metal to avoid dry-startup and corrosion in case the engine sits.
* Ability to suspend carbon and other thrash to avoid clogging of passages

None of these are a concern with name brand quality oils that meet recent API standards, and gets changed at reasonable intervals. So, stating that this is what actually matters in a quality oil, really misses the point. See my response to Tom above.

540RAT,thanks for letting us know about this oil test,it seems like its worth reading to me.

But one thought i had was when they tested multi grade oils they are being tested at room temp so they are at the low end their viscosity rating. But if they were 1st heated to normal operating temp that a motor would see on average they might perform better when at their thicker viscosity rating,food for thought.

Whats do you guys think?

scott

The whole point of the test was simply to show how the oils compared to each other, in a precisely controlled and repeatable manner. They never stated it was exactly the same as in an engine. So yes, the precise test method was "different" than in an engine, but the concept is the "same" as in an engine, particularly, but not limited to, cold start-up. Geez guys, it baffles me how you can take some excellent oil test data, and turn it into pointless info. If you want to ignore it, perhaps because your favorite oil didn't show up very well, that's up to you. But for me, I'd like to know how oils compare, so that I can make an informed decision as to what oil to run. Without a test like this, its largely guess work, marketing hype, and personal preference based on no absolute engine failures in the past. That is hardly a scientific method for arriving at the BEST technical solution to your lubrication needs. I don't know about you, but I have a ton of money in my 540, and I'd like to give it the best chance possible to live. I'm running solid roller lifters, which have a reputation for failing in nasty big blocks, so the oil I run could have a definite impact on how well they hold up. The needles in those lifters are not caged, so their sides rub against each other in OPPOSITE directions as they roll. And the load is very high due to the stiff valve springs we run in these things, not to mention that the rpm can be quite high the way we rev them. This is just one more example of how that rubbing/shearing concept with the needles, is the same as the test. So, it is quite obvious, if you look at things objectively, that the test is indeed valid to what we run. It is often difficult to come by real test data, so we should make full use of it when it comes along.

I agree bigtime. Royal Purple won... Under extreme conditions. They won the race. :hurray: Those tests educated us more than most threads.
Thanx 540 rat.:thumbsup:
I wish they did Amsoil and a few more familiar brands.

I've always ran Valvoline oils in all my engines (exept diesel, gets Rotella). I don't run valvoline because of any adds, tests or other input. I run Valvoline because it has never dissapointed me in over 20 year of using it. This is from stock 4, 6 and 8 cylinder engines all the way to hi-performance engines. I'm personally not a big fan of synthetic oils. I change my oil religously in all my cars, and frankly I cringe at the thought of running the same oil/filter for 5,000, 7,500 or even 10,000 miles as some of the synthetic oil manufacturers would have you believe. When I was bracket racing my car full time I would change the oil every 25-35 passes as the oil spends little time at full operating temperature.

My $0.02 :D

Ken,

Since you are a Valvoline guy, you might check into Valvoline Premium Blue 15w40 HD diesel oil. Valvoline works very closely and does lubrication development work for Cummins. Good stuff

In regard to Royal Purple. From the oil analysis work I have seen, RP does stand at the top of the heap. It is expensive though.

My first experience with RP was in a HD industrial air compressor that supplied air at fairly large ASME code vessel shop I worked at when I first got out of college about 12 years ago. Changing to RP dropped compressor oil temps. 20 degrees. This could be good or bad. Either there was less friction and less heat or the RP oil was not carrying the heat away from components.

If you do have a situation where you experience oil temps., synthetics are more tolerant of higher temperatures and don't breakdown as quickly as most conventional oils. For example if you have a filled block etc. Oil temps. can increase significantly.

regular oil won't live past about 100 miles in my T Type- it turns black and smells like burnt trans fluid, with about the same viscosity- but Mobil 1 or Rotella T synthetic look and feel almost brand new after 3000 miles.

it turns black... Mobil 1 or Rotella T synthetic look and feel almost brand new after 3000 miles.

If I remember correctly from my industrial materials class in college... Oil from an engine should have some dark discoloration, as it absorbs carbon and other contaminants, thus the reason Diesel oils are usually darker. So having a "new/clean" looking oil is suspec to me, but maybe oils now are able to keep their color after absorbing all the contaminants.

Well, here is a summary of the test:

1. ROYAL PURPLE Racing Oil full syn 20W50 withstands 295,722 psi

2. ROYAL PURPLE Street Oil full syn 10W40 withstands 131,432psi

3.VALVOLINE DURABLEND semi-syn 10W40 withstands 23,858psi

4. PENNZOIL semi-syn 10W40 withstands 9,200psi

5/6. Tie RED LINE full syn 5W40 withstands 6,389psi

5/6. Tie MOBIL semi-syn 10W40 withstands 6,389psi

7. SHELL semi-syn 15W50 withstands 2,920psi

8. SHELL full syn 5W40 withstands 2,567psi

9. CASTROL full syn 0W40 withstands 2,011psi

10. MOBIL 1 full syn 0W40 withstands 1,540psi


Oil film strength is what protects an engine from wear and/or failure by preventing metal to metal contact.

You can see that cold viscosity alone didn’t really factor in all that much, because #2 was 10W40, while #7 was 15W50. You can also see that full syn vs semi-syn didn’t factor in much, because #1 and #10 were both full syn. So, looking at this chart, you just have to decide what you are willing to live with.

Timken OK Load
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Timken OK Load is a qualitative measure that indicates the possible performance of extreme pressure additives (EP Additives) in a lubricating grease or oil. The units of measure are pounds-force or kilograms-force and are determined using a special test machine.

The test machine is based on a machine manufactured by the Timken Company from 1935 to 1972. It is now an industry standard test though the meaning of the qualitative measure has become less useful as the science of tribology has advanced.

The test machine consists of a bearing race mounted on a tapered arbor rotating at high speed. The race is brought into contact with a square steel test block under load. The contact area is flooded with the lubricant being tested. The Timken OK Load is the load at which the spinning bearing race produces a score mark on the test block.

Though Timken no longer manufactures the test machine, Timken OK Loads are still listed on grease and oil property charts. It was once generally assumed that the measure and the film strength of the lubricant were directly related. Today, the primary purpose of the test is to determine whether EP additives are present and functioning. A measure of 35 pounds-force (16 kilograms-force or 155 newtons) or more means that EP additives are present and working.

The Timken OK Load test specification is ASTM 2509.

-----------------------------------

So the test is only valid for Extreme Pressure lubes (motor oil is NOT an EP lube), and then only to test whether the EP additives are PRESENT, not the the quality of them.

540 RAT: You're slamming anyone daring to question this "test" and you claim it's the definite test of quality of oils when its clearly not. What is your stake in this? Are you a RP employee? Reseller?

I have no stake in Royal Purple at all, I simply was sharing tech data on oil that I thought other gearheads might like to see. And complete oil test data can often be hard to come by. Zwede, you seem to be more against the whole idea, more than anyone, and seem to go out of your way to discredit the data. Funny thing, actual degreed engineers I discussed this with, all thought it was a good test and provided important data. I guess you know more than professional engineers. So, just ignore the whole thing and carry on as you have been.

Each to his own, but if you want max protection for real high performance/race engines, the extra Royal Purple film strength starts to look real good. As I said earlier, big blocks tend to lose roller lifters, and the extra film strength may be what is needed to make them live. Royal Purple's early products were developed for similar problems with industrial machinery, which it cured.

Plenty of hardcore dragracers use 0W? Royal Purple racing oil, which is of course very thin, so they barely hold any oil pressure. They do it for max hp that the thin oil helps with, yet the internals look like new when taken apart.

Racing Engine builder Joe Sherman got an extra 30hp in a 600hp small block Chevy just by switching from Valvoline 20W50 dino racing oil to Royal Purple 5W30 racing oil. He never saw that in any other oil. He uses it all the time in his shop and has nothing but good things to say about it. The best film strength and more hp, I'd say that was rather impressive myself.

Their street oil meets recent API requirements as well as GM's own GM4718M oil requirement for Corvette's, GTO's and others. So it must be pretty good on that count as well, because not all oil meets that requirement.

I have been using Royal Purple 5W30 street oil in two of my late model cars for some time now without issue. One is just a 200hp V6 daily driver, and the other is a 550hp supercharged V8 muscle car. They have been just fine, and in fact the supercharged engine's idle went up 100 rpm. A few other people I know, have been using it as well, and also like it just fine.

So the question I have for you naysayers is, what oil do you use in your own engines? And if the tech specs on an oil is not how you decide which oil to run, just how did you decide on that particular oil? About all that is left is guesswork and marketing hype, right?

I have nothing at all against RP. Although I don't use it myself everything I hear about it suggests its a top quality oil. But as an engineer I don't like seeing test procedures that are (IMO) misused. Using the timken test which is only meant to indicate presence of EP additives as a measure of engine oil quality is simpy incorrect science. I remember Slick 50 did the same thing years ago. Add some Slick 50 and watch that Timken test "prove" how great it is.

As to how I selected what oil to run in my cars, I relied on GM. They picked M1 for all their high performance engines for a reason. Of course there is a cost factor in that equation and I'm sure if cost was not a factor they may well have gone with RP. But to me, I think GM was right on going with M1 as the best compromise between performance and cost.

Intersting - text ( of the actual test parameters) was a little blurred when magnified, but I understood the results. I have been looking into this a lot lately as I want to switch to Synthetic for the high temp stability which I think will cure my post extended run lower than desired hot oil pressure. Short of pulling the motor out and changing out the pan for something with a lot more capacity, a swap to synthetic appears to be a good choice. From what I have gathered, I have it down to either Royal Purple, Red Line or AMSOIL for the switch with the first two being easier for me to get a hold of.

PENRITE - wonder if that's the same as the US brand PITPEN (I think?? - label look similiar).

When I broke my cam in a year ago I used rottella 15/40, I switched back to my AMSOIL 10w30 Synthetic. My 327 runs cooler,stronger. Test are all well and good but I let my engine tell me what she wants and it's Amsoil.:D

When I broke my cam in a year ago I used rottella 15/40, I switched back to my AMSOIL 10w30 Synthetic. My 327 runs cooler,stronger. Test are all well and good but I let my engine tell me what she wants and it's Amsoil.:D
you had an increase in perfromance from switching to a thinner oil. nothing spectacular about that.
i've noticed higher idle speeds and better responsiveness just from switching from Valvoline 10w-30 to Mobil1 10W-30 before. my Nova gained 300 rpm in idle speed, and just felt all around snappier after doing nothing but an oil change.

good news...I have been using the std royal purple for years now...with great results....even use it in the generator in my boat...that has been run for more than 24 hours without shutting off..has over 1000 hours on it....great stuff..

good news...I have been using the std royal purple for years now...with great results....even use it in the generator in my boat...that has been run for more than 24 hours without shutting off..has over 1000 hours on it....great stuff..


Thanks for the imput EZ.

The Timken OK Load test specification is ASTM 2509.

-----------------------------------

So the test is only valid for Extreme Pressure lubes (motor oil is NOT an EP lube), and then only to test whether the EP additives are PRESENT, not the the quality of them.



Actually you didn't quite finish your homework Zwede. The ASTM 2509 you listed above is for Greases, but to try and make your point, you omitted the fact that ASTM-D 2782 is for Fluids, such as..........well, motor oil.

If you do the Timken OK Load test or the 4 Ball wear test, if you prefer, you are comparing the lubricants film strength. And film strength is the primary characteristic that prevents engine wear. Wear does not occur when metal is seperated by oil, only when there is metal to metal contact, and it doesn't have to seize to wear. That is why most engine wear occurs during start-up, because the hot thin oil has largely run off after the last shut-down. Then the only thing that prevents wear on start-up is, you guessed it, oil film strength. That's why preventing metal to metal contact is the most important, number one job of motor oil, and why all other motor oil characteristics come AFTER that.

While those oil film strength tests are not exactly engine components being rubbed together, as long as all the oil samples are subjected to the same test conditions, you do absolutely get a relative comparison between the various oils being tested. Make up your own impartial film strength test, and you'll get the same ranking. The highest film strength will give you the highest level of start-up protection. And that is just talking about everyday engines. Once you start talking high performance and race engines, and the heavy loads they see, oil film strength can obviously come into play even during running operation as well, especially when things start to go bad.

I can't imagine why any high performance enthusiast wouldn't want to give his beloved engine the best protection he could. I know you are a Mobil 1 user, which is obviously why you wanted to put down the test, since your oil was the worst performer of the U.S. sold oils. Just because the General calls for it, DOESN'T mean it is the best. I know you are not a Mechanical Engineer, nor a Petroleum Engineer, but even as an Electrical or Computer Engineer, you should be able to recognize the value of good oil film strength, and the fact that it should not be overlooked. It is part of the overall motor oil package. You wouldn't build a killer engine and then leave in wimpy stock rods would you? Of course not, you'd consider the whole package. And the same thing should be done for the motor oil you choose.

you had an increase in perfromance from switching to a thinner oil. nothing spectacular about that.
i've noticed higher idle speeds and better responsiveness just from switching from Valvoline 10w-30 to Mobil1 10W-30 before. my Nova gained 300 rpm in idle speed, and just felt all around snappier after doing nothing but an oil change.
What I failed to state was I have used all the premium synthetics in my 327 and I feel and know she runs the best with AMSOIL 10w30, thats the end of my story. Good luck with all your oil changes guys. ps.. go to Amsoil's web site and send them a question about your concern about flat tappet cam and synthetic oil.:D

Actually you didn't quite finish your homework Zwede. The ASTM 2509 you listed above is for Greases, but to try and make your point, you omitted the fact that ASTM-D 2782 is for Fluids, such as..........well, motor oil.

If you do the Timken OK Load test or the 4 Ball wear test, if you prefer, you are comparing the lubricants film strength. And film strength is the primary characteristic that prevents engine wear.

I guess I fail to see your point... Timken never claimed their machine was suitable for testing the quality of motor oils. I also recall Slick 50 using the same Timken test to show that adding Slick 50 greatly improved the results. For this, they got sued by the FTC and forced to stop that advertising as they failed to prove any correlation between the Timken test and engine oil quality/motor longevity.

Why should this test suddenly be relevant?

I guess I fail to see your point... Timken never claimed their machine was suitable for testing the quality of motor oils. I also recall Slick 50 using the same Timken test to show that adding Slick 50 greatly improved the results. For this, they got sued by the FTC and forced to stop that advertising as they failed to prove any correlation between the Timken test and engine oil quality/motor longevity.

Why should this test suddenly be relevant?

OK, forget the Timken test already, that's not really even the point. It was simply a way to measure and document the relative oil film strengths between various oils, then see how they compare to each other (according to the latest Amsoil literature I've seen, they use the 4 ball wear test to compare their own oil film strength to others. It, in effect, does the exact same thing as the Timken test - compares oil film strength. Pretend it was done that way, if it'll help you understand the idea). Geez, do a test with oil between two rocks, if that blows your dress up. All that matters is that you use the same repeatable test for all the oils, to see how they compare to each other. You can't get that info by just looking at the back of the bottle. Come on Markus, I know you are smarter than this. I don't know why you are playing dumb about the merits of including oil film strength in your decision about what oil to run. Talk to your Texas buddies Jim or Nick, I know they "get" this stuff. I've tried my best to explain it, and you still don't see it. There's not much more I can add, but maybe your buddies can get through to you. If you really are an engineer, I know you can grasp this. Its not Rocket Science.

For more reading about Mobil 1 and Royal Purple, take a look at your own Corvette Forum here:

http://forums.corvetteforum.com/showthread.php?p=1561613187&posted=1#post1561613187

OK, forget the Timken test already, that's not really even the point. It was simply a way to measure and document the relative oil film strengths between various oils, then see how they compare to each other (according to the latest Amsoil literature I've seen, they use the 4 ball wear test to compare their own oil film strength to others. It, in effect, does the exact same thing as the Timken test - compares oil film strength. Pretend it was done that way, if it'll help you understand the idea). Geez, do a test with oil between two rocks, if that blows your dress up. All that matters is that you use the same repeatable test for all the oils, to see how they compare to each other. You can't get that info by just looking at the back of the bottle. Come on Markus, I know you are smarter than this. I don't know why you are playing dumb about the merits of including oil film strength in your decision about what oil to run. Talk to your Texas buddies Jim or Nick, I know they "get" this stuff. I've tried my best to explain it, and you still don't see it. There's not much more I can add, but maybe your buddies can get through to you. If you really are an engineer, I know you can grasp this. Its not Rocket Science.

I work at a lubricant test company. I don't design oil, I design\build the test stands and equipment that tests the oil.

Basically, any API certified oil has been deemed acceptable by the OEMs and will work fine. The oil and additive package has to pass a series of tests to become certified. Look for the API seal and you'll be fine. That said, some of these older tests may be more applicable to our type of engines (carbed, flat tappet, pushrod). It really depends upon what you think is important. If film strength is your main criteria, then pay attention to the EP type tests (like the one you linked). How it responds to fuel dilution, temp related viscosity increase, etc., is probably more important. Read more here:http://www.bobistheoilguy.com/basic_lubrication_design.htm

Honestly though, you can't really go wrong with any API certified oil and Royal Purple is a fine oil.

The only reason I run synthetic is that it is rated for 300 degree F operation. I have read that you do not want to run petroleum oils over 230F as their film strength starts to go away.
I have run Mobil 1, and now Amsoil, as they are an API rated synthetic. I find that on cool track days my oil temperature is up at 230 F after about 7 laps at Thunderhill and can get to 250 F on hot days.
I don't use synthetic on the 2005 Lincolin LS that I have because I don't take it in the track, my wife does. She will not push anywhere near as hard as I will.
Her VW turbo 1.8 Golf however wouldn't have a warranty if I used conventional oil. The dealer tried to tell us once that we didn't need to use synthetic (the bill showed we were charged for conventional oil) so I called VW who had a field rep call me about 10 min later and asked who told me not to use synthetic. I then got a call from the dealer apologizing for being wrong and that they would change my oil for free to correct the problem.

There is a place for all these oil products which is why they are specified by the manufacturers and produced by reputable petroleum firms.

What any individual wants has to do with emotion as much as technology or economics.

i dont think its that important which oil you use, its the quality of the engine parts and specs.-sludge build up prob. causes more harm, and some of the oils do that more than others, as i have found
i use pennzoil, just because i like the way it feels, kind of sticky compared to others, and that is as scientific as i get-use what works for you
i remember when i worked with a guy who raced go carts, and they had to run stock engines, b & s 5 hp-he would go thru rods pretty offen, put some slick 50 in it, and it extended the life of the engine pretty good-so i guess in that case, an additive helped