mobil says " viscosity is most important"
- Thread starter chet2
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go to the numbers. here are the results of a survey i did a few months ago. these are raw, ie different engines, oils, etc. only commonality arethe viscosities. take from it what you will.
10w30
sample size 7
avg vis at 100 11.1
avg Fe/1000 miles 2.22
avg Pb/1000 miles 1.523
avg mileage 5158
5w30
sample size 8
avg vis at 100 9.63
avg Fe/1000 miles 3.57
avg Pb/1000 miles 0.342
avg mileage 7662
0w30
sample size 7
avg vis at 100 10.966
avg Fe/1000 miles 2.07
avg Pb/1000 miles 0.987
avg mileage 6077
0w40
sample size 6
avg vis at 100 11.98
avg Fe/1000 miles 1.83
avg Pb/1000 miles 0.29
avg mileage 5733
5w20
sample size 7
avg vis at 100 7.91
avg Fe/1000 miles 1.56
avg Pb/1000 miles 0.13
avg mileage 5400
0w20
sample size 7
avg vis at 100 8.58
avg Fe/1000 miles 1.257
avg Pb/1000 miles 0.62
avg mileage 10884
note that the 5w-20 did the best on lead wear, and the 0w-20 did the best on iron. these were all synthetic oils, and i believe (note i said "believe") that the 0w-20 lead numbers were skewed badly by all the priuses (priusi?) in the sample. the start/stop cycle on the engine at every stoplight is pretty rough.
10w30
sample size 7
avg vis at 100 11.1
avg Fe/1000 miles 2.22
avg Pb/1000 miles 1.523
avg mileage 5158
5w30
sample size 8
avg vis at 100 9.63
avg Fe/1000 miles 3.57
avg Pb/1000 miles 0.342
avg mileage 7662
0w30
sample size 7
avg vis at 100 10.966
avg Fe/1000 miles 2.07
avg Pb/1000 miles 0.987
avg mileage 6077
0w40
sample size 6
avg vis at 100 11.98
avg Fe/1000 miles 1.83
avg Pb/1000 miles 0.29
avg mileage 5733
5w20
sample size 7
avg vis at 100 7.91
avg Fe/1000 miles 1.56
avg Pb/1000 miles 0.13
avg mileage 5400
0w20
sample size 7
avg vis at 100 8.58
avg Fe/1000 miles 1.257
avg Pb/1000 miles 0.62
avg mileage 10884
note that the 5w-20 did the best on lead wear, and the 0w-20 did the best on iron. these were all synthetic oils, and i believe (note i said "believe") that the 0w-20 lead numbers were skewed badly by all the priuses (priusi?) in the sample. the start/stop cycle on the engine at every stoplight is pretty rough.
^ That data suggests two things 1)Mobil 1 leaches iron, either chemically or just plain ol wear 2)'Mobil' contradicts themselves even in the face of their products' performance. I think I trust them even more now.... and as I've always suspected, their 5w30 performs the worst and is more than likely the cheapest formula to produce. It could just be simply the sample sizes, but Mobil 1 5w30 in vehicles requiring 5w30 just ALL seem to be grinding the iron out.. coincidence? Also taking into account the avg. miles run/sample could also support the less wear the older the oil argument, but thats such a stretch since 0w20 is being run in "unique" applications
Kill this thread
i know i am going to regret the response, but exactly how do you judge 5w30 to be the "worst"? it had approx 150% of the Fe of the 10w30, but under 25% of the Pb?
max, i don't think it is possible to make sense of any of the responses that you have made here. i expect the response to this will be of the same caliber.
max, i don't think it is possible to make sense of any of the responses that you have made here. i expect the response to this will be of the same caliber.
life is too complicated
Tell an engineer at SWRI that viscosity doesn't matter and they'll laugh...They have testing procedures that allow them to measure wear rates of individual components while the engine is running that allow them to measure wear in the parts per billion range...They do used oil analysis...They disassemble the entire engine and inspect components for wear after tests...Some tests run 24 hours a day...They have the ability and resources to perform these tests on the same engine, under the same condition day after day and compare results with the same engine, same condition, with different oils and weights day after day...
Here's a quote from someone directly involved with running the tests at SWRI...Interesting they've traced more wear to thinner oil films...
"FYI, more wear occurs at low rpm and high load/peak torque rpm. Why ? Lower sliding speed generate thinner oil films and higher load and higher temps. Fuel rate in lbs/hr maybe higher at max power but fuel burned per combustion event is higher at peak torque rpm, do the math. Wear difference we see in actual full scale test and radioactive ones 4-10X ! One of the graphs I'll post next week shows this, ring and cylinder wear vs vis grade at peak torque rpm and rated power. 10w30 vs the 20W-50 20 times higher. We measure new oil HTHS, high temp high shear vis and it is key. It's the vis the engine sees not the label on the bottle."
"On my engine test we sample every 12 hours over even 500 hour length tests and I can predict the ring or liner or valvetrain wear from the ppm levels at 95 % confidence level and for you stat guys, R^2 on regression/prediction 0.99. What I can't tell until tore apart was it the rings, cylinders, valve train, bearings etc... why we do radioactive wear studies."
Here's a quote from someone directly involved with running the tests at SWRI...Interesting they've traced more wear to thinner oil films...
"FYI, more wear occurs at low rpm and high load/peak torque rpm. Why ? Lower sliding speed generate thinner oil films and higher load and higher temps. Fuel rate in lbs/hr maybe higher at max power but fuel burned per combustion event is higher at peak torque rpm, do the math. Wear difference we see in actual full scale test and radioactive ones 4-10X ! One of the graphs I'll post next week shows this, ring and cylinder wear vs vis grade at peak torque rpm and rated power. 10w30 vs the 20W-50 20 times higher. We measure new oil HTHS, high temp high shear vis and it is key. It's the vis the engine sees not the label on the bottle."
"On my engine test we sample every 12 hours over even 500 hour length tests and I can predict the ring or liner or valvetrain wear from the ppm levels at 95 % confidence level and for you stat guys, R^2 on regression/prediction 0.99. What I can't tell until tore apart was it the rings, cylinders, valve train, bearings etc... why we do radioactive wear studies."
I have not seen too many engines wear out because of "too much wear." You can go 200k miles with any weight oil and cylinder wall wear, cam wear, etc will all be minimal as long as you follow a reasonable OCI. IF it is true that thinner oils allow more wear, so what, it is not going to affect your engines life.
Also, thinner oils may allow more wear at the cylinder walls, but less on the valve train. I think bearing wear was similar for the different grades.
Also, thinner oils may allow more wear at the cylinder walls, but less on the valve train. I think bearing wear was similar for the different grades.
If you are running an industrial engine then continuous fixed rpm wear may make a difference in the engine life. Most engine, unless mechanical damage (abuse, head gasket, bad ignition, injector, fuel, incorrect modification, running too lean/rich, etc), will have low enough wear that last longer than the rest of the components (gaskets, mechanical cracks).
More importantly, transmission, suspension, chassis usually last much shorter than engine. So unless you are planning to keep your car for 20+ years it doesn't matter as long as the oil is good enough for the protection.
Are we going to run 20W50 in engines? Heck no, you are going to drop fuel economy 20% or so, enough money to buy a rebuild in case you need one (which you most likely don't).
What about start up wear? Since start up wears are higher than continuous wears, you probably should minimize it in passenger cars first.
In the end, Mobil is right, as long as you use the correct spec oil (i.e. SM) the only thing you have to worry about is putting in the wrong viscosity, because the API spec should protect your engine enough from lube related failure.
This is not just 5w20, but every visc out there. A typical user should use only the recommended grade unless you have mechanical issues (loudness, excessive burn, extreme weather, etc).
More importantly, transmission, suspension, chassis usually last much shorter than engine. So unless you are planning to keep your car for 20+ years it doesn't matter as long as the oil is good enough for the protection.
Are we going to run 20W50 in engines? Heck no, you are going to drop fuel economy 20% or so, enough money to buy a rebuild in case you need one (which you most likely don't).
What about start up wear? Since start up wears are higher than continuous wears, you probably should minimize it in passenger cars first.
In the end, Mobil is right, as long as you use the correct spec oil (i.e. SM) the only thing you have to worry about is putting in the wrong viscosity, because the API spec should protect your engine enough from lube related failure.
This is not just 5w20, but every visc out there. A typical user should use only the recommended grade unless you have mechanical issues (loudness, excessive burn, extreme weather, etc).
Originally Posted By: whitesands
They have the ability and resources to perform these tests on the same engine, under the same condition day after day and compare results with the same engine, same condition, with different oils and weights day after day
awesome, i'd like to see more of that kind of data. I suppose you can't disclose the brands of oil, but what kind of oils do you like?
They have the ability and resources to perform these tests on the same engine, under the same condition day after day and compare results with the same engine, same condition, with different oils and weights day after day
awesome, i'd like to see more of that kind of data. I suppose you can't disclose the brands of oil, but what kind of oils do you like?
For extremes in cold weather, no you wouldn't want an oil that's too thick...Yes, it is unlikely an engine with frequent OCI's with a quality oil would allow wear to the point of failure unless there was something mechanically wrong...But the point is it is proven that the thinner oils show increased wear over the heavier weights, and no that is not a prescription for an absurdly heavy weight either...It means that the move toward super thin oils was for CAFE, not because super thin oils protect the engine better which is commonly claimed by some here but unbacked by real data which the folks at SWRI have...How it was explained to me is that the person using the light oils may notice only a small difference in fuel economy however as a nation each little bit adds up to quite a bit of fuel savings...Basically it comes down to the government trying to trim as much off the trade deficit as possible...
Quote:
What about start up wear? Since start up wears are higher than continuous wears, you probably should minimize it in passenger cars first.
Yes you have a valid question here...I'm fairly certain just about every test parameter you can think of is covered at SWRI...And if you are someone that takes alot of short trips in extremely cold weather it's definitely something to consider.
Quote:
What about start up wear? Since start up wears are higher than continuous wears, you probably should minimize it in passenger cars first.
Yes you have a valid question here...I'm fairly certain just about every test parameter you can think of is covered at SWRI...And if you are someone that takes alot of short trips in extremely cold weather it's definitely something to consider.
Quote:
Tell an engineer at SWRI that viscosity doesn't matter and they'll laugh...They have testing procedures that allow them to measure wear rates of individual components while the engine is running that allow them to measure wear in the parts per billion range...They do used oil analysis...They disassemble the entire engine and inspect components for wear after tests...Some tests run 24 hours a day...They have the ability and resources to perform these tests on the same engine, under the same condition day after day and compare results with the same engine, same condition, with different oils and weights day after day...
Expensive.
Tell an engineer at SWRI that viscosity doesn't matter and they'll laugh...They have testing procedures that allow them to measure wear rates of individual components while the engine is running that allow them to measure wear in the parts per billion range...They do used oil analysis...They disassemble the entire engine and inspect components for wear after tests...Some tests run 24 hours a day...They have the ability and resources to perform these tests on the same engine, under the same condition day after day and compare results with the same engine, same condition, with different oils and weights day after day...
Expensive.
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Well, if he's talking about the full battery of tests ..then he kinda has a false impression about viscosity. Nobody I know puts an engine through the Sequence III-G test ..ever.
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