Dr.T, their isn't really much difference between what you believe and what I believe. Again, all I'm saying is match the engine with the right viscosity through analysis and take it from their. I would never put a 0w-20 in a Corvette, but I would put it in a Honda. That is the point and that is the key to the arguement IMO.
"Engine oil viscosity has VIRTUALLY NO EFFECT ON WEAR."
- Thread starter berge
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Oh don't try and backpedal from your 20 weight agenda now, buster!! We all know your light weight vision for the American motoring public!!!! You can't fool us!!
You ...you oil socialist!!
You ...you oil socialist!!
That was only about a $100 tongue lashing. What does it take to get a full $200 worth.quote:
Originally posted by Gary Allan:
Oh don't try and backpedal from your 20 weight agenda now, buster!! We all know your light weight vision for the American motoring public!!!! You can't fool us!!
You ...you oil socialist!!
Nice.
I never quite understood why this debate kept going on and on....
I figured if your UOA looks good with a 20wt, stick with it. If consumption goes up, go up a grade.
I have to say some of the HT/HS links and studies are thought provoking.
From RL on their 10w-40
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Yes, if you have no specific need for a heavier oil (or any rational type of evidence) then the lightest oil that can sustain your typical service duty for severity (or lack there of) and duration would be the wisest choice.
That's reserved for those that are members of the gentlemen's club. For those of distinctive tastes ...nothing but the best will do.quote:
That was only about a $100 tongue lashing. What does it take to get a full $200 worth.
MolaKule
Staff member
Because you are comparing apples and oranges.
The HT/HS is at the microscopic level of description while the viscosity thickening is at the "Bulk" or macrosopic description level.
Where has Amsoil actually thickened or switched "up to" another grade level, and if so, what were the circustances surrounding that situation?
I would say it is because Amsoil starts out near the top of its viscosity range and Mobil 1 starts out near the bottom of its viscosity range with respect to Xw30 oils. Mobil 1 would have to thicken at a rate 3.5 times Amsoils to go out of range. Mobil 1 must thicken almost 24% compared to Amsoil only having to thicken 6.8%.quote:
Originally posted by buster:
I have to say though, why does Amsoil thicken out of grade much more then Mobil 1, yet Mobil 1 has a lower high temp/high shear for the Xw-30 wts?
If you want to compare rates of thickening then you have to do a test with the same vehicle and same conditions. If you compare the rates on the recent mobil vs amsoil test you will find them similar with respect to mileage and oil replenishment.
If you are comparing oil results from different vehicles with different mileage and driving conditions then you are comparing apples to oranges and no such fair comparison or conclusion can be drawn.
Anecdotal, but all I have personally: Amsoil 15w40 synthetic, 5,000 highway miles in a really good running VW TDI (ave 58mpg). 35,000 on the engine and running an oilguard bypass. Oil was 16.8cSt. Tested again at 6,800 miles (thought maybe they messed up) and it was still 16.8. Usually starts at about 15.5.
At least it didn't get any thicker! Soot was 0.5% btw, and I was running Soy Shield in every tank.
The most amazing thing to me about all that, was this car's ability to get that kind of mileage with 16.8cSt oil in it! I can only imagine what my average would have been if I ran 5w30 Series 3000...
Tim
More data to add to the pile. In another thread scount said:
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Originally posted by 1sttruck:
The following link has a Shell article on piston rings, with a chart showing the oil film thickness vs oil weight; the 20W has a higher film thickness than heavier oils.
http://www.iantaylor.org.uk/papers/Additives2001.pdf
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Yes, because more of the thinner oil gets pumped up there, which is very good to a point. But the same guy has *another* article in his collection that describes another wear study.
http://www.iantaylor.org.uk/papers/ITC95.pdf
To keep this brief, following measurements made on an actual engine, they derived the following formula for top-ring wear (in paragraph 5):
new wear = old wear * (old HTHS/new HTHS)**2.15
To illustrate, this would give (3.6/2.6)**2.15 = 2 times more top ring wear using Mobil 1 0W-20 versus Mobil 1 0W-4
*********************************
Originally posted by 1sttruck:
The following link has a Shell article on piston rings, with a chart showing the oil film thickness vs oil weight; the 20W has a higher film thickness than heavier oils.
http://www.iantaylor.org.uk/papers/Additives2001.pdf
*********************************
Yes, because more of the thinner oil gets pumped up there, which is very good to a point. But the same guy has *another* article in his collection that describes another wear study.
http://www.iantaylor.org.uk/papers/ITC95.pdf
To keep this brief, following measurements made on an actual engine, they derived the following formula for top-ring wear (in paragraph 5):
new wear = old wear * (old HTHS/new HTHS)**2.15
To illustrate, this would give (3.6/2.6)**2.15 = 2 times more top ring wear using Mobil 1 0W-20 versus Mobil 1 0W-4
Visions of Rosanne Rosannadanna again.
AEHaas's Ferrari specs a higher viscosity under racing conditions. Thicker oil will simply offer more of a safety layer so to speak, even though in many cases your robbing HP and generating more heat. You thick oil lovers might have a point here.
The second study was done with oils that had no friction modifiers. This study is 10 years old, well before the current 0Wand 5W-20 oils were developed. In the conclusion he stated "the changes in wear that occur over the HTHS viscosity range 2.7 - 3.5 mPas are small."
The data does support recent studies that show decreasing friction and power loss in rings / cylinder bores with decreasing viscosity.
aehaas
The data does support recent studies that show decreasing friction and power loss in rings / cylinder bores with decreasing viscosity.
aehaas
With no other changes. Of course, Mobil's additive and blend stocks differ between the 0W-20 and OW-40.
Mobil's position, more or less, over the last three decades is that most people run an oil at least one SAE grade higher than they need to, and the original Mobil 1, a 5W-20W, showed wear numbers better than the existing SAE 30 oils in test track and field tests.
In the kind of driving that most people do that's probably still true.
.
Is Mobil 1 0W-20 going to have a better additive package than Mobil 1 T&S 5W-40 ? Will the synthetic base make for less wear than Delvac 1300 15w40 in a turbo diesel ? If so I'd suspect that it would be used a lot for the fuel savings.
I think we need to also remember that engine materials have become better and that also has a big impact on things.
This is from Mobil Austrailia on the 4.7 Toyota V8.
[ January 30, 2005, 08:02 PM: Message edited by: buster ]
This is from Mobil Austrailia on the 4.7 Toyota V8.
Found this on Noria from a member:
[ January 30, 2005, 08:02 PM: Message edited by: buster ]
Amsoil always seems thickens in most cases, in well maintained engines too, from what I've seen on BITOG. It was said before they might not use good anti-oxidants.
This quote above is implying that an A3 rated oil will thicken LESS then a A1 rated, which in this case would be Amsoil and Mobil 1.
On a % basis, I think Amsoil thickens more then Mobil 1. We see their ASL 5w30 become a 40 and 50wt oil before many times. So when looking at spec sheets, TFOUT and HT/HS, one would draw the conclusion that Amsoil is more stable then Mobil 1. I do not think that is the case at all IMO. Oil analysis really tells the story I guess.
It is strange though that in Amsoil's case where it thickens, wear is never affected.
[ January 30, 2005, 12:27 PM: Message edited by: buster ]
MolaKule
Staff member
If an oil starts out thicker and then thickens a bit, then that can be expected.
I guess we'll know about ASL soon because that's what I am running right now.
I guess we'll know about ASL soon because that's what I am running right now.
http://www.shell.com/home/ExitPage?...=INHERIT_SITEID&Source=CON&SourcesiteId=au-en
Check out the Shell Austrailia recommended viscosities for the Holden LS1 GTO, Civice and Corolla. They recommend 5w-40 and 15w-50.
Check out the Shell Austrailia recommended viscosities for the Holden LS1 GTO, Civice and Corolla. They recommend 5w-40 and 15w-50.
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