Quote:
Wow, I'm learning a lot. Mobil 1 0w-40 does not shear and Syntec 5w-50 creates deposits.
and:
I'm happy for you. Too bad what you learned isn't what was said.
Polymeric Viscosity Index Improvers and Deposits
- Thread starter JAG
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I'm happy for you. Too bad what you learned isn't what was said.
It was RLI that would not send a sample, not Redline.
No way am I using Redline. I know some will think that's weird but oh well.
When you talk about sheer stable are you talking about a drop in viscoity at 40C or 100C? Does one always follow the other? If being sheer stable is a problem would not manufacturers recomment 10w30 over 5w30? And is 5w30 more stable that 15w40, given that they both cover the same spread. If viscosity is not exactly linear is the spread covered by 15w40 larger than 5w30? Or is this all %^&* and it's really the quality of the oil and not the viscosity ratings that make the difference?
Lonnie, these polymers expand as temps rise so they add more viscosity at 100C than at 40C. The xW-Y viscosity classification is crude enough that just looking at Y-x is not a good predictor of how much polymer VIIs an oil has. 15w40 oils can be quite shear stable.
Earlier I told one way of looking into it. ANother way is TooSlick's idea of looking at (Viscosity at 100C/HTHS). The bigger the number, generally the less shear stable the oil is. Of course there are exceptions. The best way is to look at UOAs. BTW, high HTHS by itself does not mean an oil is shear stable. Need to consider the viscosity at 100C as well.
Earlier I told one way of looking into it. ANother way is TooSlick's idea of looking at (Viscosity at 100C/HTHS). The bigger the number, generally the less shear stable the oil is. Of course there are exceptions. The best way is to look at UOAs. BTW, high HTHS by itself does not mean an oil is shear stable. Need to consider the viscosity at 100C as well.
Yeah I had the TBN tested. It will be interesting because ML Synthetic starts at only TBN=7. My run was not very long though - only 4000 miles.
BTW, running the new SM Synpower 5w-40 now. The stuff must be really thick because the turbo response is completely different. The engine is very smooth with it - hardly any turbo lag. But it also feels "slower" although when I look at the speedometer, I'm always surprised how fast it's going.
BTW, running the new SM Synpower 5w-40 now. The stuff must be really thick because the turbo response is completely different. The engine is very smooth with it - hardly any turbo lag. But it also feels "slower" although when I look at the speedometer, I'm always surprised how fast it's going.
Thanks TeeDub. I've been tempted to try Synpower 5W-40 again so will be interested in how it works out for you over the whole OCI.
Time for me to log off and be a better employee today at work than I have been so far!
Time for me to log off and be a better employee today at work than I have been so far!
What about AN blendstock like Synesstic ?
AN is great in many ways but it has a low VI compared to most other synthetic fluids. It's more like a VI decreasor when added to most synthetics. But it has been used a pour point depressant in non-synthetic motor oils. I like it mostly because it adds chemical stability when mixed with PAO compared to PAO alone. Also increases solubility of the basestocks...decreases the aniline point when added to Groups 3 and 4 basestocks.
Some of Mobil's high viscosity PAO oils have extremely high VIs so can be used as VIIs but they are so viscous that not much of it can be used in motor oils. I think that esters that are designed with very high VIs have been and still are used as VIIs in some motor oils. It's been a while since I read it, but this may be similar to what GC uses as a VII. Don't quote me on that.
Some of Mobil's high viscosity PAO oils have extremely high VIs so can be used as VIIs but they are so viscous that not much of it can be used in motor oils. I think that esters that are designed with very high VIs have been and still are used as VIIs in some motor oils. It's been a while since I read it, but this may be similar to what GC uses as a VII. Don't quote me on that.
Actually, I'm 180 degrees in the oposite direction - VI Index Improvers are your engine's friend!
Sure, I can understand some of the bad rap is deserved for 10W-40 in a VW turbo engine that beats the snot out of whatever oil is poured down the fill tube.
But in a engine that spec's GF-4 5w30, the VII's serve duty as friction modifiers for better gas mileage & in my opinion, lead to quieter engine operation.
And, as Molakule pointed out in several of his threads, VI improvers as a fluid also have good lubricant properties.
""the VII's serve duty as friction modifiers""
Not really that is a false statement love to see data since I have not seen any but it maybe out there.
bruce
remeber "common" VII are "plastic" Duh they will form sludge and deposits and as far as lube inhancer Not at all.
bruce
Not really that is a false statement love to see data since I have not seen any but it maybe out there.
bruce
remeber "common" VII are "plastic" Duh they will form sludge and deposits and as far as lube inhancer Not at all.
bruce
Hi Bruce and Blue99,
You guys may have seen this but if not, you may find it interesting reading. If the link doesn't work I apologize. My laptop cannot open PDF's well so I can't verify the link as a PDF file.
http://www.cheric.org/PDF/KARJ/KR15/KR15-3-0117.pdf
You guys may have seen this but if not, you may find it interesting reading. If the link doesn't work I apologize. My laptop cannot open PDF's well so I can't verify the link as a PDF file.
http://www.cheric.org/PDF/KARJ/KR15/KR15-3-0117.pdf
Hey JAG!
What you need is some ultra shear stable GTX HD40. As in STRAIGHT 40.
What you need is some ultra shear stable GTX HD40. As in STRAIGHT 40.
The test results in the above link are very astounding. Take Oil A that has no polymers. Test for film thickness as function of load and shear rate. Add polymers to Oil A. Now it's a more viscous oil in the classical sense (in very low shear rates as in gravity powered flow). Test it and find that under those same conditions as Oil A was tested, the film thicknesses have decreased relative to Oil A.
This is astounding because it's not comparing two oils of same kinematic viscosity; it's comparing oils of different kinematic viscosities that results only from adding polymeric VIIs.
This is astounding because it's not comparing two oils of same kinematic viscosity; it's comparing oils of different kinematic viscosities that results only from adding polymeric VIIs.
Yawn.
""Test it and find that under those same conditions as Oil A was tested, the film thicknesses have decreased relative to Oil A.""
I was told by one of the formost experts on gear lubrication that a gear set "sees" only the base oil viscosity when VII are used so if a iso 100 oil is thickened to iso 460 the gears will only "see" the iso 100 base oil they do not respond to the VII.
I was told by one of the formost experts on gear lubrication that a gear set "sees" only the base oil viscosity when VII are used so if a iso 100 oil is thickened to iso 460 the gears will only "see" the iso 100 base oil they do not respond to the VII.
What's wrong with Redline?
Thanks everyone for the last few posts.
glxpassat, I used Redline 10w30 in 2002 or so in a 2002 2.5L Subaru Impreza engine that burned 3/8 qt of oil since new. I think it had issues with one or more piston rings and/or valve seals. But anyhow, the Redline oil used for at least 4 OCIs doubled the oil consumption rate. Perhaps that can be explained away. But the kicker was that the Redline transmission oil (manual) leaked out of both driveshaft seals at an alarming rate, as soon as I put it in and kept doing so for at least a few thousand miles. Alarming, as in dripping onto headers and making one heck of a stink. I drained it out and put in Valvoline Synthetic transmission oil and leaking stopped 100%. So I've lost faith in Redline from my experiences with their products.
glxpassat, I used Redline 10w30 in 2002 or so in a 2002 2.5L Subaru Impreza engine that burned 3/8 qt of oil since new. I think it had issues with one or more piston rings and/or valve seals. But anyhow, the Redline oil used for at least 4 OCIs doubled the oil consumption rate. Perhaps that can be explained away. But the kicker was that the Redline transmission oil (manual) leaked out of both driveshaft seals at an alarming rate, as soon as I put it in and kept doing so for at least a few thousand miles. Alarming, as in dripping onto headers and making one heck of a stink. I drained it out and put in Valvoline Synthetic transmission oil and leaking stopped 100%. So I've lost faith in Redline from my experiences with their products.
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