Let's say you wanted to thicken up 30 weight Mobil1 a little...

Messages
658
Location
EU
Criticism #1 of this oil: "it's on the thin side". Which means its viscosity is formulated at the lower end of the scale range. OK, then. Using only Mobil1 products, what volume of higher viscosity M1 would you add to 5w-30 M1 to get an oil with a viscosity at the high end on the 30 weight scale? Shoot for 11.3-11.8. Use a 6-quart final volume as typical. Example: 4 quarts 5w-30 + 2 quarts 0w-40. Bonus points for anyone who can actually calculate the final viscosity, if it is possible.
 
Messages
243
Location
Reno Nevada
You can't simply use a proportion to predict the final viscosity of a heterogeneous polymeric solution. The largest molecules contribute disproportionately to viscosity. It doesn't take much 50 weight added to a 30 weight to achieve a 50 weight final viscosity. However, the mixture will shear faster than a true 50 weight.
 
Messages
204
Location
Cordova, TN
I just add a couple of ounces of Shaeffers #132 Moly EP to the M1 10w-30 I use to accomplish what I think a little higher viscosity would in terms of benefits. Plus there are additional benefits to the #132 and it is relatively inexpensive.
 
Messages
231
Location
Ontario
Why not use a brand that has a viscosity closer to the range you seek in the first place? Amsoil, Shaeffers etc. If the thinner Mobil 1 is what you need then maybe using it as is would work and if not try something a little thicker or even just 0W40 by itself.
 
Messages
1,992
Location
Windsor,Ontario
My Jeep's sump holds 6 quarts on the 4.0L straight six...in the summer I use 4 quarts 10W-30 and 2 quarts 15W-50..both Mobil SS..runs great..quiter also...these engines are know for piston slap...they (I own two) use no oil thats noticable on the dipstick between changes...Mobil's web page says this type of "mixing" can be done.
 
Messages
1,992
Location
Windsor,Ontario
quote:
Originally posted by Drstressor: You can't simply use a proportion to predict the final viscosity of a heterogeneous polymeric solution. The largest molecules contribute disproportionately to viscosity. It doesn't take much 50 weight added to a 30 weight to achieve a 50 weight final viscosity. However, the mixture will shear faster than a true 50 weight.
What if you aren't really going for a 50W oil...but closer to a 40W...will this mix shear down to dangerous levels between 5-6k oil changes?I can't get 40w Mobil around here so I mix a bit in the summer to get a slightly thicker oil...in winter it's back to the factory specs of a 10W-30.I'm not a chemist but in theory the final results of this mix should be a little thicker on the viscosity scale between changes if they are not an extended drain...tell me if I'm wrong here.
 
Messages
2,480
Mathematically, I come up with 3.75w-32.5. If you do equal parts, it will be a 2.5w-35. But, in reality, the viscosity will be different and unknown without testing. I still say no harm done...go for it. But, can't comment on the realiability of such a mix for long-drain intervals (>9k)...but 5-6 should be fine. Why not mix 15-50 with the 5-30. Here, mathematically you would get a 10w-40 with equal parts or 7.5w-35 with a 2:1 mix (5-30:15-50).
 

YZF150

Thread starter
Messages
658
Location
EU
This is good. Actually, I wasn't asking because I was set on doing this. It is more of an intellectual exercise, really. This characterization of Mobil1 is so prevalent that I just starting thinking about what one could do to improve upon the basic forumula. I'd really be interested to read more from anyone who's done some blending of M1--what were the circumstances, what were you trying to accomplish/fix, what was the mix, etc. Let me add this other condition to maybe make it easier: assume no really long drain intervals. Say 6000-7500 miles, tops.
 
Messages
1,992
Location
Windsor,Ontario
quote:
Originally posted by Dr. T: Mathematically, I come up with 3.75w-32.5. If you do equal parts, it will be a 2.5w-35. But, in reality, the viscosity will be different and unknown without testing. I still say no harm done...go for it. But, can't comment on the realiability of such a mix for long-drain intervals (>9k)...but 5-6 should be fine. Why not mix 15-50 with the 5-30. Here, mathematically you would get a 10w-40 with equal parts or 7.5w-35 with a 2:1 mix (5-30:15-50).
HUH...how can a 10W/15W on the low end come up to 2.5?Math never was my strong subject but this seems odd [I dont know]
 
Messages
2,480
Well, the question was in reference to mixing 5/30 with 0-40. This would give you a slightly thicker cold visc. than a 0 and a slightly thinner hot visc. than a 40...ie. equal parts would give you a mathematical 2.5/35
 
Messages
1,992
Location
Windsor,Ontario
quote:
Originally posted by Dr. T: Well, the question was in reference to mixing 5/30 with 0-40. This would give you a slightly thicker cold visc. than a 0 and a slightly thinner hot visc. than a 40...ie. equal parts would give you a mathematical 2.5/35
OK..Then lets get a "mathematical" viscosity for 4 quarts 10W-30 and 2 quarts 15W-50..thats what I use...and I know it's not a "real" viscosity..just a mix [Big Grin]
 
Messages
2,794
Location
NM
I mix 3 qts of 10W-30 and 3 qts of 15W-50 M1 on my 02 Z28. I was trying to cure the piston slap and have a thicker oil for Texas. I don't know how thick the oil is, but the slap never went away. I might try Redline someday [Roll Eyes] Rick [ July 11, 2003, 01:21 PM: Message edited by: Last_Z ]
 
Messages
951
Location
Loveland, Colorado
quote:
Originally posted by Patman: ... the oil companies should list their viscosities on a different scale, so that you could tell exactly how thick the oil is, not just seeing it in a rather vague range like it is now. The difference between an oil that is 9.3cst and another that is 12.4cst is pretty big, but yet both of those oils could be labelled as 30 weight oils.
Hear!-Hear! Patman for API president!! [Patriot] [Canada]
 
Messages
2,480
I agree, but it's fun trying. I was doing this too when deciding whether to go full 15-50 or not. So 4 qts. 10-30 and 2 of 15-50 would come out to 11.25w-35 Happy lubricating [Burnout]
 
Messages
1,992
Location
Windsor,Ontario
quote:
Originally posted by Dr. T: I agree, but it's fun trying. I was doing this too when deciding whether to go full 15-50 or not. So 4 qts. 10-30 and 2 of 15-50 would come out to 11.25w-35 Happy lubricating [Burnout]
Thats about what I came up with [Big Grin]
 

YZF150

Thread starter
Messages
658
Location
EU
Well, the question was in reference to mixing 5/30 with 0-40. Doc, that was an example. Just referring to the generic "30 weight" specified in the thread title, what would anyone use to get a thicker 30? The "xw" end of the oil viscosity doesn't matter. There are multiple possibilities. There is 0w, 5w, and 10w-30. There is 0w-40, 15-50. (Is there a M1 10w-40? Don't recall.) etc. etc. Would one combo be any better than another?
 

Patman

Staff member
Messages
21,989
Location
Oakville, Ontario
quote:
Originally posted by Dr. T: Well, the question was in reference to mixing 5/30 with 0-40. This would give you a slightly thicker cold visc. than a 0 and a slightly thinner hot visc. than a 40...ie. equal parts would give you a mathematical 2.5/35
It never works out that way for two reasons. One, you could have one oil that is a 5w30 and another that is a 0w40, but with virtually the same viscosity (one could be 12.4cst, the other 12.6cst) so mixing those two won't result in a 35wt at all (not that there is such a thing as 35wt oil anyways) Also, with different levels of VII, a different thickness of the base oil, etc., you can't just mix two oils and get an exact average of the two. If you mixed 20w50 with 0w30 for instance, you'd most likely end up with an oil closer to 15w40 than you would to 10w40. The low end number would be especially affected when you mix in any amount of thicker oil with it. [ July 11, 2003, 12:13 PM: Message edited by: Patman ]
 
Messages
951
Location
Loveland, Colorado
quote:
Originally posted by Patman: ... (not that there is such a thing as 35wt oil anyways) ...
Sure there is! We simply don't "label" them that way. Viscosity's an inclined scale, not a bunch of steps. And since nobody lists xW- vis in a VOA/UOA report, how do we know what happens at the low end?
 
Top