why not use single grade synthetic oil?
- Thread starter kickster
- Start date
- Status
Modern-Day Synthetic mono-grades pour and flow at extreme temperatures at least as good as any Dino mono or multi grade out there.
Why don't people use mono-grade Synthetics? Try finding it on the shelves and you'll see why.
From what I understand, most synthetics don't contain much in the way of VI's anyway; so why not run a multigrade?
A lot of synthetics likey are monogrades and have little or no VI modifiers. But since they meet the specifications for multigrades they are sold as such...
Interesting, the VI numbers look like they are actual straight weight oils.
The problem is that even with a true synthetic the viscosity at say 32F is likely to be too high. I still say that with the good quality synthetic oils now there is really little problem with shearing. Even if the oil shears..unless we are talking super performance the shearing won't cause higher wear.
Mobil 1 V-Twin 20W-50 contains no VI.
Mobil 1 MX4T 10W-40 contains almost none.
Amsoil offers SAE 30 Synthetic Diesel Oil and SAE 60 Synthetic Heavy Racing Oil.
There are a number of others out there.
However, the VI enhancers used today don't create problems in most applications, even in diesels.
Schaeffers Straight SAE30 #256 is a 5W when cold pumpability is tested.
MRV is -35F
Pourpoint is -45F
I suspect many 10W-30 Synthetics have no VII so are in fact Straight 30's as well.
Gene
MRV is -35F
Pourpoint is -45F
I suspect many 10W-30 Synthetics have no VII so are in fact Straight 30's as well.
Gene
According to several posts on this site all the Redline multigrade oils, except 5w40, are without viscosity index improvers.
If it has no VI improvers and still has suitable cold temperature properties it will meet one of the winter viscosity ratings and then be appropriately labelled as such so that people will buy it.
Ugly3 was probably referring to the automotive oil market!
This makes me wonder though: if a company makes a synthetic 10W-30 that meets all the required specs for that engine, can it be rebadged as a straight 30 and used?
MolaKule
Staff member
Just to add to what was already stated, keep in mind that a full synth 30 weight, which can be badged as a 10W30, does NOT contain a single straight 30 weight oil base oil.
It would contain two or more weights to give it a large VI 30 weight or 10W30 charateristics. In other words, the oil might contain a 6 cSt oil, a 10 cSt oil, and a 25 cSt oil in various proportions to attain a 30 weight or 10W30.
Rarely does one formulate with a single viscosity oil.
It would contain two or more weights to give it a large VI 30 weight or 10W30 charateristics. In other words, the oil might contain a 6 cSt oil, a 10 cSt oil, and a 25 cSt oil in various proportions to attain a 30 weight or 10W30.
Rarely does one formulate with a single viscosity oil.
So, I'm a bit confused.
Is there any advantage whatsoever to using an SAE 30 over a 10W30 (for example)?
I use Royal Purple oil - they offer multi weights and straight weights - and I live in Houston, where it seldom gets anywhere close to the freezing point. I've always used the 5W30 or 10W30 and I've never really given straight weight oils any thought, but now I'm curious.
God I love BITOG!
Hehehehe....
Is there any advantage whatsoever to using an SAE 30 over a 10W30 (for example)?
I use Royal Purple oil - they offer multi weights and straight weights - and I live in Houston, where it seldom gets anywhere close to the freezing point. I've always used the 5W30 or 10W30 and I've never really given straight weight oils any thought, but now I'm curious.
God I love BITOG!
Hehehehe....
Not per se.
Some SAE 30 oils could be classed as 10W-30, so the difference is semantic.
The original question assumed that all multi-weights used a VI enhancer, which is false.
It also assumed that VI enhancers were "bad". That's not true, either.
At the end of the day the only question is whether the particular motor oil you're using does what you want in the application you're using it in.
For Houston area, most of the time thicker oils do nicely. Castrol GTX 20w-50, or even better, Castrol HD-30. You will not need 5w-30 or 10w-30 in such a torrid, sweltering environment, except for the very rare cold Winter. Even then, it is thin oil in by December, out by end- February.
MolaKule
Staff member
Most VII's today are also incorparated with the Dispersant, or the Dispersant-type VII .
The VII/Dispersant is of excellent quality and is used to "tune" the final oil to target viscosity while, providing at the same time, a dispersant for the final formulation. Most VII's today are very shear stable. Tribo-chemically speaking, we have learned much about about how to make a shear-stable VII ever since Shell introduced their cutting-edge "Star" molecule.
Another case of a "Multifunctional" additive.
If I lived in an environment in which the temperature was constantly "temperate" I would use a straight 30 weight blend or synthetic.
The VII/Dispersant is of excellent quality and is used to "tune" the final oil to target viscosity while, providing at the same time, a dispersant for the final formulation. Most VII's today are very shear stable. Tribo-chemically speaking, we have learned much about about how to make a shear-stable VII ever since Shell introduced their cutting-edge "Star" molecule.
Another case of a "Multifunctional" additive.
If I lived in an environment in which the temperature was constantly "temperate" I would use a straight 30 weight blend or synthetic.
- Status
Similar threads
