Originally Posted By: CATERHAM
If you're implying that this blend could result in the 5W-30s somehow being converted into a 10W-30 I can't see how that is remotely possible.
CATERHAM, please read what I said, not what you would like to strawman me with...your standard OP.
You continually state that things are "self evident", "obvious", "don't appear remotely possible", but never bring any science to your arguments, other than "feelings.
I didn't say that the oils would somehow be converted to 10W30, I said that the "W" performance is the area most likely to be affected by negative additive interactions....sometimes VERY badly, and not just slipping a grade.
e.g.
http://papers.sae.org/2000-01-2942/
Go back to the 0W40 thread, and there's others.
As to attributing statements to others, your continual reference to ASTM D6922...
Originally Posted By: CATERHAM
Firstly, as per ASTM D6922, their PPs cannot be adversely affected.
Surely, as an Insurance Salesman, versed in reading and comprehension, you have read said standard and comprehend it. It neither states, nor implies those arguments that you continuously attribute to it.
I'll refresh your memory if you like.
In short, the standard is a "miscibility standard", not a guarantee of mixed oil's field performance.
The oil is mixed with 6 ASTM reference oils (not every available oil out there),
Quote:
Visual color determinations and observations are made
on an undiluted test oil specimen, along with six blends of the
same test oil that have been combined with specific reference
oils. The pour point is then determined for the undiluted test oil
specimen and the six blends. The undiluted test oil specimen
and six blends are then allowed to warm to room temperature.
Color determinations and observations are again made on the
undiluted test oil specimen and six blends. The undiluted test
oil specimen and six blends are heated to 232°C, then allowed
to cool to room temperature, and then stored at their pour point
temperatures for 18 to 24 h. The undiluted test oil specimen
and six blends are then allowed to thaw and a series of color
determinations and observations are made as they reach room
temperature. All data are recorded on a report form.
That's it...there's nothing other than colour, and the fact that it doesn't split, separate, gell, or form a precipitate. It doesn't test for pour point, other than the mix as the start point for the testing.
It does NOT guarantee that the blends maintain their W rating. It Does not guarantee that any other test that either oil meets on it's own, wear, scuffing, you name it...regardless of how many times that you, CATERHAM, say that it does.
Was discussed
here if you want to get up to speed with what ASTM D6922 DOES promise.
Originally Posted By: CATERHAM
Secondly, a 10W-30 is formulated from heavier base oils with a resultant lower VI. Both these 5W-30s have 170+ VIs and that's what you're still going to get when blended.
You can't make a 10W-30 with a 170+ VI.
Again, read what I said, not the strawman that you would like to beat down. That's not what I said, and there is literature to support that sometimes the interactions are a horrible loss in cold performance, while the KV40/KV100 re relatively unaffected...cases...and cases occur because the ASTM D6922 can only screen every test oil with 6 reference oils and check if they "split"...not check every oil against every other oil
You, of all people should understand that VI doesn't promise anything with regard to the cold weather performance "W" rating.
discussion here
Pictorially, to better enable it to be "felt". Two "synthetic" basestocks of same KV40/KV100, and therefore Viscosity Index (calculated from KV40/KV100, not an inherent measurement)...vastly different "W" performance....nothing to do with the possible negative interactions of blending, but answering your point.
Obviously, and clearly self evidently, these two basestocks need a different low end add pack to meet whatever cold weather "W" standard that's required, and surely it's obvious that the behaviour of two finished oils, with these two basestocks, when mixed isn't easily and linearly predictable, which is your blending posit, and one that I've repeatedly requested that you defend with other than motherhood statement.
(Oh, and the chart DOES support your argument that some racing oils get their 0W "by accident" on their choice of basestocks...not really for street oils).