Low VI vs High VI
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I'm currently running a blended mix of M1 15w-50 and M1, EP, 5w-20 in my Toyota 4 Runner.
The only reason for the 15w-50, in my situation, was the price.
I picked up a load of quart bottles of M1, 15w-50, SN at Kmart on clearance for $2 to $3 a quart. It appears that the HD oil was not in demand by customers...so I found a use for this quality oil in HD...by using a blended mix.
All M1 oils are compatible with each other and can be mixed.
My mix is 4+ quarts of M1, extended performance 5w20 and 2 quarts of M1, 15w-50.
I'll use the same mix for summer but only 50/50 of both oils.
The only reason for the 15w-50, in my situation, was the price.
I picked up a load of quart bottles of M1, 15w-50, SN at Kmart on clearance for $2 to $3 a quart. It appears that the HD oil was not in demand by customers...so I found a use for this quality oil in HD...by using a blended mix.
All M1 oils are compatible with each other and can be mixed.
My mix is 4+ quarts of M1, extended performance 5w20 and 2 quarts of M1, 15w-50.
I'll use the same mix for summer but only 50/50 of both oils.
Mobil 1 15w50 use to be my oil of choice for my harley. I know a lot of others used it too. You just need to think out of the box a little.
Honestly, in Melbourne, 15W-anything won't be an issue for you, over the 5W-50.
When the 5W-50 became the "standard" M1, I sort of stopped playing with it...VII of 179 for the 5W-50 versus 165 for the 15W-50 didn't really seem worth the additional spread in Oz. (although the 5W has a way better PP...nothing as good as the 150VI V-Twin, which has a PP of -50+C)
When the 5W-50 became the "standard" M1, I sort of stopped playing with it...VII of 179 for the 5W-50 versus 165 for the 15W-50 didn't really seem worth the additional spread in Oz. (although the 5W has a way better PP...nothing as good as the 150VI V-Twin, which has a PP of -50+C)
Actually the oils with such a big spread like M1 5W-50, Eneos Sustina 0w50 have demonstrated to be quite a low sae 50, they really show to be closer to some high sae 40 than a real sae 50.
To be achieved such a large spread (5W-50, 0w50) takes much VII in the make, which not always is a good thing.
A 15W-50 oil normally is a real sae 50 and IMO these oils are very stable, but you must have a car that can run with such a thick oil, and convenient weather conditions also (quite hot climate), because a 15W-50 isn't what I want to start my engine with in temperatures below 0 .
To be achieved such a large spread (5W-50, 0w50) takes much VII in the make, which not always is a good thing.
A 15W-50 oil normally is a real sae 50 and IMO these oils are very stable, but you must have a car that can run with such a thick oil, and convenient weather conditions also (quite hot climate), because a 15W-50 isn't what I want to start my engine with in temperatures below 0 .
Fair call, and I agree. If by 0, you are talking F, as 20W-50 dinos worked OK down to -11C for the first half of my life.
Have been tempted in the past to use the 15W-50 or V-Twin as the basis of a dumbell like blend to make a super stout 40, by starting with a highly shear stable, low PP (for the V-Twin, or the Motorbike 15W-50), then using a lighter viscosity to cut it back to where I was targetting.
I'm thinking that a more robust, shear stable, low volatility base, thinned with an oil that's more shear prone, higher volatility, and VII lighter oil (and with xW-20s fairly well available at my local mechanic), the oil will if anything "fail" into an area of higher safety margin.
That or start with Delvac 1 in the first place.
Have been tempted in the past to use the 15W-50 or V-Twin as the basis of a dumbell like blend to make a super stout 40, by starting with a highly shear stable, low PP (for the V-Twin, or the Motorbike 15W-50), then using a lighter viscosity to cut it back to where I was targetting.
I'm thinking that a more robust, shear stable, low volatility base, thinned with an oil that's more shear prone, higher volatility, and VII lighter oil (and with xW-20s fairly well available at my local mechanic), the oil will if anything "fail" into an area of higher safety margin.
That or start with Delvac 1 in the first place.
Exuse me, i didn't specified, i was talking of 0 degrees Celzius. Here where i live the temperatures go down to -25C in the winter, I meant such low temps.
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There are some low VI oils that are quite stout -- Red Line 5w30 comes to mind. Even though the VI is only in the 160s, they use no VIIs. Generally speaking, it means the oil can withstand a lot of punishment.
To get the viscosity spread in that 5w50, they're definitely using VIIs (good ones, but they're still there).
To get the viscosity spread in that 5w50, they're definitely using VIIs (good ones, but they're still there).
Originally Posted By: supercity
Is there any benifet using a lower VI oil in some situations?
e.g. Redline make a 5w50 ad a 15w50, so does Mobil 1. Why would you ever choose the 15w50?
Yes, there can be a benefit to using a lower VI oil in some situations. If you are racing an engine that is known to aggressively shear oils, a lower VI oil will in general resist shear-related viscosity loss better than an oil with higher VI.
Is there any benifet using a lower VI oil in some situations?
e.g. Redline make a 5w50 ad a 15w50, so does Mobil 1. Why would you ever choose the 15w50?
Yes, there can be a benefit to using a lower VI oil in some situations. If you are racing an engine that is known to aggressively shear oils, a lower VI oil will in general resist shear-related viscosity loss better than an oil with higher VI.
The lower VI oil should be less prone to shear and generally have a higher HTHS as well, just depends on what you find important.
We want a low first number. A 0 or 5 has advantages over a 10 or 15 .
The second number? No reason to go thicker than we need. First is the car mfr recommendation. In the USA, we can go up one grade thicker.
Shannow would know what is available to you, and your approx. weather conditions.
The second number? No reason to go thicker than we need. First is the car mfr recommendation. In the USA, we can go up one grade thicker.
Shannow would know what is available to you, and your approx. weather conditions.
Originally Posted By: KCJeep
The lower VI oil should be less prone to shear and generally have a higher HTHS as well, just depends on what you find important.
This is what I was thinking. I have noticed higher VI oils have a lower HTHS and KV100 for the same grade. I was wondering if this was actually intended by design or really just a trade off. Does the higher VI make up for the lower HTHS if operated under very high temperatures?
The lower VI oil should be less prone to shear and generally have a higher HTHS as well, just depends on what you find important.
This is what I was thinking. I have noticed higher VI oils have a lower HTHS and KV100 for the same grade. I was wondering if this was actually intended by design or really just a trade off. Does the higher VI make up for the lower HTHS if operated under very high temperatures?
The higher the VI of an oil the better providing it doesn't shear too much and loose a significant portion of that high virgin VI. This can happen with the 5W-50 grade which tends to use high molecular weight shear prone polymer thickeners.
By the same token the highest VI oil available, Sustina 0W-20 with it's 229 VI doesn't shear at all even after over 10,000 miles in service.
So it really comes down to the quality of the oil. Another example of of shear stable high Vi oils are Red Line 0w30 (183 VI and 0W-40 (197 VI). And of course the benchmark Mobil 1 0W-40 (185 VI) is very shear stable in most applications.
By the same token the highest VI oil available, Sustina 0W-20 with it's 229 VI doesn't shear at all even after over 10,000 miles in service.
So it really comes down to the quality of the oil. Another example of of shear stable high Vi oils are Red Line 0w30 (183 VI and 0W-40 (197 VI). And of course the benchmark Mobil 1 0W-40 (185 VI) is very shear stable in most applications.
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