The Point Spread

[Jeffs2006EvoIX]

I was just curious about the "Point Spread" of multi vis oil. For example, using my car as an example. Manual recommends: 10/30 fully synthetic motor oil. So if you switch to lets say GC that is a 0-30, you now have a 30pt gap, vs. a 20 pt gap of the 10/30. Am I making sense?

It just seems that if the gap narrower, in essence, there should be less additives in the oil or VI's. I know this would vary greatly with Dino oil, so lets stick to synthetics. Would the point spread matter much in a synthetic oil? Or is the smaller the gap the better still apply?

Hope this makes sense? haha. Any input would be great just learing here.

 

[rslifkin]

Smaller is still better in the same ways, but it's less of a concern with synth, until you get into huge spreads (such as 5w-50, 10w-60, etc).

 

[bepperb]

Keep in mind you can have a really high "point spread" without any viscosity index improvers. RedLine touts having none. So in that case, a smaller spread really isn't doing anything for you.

Now for other group 3 synthetics, where the VI of the base oil is only 120~140 but they finished product is 150~170 then yes, you have a valid concern, though I don't think there's much UOA or anecdotal evidence that it matters, especially in PCMO (not HDEO).

 

[Jeffs2006EvoIX]

my experience with huge point spread is limited. Only application I can pull info from is my own air compressor. It uses a 5/50 synthetic as recommended. I use Syntec 5/50 in it and when I change the oil every 20 hrs of use or so, it comes out looking all "frothy" if that makes sense. It goes in amber color and liquidy, coming out the drain plug used, it looks yellowish and frothy, like a frapiccino from starbucks. I have never seen oil look like that before. I definately don't want oil coming out of my motor looking like that.

I would think common sense would be to keep the gap as small as possible. Correct?

 

[river_rat]

The froth is probably from the crank dipping into the oil sump for splash lubrication.
The point spread worry is an old one and not very important with today's oils. It is more important to get good cold flow on start-up and proper running viscosity. Even the viscosity improvers in conventional oils are better nowadays.

 

[HangerHarley]

Originally Posted By: Jeffs2006EvoIX
It goes in amber color and liquidy, coming out the drain plug used, it looks yellowish and frothy, like a frapiccino from starbucks. I have never seen oil look like that before. I definately don't want oil coming out of my motor looking like that.


If your engine had that Oil come out looking that color, then it makes me feel better as mine did the same. And it was in a car.

We thought the engine was that of a Milkshake-producing variety.. up-close analysis of the Oil did not confirm. Glad the 5W-50 itself can be suspect.

Te first number isnt "Really" related to the second, though it USED to be true that if an Oil had a higher W number, it would be more shear-stable, and 10w30 was ideal. Thats still true.. but some people think 5w30 is better than 10w30.

It really doesnt make a difference until you get into freezing and below. All nit-picking aside.

 

[Audi Junkie]

Just stop using that term and forget about it.

 

[HangerHarley]

Originally Posted By: Audi Junkie
Just stop using that term and forget about it.


+1

I had an old-school mechanic explain to me how the smaller the spread, the better the Oil

And i still like 10w30 better and always will use 10w30 if i have a car that needs a 30, except in a -new new car- or a Honda, it IS a little thicker (though the "same when hot" its still thicker in other ways when warming up, the Base Oil concept)

And when thinking about it in that light, if the Base Oil (All of them are, ALL OF THEM) nowadays.. Its really a matter of preference

And 5w30 is better than 10w30 below Freezing actually thats not true it has to be lower than 32 for "10W" to begin to be borderline, and a 5W will do better at/around Freezing, and ultimately to 0W, its fine.

If you are like me, you ask why you need a low "W" number in heat, except with the BEST Base-stocks and most expensive Oil you still can though, but why. If you live somewhere Hot, the W number loses relevance, short trips vs long trips/engine idle/type of engine means a lot.

HTH

 

[Jeffs2006EvoIX]

Dave at Redline recommended their 5w30 over the 10/30 for my application stating and I quote "The 5w30 will create quicker spool up of your turbo over our 10/30 without sacrificing durability" Sounds like a winner to me. I have the 5w30 Redline in my car as of now.

 

[Audi Junkie]

Don't use that term anymore, it's a nonsense expression.

 

[Ben99GT]

Originally Posted By: Jeffs2006EvoIX
Dave at Redline recommended their 5w30 over the 10/30 for my application stating and I quote "The 5w30 will create quicker spool up of your turbo over our 10/30 without sacrificing durability" Sounds like a winner to me. I have the 5w30 Redline in my car as of now.

Redline 20W-50, 15W-50, 10W-40 (IIRC), 10w30, 5w30, 5W-20, and 0W-20 contain no viscosity index improvers whatsoever. RL 10w30 is kind of a pointless grade, I guess they just offer it because so many cars call for it.

 

[CATERHAM]

Neither RL's 5w30 nor 10w30 contain any VII's and they both has the same HTHS viscosity and not surprisingly the 5w30 has a higher VI; 162 vs 142.
So name one possible scenario where their 10w30 would hold an advantage? Exactly there isn't one.

Oh yeah, forget the "point spread" expression. What you should really be asking about is an oil's viscosity index. And the oil's with the highest "spread" such as ENEOS 0w50 (VI 193) don't necessarily have the highest VI's such as Castrol Edge 0W-20 (VI 220).

 

[CATERHAM]

Looks like Ben99GT beat me to it.

 

[Errtt]

I have seen the other way...

5w30 = 6
5w-20 = 4
10w-30 = 3
20w-40 = 2
etc.

smaller sum = better stability. It's old but it was more widely used (as far as I know) in the motorcycle world. Something about smaller sum, less VII's etc.

 

[SuperFast]

Originally Posted By: Errtt
I have seen the other way...

5w30 = 6
5w-20 = 4
10w-30 = 3
20w-40 = 2
etc.

smaller sum = better stability. It's old but it was more widely used (as far as I know) in the motorcycle world. Something about smaller sum, less VII's etc.


I got 10W30 in my 84 Camaro i could have gotten 5W30 but i didnt because im sure 10W30 is more stable. 5 less cold flow number, so what. Its HOT out here

I dont think 10W30 is as pointless as you say its tried and true and i believe 10W30 is what you will call a touch thicker even though thats not the most accurate way fof putting it, the 10 number vs the 5 number makes it a thicker oil in all aspects to a minor degree even though it is still a "30" so i must minorly digress. Im old scool. 10w30.

 

[Errtt]

Originally Posted By: SuperFast
Originally Posted By: Errtt
I have seen the other way...

5w30 = 6
5w-20 = 4
10w-30 = 3
20w-40 = 2
etc.

smaller sum = better stability. It's old but it was more widely used (as far as I know) in the motorcycle world. Something about smaller sum, less VII's etc.


I got 10W30 in my 84 Camaro i could have gotten 5W30 but i didnt because im sure 10W30 is more stable. 5 less cold flow number, so what. Its HOT out here

I dont think 10W30 is as pointless as you say its tried and true and i believe 10W30 is what you will call a touch thicker even though thats not the most accurate way fof putting it, the 10 number vs the 5 number makes it a thicker oil in all aspects to a minor degree even though it is still a "30" so i must minorly digress. Im old scool. 10w30.

I don't think it was a thickness thing - more toward VII stability, or something like lower number for less VII, shear stability

 

[BobFout]

100C visco / HTHS = quasi shear-stability ratio

 

[dparm]

^ This.

Modern oils have proven that the spread in viscosity is less important than the basestocks and additives.

 

[electrolover]

Originally Posted By: SuperFast
Originally Posted By: Errtt
I have seen the other way...

5w30 = 6
5w-20 = 4
10w-30 = 3
20w-40 = 2
etc.

smaller sum = better stability. It's old but it was more widely used (as far as I know) in the motorcycle world. Something about smaller sum, less VII's etc.


I got 10W30 in my 84 Camaro i could have gotten 5W30 but i didnt because im sure 10W30 is more stable. 5 less cold flow number, so what. Its HOT out here

I dont think 10W30 is as pointless as you say its tried and true and i believe 10W30 is what you will call a touch thicker even though thats not the most accurate way fof putting it, the 10 number vs the 5 number makes it a thicker oil in all aspects to a minor degree even though it is still a "30" so i must minorly digress. Im old scool. 10w30.



old school is sae30. you should give it a shot

 

[Ben99GT]

Originally Posted By: SuperFast
I got 10W30 in my 84 Camaro i could have gotten 5W30 but i didnt because im sure 10W30 is more stable. 5 less cold flow number, so what. Its HOT out here


We were talking about RL oils in particular. RL's 5w30, like their 10w30, doesn't use any VIIs. Both grades are just this side of shear proof.