Oil Brew/Blend Calculator?

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maverickfhs

I have seen many guys here make their own oil brew and mention, if 0W20 is mixed with 0W40 with 4/1 parts, it'll be close to 0W30 and what not terms of ratios... Question is, how do you get that approximation of mixing blends? Is there an online calculator for viscosity and all and for that what do I need? Thanks for any advice and help

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Originally Posted By: oil_film_movies
http://www.widman.biz/English/Calculators/Calculators.html What's interesting is that its not linear. Example: Mix an 8 cSt oil 50% with an 11 cSt and you'd think you might get right in the middle, 9.5 cSt. You don't; its actually 9.36 cSt. (KV100 there).
This^

That's close enough for me.

Originally Posted By: maverickfhs
I have seen many guys here make their own oil brew and mention, if 0W20 is mixed with 0W40 with 4/1 parts, it'll be close to 0W30 and what not terms of ratios...
I'm coming up with a 24 wt. 4x20 and 1x40 = 120 Divide that by 5 = 24. When doing a blend to keep things stable I would only mix in one part of a different oil ideally. And stick to the same manufacturer and type if possible.

Thanks, is there any place where actual weights can be plugged in directly? Like 20% of 20W50, 40% of 10W30 and 40% of 0W40, I am just curious, nothing crazy here

maverickfhs, No, I haven't seen anything where you put the SAE grades in directly. You have to work with the actual cSt at 100 deg C or 40 deg C on the Widman tool. This is probably because the J300 SAE viscosity tables allows a range of viscosities within a particular grade.

Originally Posted By: SatinSilver
Originally Posted By: maverickfhs
I have seen many guys here make their own oil brew and mention, if 0W20 is mixed with 0W40 with 4/1 parts, it'll be close to 0W30 and what not terms of ratios...
I'm coming up with a 24 wt. 4x20 and 1x40 = 120 Divide that by 5 = 24. When doing a blend to keep things stable I would only mix in one part of a different oil ideally. And stick to the same manufacturer and type if possible.
Since the grades are just ranges, it's not particularly useful to employ them to calculate blended viscosity. It's much better to use actual viscosities of both oils in these calculations.

Take your example of mixing 4/1, mostly 0w20. That is 0w40 at 20%. Say both Mobil1. Widman: plug in 8.7 cSt at 80% and 12.9 at 20% at 100 deg C. Result: 9.39 cSt. Then notice its a "light" 0w30 since "30 weight SAE" is defined as 9.3 to 12.5 cSt. The zeroW part is probably intact, as its a pumping requirement, and both 0w40 and 0w20 grades are typically made from light base oils (relative to their 5w cousins).

Originally Posted By: maverickfhs
Thanks, is there any place where actual weights can be plugged in directly?
That would be kind of pointless because each grade represents a fairly wide range of possible viscosities.

Originally Posted By: oil_film_movies
Take your example of mixing 4/1, mostly 0w20. That is 0w40 at 20%. Say both Mobil1. Widman: plug in 8.7 cSt at 80% and 12.9 at 20% at 100 deg C. Result: 9.39 cSt. Then notice its a "light" 0w30 since "30 weight SAE" is defined as 9.3 to 12.5 cSt. The zeroW part is probably intact, as its a pumping requirement, and both 0w40 and 0w20 grades are typically made from light base oils (relative to their 5w cousins).
Thanks very much, makes sense!!

It gets tricky if you mix a 5w30 with a 0w30. I don't know if the result will be a 5w or a 0w when its cold. I assume linear proportional there.

So I have to know cST for each oil. Now, how can I find it for each specific oil type? Is it mentioned on the bottle or have to looks at the datasheet?

I don't get it... What's wrong with just buying the oil your engine actually NEEDS, and just using that?

Originally Posted By: rooflessVW
I don't get it... What's wrong with just buying the oil your engine actually NEEDS, and just using that?
Sorry, just trying to learn it I have enough oil in my stash to comfortably take care of all vehcile manufacturer recommended SAE grades for now.

Originally Posted By: rooflessVW
I don't get it... What's wrong with just buying the oil your engine actually NEEDS, and just using that?
People buy all sorts of "wrong" oils because it's on sale. Then they are trying to make it work by playing backyard chemists. It's the BITOG way.

Originally Posted By: Quattro Pete
Then they are trying to make it work by playing backyard chemists. It's the BITOG way.

Originally Posted By: Quattro Pete
Originally Posted By: rooflessVW
I don't get it... What's wrong with just buying the oil your engine actually NEEDS, and just using that?
People buy all sorts of "wrong" oils because it's on sale. Then they are trying to make it work by playing backyard chemists. It's the BITOG way.
I suppose.

Here's two of them:
Originally Posted By: car51
Originally Posted By: Linctex
I am going to take the same Castrol Edge High Mileage 10w-40 at the recent Autozone clearance. (\$2/quart) and mix it 50/50 with the cheapest Harvest King 0w-20 or 5W-20 and run it in my F150. (\$12 for a 5 quart jug)
AMEN! I got 10w40 EDGE hm and GTX ULTRA CLEAN 5w20 mixed 50/50%. Going in next OCI

Originally Posted By: maverickfhs
So I have to know cST for each oil. Now, how can I find it for each specific oil type? Is it mentioned on the bottle or have to looks at the datasheet?
Never is KV40, KV100, or even HTHS is on the bottle or jug. Too bad its not! It should be. I usually google Mobil1 0w40 kv100 for example. Then make sure the datasheet is current enough, look for a date on it somewhere or recent certification such as dexos1 Gen2 or SN or whatever is relevant.

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