Cristobal, thanks for the equation. I knew there was one, but I couldn't remember it's name or where to look for it. Honestly, I've considered running fills of sae30 and 20W-50 mixed. I just did the math, and if I mix 3 quarts 20W-50 and 3 quarts 30 I'd end up with a 10W-40, correct?
Why The Dislike For 20W-50?
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That doesn't really work, as there is no spec for a 7.5W33.
Its either in a 30 grade or it rolls over into the 40 grade spec.
http://www.widman.biz/English/Tables/J300.html
http://www.widman.biz/English/Calculators/Mixtures.html
Using Pennzoil Conventional as an Example:
5W30 KV@40C:63.9 KV@100C:10.5
20W50 KV@40C:158.3 KV@100C:17.6
A mixture of 1 quart 20W50 with 5qts 5W30 would have a KV@100C of 11.4 which is still soundly a 30. KV@40C would be 73.7. Its harder to get the W rating, but I would guess its probably a 10W.
Its either in a 30 grade or it rolls over into the 40 grade spec.
http://www.widman.biz/English/Tables/J300.html
http://www.widman.biz/English/Calculators/Mixtures.html
Using Pennzoil Conventional as an Example:
5W30 KV@40C:63.9 KV@100C:10.5
20W50 KV@40C:158.3 KV@100C:17.6
A mixture of 1 quart 20W50 with 5qts 5W30 would have a KV@100C of 11.4 which is still soundly a 30. KV@40C would be 73.7. Its harder to get the W rating, but I would guess its probably a 10W.
Originally Posted By: Red91
Cristobal, thanks for the equation. I knew there was one, but I couldn't remember it's name or where to look for it. Honestly, I've considered running fills of sae30 and 20W-50 mixed. I just did the math, and if I mix 3 quarts 20W-50 and 3 quarts 30 I'd end up with a 10W-40, correct?
Are you referring to a straight 30W oil for the latter three quarts?
Cristobal, thanks for the equation. I knew there was one, but I couldn't remember it's name or where to look for it. Honestly, I've considered running fills of sae30 and 20W-50 mixed. I just did the math, and if I mix 3 quarts 20W-50 and 3 quarts 30 I'd end up with a 10W-40, correct?
Are you referring to a straight 30W oil for the latter three quarts?
20W-50
20W-50
20W-50
30W-30 straight 30W.
30W-30 " "
30W-30 " "
150/6 = 25. 240/6 = 40.
It will be about a 25W-40 oil at these figure. This formula is not exact. Think of it as "more or less."
20W-50
20W-50
30W-30 straight 30W.
30W-30 " "
30W-30 " "
150/6 = 25. 240/6 = 40.
It will be about a 25W-40 oil at these figure. This formula is not exact. Think of it as "more or less."
Originally Posted By: Red91
Cristobal, thanks for the equation. I knew there was one, but I couldn't remember it's name or where to look for it. Honestly, I've considered running fills of sae30 and 20W-50 mixed. I just did the math, and if I mix 3 quarts 20W-50 and 3 quarts 30 I'd end up with a 10W-40, correct?
Not really. A straight 30 has no W rating, but most are pure enough these days to probably pass for 25W with no problems.
Essentially what you'd end up with is probably like a 25W40.
Cristobal, thanks for the equation. I knew there was one, but I couldn't remember it's name or where to look for it. Honestly, I've considered running fills of sae30 and 20W-50 mixed. I just did the math, and if I mix 3 quarts 20W-50 and 3 quarts 30 I'd end up with a 10W-40, correct?
Not really. A straight 30 has no W rating, but most are pure enough these days to probably pass for 25W with no problems.
Essentially what you'd end up with is probably like a 25W40.
So, how well would this 25W-40 hold up in a 5K OCI? I wasn't sure how to factor in the 30. Yes, it's straight 30.
Originally Posted By: Colt45ws
Originally Posted By: Red91
Cristobal, thanks for the equation. I knew there was one, but I couldn't remember it's name or where to look for it. Honestly, I've considered running fills of sae30 and 20W-50 mixed. I just did the math, and if I mix 3 quarts 20W-50 and 3 quarts 30 I'd end up with a 10W-40, correct?
Not really. A straight 30 has no W rating, but most are pure enough these days to probably pass for 25W with no problems.
Essentially what you'd end up with is probably like a 25W40.
Sort of where it ends up anyway. So "more or less" is the best description. I do not think it matters much in practical use.
The best thing about these heavy oils is they go on sale cheap, and in warm to hot weather, they work great, at least in my experience.
Originally Posted By: Red91
Cristobal, thanks for the equation. I knew there was one, but I couldn't remember it's name or where to look for it. Honestly, I've considered running fills of sae30 and 20W-50 mixed. I just did the math, and if I mix 3 quarts 20W-50 and 3 quarts 30 I'd end up with a 10W-40, correct?
Not really. A straight 30 has no W rating, but most are pure enough these days to probably pass for 25W with no problems.
Essentially what you'd end up with is probably like a 25W40.
Sort of where it ends up anyway. So "more or less" is the best description. I do not think it matters much in practical use.
The best thing about these heavy oils is they go on sale cheap, and in warm to hot weather, they work great, at least in my experience.
Originally Posted By: Red91
So, how well would this 25W-40 hold up in a 5K OCI? I wasn't sure how to factor in the 30. Yes, it's straight 30.
Red, I am sure it would work fine if the outside temperatures would be in the appropriate range.
So, how well would this 25W-40 hold up in a 5K OCI? I wasn't sure how to factor in the 30. Yes, it's straight 30.
Red, I am sure it would work fine if the outside temperatures would be in the appropriate range.
By the way, I am right now looking at some Supertech HD oil.
It is straight 30W, but is rated SN.
It is straight 30W, but is rated SN.
My final mix would more than likely be 3 quarts Quaker State Conventional 20w50 and 3 quarts Havoline conventional 30. Either brand can be swapped for the other weight, but in my area Quaker State Conventional 20w50 shows up at auto parts stores only, and Havoline 20W-50 and 30 show up everywhere that sells Havoline. No Quaker State Conventional 30 in my area. Can also get Delo 30.
Originally Posted By: Cristobal
Originally Posted By: Red91
If I had an older car, I'd probably run it for the heck of it. The 20W-50 of today will be like all other modern oils, in the sense that is has improved. Of course there are "better" oils available, but I can't imagine why it wouldn't work now if it worked in the 80's. I recommend 5w30 for almost all applications if asked, but for my personal use the 20W-50 has a certain charm to it. Plus, I'm not running the 20W-50 I have as a full fill, just a top off. Quick question: if I have 5 quarts of 5w30 and 1 quart of 20W-50, what is my final viscosity? I'm thinking it would be a 13.5W-40? I'd also use SAE 30 for top off too if I had some, and that would actually be more appropriate for top off to a pre-existing 5w30.
Add the quart values and divide. For instance, five quarts at 5W adds to 25. Add 20 for that one quart and you get 45.
45/6 = 7.5. For the second value, 150 + 50 = 200. 200/6 is 33.333.
You wind up with 6 quarts of a 7.5W33.33 blend, more or less.
Let me know if I did the math wrong.
Isn't there more to it than just averaging the viscosity numbers?
Originally Posted By: Red91
If I had an older car, I'd probably run it for the heck of it. The 20W-50 of today will be like all other modern oils, in the sense that is has improved. Of course there are "better" oils available, but I can't imagine why it wouldn't work now if it worked in the 80's. I recommend 5w30 for almost all applications if asked, but for my personal use the 20W-50 has a certain charm to it. Plus, I'm not running the 20W-50 I have as a full fill, just a top off. Quick question: if I have 5 quarts of 5w30 and 1 quart of 20W-50, what is my final viscosity? I'm thinking it would be a 13.5W-40? I'd also use SAE 30 for top off too if I had some, and that would actually be more appropriate for top off to a pre-existing 5w30.
Add the quart values and divide. For instance, five quarts at 5W adds to 25. Add 20 for that one quart and you get 45.
45/6 = 7.5. For the second value, 150 + 50 = 200. 200/6 is 33.333.
You wind up with 6 quarts of a 7.5W33.33 blend, more or less.
Let me know if I did the math wrong.
Isn't there more to it than just averaging the viscosity numbers?
Yeah, I posted a couple posts up about how to actually do it.
Originally Posted By: HerrStig
The owner's manual for my BMW airhead shows a chart in which 20W 50 is the oil of choice for about any weather I would ever ride in.
20-50 is good down to -10C in an Airhead, and that's what it gets. Have run 15-50 and 25-50 in it with no problems, but 20-50 is my oil of choice.
Picked up my daughter's Laser Lynx last night, and heard a tap,tap, tap from the engine - checked the oil and nothing on the stick. Picked up 2 litres of 20-50 and topped it up, and all is good - I'll call that an oil change.
The owner's manual for my BMW airhead shows a chart in which 20W 50 is the oil of choice for about any weather I would ever ride in.
20-50 is good down to -10C in an Airhead, and that's what it gets. Have run 15-50 and 25-50 in it with no problems, but 20-50 is my oil of choice.
Picked up my daughter's Laser Lynx last night, and heard a tap,tap, tap from the engine - checked the oil and nothing on the stick. Picked up 2 litres of 20-50 and topped it up, and all is good - I'll call that an oil change.
In the 90's, I serviced more Lasers than I care to remember, just about all of 'em did fine on good old 20w50. The Lynx is quite a rare beast these days!
We have a couple of Mazda Neo's in town, but a Lynx just sounds better. I wish she would get a car that could keep it's oil between oil changes, because she never checks.
I use 20W50, SAE40 and SAE 50 for my proving grounds.
I'll put all three of the above in a new vehicle that
specifies 5W20 just to prove that the thick oil fears
are base-less.
In the cold winter I'll do the opposite. I'll use a 0W20 in an
engine that calls for 5W30, just to prove that thin oil
fears are base-less.
I'll put all three of the above in a new vehicle that
specifies 5W20 just to prove that the thick oil fears
are base-less.
In the cold winter I'll do the opposite. I'll use a 0W20 in an
engine that calls for 5W30, just to prove that thin oil
fears are base-less.
used_Oil,
I did an SAE30 summer, and 25W70 winter in a J-Car back in the day for similar experiment...the 25W70 cost a measureable amount of fuel, cranked slower definitely, but looking through at the spinning camshaft, oil was fairly flowing very quickly, no real difference to the (specified) 20W50.
Would still be happy to have a crack at a 20W20 in my Holden, even 'though 20W50 is the specced grade (15W40 for snow)...although the alloy rocker covers I've got on order may well be defacto oil coolers.
I did an SAE30 summer, and 25W70 winter in a J-Car back in the day for similar experiment...the 25W70 cost a measureable amount of fuel, cranked slower definitely, but looking through at the spinning camshaft, oil was fairly flowing very quickly, no real difference to the (specified) 20W50.
Would still be happy to have a crack at a 20W20 in my Holden, even 'though 20W50 is the specced grade (15W40 for snow)...although the alloy rocker covers I've got on order may well be defacto oil coolers.
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