Does a synthetic 20w50 "act thinner", flow better than than a conventional 20w50? I not just talking about cold climates, just in general. I know that conventional 20w50 is thick but for a car that it is recommended for would you see less drag, more hp gains etc... with a synthetic 20w50?
Synthetic 20w50
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I don't know if a pour point depressent is really all that necessary with a 20W-50. However - I believe some PPDs also serve as anti-oxidants. So additive X be added primarily used as an anti-oxidant and secondarily as a PPD.
Still - an oil with a "Synthetic" base but a minimal additive package could be outperformed by a "Conventional" base and a superior additive package.
The only time a synthetic 20W50 is going to do you any good is if the peak engine loading is takeing place mostly at operateing temp. and above for extended periods of time. For a daily driver synthetic 20W50 is more of a liability then an assest in most cases.The exceptions would be if you have a cooling issue or are hot labing your car at a track.
My truck manual calls for a 20W-50 for temps over 60F I believe. The trooper does run pretty hot. Why would a 20W50 be a liability? Excessive oil pressures?
If your book calls for it, then it should not be a liability. But it would be a liability in most vehicles on the street as they typically call for a 30 weight or thinner. You could get away with 10w40 Redline as Redline's web site states you can drop one grade when using their oil. Somewhat it would also depend on your oil pressure as you would not want pressure to get too low.
Well it is a liability because it is not going to protect well until the oil has reached operateing temp. Few people drive far enough to reach operateing temp let alon reach it with a 20W50. I am not talking about water temp. A synthetic 5W40 will almost always outperform a synthetic 20W50 in around town driveing. In a non-synthetic a quality 15W40 will almost always outperform a PCMO 20W50 both hot and cold.
You want an oil that has a good HTHS, good additive package, enough viscosity for the application and the best flow you can get for the usage and ambient temp's!
You want an oil that has a good HTHS, good additive package, enough viscosity for the application and the best flow you can get for the usage and ambient temp's!
I would think that the synthetic, because of the much more uniform molecular size distribution, would flow with less friction than a dino, both at the same viscosity.
It might be possible, but I'd think any gains would be minimal. You might find a slightly different viscosity curve. Also depends on the particular oil.
Here's Valvoline's 20W-50 PDSs.
https://www.valvoline-technology.co...A8C/$file/SynPower+Motor+Oils.pdf?OpenElement
https://www.valvoline-technology.co...82/$file/All-Climate+Multi+SM.pdf?OpenElement
cSt at 40°C: 155.42 (SynPower), 165.9 (All-Climate)
cSt at 100°C: 20.82 (SynPower), 18.5 (All-Climate)
Here's Valvoline's 20W-50 PDSs.
https://www.valvoline-technology.co...A8C/$file/SynPower+Motor+Oils.pdf?OpenElement
https://www.valvoline-technology.co...82/$file/All-Climate+Multi+SM.pdf?OpenElement
cSt at 40°C: 155.42 (SynPower), 165.9 (All-Climate)
cSt at 100°C: 20.82 (SynPower), 18.5 (All-Climate)
Amsoil S2K 20W-50
Remember - the SAE ratings are specification ranges......in general it depends on the formulation itself. Because of the low temp properties and the naturally wider VI, a synthetic may have better flow properties than a dino 20W-50.
Remember - the SAE ratings are specification ranges......in general it depends on the formulation itself. Because of the low temp properties and the naturally wider VI, a synthetic may have better flow properties than a dino 20W-50.
James,
A synthetic basestock would flow the same as a dino basestock if both lubes had the same cSt at 100°F,
some of the differences would be that a dino lube basestock may require more VII (Viscosity Index Improver) then a synthetic basestock if specific requirements needed to be met, and Pour Point Depressant would be added to the dino lube additive package to help the dino lube flow better at lower temperatures, some synthetic lubes have these additives but may require less or none of these the additives, having more additives can allow for more things to go wrong with the lubricant, VII is sheared, Pour Point Depressant is used up (degredation of the additive), the additives may not work as well as a new additive, synthetic lube having less or none of these additives allows for less to go wrong with the lube.
A synthetic basestock would flow the same as a dino basestock if both lubes had the same cSt at 100°F,
some of the differences would be that a dino lube basestock may require more VII (Viscosity Index Improver) then a synthetic basestock if specific requirements needed to be met, and Pour Point Depressant would be added to the dino lube additive package to help the dino lube flow better at lower temperatures, some synthetic lubes have these additives but may require less or none of these the additives, having more additives can allow for more things to go wrong with the lubricant, VII is sheared, Pour Point Depressant is used up (degredation of the additive), the additives may not work as well as a new additive, synthetic lube having less or none of these additives allows for less to go wrong with the lube.
Sometimes a thicker oil is needed as an engine packs on the miles. In my case I've gone from 5w-30 to 20w-50 over 21 years and 375k+ miles without ever having the head off. I tried going back to a 10w-40 and the oil consumption shot up, so I went back to the 20w-50. My next step may be 20w-60. I posted a uoa at 375k on 20w-50 and it's just fine. I burn a quart every 5k miles. Thicker oil isn't always a bad choice.
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