One more bite at the 5w20 v. 5w30 debate:

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ChrisD46, usually the more the spread in xW-y, the thinner the base oil needs to be for a given x. This is because the more the xW-y spread, the more the more the VII is in there and this forces a thinner base oil to meet the xW cold spec, as the VII decreases the cold pumpability and increases the MRV. 5w-20 oils can be formulated monograde-like with minimal VII, which means the base oil tends to be thicker.
 
Originally Posted by mcwilly
Go easy on me, I'm still learning.

Do viscosity improvers really take up that much space? With some comments saying less VI's means more room for real oil. Do we know how much VI's there are in say a 5w20 vs a 0w40 within the same brand? Like 50ml/liter vs 100ml/liter?
The various grades of oil within a brand typically all have the same mileage claims on the bottle. Should a 0wXX oil be run for shorter OCI's because of VI's? Are they really that detrimental to an oils lifespan that an OCI should be cut short or can it comfortably be run for the whole manufacturer's recommended OCI? Is technology improving in this area?

You've got me worried up here in Canada running 0w40's.

0W-40 is not that bad because it uses top-notch GTL/PAO base oils with a very high viscosity index (VI), which helps keep the VII content reasonable, similar to a 5W-30.

The actual VII solid polymer content is around a percent or two. However, it's usually sold as dissolved in some solvent (like a Group I base oil), and the typical treat rate including the solvent can be between about a few percent (for monograde-like grades like 5W-20 and 10W-30) and as much as around 15% (for VII-monster grades like 5W-50 and 10W-60).

Oils with less VII should result in less engine and turbocharger deposits and less sludge. Most use VIIs with good thermal stability though. Some VII types such as PMA require a very high solid-polymer treat rate (several times more than other VII types) but they are rarely used, perhaps a typical application being ultra-high-VI Japanese-OEM oils, as they increase the VI by a great amount.

I have a table that estimates it here. Note that the VII content includes the solvent but it's in arbitrary units and should only be used as a rough estimate to give you an idea. The main goal of the table is to estimate the base-oil viscosity at 150 °C (BO DV150 or HTFSV), which is a more reliable estimate:

https://www.bobistheoilguy.com/foru...erature-full-shear-viscosity#Post5133467
 
Originally Posted by Gokhan
ChrisD46, usually the more the spread in xW-y, the thinner the base oil needs to be for a given x. This is because the more the xW-y spread, the more the more the VII is in there and this forces a thinner base oil to meet the xW cold spec, as the VII decreases the cold pumpability and increases the MRV. 5w-20 oils can be formulated with minimal VII, which means the base oil tends to thicker.

*I see - thanks for the explanation ... I've yet to try a 5W20 synthetic D1 / Gen 2 SN+ oil in my 2.4L Hyundai and may do so for one OCI as an experiment. In the newer Hyundai Theta II 2.4L GDI engines which have 5W20 on the oil cap - it's probably more important to : "Keep the oil level on the dipstick at the full mark and keep the oil clean" (i.e. shorter OCI's) than whether you use 5W20 or 5W30 synthetic oil . Besides , I'm now enrolled in the : "Hyundai Can't Lose Lottery" in that if my 2.4L develops the Theta II tick of death and the rod bearings go - then I get a new long block engine and a 120K mile warranty (yes , I have a digital file of all oil receipts) .
 
Originally Posted by ChrisD46
Originally Posted by Gokhan
ChrisD46, usually the more the spread in xW-y, the thinner the base oil needs to be for a given x. This is because the more the xW-y spread, the more the more the VII is in there and this forces a thinner base oil to meet the xW cold spec, as the VII decreases the cold pumpability and increases the MRV. 5w-20 oils can be formulated with minimal VII, which means the base oil tends to thicker.

*I see - thanks for the explanation ... I've yet to try a 5W20 synthetic D1 / Gen 2 SN+ oil in my 2.4L Hyundai and may do so for one OCI as an experiment. In the newer Hyundai Theta II 2.4L GDI engines which have 5W20 on the oil cap - it's probably more important to : "Keep the oil level on the dipstick at the full mark and keep the oil clean" (i.e. shorter OCI's) than whether you use 5W20 or 5W30 synthetic oil . Besides , I'm now enrolled in the : "Hyundai Can't Lose Lottery" in that if my 2.4L develops the Theta II tick of death and the rod bearings go - then I get a new long block engine and a 120K mile warranty (yes , I have a digital file of all oil receipts) .

Give the Valvoline Advanced Synthetic 5W-20 a try -- it is practically a monograde with almost no VII or perhaps actually a monograde with no VII at all. It has Noack = 7.6%, which also indicates that the base oil is a thick, high-quality one.

Alternatively try the Valvoline Advanced Synthetic 5W-30 -- while the base oil is as thick as its 5W-20 sibling, you get a higher HTHS viscosity, and the VII content is still minimal. It has Noack = 9.3%, which is a little higher than of its 5W-20 sibling, possibly as a result of the Group I solvent of the small amount of VII it has.

Valvoline Advanced Synthetic engineers really seem to have excelled in the base oil/VII business.
 
Originally Posted by Gokhan
Originally Posted by ChrisD46
Originally Posted by Gokhan
ChrisD46, usually the more the spread in xW-y, the thinner the base oil needs to be for a given x. This is because the more the xW-y spread, the more the more the VII is in there and this forces a thinner base oil to meet the xW cold spec, as the VII decreases the cold pumpability and increases the MRV. 5w-20 oils can be formulated with minimal VII, which means the base oil tends to thicker.

*I see - thanks for the explanation ... I've yet to try a 5W20 synthetic D1 / Gen 2 SN+ oil in my 2.4L Hyundai and may do so for one OCI as an experiment. In the newer Hyundai Theta II 2.4L GDI engines which have 5W20 on the oil cap - it's probably more important to : "Keep the oil level on the dipstick at the full mark and keep the oil clean" (i.e. shorter OCI's) than whether you use 5W20 or 5W30 synthetic oil . Besides , I'm now enrolled in the : "Hyundai Can't Lose Lottery" in that if my 2.4L develops the Theta II tick of death and the rod bearings go - then I get a new long block engine and a 120K mile warranty (yes , I have a digital file of all oil receipts) .

Give the Valvoline Advanced Synthetic 5W-20 a try -- it is practically a monograde with almost no VII or perhaps actually a monograde with no VII at all.

Alternatively try the Valvoline Advanced Synthetic 5W-30 -- while the base oil is as thick as its 5W-20 sibling, you get a higher HTHS viscosity, and the VII content is still minimal.

Valvoline Advanced Synthetic engineers really seem to have excelled in the base oil/VII business.

*In my signature - I have Valvoline Advanced 5W30 synthetic in the 2.4L already with 1,600 miles on the fill - so far a real nice oil . I'll consider the 5W20 Valvoline Advanced next for grins to compare ...
 
Per Gokhan : "Give the Valvoline Advanced Synthetic 5W-20 a try -- it is practically a monograde with almost no VII or perhaps actually a monograde with no VII at all.

Alternatively try the Valvoline Advanced Synthetic 5W-30 -- while the base oil is as thick as its 5W-20 sibling, you get a higher HTHS viscosity, and the VII content is still minimal.

Valvoline Advanced Synthetic engineers really seem to have excelled in the base oil/VII business".

* Not to get off topic - I wonder how Valvoline Advanced Synthetic base oil / amount of VII's stack up against: Mobil 1 , Pennzoil Platinum , QSUD and Castrol Edge ? ... There are some experts that suggest excessive VII's and GDI engines are not a great combination leading to an increase in input valve deposits ? Perhaps there is more to the Valvoline Advanced Synthetic than a really nice looking VOA ?
 
Originally Posted by Gokhan
What I like about 5W-20 is that it uses a thicker base oil than 5W-30 does. So, while the HTHS viscosity, which is relevant to the wear protection of the bearings, is a little less, the valvetrain, timing chain, and rings and liners will have less wear with 5W-20 than with 5w-30 because the base oil is thicker.


Not so sure about that. There's been quite a few papers that show less wear on most engine parts with higher HTHS viscosity. Looks like when the HTHS starts going below 2.6 cP is when the wear really starts to increase. Most xW-20 weight oils have a HTHS around 2.6~2.7 cP ... so basically they are starting out real close to the point on the graph where the wear starts increasing noticeably - so what happens with a lot of fuel dilution and/or oil shearing to decrease the viscosity even further?. Also, higher RPM has a big effect on ring wear ... so cruising around like a grandpa will result in less wear.


Piston Ring Wear vs HTHS at 130C Oil Temp.JPG
 
"Valvoline Advanced Synthetic engineers really seem to have excelled in the base oil/VII business".




I was under the impression that Valvoline bought base oils from other sources and blended them.
 
Originally Posted by PimTac
"Valvoline Advanced Synthetic engineers really seem to have excelled in the base oil/VII business".

I was under the impression that Valvoline bought base oils from other sources and blended them.

Of course, they do so!

What I mean is that they excel in optimizing the base oil/VII when blending oil.
 
Originally Posted by PimTac
"Valvoline Advanced Synthetic engineers really seem to have excelled in the base oil/VII business".




I was under the impression that Valvoline bought base oils from other sources and blended them.


Whatever they are up to in Kentucky,
that Valvoline Advanced Full Synthetic 5W20
is a real winner in my book.

Very low Noack @ < $5/qt from Walmart in the 5 quart jug.
Near the top on the BBQ index.
 
Originally Posted by ZeeOSix
Originally Posted by Gokhan
What I like about 5W-20 is that it uses a thicker base oil than 5W-30 does. So, while the HTHS viscosity, which is relevant to the wear protection of the bearings, is a little less, the valvetrain, timing chain, and rings and liners will have less wear with 5W-20 than with 5w-30 because the base oil is thicker.

Not so sure about that. There's been quite a few papers that show less wear on most engine parts with higher HTHS viscosity. Looks like when the HTHS starts going below 2.6 cP is when the wear really starts to increase. Most xW-20 weight oils have a HTHS around 2.6~2.7 cP ... so basically they are starting out real close to the point on the graph where the wear starts increasing noticeably - so what happens with a lot of fuel dilution and/or oil shearing to decrease the viscosity even further?. Also, higher RPM has a big effect on ring wear ... so cruising around like a grandpa will result in less wear.

[Linked Image]


Let's not read too much into one plot, especially with no additional info on the test oils having been provided.

If you look at the plot, HTHS viscosity = 2.6 cP is producing the least ring wear -- the effect being drastic at 3000 rpm and 6000 rpm -- at virtually all rpms. So, perhaps this oil has a thicker base oil than the 3.1 cP oil.

We have no information on the 2.2 cP and 2.4 cP oils -- they may also be using very thin base oils as well. Therefore, we don't know if the rise in the wear is because of the fall in the HTHS viscosity or the fall in the base-oil viscosity.
 
Originally Posted by ChrisD46
Per Gokhan : "Give the Valvoline Advanced Synthetic 5W-20 a try -- it is practically a monograde with almost no VII or perhaps actually a monograde with no VII at all.

Alternatively try the Valvoline Advanced Synthetic 5W-30 -- while the base oil is as thick as its 5W-20 sibling, you get a higher HTHS viscosity, and the VII content is still minimal.

Valvoline Advanced Synthetic engineers really seem to have excelled in the base oil/VII business".

* Not to get off topic - I wonder how Valvoline Advanced Synthetic base oil / amount of VII's stack up against: Mobil 1 , Pennzoil Platinum , QSUD and Castrol Edge ? ... There are some experts that suggest excessive VII's and GDI engines are not a great combination leading to an increase in input valve deposits ? Perhaps there is more to the Valvoline Advanced Synthetic than a really nice looking VOA ?


You'll be fine either way Chris. I suspect that if you do run the 30 and then the 20 (or vice versa) for the purpose of testing, you'll see little difference. I ran the magnetized plug after 50K miles and used various oils and viscosity until trading it in.
 
Originally Posted by Gokhan
Originally Posted by ZeeOSix
Originally Posted by Gokhan
What I like about 5W-20 is that it uses a thicker base oil than 5W-30 does. So, while the HTHS viscosity, which is relevant to the wear protection of the bearings, is a little less, the valvetrain, timing chain, and rings and liners will have less wear with 5W-20 than with 5w-30 because the base oil is thicker.

Not so sure about that. There's been quite a few papers that show less wear on most engine parts with higher HTHS viscosity. Looks like when the HTHS starts going below 2.6 cP is when the wear really starts to increase. Most xW-20 weight oils have a HTHS around 2.6~2.7 cP ... so basically they are starting out real close to the point on the graph where the wear starts increasing noticeably - so what happens with a lot of fuel dilution and/or oil shearing to decrease the viscosity even further?. Also, higher RPM has a big effect on ring wear ... so cruising around like a grandpa will result in less wear.

[Linked Image]


If you look at the plot, HTHS viscosity = 2.6 cP is producing the least ring wear -- the effect being drastic at 3000 rpm and 6000 rpm -- at virtually all rpms. So, perhaps this oil has a thicker base oil than the 3.1 cP oil.


Guess we are reading the plot differently. What I see is increased ring wear at all RPM (except 2000) where the HTHS starts falling below 2.6 cP.

Piston-Ring-Wear-vs-HTHS-at-130C-Oil-Temp(2).JPG
 
Originally Posted by ZeeOSix
Guess we are reading the plot differently. What I see is increased ring wear at all RPM (except 2000) where the HTHS starts falling below 2.6 cP.

Their curve fits are sloppy to say the least. These are the actual data points. HTHS viscosity = 2.6 cP produced the least ring wear at all rpms except 5000 rpm.

Code
2.2 cP 2.4 cP 2.6 cP 3.1 cP



2000 rpm 0.3 µg 1.2 µg 0.0 µg 0.9 µg

3000 rpm 8.4 µg 7.1 µg 0.6 µg 3.6 µg

4000 rpm 9.3 µg 8.6 µg 5.3 µg 6.3 µg

5000 rpm 7.0 µg 6.5 µg 4.2 µg 3.5 µg

6000 rpm 14.5 µg 13.8 µg 5.5 µg 7.4 µg
 
Yeah, there are a few "flyers" in the data, but the graph clearly shows the trend that ring wear increases noticeably with HTHS viscosity below 2.6 cP. I'd say the wear was basically indistinguishable as the curve fits show in the range between 2.6 to 3.1 cP, but below 2.6 cP is definitely increases ... that was my main point. And that's why I like to use 5W-30 instead of xW-20 in my engines.
 
Originally Posted by ZeeOSix
Yeah, there are a few "flyers" in the data, but the graph clearly shows the trend that ring wear increases noticeably with HTHS viscosity below 2.6 cP.

Considering most engines are cursing between 2-3K rpms it looks like 2.6 cP has the clear advantage. What about cam, lifter, and bearing wear?

What casts doubt im my mind [if I'm reading it correctly} is there is no wear at 2,000 rpms for 2.6 cP? That's hard to believe.
 
Originally Posted by demarpaint
Originally Posted by ZeeOSix
Yeah, there are a few "flyers" in the data, but the graph clearly shows the trend that ring wear increases noticeably with HTHS viscosity below 2.6 cP.

Considering most engines are cursing between 2-3K rpms it looks like 2.6 cP has the clear advantage. What about cam, lifter, and bearing wear?

What casts doubt im my mind [if I'm reading it correctly} is there is no wear at 2,000 rpms for 2.6 cP? That's hard to believe.


You have to look at the curve fit of the data, not individual data points. The graph basically says there is very low wear at low RPM, regardless of the HTHS viscosity.

Per the testing the SwRI did between 0W-16 and 5W-30, there was no noticeable wear difference in the journal bearings. So seems journal bearings are more forgiving to the viscosity used because of the full hydrodynamic lubrication realm they live in.

Wear on other parts like rings, cylinder bores, camshafts, etc rely pretty heavily on anti-friction/anti-wear additives, but having a higher HTHS will also help reduce wear in those areas like the graph shows for ring wear.
 
Last edited:
Originally Posted by ZeeOSix
Originally Posted by demarpaint
Originally Posted by ZeeOSix
Yeah, there are a few "flyers" in the data, but the graph clearly shows the trend that ring wear increases noticeably with HTHS viscosity below 2.6 cP.

Considering most engines are cursing between 2-3K rpms it looks like 2.6 cP has the clear advantage. What about cam, lifter, and bearing wear?

What casts doubt im my mind [if I'm reading it correctly} is there is no wear at 2,000 rpms for 2.6 cP? That's hard to believe.


You have to look at the curve fit of the data, not individual data points. The graph basically says there is very low wear at low RPM, regardless of the HTHS viscosity.

Thanks. I was never good at understanding charts like that.
 
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