Recent Topics
Broken sway bar bolt
by HoosierJeeper - 03/29/20 04:00 PM
can I use it?
by avi1777 - 03/29/20 03:54 PM
Service Champ OF2222 75% OLM, unknown miles
by bullwinkle - 03/29/20 03:50 PM
Gas Buddy Question
by Wolfshead - 03/29/20 03:30 PM
Caliper piston boot
by painfx - 03/29/20 03:25 PM
Graphene the next detailing protection
by Mamala Bay - 03/29/20 02:17 PM
Anyone here a blacksmith?
by 53' Stude - 03/29/20 02:13 PM
Buying products made outside the USA
by 007 - 03/29/20 01:22 PM
Marine oils on sale at Canadian Tire
by Snagglefoot - 03/29/20 12:42 PM
0W16 instead of 0w20?
by Mter00s - 03/29/20 12:36 PM
XG10575 Walmart.com deal
by 762fermeandyou - 03/29/20 12:29 PM
Virgin ACDelco PF1245 cut and post
by nwjones18 - 03/29/20 11:49 AM
Oups, forgot oil cap...
by M119 - 03/29/20 11:46 AM
Recommendation for tuned BMW N55?
by RIPGermanCastrol - 03/29/20 11:15 AM
Electrician's Help With Circuit Breaker ?
by doitmyself - 03/29/20 11:07 AM
Get your physicals done people
by BeerCan - 03/29/20 08:41 AM
2004 Silverado
by mjk - 03/29/20 08:29 AM
Shimmy on the Hiwy
by Char Baby - 03/29/20 06:06 AM
10w40 over 5w30 diesel
by angryorc - 03/29/20 03:20 AM
Clover Overseeding.
by GumbyJarvis - 03/29/20 01:52 AM
Newest Members
yulichris, jeff58, jimmyturner, ChainsawGuy, jbr
71038 Registered Users
Who's Online Now
109 registered members (2K2AcuraTL, alphadog, 53' Stude, 01rangerxl, 007, 762fermeandyou, 13 invisible), 2,123 guests, and 21 spiders.
Key: Admin, Global Mod, Mod
Forum Statistics
Forums67
Topics303,322
Posts5,233,908
Members71,038
Most Online4,538
Jan 20th, 2020
Donate to BITOG
Print Thread
Hop To
Page 1 of 11 1 2 11
HTFSV: High-temperature, full-shear viscosity #5072217 04/12/19 03:59 AM
Joined: Dec 2010
Posts: 4,774
G
Gokhan Online Content OP
OP Online Content
G
Joined: Dec 2010
Posts: 4,774
It's theorized that the wear for the following components depends on these variables among other things:

  • Bearings: High-temperature, high-shear viscosity (HTHSV), TBN/TAN/base-oil-oxidation performance (lead and copper corrosion).
  • Piston rings: Base-oil viscosity, TBN/TAN/base-oil-oxidation performance (chromium corrosion), AW/EP/FM additives.
  • Valvetrain and timing chain: Base-oil viscosity, AW/EP/FM additives.

The shear rates at parts of the pistons and valvetrain are too large for the viscosity-index improver (VII) to have any significant effect on wear -- they simply get squeezed out and you're left in the boundary or mixed lubrication regime with an atomic layer of oil and additive films.

Therefore, I define the high-temperature, full-shear viscosity (HTFSV) as the dynamic viscosity of the base oil at 150 C where the shear rates are so large that the VII plays no role in increasing the viscosity. In other words, HTFSV is the dynamic viscosity of the base oil without the VII at 150 C. For a monograde oil, HTFSV = HTHSV. For multigrade oils, HTFSV < HTHSV, the inequality increasing with the increasing VII content. The units for the dynamic viscosity are cP.

I attempted a rough calculation using the A_Harman index.

I take the approximate VII content as (1- A_Harman index)/2.

I calculated HTFSV = DV150/(1 + VII*20) = DV150/(1 + [1 - A_Harman index]*10) = DV150/(1 + [1 - HTHSV/DV150]*10).

I tried to calibrate it for the M1 EP 0W-20 so that it would have the known HTFSV in the Exxon Mobil blending guide.

Now, the HTFSV values tabulated here are guesstimates. There are many assumptions that go into that and there are also inaccuracies in the oil data provided, such as A_Harman index being greater than 1. So, use them as a guide rather than absolute values. Among other things, the calibration factor (20) I used depends on the type of the VII.

Important notes:

  • SAE 15W-40 oils topped the chart. This is in agreement with the fact that no other SAE viscosity (other than the SAE 40 and SAE 30 monogrades) protects HDEO engines better.
  • Amsoil ACD SAE 10W-30/SAE 30 monograde is at the top despite obvious inaccuracies with the Amsoil numbers provided.
  • VAS 5W-20 and PPPP 10W-30 did very well.
  • ACEA C5 0W-20 oils (Castrol LL IV and Mobil 1 ESP x2) are virtually VII-free and did very well.
  • The GTL-based PPPP in general did well.
  • Some popular oils such as M1 HM 5W-30 and M1 EP HM 5W-30 did very poorly due to their mega dose of VII.
  • The ultra-high-VI TGMO 0W-20 hit rock bottom as far as the HTFSV is concerned.

[Linked Image]


2020 Toyota Prius Prime XLE plug-in hybrid, 2ZR-FXE engine, ~ 70 mpg on gas, ~ 5,000 mi
TGMO 0W-16 SN/RC Japan
OEM spin-on oil filter Japan
Re: HTFSV: High-temperature, full-shear viscosity [Re: Gokhan] #5072223 04/12/19 04:09 AM
Joined: Dec 2002
Posts: 43,543
S
Shannow Offline
Offline
S
Joined: Dec 2002
Posts: 43,543
Wrong...viscosity index improvers ALWAYS increase viscosity in the second Newtonian phase.

There is no phase that the VII have zero impact above and beyond the base oil viscosity.


If it's the truth....it can handle the pressure !!!
Re: HTFSV: High-temperature, full-shear viscosity [Re: Gokhan] #5072227 04/12/19 04:31 AM
Joined: Jul 2018
Posts: 174
C
ChemLabNL Offline
Offline
C
Joined: Jul 2018
Posts: 174
ACD 10W-30/30 is just friggin outstanding!

Re: HTFSV: High-temperature, full-shear viscosity [Re: ChemLabNL] #5072233 04/12/19 04:42 AM
Joined: Dec 2010
Posts: 4,774
G
Gokhan Online Content OP
OP Online Content
G
Joined: Dec 2010
Posts: 4,774
Originally Posted by ChemLabNL
ACD 10W-30/30 is just friggin outstanding!

There is some inaccuracy in the Amsoil data provided. Note that the A_Harman index is greater than 1.

Since it's a monograde, HTFSV = HTHSV = 3.6 cP.

Nevertheless, it ties with the Amsoil Signature Series Max-Duty (DME) 15W-40 and beats everything else except the Mobil Delvac 1300 Super 15W-40 CK-4/SN.


2020 Toyota Prius Prime XLE plug-in hybrid, 2ZR-FXE engine, ~ 70 mpg on gas, ~ 5,000 mi
TGMO 0W-16 SN/RC Japan
OEM spin-on oil filter Japan
Re: HTFSV: High-temperature, full-shear viscosity [Re: Gokhan] #5072242 04/12/19 05:17 AM
Joined: Dec 2002
Posts: 43,543
S
Shannow Offline
Offline
S
Joined: Dec 2002
Posts: 43,543
Originally Posted by Gokhan
Originally Posted by ChemLabNL
ACD 10W-30/30 is just friggin outstanding!

There is some inaccuracy in the Amsoil data provided. Note that the A_Harman index is greater than 1.


Given that the Amsoil data sheet goes to what ... ummm....two significant figures, your index does no point to an error in AMsoil's data sheet, but an error in your process.

Seriously, how does your lab deal with error analysis and number of significant figures....

For instance, when you are calculating Harman Index, how are you calculate density ?

Or are you using the rules of thumb that are in a couple of the formulae ?

Again...your error stack doesn't make a >1 number an error in the data sheet

Last edited by Shannow; 04/12/19 05:18 AM.

If it's the truth....it can handle the pressure !!!
Re: HTFSV: High-temperature, full-shear viscosity [Re: Gokhan] #5072243 04/12/19 05:19 AM
Joined: Dec 2002
Posts: 43,543
S
Shannow Offline
Offline
S
Joined: Dec 2002
Posts: 43,543
So in summary, thick, low VI is now the "in thing" for Gokhan ?

How many flip flops is the 2019 count ????


If it's the truth....it can handle the pressure !!!
Re: HTFSV: High-temperature, full-shear viscosity [Re: Shannow] #5072263 04/12/19 05:59 AM
Joined: Dec 2010
Posts: 4,774
G
Gokhan Online Content OP
OP Online Content
G
Joined: Dec 2010
Posts: 4,774
Originally Posted by Shannow
when you are calculating Harman Index, how are you calculate density ?

Fair criticism.

I've been using A_Harman's rule of thumb of multiplying with 0.885 to extrapolate from 15 C to 150 C but this doesn't seem to work well.

If I use 0.905 instead, I get a monograde (A_Harman index = 1) for both Amsoil ACD 10W-30/30 and VAS 5W-20. All A_Harman indexes greater than 1 disappear.

Also updating the calibration constant from 20 to 15, here is the new table. Main conclusions remain the same but the numbers shift a little. Amsoil ACD 10W-30/30 monograde is at the top of the list -- as it should be because it's a SAE 30 monograde and we don't have any SAE 40 monograde in the list.

HTFSV = DV150/(1 + VII*15) = DV150/(1 + [1 - A_Harman index]*7.5) = DV150/(1 + [1 - HTHSV/DV150]*7.5)

[Linked Image]


2020 Toyota Prius Prime XLE plug-in hybrid, 2ZR-FXE engine, ~ 70 mpg on gas, ~ 5,000 mi
TGMO 0W-16 SN/RC Japan
OEM spin-on oil filter Japan
Re: HTFSV: High-temperature, full-shear viscosity [Re: Gokhan] #5072273 04/12/19 06:22 AM
Joined: Oct 2005
Posts: 11,770
D
d00df00d Offline
Offline
D
Joined: Oct 2005
Posts: 11,770
Originally Posted by Gokhan
The shear rates at parts of the pistons and valvetrain are too large for the viscosity-index improver (VII) to have any significant effect on wear -- they simply get squeezed out and you're left in the boundary or mixed lubrication regime with an atomic layer of oil and additive films.

1. When you say "atomic", do you mean molecular?
2. How is viscosity even a meaningful concept at that point?


2008 BMW M3 Sedan 6MT
Re: HTFSV: High-temperature, full-shear viscosity [Re: d00df00d] #5072282 04/12/19 06:40 AM
Joined: Dec 2002
Posts: 43,543
S
Shannow Offline
Offline
S
Joined: Dec 2002
Posts: 43,543
Originally Posted by d00df00d
Originally Posted by Gokhan
The shear rates at parts of the pistons and valvetrain are too large for the viscosity-index improver (VII) to have any significant effect on wear -- they simply get squeezed out and you're left in the boundary or mixed lubrication regime with an atomic layer of oil and additive films.

1. When you say "atomic", do you mean molecular?
2. How is viscosity even a meaningful concept at that point?


It's neither atomic, nor molecular at that point.

It's the asperities in contact, and the local surface roughness is like you standing at the bottom of Everest and looking up.


If it's the truth....it can handle the pressure !!!
Re: HTFSV: High-temperature, full-shear viscosity [Re: Gokhan] #5072373 04/12/19 08:41 AM
Joined: Mar 2017
Posts: 12,977
PimTac Offline
Offline
Joined: Mar 2017
Posts: 12,977
Is this another index?


2017 Mazda CX5
Valvoline Advanced Synthetic 0w20
Roki OEM filter.
Re: HTFSV: High-temperature, full-shear viscosity [Re: PimTac] #5072380 04/12/19 08:51 AM
Joined: Oct 2005
Posts: 11,770
D
d00df00d Offline
Offline
D
Joined: Oct 2005
Posts: 11,770
Originally Posted by PimTac
Is this another index?

It is if people adopt it.

Validity is another question.


2008 BMW M3 Sedan 6MT
Re: HTFSV: High-temperature, full-shear viscosity [Re: Gokhan] #5072463 04/12/19 10:13 AM
Joined: Oct 2015
Posts: 3,396
F
FordCapriDriver Offline
Offline
F
Joined: Oct 2015
Posts: 3,396
So if i want to minimize say valvetrain wear, the way to go is a thick base oil and hefty does of AW additives?


1975 Ford Capri II Ghia 3000 V6 - Repsol Elite Super 20W-50
1988 Ford Escort XR3i Cabrio - Whatever keeps the lifters quiet...

Re: HTFSV: High-temperature, full-shear viscosity [Re: FordCapriDriver] #5072697 04/12/19 02:06 PM
Joined: Dec 2010
Posts: 4,774
G
Gokhan Online Content OP
OP Online Content
G
Joined: Dec 2010
Posts: 4,774
Originally Posted by FordCapriDriver
So if i want to minimize say valvetrain wear, the way to go is a thick base oil and hefty does of AW additives?

Yes, especially for a classic car like yours and other classic cars, you need a thick base oil, such as a 10W-30, 15W-40, and even SAE 30 or SAE 40 if the climate allows them, to reduce the camshaft and ring wear. Amsoil ACD 10W-30/SAE 30 is a great choice for example but there are cheaper choices as well. Look at the second table with the improved calculation to pick an oil with a thick base oil (high HTFSV). Valvoline Advanced Synthetic (VAS) 5W-20 is also an exceptional choice but it may not be the best choice for all classic cars, as they may require a high HTHSV for bearing protection in addition to a thick base oil (high HTFSV).

You don't need a heavy dose of ZDDP these days because other modern AW/EP/FM additives are also used in addition to ZDDP now. In fact, most CK-4 HDEOs now get away with 800 ppm phosphorus. Too much ZDDP (over 1200 ppm phosphorus) or an unbalanced additive package (such as using aftermarket additives) can make things worse and increase wear.

Also, don't neglect the importance of an oil's TBN/TAN/base-oil-oxidation performance and/or OCI length/frequent-enough oil changes, as the corrosion of lead, copper, and chromium is an important factor that increases the bearing and ring wear.


2020 Toyota Prius Prime XLE plug-in hybrid, 2ZR-FXE engine, ~ 70 mpg on gas, ~ 5,000 mi
TGMO 0W-16 SN/RC Japan
OEM spin-on oil filter Japan
Re: HTFSV: High-temperature, full-shear viscosity [Re: Gokhan] #5073008 04/12/19 07:26 PM
Joined: Dec 2002
Posts: 43,543
S
Shannow Offline
Offline
S
Joined: Dec 2002
Posts: 43,543
So the units are viscosity ?

What correlation does say a number of "4" have with any actual, measured parameter ?

How does it relate to the Stribeck curve ?

How does it fit into the Somerfeld number, when it comes to calculating MOFT ?

I mean there's a whole science about tribology that had been around for a century...where does this new calculated viscosity actually fit into the science ?


If it's the truth....it can handle the pressure !!!
Re: HTFSV: High-temperature, full-shear viscosity [Re: Shannow] #5073010 04/12/19 07:31 PM
Joined: Sep 2010
Posts: 8,307
2015_PSD Offline
Offline
Joined: Sep 2010
Posts: 8,307
Originally Posted by Shannow
I mean there's a whole science about tribology that had been around for a century...where does this new calculated viscosity actually fit into the science ?
You already know the answer to that question...


2019 o)|||||(o Rubicon Wrangler Unlimited 3.6L V6 [Castrol Edge + Hastings]
2018 Mercedes Benz C300 2.0L Turbo [Pennzoil Platinum + Mann filter]
Page 1 of 11 1 2 11
Previous Thread
Index
Next Thread

BOB IS THE OIL GUY® Powered by UBB.threads™