paul39
Titanium
- Joined
- Jul 12, 2008
- Location
- Asheville, NC
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Oil Viscosity Chart
- Thread starter paul39
- Start date
- Replies 4
- Views 4,105
WizardOfBoz
Diamond
- Joined
- Sep 30, 2006
- Location
- SE PA, Philly
Paul,
Thanks - I had been looking for something like this. I have one beef with the chart. It lists viscosities as kinematic (in centistokes) and Saybolt Universal Seconds. Both units are, in fact, measures of kinematic viscosity.
Absolute viscosity (normally measured in Centipoise) is strictly a measure of resistance to flow. Normally designated as mu, µ. Kinematic viscosity is absolute viscosity divided by density, normally shown as nu (I've used the letter v, here). It's used a lot because you can use a glass tube of a specific volume (normally 60mL) , with a precise hole in the bottom, and you time how long a liquid takes to empty to get kinematic viscosity.
ν = μ / ρ
where
ν = kinematic viscosity, in centistokes
μ = absolute or dynamic viscosity
ρ = density
For kinematic viscosity in Saybolt Universal Seconds,
ν = 4.63 μ / SG
where
ν = kinematic vicosity in SSU
μ = dynamic or absolute viscosity (cP)
SG = Specific Gravity.
J
Thanks - I had been looking for something like this. I have one beef with the chart. It lists viscosities as kinematic (in centistokes) and Saybolt Universal Seconds. Both units are, in fact, measures of kinematic viscosity.
Absolute viscosity (normally measured in Centipoise) is strictly a measure of resistance to flow. Normally designated as mu, µ. Kinematic viscosity is absolute viscosity divided by density, normally shown as nu (I've used the letter v, here). It's used a lot because you can use a glass tube of a specific volume (normally 60mL) , with a precise hole in the bottom, and you time how long a liquid takes to empty to get kinematic viscosity.
ν = μ / ρ
where
ν = kinematic viscosity, in centistokes
μ = absolute or dynamic viscosity
ρ = density
For kinematic viscosity in Saybolt Universal Seconds,
ν = 4.63 μ / SG
where
ν = kinematic vicosity in SSU
μ = dynamic or absolute viscosity (cP)
SG = Specific Gravity.
J
JRIowa
Diamond
- Joined
- May 27, 2003
- Location
- Marshalltown, Iowa, USA
It's an OK chart. The trouble with charts is that there are a lot of people that don't know what they're looking at with the chart in front of them.
There are 2 typos on the chart. Standard Saybolt (@100F or 40C) is SSU, Saybolt Seconds Univeral and the other designation is SSF or Saybolt Seconds Furol.
The chart also does not go to the bottom end of the ISO range which is an ISO 2.
There are also some inconsistancies on the SAE ranges. 20 and 20W have the same minimum @ 5.6 Cst, 20W is not tested at 100C, but 20 is.
That's why it's not my favorite.
JR
There are 2 typos on the chart. Standard Saybolt (@100F or 40C) is SSU, Saybolt Seconds Univeral and the other designation is SSF or Saybolt Seconds Furol.
The chart also does not go to the bottom end of the ISO range which is an ISO 2.
There are also some inconsistancies on the SAE ranges. 20 and 20W have the same minimum @ 5.6 Cst, 20W is not tested at 100C, but 20 is.
That's why it's not my favorite.
JR
JRIowa
Diamond
- Joined
- May 27, 2003
- Location
- Marshalltown, Iowa, USA
My favorite charts are in books that I have picked up from different classes over the last 35 years. I've never seen any online. I've got 2, 3-ring binders that I pull down if somebody has a question.
IMO, viscosity charts are some of the most misused pieces of information out there. As long as there are those that want to use chain bar oil, ATF, or 80-90 gear grease instead of "investing" in the lubes the manufacturers specifies, I'll keep ranting.
JR
IMO, viscosity charts are some of the most misused pieces of information out there. As long as there are those that want to use chain bar oil, ATF, or 80-90 gear grease instead of "investing" in the lubes the manufacturers specifies, I'll keep ranting.
JR