Originally Posted By: Shannow
Here's CATERHAM's data
http://www.itinerant-air-cooled.com/viewtopic.php?t=8721
Quote:
All oil pressure readings were made at 6,500 rpm and oil temp' of 95C:
M1 5W-50 ..... KV100 17.5 cSt...HTHS 4.21 cP...OP 92 ...psi
M1 0W-40 ..... KV100 14.0 cSt...HTHS 3.7 .cP...OP 86 ...psi
RL 10W-30 .... KV100 11.0 cSt...HTHS 3.8 .cP...OP 87 ...psi
RL 5W-30 ..... KV100 10.6 cSt...HTHS 3.8 .cP...OP 87 ...psi
GC 0W-30 ..... KV100 12.2 cSt...HTHS 3.5 .cP...OP 83-84 psi
RL 5W-20 ..... KV100 9.1 cSt...HTHS 3.3 .cP...OP 80 ...psi
M1 5W-30 ..... KV100 11.3 cSt...HTHS 3.09 cP...OP 78 ...psi
PP 5W-30 ..... KV100 10.3 cSt...HTHS 3.1 .cP...OP 78 ...psi
RL blend, 3qts 5W-20 and 1qt 0W-10 race oil *
...............KV100 8.2cSt est HTHS 2.85 cP...OP 74 ...psi
Toyota (Nippon Oil) 0W-20 virgin, less than 30 miles on oil
...............KV100 8.8 cSt...HTHS 2.6 .cP...OP 71 ...psi
Toyota 0W-20 used with 150 miles on oil **
...........est KV100 8.0cSt est HTHS 2.4 .cP...OP 65 ...psi
And here are some graphs I made of the above indicating a 99.4% accuracy in oil pressure predictabilty using HTHS viscosity, vs ~73% for kv alone.
There is some relationship in the latter, but only as far as HTHS tends to go up in oils of thicker weights.
I tabled and graphed the above data. Since kinematic and dynamic viscosity mean different things and are measured differently, I'd like to see the KV100 values converted to cP via the specific gravity of each oil to see if the KV100 data become more linear to oil pressure.
Dynamic viscosity measured in cP, measure of tangential force to shear layers (internal resistance to flow similar to shearing effect in journal bearings).
Kinematic viscosity measured in cSt, measure of ratio of dynamic viscosity to density (typically measured by flow through an orifice via force of gravity).
CentiPoises(cP) = CentiStokes (cSt) x SG (Specific Gravity) or, cP divided by density = cSt.
Two fluids with the same dynamic viscosity can have very different values for kinematic viscosity, depending on their densities.
https://sciencing.com/convert-centistoke-centipoise-8279085.html
https://www.tedpella.com/company_html/viscosity.htm
Here's CATERHAM's data
http://www.itinerant-air-cooled.com/viewtopic.php?t=8721
Quote:
All oil pressure readings were made at 6,500 rpm and oil temp' of 95C:
M1 5W-50 ..... KV100 17.5 cSt...HTHS 4.21 cP...OP 92 ...psi
M1 0W-40 ..... KV100 14.0 cSt...HTHS 3.7 .cP...OP 86 ...psi
RL 10W-30 .... KV100 11.0 cSt...HTHS 3.8 .cP...OP 87 ...psi
RL 5W-30 ..... KV100 10.6 cSt...HTHS 3.8 .cP...OP 87 ...psi
GC 0W-30 ..... KV100 12.2 cSt...HTHS 3.5 .cP...OP 83-84 psi
RL 5W-20 ..... KV100 9.1 cSt...HTHS 3.3 .cP...OP 80 ...psi
M1 5W-30 ..... KV100 11.3 cSt...HTHS 3.09 cP...OP 78 ...psi
PP 5W-30 ..... KV100 10.3 cSt...HTHS 3.1 .cP...OP 78 ...psi
RL blend, 3qts 5W-20 and 1qt 0W-10 race oil *
...............KV100 8.2cSt est HTHS 2.85 cP...OP 74 ...psi
Toyota (Nippon Oil) 0W-20 virgin, less than 30 miles on oil
...............KV100 8.8 cSt...HTHS 2.6 .cP...OP 71 ...psi
Toyota 0W-20 used with 150 miles on oil **
...........est KV100 8.0cSt est HTHS 2.4 .cP...OP 65 ...psi
And here are some graphs I made of the above indicating a 99.4% accuracy in oil pressure predictabilty using HTHS viscosity, vs ~73% for kv alone.
There is some relationship in the latter, but only as far as HTHS tends to go up in oils of thicker weights.
I tabled and graphed the above data. Since kinematic and dynamic viscosity mean different things and are measured differently, I'd like to see the KV100 values converted to cP via the specific gravity of each oil to see if the KV100 data become more linear to oil pressure.
Dynamic viscosity measured in cP, measure of tangential force to shear layers (internal resistance to flow similar to shearing effect in journal bearings).
Kinematic viscosity measured in cSt, measure of ratio of dynamic viscosity to density (typically measured by flow through an orifice via force of gravity).
CentiPoises(cP) = CentiStokes (cSt) x SG (Specific Gravity) or, cP divided by density = cSt.
Two fluids with the same dynamic viscosity can have very different values for kinematic viscosity, depending on their densities.
https://sciencing.com/convert-centistoke-centipoise-8279085.html
https://www.tedpella.com/company_html/viscosity.htm
