This is a great thread guys, I hope it keeps going for a while!
Question regarding KV vs HTHS. At what point does oil flow go from KV scenario to HTHSV scenario?
Thoughts:
An oil galley in the block whose purpose is to transport oil from point A to point B will have a relatively low oil velocity and low overall oil shear. Properly sized, this type of flow environment would produce minimal restriction related oil pressure rise.
At the end of that galley is a restriction orfice who's purpose is to control oil flow by introducing a significant restriction and therefore cause a pressure increase. Inside that orfice, oil velocity increases dramatically as does shear.
KV is measured under the force of gravity only AFAIK, and would present an extremely low-shear environment. Every oil flow restriction in the engine has the operating oil pressure behind it forcing oil through at relatively high velocity.
Comments here suggest that engineered flow restrictions other than journal bearings correlate only to the KV oil specs. Is this really the case, or does the higher shear environment of an oil restriction present to the oil something IN-BETWEEN the KV and HTHSV test environments? i.e. what would happen to KV measurements if they were taken using increasing pressures to force the oil through the test orfice? Would we present "higher" shear conditions, the trend line of which may or may not point in the general direction of the HTHSV spec?
I realize it would take higher than normal operating pressures to reach the shear rates seen in journal bearings, just wondering about the potential of a trend line that may point in that direction and how far along that line our engine's oil flow restrictions are actually operating.
Question regarding KV vs HTHS. At what point does oil flow go from KV scenario to HTHSV scenario?
Thoughts:
An oil galley in the block whose purpose is to transport oil from point A to point B will have a relatively low oil velocity and low overall oil shear. Properly sized, this type of flow environment would produce minimal restriction related oil pressure rise.
At the end of that galley is a restriction orfice who's purpose is to control oil flow by introducing a significant restriction and therefore cause a pressure increase. Inside that orfice, oil velocity increases dramatically as does shear.
KV is measured under the force of gravity only AFAIK, and would present an extremely low-shear environment. Every oil flow restriction in the engine has the operating oil pressure behind it forcing oil through at relatively high velocity.
Comments here suggest that engineered flow restrictions other than journal bearings correlate only to the KV oil specs. Is this really the case, or does the higher shear environment of an oil restriction present to the oil something IN-BETWEEN the KV and HTHSV test environments? i.e. what would happen to KV measurements if they were taken using increasing pressures to force the oil through the test orfice? Would we present "higher" shear conditions, the trend line of which may or may not point in the general direction of the HTHSV spec?
I realize it would take higher than normal operating pressures to reach the shear rates seen in journal bearings, just wondering about the potential of a trend line that may point in that direction and how far along that line our engine's oil flow restrictions are actually operating.