Thanks for the link. Interesting discussion on modern oil lubrication showing the importance placed on high flow and high pressure. Might be a good reason why 5W-20 and smaller better flow oil filters are spec'd more and more:
“Older oil pump designs were ‘over-engineered.’ That is, they didn’t need to generate as much pressure and flow as they did, and they had considerable reserve capacity,” he said. “Now, engine bearings have been redesigned to need less oil.”
Despite the smaller pumps, automakers are maintaining significant pressure inside their lubrication systems.
“Ten years ago, most vehicle lubrication systems pushed three gallons of oil per minute through the filter. Now, most are moving 12 gallons per minute,” Birch said. “And some, like the new supercharged 4.4L V8 Northstar engine that some Cadillacs are using, push 19 gallons per minute through the filter.”
Birch said the extra flow and, in some cases, higher pressure is needed because engineers are constantly coming up with new demands for motor oil.
“The Northstar V8 has a system that sprays oil on the bottom of the pistons in order to keep them cool,” he said. “The flow rate through the piston coolers alone is three gallons-per-minute at 70 psi.
“Overhead-cam engines need more oil flow than overhead-valve engines, and variable-valve timing engines need 30 percent more oil flow than overhead-cam engines.”
Makes you wonder about some of the board advice of using 5W-40 in a VVT Civic calling for 5W-20.
“Older oil pump designs were ‘over-engineered.’ That is, they didn’t need to generate as much pressure and flow as they did, and they had considerable reserve capacity,” he said. “Now, engine bearings have been redesigned to need less oil.”
Despite the smaller pumps, automakers are maintaining significant pressure inside their lubrication systems.
“Ten years ago, most vehicle lubrication systems pushed three gallons of oil per minute through the filter. Now, most are moving 12 gallons per minute,” Birch said. “And some, like the new supercharged 4.4L V8 Northstar engine that some Cadillacs are using, push 19 gallons per minute through the filter.”
Birch said the extra flow and, in some cases, higher pressure is needed because engineers are constantly coming up with new demands for motor oil.
“The Northstar V8 has a system that sprays oil on the bottom of the pistons in order to keep them cool,” he said. “The flow rate through the piston coolers alone is three gallons-per-minute at 70 psi.
“Overhead-cam engines need more oil flow than overhead-valve engines, and variable-valve timing engines need 30 percent more oil flow than overhead-cam engines.”
Makes you wonder about some of the board advice of using 5W-40 in a VVT Civic calling for 5W-20.
