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Old 05-18-2009, 11:08 AM   #38 (permalink)
Modshack
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Quote:
Originally Posted by wstar View Post
I have no idea how our (or other) oil pumps are designed, but I would think depending on the pump design you would either see a drop in flow rate (from moving a larger volume of oil using the same force), or an increase in oil pump 'drag' on the engine but same flow rate (in the case that the pump is designed to move a fixed volume per stroke/rev/whatever regardless).
I would think that the limitations in pressure and flow would be determined downstream of the filter and cooler, limited by Bearing clearances, oiling orfice sizes, the relief valve, viscosity, heat levels, thermal expansion etc. Once the system (cooler and filter) is pressurized the factors just listed will determine pressure and flow. There will naturally be less flow and higher pressure with cooler oil. This is mentioned in the service manual when testing on a cool engine and anyone who's ever had an oil pressure gauge on a car can confirm by observing pressure drops as an engine comes up to temperature....The VVEL failsafe system seems to be sensitive to pressure but is triggered by temps as it is assumed pressure and viscosity drops with extreme temperature rises (see graph at the top of my DIY)
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Last edited by Modshack; 05-18-2009 at 04:17 PM.
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