Fram PH/TG/XG8A + HP1 flow rate

[WellOiled]

If this is true, then many of those filters would be in bypass or at least very close to bypass at 34F and 3GPM.

 

[geeman789]

Originally Posted by WellOiled
If this is true, then many of those filters would be in bypass or at least very close to bypass at 34F and 3GPM.


Someone told me that on a cold winter morning ( 0*F) , an oil filter operates in by-pass mode for upwards of 15 minutes, until the oil gets some heat into it. Not sure if that's true, or how to prove that outside of a test stand. I'm sure the filter manufacturers have extreme cold flow data.

The first chart ( at a toasty 34*F ) would seem to support that statement.

 

[WellOiled]

There used to be a sticky on the filter forum where Bob instrumented his truck and gathered data showing bypass events were very rare. Bob also was conservative and would not abuse his engine by doing WOT at -20F just to get a data point.

The viscosity of the oil increases rapidly with decreasing temperature. The PI sheets generally give three data points for viscosity. For Valvoline AFS 5W30 the PI sheet gives: KV100 = 10.2 cSt, KV40 = 60.1 cSt and less than 6000 cP @ -30C or roughly 7059 cSt.

At 0F, I limit RPMs to high idle until the oil temperature increases a bit. When the defrosters begin to work, I get more aggressive with the throttle and reserve very aggressive throttle for 10 to 15 minutes after the coolant reaches the normal operating point.

The oil temperature lags the coolant temperature by 10 to 15 minutes.

My 2cents