Does anyone have a diagram that shows the path of oil flow through the engine?

 

Here's a basic diagram for oil flow through an engine, although this happens to be a V8 engine. The flow through our engines is similar.



On the F20C & F22C engines, oil passes through the filter before it goes to the oil pressure switch.

 

Thanks for that. Are you saying the oil pressure switch (or port) is directly after the oil filter OUT?

I have a choice for oil supply for my turbo. Either tapping the IN side of the oil filter relocator (high pressure but unfiltered) or from the oil pressure sensor port (considerably lower pressure it seems).

 

The pressure sensor port on the block should be a high pressure port. I am reading a pressure sensor there with my DL1 data logger. Your problem may be volume. As the volume require increases the pressure drops.

Don't you have that canton block adapter? Install a canton fuel filter inline and feed the turbo from that extra port I had drilled. Or better yet install a T in the AN lines and feed the turbo from the post filter line.

 

Why would the pressure be less after the oil filter ?

ROD

 

Because the filter is a restriction. Any given restriction results in a pressure loss that increases with flow rate.

 

Yes it is. I confirmed this by pouring oil into the pressure switch port (using a funnel & tube setup)with the filter removed. Oil poured out of the center tube of the oil mounting port.

The pressure drop across most filters is around 7 psi, IIRC. There was a demonstration on BITOG years ago showing this. Oil pressure at the pressure switch at startup with cold oil is around 85 psi. It drops below 30 psi at idle with a warm engine.

 

interesting.......

 

That's just one more reason to use the largest oil filter that will fit. Small filters have more restriction(until the by-pass opens) than a large filter, the filter I use is about twice as big as the stock Honda filter for the "S".

ROD

 

what filter do you use?