Another data point:
The stock 20B pickup tube is rather long with a number of bends,

which

seemed to me could be a limiting factor in oil flow.  I have a

custom

deeper

pan (about 6"), and I made a custom pickup tube going straight down

from the

pump inlet - as I recall the tube is about 5-1/4" long.  I used a

3/4"

SS

tube with an i.d. that matches the pump inlet quite closely (a tad

larger).

I intended to flare the inlet end of the tube, but decided to forego

that in

order to install the stock inlet screen.

For the dyno runs we ran Castrol 20-50.  The oil pressure regulator

valve in

the engine is 100psi.  The oil goes first through the dyno cooler

loop, and

I don't know what the pressure drop there is.  The flow rate as a

function

of engine RPM is shown on the attached chart. I don't know what pump

speed

is.

The curve is quite linear up to about 5000, and then begins to bend

over a

bit.  Flow at 6000 it is 14.2 gpm.  At 5450 engine rpm the flow is

13.6 gpm

- lower than Francois reports on their engine, but I don't know if

the

gearing ratio is the same.

FWIW,
Al

Thanks Al for this data.

What oil pump model do you have on that 20B?

Assuming you have the '93 model with the side passageway, we get
approximately 45% higher flows on the test rig, with a straight pickup
tube and NO INLET SCREEN.  If we change the pickup tube to one with

the

stock inlet screen, then we get PRECISELY the same flow curve as you

do.

We would have thought that this inlet screen could make that much
difference.  We'll have to test different screen geometries as we

cannot

afford to lose that much flow.

Francois Badoux

Francois, do you have a transparent section of pipe between the pump
and the pressure restrictor valve?

Paul Lamar


Nope!

Francois Badoux

I have been thinking about this for the last couple of weeks and was getting
ready to duplicate your experiment with a front cover and 2d gen oil pump. 
You mentioned oil foam in some of your early posts on this subject. At what
point in the system was that observed? That concerned me because some of our
oil cooling problems could be explained by the existence of oil foam in the
oil cooler. First thing I am going to do is find transparent line
that will live over 100 psi.
 
Paul Lamar
 
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