Paul,
              What size oil cooler pipe size does mazda use to supply the oil cooler.  I am looking to use 1/2 inch.    Neil.

As I recall it is dash 8.

Available Hose Sizes
-2   -3   -4   -5   -6   -8   -10   -12   -16   -20
Hose Size is the measurement of the Inner Diameter of the hose measured in units of 1/16th of an inch.
Examples:
a -2 hose has an I.D. of 1/8" [306 only]
a -3 hose has an I.D. of 3/16"
a -4 hose has an I.D. of 1/4"
a -5 hose has an I.D. of 5/16"
a -6 hose has an I.D. of 3/8"
a -8 hose has an I.D. of 1/2"
a -10 hose has an I.D. of 5/8"
a -12 hose has an I.D. of 3/4"
a -16 hose has an I.D. of 1"
a -20 hose has an I.D. of 1 1/4"

The pressure is 150 psi or
10.206  atmosphere
10.546 kilogram-force/square centimeter
1.034 newton/square millimeter

You can find adapters here.

http://www.pegasusautoracing.com/advcat.asp?CategoryID=PLUMADAPT

And here

http://fittingsandadapters.com/hydadsteelfi.html

Paul Lamar