looking for a good sandwhich adaptor to add an oil cooler. want one with a thermostat built in, I see several brands for sale, there are some big price differances too.
at any rate there are some ones that have 3/8 inch NPT inlet/outlet threads, and others that have 1/2 inch NPT threads inlet and outlet. the price differenace is considerable (nearly 3X)
seeing as the oil passages upto the filter are not all that fat anyway I figure, how much benifit would one get out of a 3/8 NPT fitting verses the 1/2 NPT? I still plan to use AN10 hose and fittings and have 1/2 inch NPT on the oil cooler itself, so the biggest restriction in the new system would be the 3/8 NPT fittings on the sandwhich adaptor. will this be a significant flow restriction or not verses the larger adaptor? the engine will be a daily driver motor, not a high rpm race motor.