Just got around to plumbing in mechanical gauge before cooler to see whats really happening with my oil flows, wish I’d done it years ago! Learnt so much in a couple of minutes on things that I have wasted so much time second guessing. my second attempt oil cooler did work better than the original mazda cooler, but was atrocious overall, Pressure drop was about 60psi at 1400 prop rpm. No wonder I cant cool the oil, bugger all is going through it, just enough to give me about 80psi oil pressure.

Ended up bypassing cooler all together to confirm it is the cooler that is problem not lines or anything else, well what a diference pressures constant at 78psi at all rpm’s

Trouble is no cooler manufacturer here seems to have charts of flow & pressure drop on their coolers, very frustrating especially as prices seem to range between $100-900 for similar sizes, so makes it very hard to select correct one.

Andrew