I just finished swapping a VVT motor into my NA. Once the motor is warmed up, I noticed that the max oil pressure is about 50psi. Cold is around 75psi.

I currently have a remote filter with a FC RX7 oil cooler in the bumper (no direct air flow). 8AN lines in between everything. The 140* thermostat in the FC oil cooler is in place with no other thermostat. The pressure gauge is mounted the remote filter base. Stock oil pump.

Is there any cause for concern? Should I bump up the oil line size? Get a higher temp thermostat?

 

Sounds like you might need some 10AN.

 

I had similar issues on my vvt engine with 8an oil cooler lines. When fully warmed it would hover between 45-50psi. Upgraded to -10 and I now get a steady 60 psi while driving.

 

I have a 94 with a VVT swap (no oil cooler) and it'll cruise all day hovering around 60-70psi (stock gauge) with Rotella T6 for reference.

 

I'll get some 10AN on order it sounds like. I'm running Rotella as well. Thanks.

 

With a remote oil filter and oil cooler, you will suffer a fairly large pressure drop. I used to have an RX-7 and starting in cold weather, the pressure would drop steadily after about 2 km from 4 bar (56 psi) to 2 bar (28 psi) and would slowly recover after that so by the time I had gone about 5 km, the pressure was back to normal. You need bigger lines if you retain the current system but if, as you say, you have the oil cooler out of the airflow, why bother with it? The oil to water heat exchanger that the stock oil filter mounts on is probably good enough and a change to the Mazda Millenia filter (either engine, any year, they all use the same one) which is 0.9 inches longer makes removal and installation much easier.

 

I'm actually just going to by-pass the oil cooler with the -8AN lines for now and monitor my oil temps at my next track day. I do still have the factory oil cooler in place. If the oil temps are too great, I'll move to 10AN lines and maybe a smaller cooler too.