I have a standard EK radiator at present and when round the ring with my B16 the thermostat certainly raised a lil. I have since removed the aircon to allow more air into the engine bay for cooling.
Having removed the AC to allow for air to flow into the engine bay can actually RAISE the coolant temperature even more.
Why?
Air is lazy and seeks the path of least resistance. Ever wonder why non-AC civics had that plastic block off plate? It's to ensure air is forced THROUGH the radiator and not AROUND it.
Ever see those nifty
radiator cooling plates to block off the holes at the top of the radiator support? Same idea.
The OEM oil cooler does a fine job of controlling oil temps while maintaining proper oil flow/pressure. The crux of the system is the stock radiator - since it is an air-to-fluid exchange setup, the size of the radiator can and will directly affect the oil temp.
I suggest getting a dual core, full width radiator while paying particular attention blocking off any gaps on the sides/top and bottom of the core. This can be achieved with fabricating aluminum fins/shields or some race teams even opt to use expanding foam....which is a great idea. When was the last time you had to remove your rad?
FWIW, the Super Taikyu Spoon DC2 I had the pleasure of inspecting very closely years ago DOES NOT run an external oil cooler and to this very day, it continues to compete in the eastern United States without one. It does not even have an oil temperature gauge!
I spoke to Spoon president about this and he says that oil pressure is a lot more important than oil temperature - when using a good oil (they swear by Motul 300V). Personally, I'd like to have both monitored.... but he's the one with worlds of experience and many winning cars...
Does this mean an external oil cooler is not necessary at all? No.
I would run one in a Turbo Honda or high compression, larger displacement (2.0L) Honda that sees track duty.
It is said that the smaller oil filter is better since it has less surface area to expand which can cause oil pressure fluctuations. Supplement this with a hose clamp (the type used to secure silicone sleeves on your intake) fitted tightly around it and of course, always use a baffled oil pan.
If possible, increase your oil capacity.