BP Na + Turbo - Do I need oil coolers?
 

Hi,

I have a BP Na + turbo set up with a Subaru aluminum radiator with 2 slim fans. I plan to use it to go uphill/ downhill touges on mountain passes with it. It usually lasts 10 to 15 mins of consistent high revs.

Water temp marks 3/4 on the stock gauge. At what point do I need oil coolers?

when you oil is consistantly over 100C.

i'd be tempted to sort out your coolent overheating problem before looking at oil temps.

the early BPs comes with a water cooled oil cooler... it works as long as your cooling system is working right.... it's likely yours is not

get a REAL temperature gauge... the stock gauge sucks because you don't know your exact temperatures!

if you do see overheating, you need to fix that
a low temp thermostat is one of the possible fixes

If your loaction is right. Being in Cebu City - well you might want to also look at getting air in and out from your radiator. the Hi Humidity of a tropical area makes it more difficult to cool.
But As above solve the cooling issues first.

Thanks for the suggestions. You got my city right. I guess I'll have to get oil and water temp gauges.

I'm the only non-Subaru in the group and I've observed that their water temp gauges marks around 60% to 70% on their water temps when we go uphill. I had the impression that this temp was normal. Is it possible for the oil to overheat while water temp is around 75% on the stock gauge? Also, what happens if the oil overheats and how would I know when it does?

The guage being at 3/4 means your water temps will be 110C +/- 10C due to the guages not being very actuate. It should be at 1/2 which is 90C-100C.

If the oil overheats, it shears and stops doing it's job. You will not know exactly when this may be happening. But it will kill your engine slowly if it is happening. There are always thinker oils available that will resist higher temps.

I you try as suggested above a low temp thermostat. Maruha is 78C, and Mishimoto is 62C. Well under the 82/88C that you would currently have.

there's also a thing as "too thick".... MX-5 owners in Arizona has tested varying thickness of oils, and they all found elevated oil temperatures when using very thick oils... so use only as thick as you need as the pumping losses in thicker oils reduces power and raises temperatures... more does not mean better!

I'm using Castrol magnatec 10w-40. I plan to replace it every three months. Am I using the right grade? Do you have any recommendations on what oil to use?

Also,I think my thermostat has been removed so I don't have one. The two slim radiator fans are on as soon as Ii turn the key. Is there something wrong if my engine is running too cold. On a normal driving mode, my water temp marks 1/8 on the stock gauge even during a noon traffic.

I've been using royal purple 10w-40 for about 3 years now and my engine is still great with good compression and no smoke or eating fluids.

running with no thermostat can cause overheating

May I ask why?