Whats up everyone!
I have a 94 FD with a TO4S single turbo and I live in Okinawa, Japan. How much oil and what kind should I use? Synthetic vs Mineral? Also, the OMP is deleted and I run 1oz of Idemitsu premix per gallon.

Im thinking Castrol GTX 20w-50. Not sure how much though 🤔

 

I would recommend searching before you get snapped at. This is a pretty dead subject with many opinions. You pretty much have to do your own research and decide for your self. Many people run
Castrol 20w50 with no issue
idemitsu 10w30 or 20w50 or other synthetic with no issue
Some run rotella 15w40 diesel with no issue

I run catrol 20w50 and may switch to idemitsu soon. My engine guy uses penzoil straight 40

It will be up to you.

 

Have you tried searching the forum for your question? This topic has been beat to death over the past few decades.. I want to say there was even ANOTHER recent thread within the past couple weeks on the subject.

Everybody has their own opinions on "best" oil.. personally I'd stick with the factory recommended weights. The key is to change your oil early and often due to fuel dilution.

 

+1, agreed. to that end i tend to run a mineral oil, as its less expensive.

here is the 93-95 shop manual blub about the oil, no idea what the later cars got. if its making power there is no trouble going to a 50 weight oil,

 

The whole and only reason I stayed mineral. To change it more often...$$$$... I am still running super rich so I believe I am getting a lot of dilution. As I lean my normal drive and cruise out and now that I am broke in I will probably switch to synthetic soon.

 

Castrol. Cheap, proven, available anywhere. Been using it for decades on 3 different RX-7s with no oil related issues ever.

 

There are a lot of factors that come in to picking the proper oil for your car. Power levels, RPM limit, purpose, and climate being the main four I can think off of the top of my head. With a higher RPM, a 15w-Xw is going to be overkill due to the fact that we run our cars more so at higher rpms and the loads the e shaft sees really isn't that high compared to a piston engine as it never has to change directions. A 5w-Xw or 10w-Xw oil would be most ideal for these engines. 5 if you are near stock power, 10 if you are running say a big single. Now for the cold end of the range, an Xw-30w would be better for a colder climate car or something that sees highway miles and low stress environments. An Xw-40w would be better if your climate is warmer or if you track your car. While you can run an Xw-50w, it really seems like over kill even if you are trying to compensate for fuel dilution. It's all up to you, but a synthetic handles heat far better and has better longevity. For reference, the first number i.e. a 5w or 10w is a viscosity index rating at 212 degrees F and the second number is the viscosity index at 100 degrees F. Viscosity is resistance to flow which is why a lower viscosity pours faster. (I'm sure you all have seen how much faster warm oil comes out of an engine). Any machinery handbook can give you a good run down of how journal bearings work and that's basically what you're picking oil for.

 

I third this...and also because a significant amount of old oil gets left sitting in the rotors, oil coolers etc. And because turbos are a high heat environment.