i did search and found a lot but this question is about my particular situation and purposes about using a car

I'm considering buying Motul dino engine oil (4000 motion). I have 2 choices: 15W40 or 20W50. As i remember in FD usualy you use 10W30 in winter and 20W50 for summer. Temperature here now is 60F and it will get hotter time after time and reach sometimes 105 in summer. I'm not driving the car much, about 500 miles per month and i autocross it ones in a month premixing motul 2 stroke oil. considering my goals and temperatures here, what type will be better for me? My car is JDM Type R with dual oil coolers and boltons listed below.

 

probably the 40w. You probably ownt harm anything either way, as long as you allow time for proper warm-up.

But the only REAL way to tell is to watch your oil pressure during idle and WOT. A good oil pressure gauge and experimentation will show you the exact viscosity you should be running in any given condition.

 

All I can say is read this in its entirety:

http://ferrarichat.com/forum/showthread.php?t=136052

It is what has me using 0w-40, dam what everyone's opinion is.

 

how is 0w-40 working? im rebuilding my motor, and after reading that article it does seem like the best choice.

 

That is a very good article.

 

There is still a lot of nervousness around about using synthetics in Rotaries though. 0w-XXw oils can only be synthetics right?

 

My Mobile 1 0w-40 runs just great. I have been very pleased with the results and it (seems to) rev just slightly easier. There are those nervous about running synthetics in rotaries, but there are thousands of others who run them just fine.

This argument has been going on since my first visit to this thread in 1999. Everyone has a different opinion, so I just try to stay with the facts and enjoy my 0w-40.


Oh yeah, and congrats on opening a can of worms and pulling scabs off old wounds. Once everyone gets off work, the fire storm of oil wars will ensue.