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My brain just shut down on me after seeing those equations. yes, would love to see some technical or chemical details about each of the oil groups, especially the POM and PAO based group IV.
keep those infos coming

 

I think this is all good info. However there are always going to be people that will only do what the owners manual explicitly states because they can't formulate a rational logic based thought on their own. What that means is that some people will always continue to use only 5W20 conventional oil even though it's not the best thing for the engine and no amount of proof will change their mind until someone gets Mazda to directly rewrite the owners manual.

 

I understand your thoughts on that, I hoped the fact that Mazda was a member of JAMA, who in turn is a member of ILSAC might bring to light the fact that the initiatives I've shown in this document come partially from the needs of Mazda for motor oil. Fuel economy is the driving force in Mazda's selection of 5w-20 motor oil, they say so in the GF-4 background and in the outline for the new GF-5.

 

Believe me, I'm all for educating people and getting them to finally see the light. Unfortunately for some people the light at the end of the tunnel is turned off!

 

Will do...

 

kinda funny, i just threw in some basic info i got off of my old text book. its in a new thread as well.

but yours have a wealth of information, and very good equations to knock out... had anyone had a specific question that needed answered.

good find, and guidelines to follow.

 

ok well my brain as well shutdown as eyes popped out of my head after trying to read everything, one of you said 5 20 isnt best for the motor could you tell me what is better for the 8? 5w 30?

 

Haha, well like I said I'm planning to do more in depth rotary stuff at a later date. As I'm sure you can imagine, putting all this research together takes awhile.

For now I'd run a group IV 10W-30 like royal purple or amsoil (non XL). With the summer upon us, low temperature startability shouldn't be an issue since we probably wont see temperatures below the mid 60ºF range. However with the high ambient air temperatures and road surface temps we will need good high temp protection. Lets compare Mobil 1 5w-20 and AMSOIL 10W-30 . At 100ºC Mobil 1 has a kinematic viscosity of 8.8cSt and AMSOIL has a kinematic viscosity of 10.7cSt; that's a 21.6% increase in viscosity. At 150ºC (HTHS) Mobil 1 has an absolute viscosity of 2.62cP and AMSOIL has an absolute viscosity of 3.2cP; a 22.1% increase. Keep in mind that the viscosity is a measure of the energy required to pull the oil apart, so it'll take 21-22% more load to push the oil film from the internal surfaces of your engine in theory. There are other reasons, but that's for later .

 

I think my head just exploded!

 

Great info BMonkey ! I actually read almost all of them when I was studying engine oil on my own. (except for some of the newer stuff)

Hmm, like RG said, there are people, no matter what you do, any kind of facts you have, they simply will never change their mind. (Im thinking, do they pray to Mazda's bible ... I mean the user manual everyday? next thing I know is that "Mazda knows best about rotary engine, do you think they will let you use something that will damage its products?" Yes I think they will. and I already explained my opinion about it before in other post.)

IMO, SM specification is kinda like a *step down* from the older spec. It looks like they come out with something to try to save a few bucks for oil companies.

Look at this thread from RR.
https://www.rx8club.com/series-i-tech-garage-22/renesis-removal-rebuild-146186/

The wear ... he never said what engine oil was the guy using, I dont think he knows, but from the picture of the wear ... it smells like 5w20.

Did the engine work? yes, if it wasnt the water leak (seals bad), it still runs. damn this reminds me of expo's old motor.

but I do not think the oil is protecting the engine as it should.

 

as opposed to people who stare at the light a bit too long; only seeing bright whiteness and not understanding why nobody else sees it too ...

 

*Ahh, I can see the light ...*

 

Thanks for taking the time to read it.

 

What if that bright irresistable light is nothing more than a giant bug zapper waiting for us? Hmmm....

 

dang, wish I'd seen this sooner, been pondering all this for quite a while now, nice work, thanks for the info.

 

Wow. First off, thank you for all the hard work you put into making this thread.

Next, here in Florida, I rarely see temps below 35F. And that's obviously only at night for a few hours. So it would appear that I'm a prime candidate to bump up in oil viscosity. I am the exact consumer that is being referenced here. I've been using 5W-20 full synthetic since day one. I'll be bumping up to 10W-30 I suppose. Don't know how comfortable I feel going much higher than that. (I simply don't know enough about it) Now if I didn't have all this damn pre-bought 5W-20 lying around the house.

 

Best thread in a long time. Thank you for sharing some essential info with the community.

Food for thought: The manufacturer needs to do what they need to do, we the enlightened need to do what we need to do.

Paul.

 

Canola oil that is.

 

Viscosity does not mean everything. Oil flow is the same important. With the thicker oil you won't reach the maximum oil flow at high rpms- The reason is that the oil bypass valve will open earlier in the rpm range because of the thicker oil.
With a higher visc oil (thicker) you will reach earlier the pressure where the bypass open.

and the weaker flow means, that the engine's internal parts cooling will be weaker with the thicker oil. The rotary is a very high rpm (and hot), so I think the best is not to exceed the xx-30 visc. at streetuse.

 

wow, awesome thread! my head exploded trying to read it.
Will come back and finish up later...

 

If what you said is true, why is the older rotaries with 20w50 can last 200+ K miles without much effort ? and for some "strange" reason, not only Rotary, Im talking about ALL modern engines, the thinner the oil(5w20 nowdays), the *shorter* the engine life ?