got royal purple in the engine w/ royal purple filter, tranny, and diff....even racing beat sells it and prefers it. royal purple also has FAQ for the rotary engines using this stuff

 

I have no idea, lol. He's the expert, not me.

That's all I needed to hear. I've always liked Castrol and have been using GTX in just about everything I own for years.

 

Personally, I never bought the synthetic argument only because (when my OMP was working) I was burning a quart of oil every 1500 miles anyways, so needing to worry about viscosity break down didn't really matter.

Of course now that I've dumped the OMP and premixing, maybe running synthetic for other components isn't such a bad idea and going longer between oil changes.

 

I don't recommend extending the service interval past what is stated in the service manual unless the oil vendor states in writing that their oil has a longer change interval for rotary engines. Our engines run hotter than piston engines, the eccentric shaft causes a lot of shear, and RX-7 owners tend to drive the engine much harder than a typical commuter driver. Royal Purple recommends using the change interval in the service manual. Some vendors, like Mobil, don't even recommend using synthetic oil in rotary engines.
http://www.royalpurple.com/faqs-rotary.html

 

Maybe, but Royal Purple indicates it's not a problem:

 

because its always easier to say "don't recommend" than carry a big risk of being sue in a sue-happy country.

Tons of people use Mobil1 in Rotary and it works just fine.

 

You may want to lurk at an oil forum:
http://www.bobistheoilguy.com

You will learn more than you ever wanted to know about oil.

For instance, I always thought 5000 miles was a good oil change interval. The owner's manual for all of the cars I've ever owned said 7500 miles, which I thought was CRAZY!

That is until I sent a sample of oil off for analysis:
https://www.rx7club.com/automotive-repair-lounge-280/oil-changes-%40-5k-miles-%3D-too-often-930963/#post10337262


Now rather than asking which oil I should run, I'm wondering which anti-wear additive is better, calcium or sodium?

 

I go there pretty often, but I don't make post there.

That's also why I like (prefer) SL oil more than any of the more "modern" oil. Synthetic or not.

 

just a little heads up about SOME types of fully synthetic oils and what they will do long term in the engine if they do not burn and or form ceramic compounds or gum

this is an engine i had to pull down,,i cant vouch for brand oil went into it,,
but after uncountable engine strip downs i have NEVER seen anything like this from conventional dino oil and its clearly the result of something that will not burn

the pictures are taken after several days in solvent and yes abrasives where used to try and clean them, to nil avail

the compound set onto the housing all through the combustion area where under flame and high temps and friction is like a ceramic
the stuff set onto the side plates in same zones but not so cooked is like a very sticky gum










SOME types of fully syn where known to form glass compounds under some conditions and others form a gum that will not burn

dino works well ,, semi syn ( re-engineered dino ) also works
they are also cheap,, and dont hurt real bad when you change them out when you need to

in a rotary engine that reason is often due to washdown petrol contaminating the oil
-- synthetic oil and magic 20 000 km oil changes isnt going to help you here is it??
and the bloke that payed $25 in oil to get that SAME amount of kms between changes is going to be laughing at the bloke who went through $100 of full syn
and laughing harder at the bloke dearly trying to extend his km's between changes cause of the expense,, when the oil in the engine is already ruined with petrol and carbon despite what base stock it was made from


dino works,, its cheap,, you change it when need arises,, which may be exactly the same period as when having used expensive syn due to petrol washdown