Oil change / Royal Purple?
 

I'm about to do an oil change for my 1990 RX-7 GXL and I'm wondering if Royal Purple is good to use. I heard that you shouldnt use synthetic oil for your RX-7 but is Royal Purple an exception?

everyone you ask will tell u different. use 20w50 and ull b alright

Waste of money that shit. Synthetic oils don't burn as well as mineral. This might be hard for you to believe but your RX7 will prefer it if you feed it crappy oil. 20w50 and it will keep loving you. Given the price of royal purple buy yourself some floormats or something with the change, you'll appreciate it more.

Mobil1 runs well in rotas, i have been lead to believe from some reputable sources. HOWEVER, that is just 2nd hand info.

An Engine builder i know here, and a couple other builders i dont know personally, all recommend Penrite Mineral.

If you are pre-mix, go with synthetic.

Royal Purple is good stuff, it's throughly tested in Rotaries [one of their top guys runs RX-7s], it will burn clean, it will reduce wear on your stationary gear and rotor bearings.... but it's not worth the price difference - the parts it prolongs the life of are relatively low wear parts to begin with, and relatively cheap to replace when they are worn.*

The general consensus is to run mineral oil in all but *extreme* race conditions. Castrol GTX 20W-50 is usually cited as the preferred mineral oil, but it's up to around half the price of Royal Purple around here...

Personally.. If I can't get a deal on Castrol, I usually grab Chevron.
Also, buy high quality oil filters: Mazda [surprisingly cheap!], WIX, NAPA Gold, etc..

*While you're doing an engine rebuild. You wont even be able to detect any wear on them until then anyway.

which Synthetic Oil can stand the combustion temperature?

1/2 the junk are additives left overs. try it in a lab and burn the oil at 1200 celsius you will know what I mean.

and are you trying to tell me a Group II (which most mineral-based engine oils are) is more purified than anything in the higher group ? Hydrocraked/Poly/Ester ?

:scratch:

the "is it worth it" is just an opinion. Just like most of us like Rotary more than piston engines.

I switched to Royal Purple once and blew a coolant seal a weak later. Probably unrelated but I will never use again. Gtx- 20W50 for me.

S E A R C H!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!

Don't feed the monkey.

i use mobil 10w30

synthetic is a waste, just buy a case of castrol and send me the difference for how much it would cost to buy a case of royal purple.

FC3S Pro v2.0:* FAQ, Synthetic Oils in the Engine quite good info on the subject here.

I do not have a lot of knowledge about the topic, but i do know and use Idemitsu synthetic oil as it is safe to use for rotaries. It's made specifically for them. The negative being that you can't get it at any local store. I have thought about switching my girlfriend to Royal Purple in the future for convienence and to eliminate shipping costs.?

Are you using the omp or premixing?

I run castrol because thats what previous owner ran an its a good oil. When i put a new engine into it, i will run only synthetic. I've had people say that synthetic is bad for rotaries and that it will ruin stuff ect ect. But the engine builder i know showe me some rebuilds he was doing and i was able to compare standard oil and synthetic sode by side. At 200k the synthetic engine looked significantly cleaner and showed less wear than the standard oil engines. Everyone will tell you something different. We tested a bunch of oils and RP was not that great, but it was purple...Amsoil is my oil of choice but is pricey. Find what works for you an go with it

Interestingly, the cost of dino oil has gone up so much there can be little difference between the cost. For instance, I just purchased a bunch of Royal Purple on sale at Autozone for $6 a quart. GTX regular price is a little over $5 a quart.

Bloody hell that's cheap. Over here in aus I think that gtx retails for about 30 for 5 litres and royal purple costs 99 for 5 litres.

I'v always used Castrol GTX High Mileage 10w30 in my RX-7 and she still runs like the day I got it. I'v been debating on switching to 20w50, should I?

dino oil is always cheaper by the gallon or 5 quart jug, the synthetics not so much.

Probably not - 20w50 is more a choice for hot climates - like the US "sand" states in the south. You likely never see higher than 25C ambient in PEI, I'm guessing. Heavier oil is only a benefit if you are seeing high oil temps with lower pressure due to heat-related thinning - and in your climate, and presumably relatively short trips, heavier oil is just going to cost mileage, and possibly lubricate more poorly, especially at start up and short trips. If you track the car (autocrossing doesn't count, runs are too short to significantly heat-load oil), 20w50 might make sense.

I've gone with a 50/50 mix of Castrol GTX 10w30 and Mobil1 for years. The engine's never been out of the car, so I can't comment on how clean it's staying, but given my compression has dropped on about 5psi/rotor and is still well within stock specs, over the 14 years I've owned and bagged the car, it seems to be working.

Any guess on minimum daily heat you'd want to run 20w 50?

Thanks "rx7racerca"! The temp here on hot days usually ranges from 25C to 35C depending on humidity, and the most track time my RX-7 sees is the occasional run down the drag strip, so yeah I'll be sticking with 10w30.

you got a drag strip in PEI?
SPUD's Drag Strip!..has a ring to it!

Royal purple doesn't have the synerlec additive on their regular synthetic oil anymore you have to get the RP HPS which are more expensive. I used Shell Rotella T on my n/a fc

Lol Yeah we have a drag strip AND a stock car track!

well this just saved Neva bit of money, I was about to put royal in the morning.