Pnoidrummer

synthetic better or not better. i heard it is for new cars. but for old cars not as good?

VacavilleFC

supposedly synthetics do not burn off as clean as natural mineral oils do. some people use only mineral, some people have switched to synthetic, i myself use castrol gtx mineral oil

wrankin

Search. It's a FAQ.

SureShot

A search will get you hundreds of posts.
Yes - there are many low ash synthetics.
But - synthetics have a higher flash point which makes them harder to burn.

The trump:
Mazda says the RE is happier with mineral oil.

SpooledupRacing

conventional oil is not "MINERAL" oil... Synthetic is better when u put synthetic oil vs conventional oil synthetics have better properites..

as for using in a rotary.. ONLY ELF has been approved by mazda for use in the RX8

This is why I use and sell ELF oil.. I would otherwise only use Castrol 20w50

trueimport

iTrader: (8)

There are a few racing teams that have been running synthetic for years with great success. I personally run Royal Purple with no problem at all.

fcunderwater

I love royal purple in my FC (and I think my fc appreciates it as well) lol

Spectator

iTrader: (1)

Common saying:

Use mineral based oil if your OMP is running, use synthetic if you run premix.

trueimport

iTrader: (8)

Good point! I forgot to mention that I'm premixing.

SpooledupRacing

Just a heads up ther ELF oil that is recomended by Mazda for the rx8 meets the requirments for it to be burned properly in the mazda omp...

sxr 5w30 is what is recomended if u dont have a omp u can run the 10w50 like I do

Pnoidrummer

cool deal thx

Pnoidrummer

i read somewhere that oil sometimes dumps into the conbustion... so if u use synthetic it leaves residue. or maybe i read some idiotic thing online. haha.

celbii

iTrader: (2)

I run royal purple 10w30 fine in my car.

I love pop-up lights

oil does go into the rotor housings via OMP it keeps things lubed, unless your running premix. I've heard some lower quality synths can leave an ashy residue but don't take my word for it, someone more experienced can chime in any time!

celbii

iTrader: (2)

Yeah im sure the lower quality ones do IIRC. This is from Royal Purples websites FAQ. This is just for royal purple, I have no other idea about other synthetic oil's.

Rotary Engines

Can Royal Purple Motor Oil be used in a rotary engine?

Yes. A rotary engine is a modified four cycle engine that recommends the use of an API licensed motor oil for street applications.

More information and FAQs on lubrication of Rotary Engines:

In a rotary engine, the oil lubricates the eccentric shaft bearings, thrust needle bearings and rotor bearings similar to a crank and rod bearing of a piston engine as well as being injected into the combustion chambers to lubricate the apex seals, corner seals, and side seals helping to create the sealing mechanism doing the equivalent job of the piston rings.

Royal Purple provides outstanding protection for the e-shaft, rotor bearings, thrust bearings and is suitable for the oil injection system as it has proven to run cleaner than other oils and is an excellent choice for rotary apex seals, corner seals, and side seals.

Mazda makes a statement in the Owner’s Manual not to use synthetic oils in a rotary engine, why do you say that it is OK?

Royal Purple has performed seal compatibility testing on the components used in a rotary with excellent results, including older rotary engine seals dating back to the Cosmo. Royal Purple’s Technical Services Manager David Canitz has been an owner and racer of rotary engine cars and has used synthetic motor oils in rotaries since 1985 with excellent results. He has been trying to find an answer to this Mazda statement for the last 18 years.

In the early development of synthetic oils decades ago, there were purportedly some seal compatibility issues. Today’s synthetic oils do not have the compatibility issues of the old oils. There is no substantiated evidence of seal compatibility issues with Royal Purple.

Here are some facts:


The Mazda Factory racing departments recommend and use ‘synthetic’ oils including the winning 1991 Leman’s 20-G 4 rotor Mazda 787B.


MazdaComp USA printed manual (now Mazdaspeed) recommends the use of synthetic oils for racing conditions.


Royal Purple Motor Oils have been used in rotary engines (both race and street) for ten plus years with excellent results.


Royal Purple Motor Oil is compatible with the bearing material, sealing elastomers, and combustion seals used in a rotary engine.

I heard that synthetic oil doesn’t burn like mineral based oils and will coat the inside of the engine with deposits.

If this was a problem with synthetic motor oils in general, then all internal combustion engines using a ‘synthetic’ would experience increased deposits on internal surfaces. The opposite is actually the norm.

Conventional four cycle motor oils will typically leave deposits of carbon and ash when injected into the rotary apex seal, corner seal, and side seal areas. Royal Purple’s motor oil actually burns cleaner due to the synthetic base stock being free of contamination and many of the additives being ‘ashless’. This may not be true for all synthetics but Royal Purple has been proven to work extremely well in rotary engines.

Royal Purple’s formulation of synthetic hydrocarbon motor oil does burn at the nominal combustion temperatures experienced in both street and racing applications, whether normally aspirated, turbocharged, or supercharged. (500 – 1700° F idle to race rpms typical combustion temps)

Will the synthetic oil effect the oil seals?

No. Royal Purple’s Motor Oil is fully compatible with the elastomers found in rotary engines as well as more conventional piston engines. The oil seals, housing seals and other elastomers used in rotary engines typically consist of Buna N, Nitriles, Neoprene, or Viton materials which are also commonly found in piston engine cars.

I hear that synthetic is ‘thinner or lighter’ oil, is there a greater possibility that the oil will leak between the seals?

No. If an engine’s sealing surfaces are in good condition, synthetic oil should not cause any leakage. However, if an engine has marginal seals, there is a 50/50 chance the seals will leak less or more. A synthetic motor oil is going to have similar viscosity to that of a conventional motor oil – except at extreme temperatures. Due to a flatter viscosity curve, at low temperatures it will not thicken as much (easier winter cranking) and it does not thin out as quickly at higher operating temperatures (better oil film at higher rpm).

Should I go longer or shorter between oil changes?

Royal Purple recommends that the maximum oil drain / filter change interval listed in the Owner’s Manual be followed while under warranty (new RX8). For FA, FB, FC, FC Turbos, and FD rotaries, extending drain intervals from two to five fold is possible if desired. Since the rotary engine injects oil through the use of a metered oil pump, either adding oil into the carb base plate air / fuel mixture or directly injecting oil into the rotor housing, rotary engines will consume oil of one quart per 1000 – 3000 miles. It is important to maintain the proper crankcase oil level in your rotary engine if you decide to extend oil drain intervals.

If I pre-mix my fuel for the rotary engine, do I use the same ratio as with mineral based oils? Does it burn at the same rate?

In an ideal world, the rotary engine metered oil pump should inject an ashless oil designed to burn in the combustion chamber and use a four cycle oil in the crankcase for the eccentric shaft, rotor bearings, and thrust bearings. For the street, Mazda simplified the OE system to use just one oil, that being a typical four cycle oil for both the e-shaft as well as the combustion chamber. Royal Purple recommends using our standard TCW III 2 Cycle Oil if the metered oil pump is still enabled. The two cycle oil being added to the fuel tank is in addition to what Mazda designed to inject and acts as a supplement or insurance. Depending on which engine, the level of modifications (street port, Bridgeport, peripheral port, nitrous, turbocharged) and application, the typical mix ratio could vary from 200:1 to 800:1.

For a pure racing application where the metered oil pump has been disabled or removed, again based on the actual engine and modification level, the ratio could vary from 150:1 to 600:1. For this application, we recommend our Racing 2 Cycle TCW III product or the standard 2 Cycle TCW III can also be used.

A stock FD twin turbo 13B with the MOP oil injection system can typically use about one quart per 1500 miles under hard street driving. If this vehicle is getting 15 mpg, the gasoline to oil ratio is 400:1. If the oil consumption on this vehicle reduces to 1 quart per 2500 miles and fuel efficiency increases to 20 mpg, the gasoline to oil ratio increases to 600:1. The stock metering oil pump is a great system as it varies with throttle position (load on the engine). Pre-mixing has to be calculated for the ‘worst case’ that will be seen by the engine for that fuel load. Under racing conditions, that’s wide open throttle at racing rpms. This means that at idle, the ratio may be slightly fat (rich).

Evil Aviator

Engine oil: Yes, it is better. No, it is not worth the money unless racing.
Transmission/differential oil: Yes, it is better. Yes, it is worth the money.

False rumor.

... except during the engine break-in period.

Reference: 1997 Competition Parts Catalog, pg. TT-22.

celbii

iTrader: (2)

Thanks thats some good info for people who are doing rebuilds.

SpooledupRacing

ELF can be used on engien break in.. they state int directly in their pamphlets..

Royal purple is a gimick oil IMO.. Look at their dyno tests and u will see they are out to fool the blind and unaware.

Evil Aviator

You can read the internet version here if you click on Miscellaneous at the bottom of the page:
http://www.mazdamotorsports.com/weba...atalogId=10001

Hmm, no mention of ELF oil.. must be an old article.

celbii

iTrader: (2)

I think the better question is, what isnt a gimick oil these days? if your going to call royal purple a gimick might as well call elf gimick also.

DRIFT FC3S S5

use idemitsu...

Red_Rabbit86

so how is that oil??? that is the japanese stuff mazda trix sells right?

Evil Aviator

It's the best, and all the others are a gimmick!