Synthetic (Royal Purple) is OK for us!!!

[Giantkiller]

RCC,

I know, I know; my first real post and I am going to bring up an old topic. But according to Royal Purple synthetic oil is good for our rotaries! Please read the e-mail responce they sent to me. I would like to hear some feedback from any that disagree. This post starts with my orignal e-mail to Royal Purple.

-----Original Message-----
Sent: Wednesday, October 29, 2008 9:25 PM
To: rpautotech
Cc: rpindtech@royalpurple.com
Subject: Automotive Questions



Royal Purple,



I have been using your oil for over 10 years. I recently purchased an
RX-7 Efini (twin turbo). Unfortunately the forums say not to use
synthetic oil. I know that the engine uses(injects into combustion
chamber)oil to lubricate the apex seals but why is synthetic a bad
thing? Will it not combust? Is the XPR - eXtreme Performance Racing oil
the right choice(and safe one for my rotary), or should I say farewell
to synthetic oil for the engine? Thanks for any guidance.

V/R,
Jeff


- - - - - - -

Jeff,


If you car is stock then RP 5w30, RP 10w30, RP 10w40, RP 15w40, or the ultimate choices would be XPR 5w30 or XPR 10w40. If you have increased the boost beyond the factory boost or switched out your turbo, then we recommend XPR 5w30, RP 10w40, RP 15w40, or XPR 10w40.

Here are some facts about synthetic oil and the questions that were asked-

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.

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).

Have a great day.

Kyle Neal
Technical Sales Representative
1 Royal Purple Lane
Porter, Texas 77365
work- 281-354-800 ex 248
cell- 713-705-9556
kneal@royalpurple.com

Good info however I think alot of the info they give you is trying to make their oil "the same"basis as all synthetic oils which is not true..

I have never used RP in any of my cars but I have customers, clients AND friends who have used it in piston /rotary engines AND in trans/diffs and I have seen a fair share of trannys fail do to this oil


LIKE THIS

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.


NO piston engines combustion chamber is designed like a rotary, apex seals may be a similar design as rings but act differently and take abuse and "build up" differently

IMO it sounds like the RP guys really dont have any experience with the internal workings on a rotary engine..





I also still stand behind oil that is MADE to be used in rotaries

ELF/Total
Eneos
Idementsu (yes...made by Total)

[Flooder]

I sell Eneos oil .

I'm going to use eneos in my new motor after it's built and see how it stands up.

Eneos is great oil.. However IME it is no better then the ELF/Total oil (both I have used, both I have shear tested and the ELF stands up better)

If the price was right I would carry the Eneos but for the price I will continue to use the ELF/Total oil.

[Phoenix7]

Also, not that most race cars remove the oiling system....they disable OMP and oil injectors/lines in order to run synthetic while premixing.

Originally Posted by phoenix7

Also, not that most race cars remove the oiling system....they disable OMP and oil injectors/lines in order to run synthetic while premixing.

I ALWAYS block off the OMP on my rotaries and run premix.

[Cp1]

while it may be true, RP still has a job to sell its product. And mazda still stands behind their research and cant recommend any type of synthetic oil for their rotary engines for daily use. yes it may have been used in a 1100 HP lemans race car but those cars also run straight distilled water for coolant. sometimes whats best for a race car whos motor is only expected to last for the race it is running in is not best for a daily driver.

Mazda still stands behind its recommendation to only use regular mineral derived oil.

Originally Posted by Cp1

Mazda still stands behind its recommendation to only use regular mineral derived oil.

WRONG... I will get the documentation from the shop today..

Mazda now recommends ELF/Total SXR 5w30 to be used in the rotary engines

This is a picture out of the ELF spec book.. this is an add WRITEN by Mazda and it specifically says.




"Super low viscosity engine oil based on the most advanced synthetic oil technology for mazda petrol and diesel engines. Reduces fuel consumtion by up to 6% in city driving (tested on a 4 cylinder engine) and maintains high level of engine performance. Its optimum protection againstr wear contributes to a long engine life. Highly recomended for use in Renesis engines of the RX8 sports cars."

If its good enough for Mazda to stamp their seal on it then it must be good enough to use.

synthetics have changed ALOT since the introduction of the rotary engines.

This talks about how the RX8 was recalled in ther begining due to faulty omp systems.



This one clearly shows what oil u need to use in the rotary (if the OMP is functional)


I use the 10w50 because I premix and dont use the omp.

[RotaryXperiment]

good info dave, i like that.

[Phoenix7]

so, one of you pro synthetic ppl should do a long term-test of this oil in the rotaries.....

That I will be doing.. Alex (my partner RotaryXperiment) will be putting it in his car here very soon (finishing break in) and I will be dumping it in from the initial startup once I get my project done..

I used it on my n/a engine with 70K for over 15K and had NO problems.. when I tore it down it was in great shape.. no omp, premix and ELF oil.. looked VERY good.

[Phoenix7]

naw, this fresh-rebuild will be better....synthetics from start to finish (if he takes care of the car he may see 200K miles!! LOL).

he is putting it in at 2000 miles.. thats about as fresh as can be really.

I will add it from the first crank over on my car

[RotaryXperiment]

im almost there. at 1,700 miles now