Royal Purple/Synthetic oils and You
03-28-11, 11:59 AM
#1
Royal Purple/Synthetic oils and You
Rotary Engine FAQs:
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). It also is injected into the combustion chambers to lubricate the apex seals, corner seals, and side seals, all of which helps to create the sealing mechanism (the equivalent job of the piston rings).
Royal Purple provides outstanding protection for the e-shaft, rotor bearings and 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 (who has been an owner and racer of rotary engine cars using synthetic motor oils since 1985 with excellent results) 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 10+ 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. Is this true?
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 burns cleaner due to its synthetic base stock being free of contamination and the fact that many of its additives are ‘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 burns 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 affect 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. 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 will 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 2-Cycle TCW III 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 upon 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 2-Cycle TCW III Racing or the standard 2-Cycle TCW III.
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).
Click Here for the article
Click Here for a free Royal Purple T-shirt
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). It also is injected into the combustion chambers to lubricate the apex seals, corner seals, and side seals, all of which helps to create the sealing mechanism (the equivalent job of the piston rings).
Royal Purple provides outstanding protection for the e-shaft, rotor bearings and 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 (who has been an owner and racer of rotary engine cars using synthetic motor oils since 1985 with excellent results) 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 10+ 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. Is this true?
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 burns cleaner due to its synthetic base stock being free of contamination and the fact that many of its additives are ‘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 burns 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 affect 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. 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 will 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 2-Cycle TCW III 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 upon 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 2-Cycle TCW III Racing or the standard 2-Cycle TCW III.
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).
Click Here for the article
Click Here for a free Royal Purple T-shirt
Trending Topics
12-26-20, 12:42 PM
#9
I've reached out to Royal Purple with that question, as I can't find any mention on their website anymore, either. But to my knowledge, nothing has changed in their oils that would make it unsuitable. I've been using Royal Purple in all of my cars since 2006 with no negative effects. In fact, my last RX-8, before I sold it, was at 165,000 miles on the original motor. I'm not saying that's entirely due to Royal Purple, but moreso proper maintenance.
Edit: Their oil 'calculator' that picks the right grade/weight of oil based on year/make/model doesn't list any FC or FD's, either. However, it does have a recommendation for the RX-8. I'm guessing this is largely a clerical error on the website with not having the 7's listed.
Last edited by SwappedNA; 12-26-20 at 12:51 PM.
Thread
Thread Starter
Forum
Replies
Last Post
George84
2nd Generation Specific (1986-1992)
8
10-01-03 11:23 PM
