Royal Purple 5W20 - 2133 miles - Mazda RX8

[OMCWankel]

Royal Purple 5W-20
-41,593 total miles on vehicle, 2004 Mazda RX8, 1.3L Renesis Rotary, 4 spd AT
-4 qt oil at change (hot), capacity is 7 quarts, 0.5 qt added during interval
-LC added at 2 oz per Qt oil at fill, 3 oz total added per 1000 mi.
-93 octane gasoline, 1 oz Fuel Power added per 5 gal
-Mobil 1 M-110 oil filter
-Factory paper air filter
-Lab is Blackstone
-UOA#1 2072 mi on oil Motorcraft 5W-20 SL/GF-3, in service 3 months, sample date 5-1-05, 11008mi total
-UOA#2 2356 mi on oil Motorcraft 5W-20 SM/GF-4, in service 2 months, sample date 8-13-05, 15853mi total
-UOA#3 2281 mi on oil Havoline 5w-20 SM/GF-4, in service 2 months, sample date 01-21-06, 23151mi total
-UOA#4 2133 mi on oil Royal Purple 5W-20, in service 3 months, sample date on 04-21-07, 41593mi total

Element.....UOA#1..........UOA#2...........UOA#3........UOA#4
Aluminum.......1...............1...............1..........3
Chromium.......4...............2...............3..........8
Iron............23..............13..............22.........35
Copper........10...............3...............4..........1
Lead...........2...............1...............2..........4
Tin.............0...............1...............0..........0
Molybdenum.36............30............270.........84
Nickel..........0...............0...............0..........0
Manganese....0...............0...............0..........0
Silver..........0...............0...............0..........0
Titanium.......0...............0...............0..........0
Potassium......0...............0...............1..........0
Boron..........2.............174.............124.........33
Silicon.........4...............5...............8.........10
Sodium.........2...............1...............2..........0
Calcium......1520...........1556............2105.......1633
Magnesium......6...............5.............419........809
Phosphorus..579.............527.............678........704
Zinc.........718.............662.............812........880
Barium.........0...............0...............0..........0

Properties
SUS @ 210F..51.6............48.1............48.4.......52.5
Flashpoint...345.............345.............290........320
Fuel........1.3%............1.0%............3.3%.......1.8%
Antifreeze..0.0..............0.0...............0..........0
Water.......0.0..............0.0...............0..........0
Insolubles..0.1..............0.2.............0.3........0.3
TBN.............................................3.7........2.5

I did not think this was a good report. Iron, Chromium, Lead, and Aluminum are all up. Changes will be made in the oil and adds. My thanks to Terry Dyson for his analysis on this unit.

All comments welcome!

 

[Seth]

Well look on the bright side.. copper is down.

How about mixing MC with RP?

 

[badtlc]

I think he did mix it. He had 4 new quarts of RP in there with 3 old quarts of MC 5w20. The wear spiked with the initial running of RP which is expected.

 

[OMCWankel]

I have to change oil every 2000-3000 mi on the RX8, for the reason badtlc gave, not all the oil comes out. This sample of Royal Purple was the third change using Royal Purple, so very little of the Motorcraft and Havoline should have been left in the engine.

Royal Purple is getting very positive reviews on the RX8 owners groups, which is why I tried it. This shows why you must do UOA's, not just rely on suggestions from other owners.

 

[Travis99LS1]

Do you know why some say your not suppost to use synthetic in a rotary? I have heard this before, but never heard a good explanation as to why.

 

[Resolute]

My understanding is that Mazda says not to use synthetic in their rotary? Apex seal issues iirc... if it makes you feel better, RP 5W-30 has been one of the worst performers to date in the 350Z, so it's not just your engine it doesn't do so well in.
Will

 

[OMCWankel]

Responding to the question of synthetic oil in the rotary, undummy has posted the definitive answer on the RX8 UOA by compaddict using Redline. Mazda got mad at a certain synthetic oil maker years ago when they dropped racing sponsorship from Mazda’s racing program. Mazda uses synthetic in their own racing program, made by Idemitsu, and it has group IV PAO base stock, and group V components.

 

[Syntec-Man]

my girlfriend has a rx8 and i do the oil changes for her what should i put in? i put in 5w 20 syntec most of the time. How bout some GC

 

[Seth]

Didnt someone say that RL does better from second OCI onwards? Something about cleaning during first OCI...

 

[unDummy]

TBN dropped quickly and IMO way too low for OCI. Makes me wonder if most of it comes from the ~60% oil changes. Mazda is nuts to recommend those 7.5k(?) intervals.
Have you tried tilting vehicle in awkward ways to try to drain out some more old oil?

Fuel typical high from pig rich rotary.

I wouldn't bother with oil additives. If you practice a reasonable OCI, it is almost impossible to get deposits in a rotary. The oiling systems flows plenty and at a reasonably high PSI.

This report is no worse or better then your previous ones. When you figure in lab inaccuracies, along with leftover oil from partial drain/refill at OCIs, it looks pretty good.

Since frequent OCI is a must, I would skip with the fancy oil filter for a cheaper free flowing unit and I would stop using all oil additives. Some of the boutique filters don't flow as well.

If a piggyback ECU is available, I would definitely look into some A/F tuning. If thats not in the budget, consider an EFIE or voltage adding circuit to the o2.

Since your location is warm, I would consider a 30wt oil. Something just hints to me that the 20wt recommendation isn't good enough for the rotary. Some of that Fe is coming form the e-shaft and gears. I just think a 30wt will provide a hint more film thickness and that film will protect the gears, chain, pump, e-shaft......

Even though I will NOT recommend oil additives with your engine, I would definitly keep using a fuel additive. Stick with the FP60. And, consider a little 2-stroker oil or UCL too. Mazda finally admitted that they were running the oil injection too lean. Even with the latest reflashes, I'd wager that oil injection still isn't good enough. A couple ounces of oil added to each tank should help with engine longevity, compression, HP, and MPG.

I hope that you're also taking care of that transmission. Torqueless rotaries tend to abuse their automatics. They need higher stalls, more shifts, and a more aggressive driving style.

 

[OMCWankel]

UnDummy, thank you for the input. The RX8 is almost out of warranty, and I am looking at ECU mods. The oil adds will stop, and an additional oil cooler will be added. Mazda seriously undersized the oil cooler area for hot climates. I have tried tilting the car, not much extra oil comes out. I was concerned most about the additional iron in this UOA, from the stationary gears (not so bad), and the side plates (very bad). I will be switching to 5W-30 oil soon. I also believe that 5W-20 is too thin for the rotary.

I have been using pre-mix from the beginning, and the motor likes it. I use a ratio of 350 to 1, and use synthetic 2-stroke oil. I also use the recommended dose of FP. I started a pre-mix thread on an RX8 site, and got flamed big time. Lots of strong opinions on pre-mix in the rotary. Oil injection with the latest re-flash is still not enough. I can go 2000 miles with only ¼ qt added in mild driving. I should be adding 1 qt in the same distance.

The auto transmission has a fresh fill of MolaKule’s best, and is running great! This is the third change of fluid for the transmission. I believe in lots of ATF changes early in the unit’s life, to make the unit last. I will probably leave the Speciality Formulations ATF in there for 30,000 miles.

Syntec, any mostly group III oil like Syntec has shown to do well in the rotary. The most important part of rotary maintenance is frequent oil changes. Do not believe Mazda’s schedule, change oil and filter at no more than 3000 mi intervals.

 

[Syntec-Man]

omc take care of the automatic, my girlfriend ruined hers, change the fluid very often undummy is right

 

[Patman]

That chromium number of 8 is scary! I would not want to see chromium anywhere above 1 in such a short interval, that's your rings getting grinded down right there. If that chromium number stays high on your next interval, I'd switch oils asap.

 

[GenesToy]

I agree that chromium comes from rings. Where does it come from in a wankel engine?

 

[Bror Jace]

Seth, Yes, that's the 'scavenging effect' of Red Line's ester chemistry that cleans heavily when it's first used in an engine ... especially one with some serious miles on it. Esters are not just lubricants, but have solvent (and seal conditioning) properties as well.

Still, I think the RLO chemistry is still a bit too aggressive for general use and I will no longer use it in daily drivers that don't see extreme stress or temps where it is likely to make the difference between and engine that fries or survives. Too many other great oils out there ... that will get the job done for less $$$.

I thought the no-synthetic-oil-in-a-rotary issue dated back to when early PAOs had problems with lead scavenging? (early PAOs were known for poor solubility). The same problems encountered in piston-powered airplanes using heavily-leaded AvGas? Lead would build up at the top of the cylinder and eventually damage the piston? With a rotor, I could see it causing equivalent problems with rotor seals.

Of course this issue, if relevant to rotary engines, was sorted out decades ago. If I had an RX-8, I'd probably run a synthetic or synthetic blend in it ... especially during colder months. No worries, I'd say.

This motor seemed to like the Motorcraft better than the Havoline ... I'd have stuck with it. Maybe the engine responds to oils with more boron in them? Gee, aside from Motorcraft 5W-20 and some much heavier HDEOs, I can't think of any others.

badtlc: "The wear spiked with the initial running of RP which is expected."

And why is that? I don't remember hearing anything about RP's extraordinary detergent package ... nor is RP ester-heavy as Red Line and a few other synthetics are. Don't see why you'd see a spike when you switch ... unless you are claiming that for switching between all oils ... and I buy that possibility, but it's usually not so dramatic.

As for the chromium Patman mentions, I'm assuming that comes from your rings. The first thing I'd consider is that your top-oil concoction isn't performing like you want it to. Might re-think that mix. I want to try Schaeffer soy Neutra.

 

[Bror Jace]

"As for the chromium Patman mentions, I'm assuming that comes from your rings."

I know that rotary engines don't have rings ... really I do.

 

[unDummy]

Mazda uses various 'platings' on the iron side housing, on the rotor faces, and on the aluminum rotor houses. Some of the chromium could be coming from these platings.

With the spike in Si, air filtration and intake need inspecting. Maybe it was a particle streak across one of the housings?

With the lack of rotary UOAs, no conclusion can be made. Since engine enjoys supplemental premix, I doubt that there is any lack of lubrication on any 'plated' surface.

If gears are made from sintered powdered metal pressings, I would think that chromium(along with a few other components) is part of the formula. With the increase in iron, other metals from the 'parts formula' will show up in a given ratio. Some of the Cr/Si can come from these parts. But, usually Ba and Ni are in the formula. Those PPMs are zero.

With this being the 3rd RP run, I'd expect Mo to be higher. Just look at all the other RP runs in various other vehicles.

I blame the numbers on lab accuracy, sampling method, or simple fluke. Nothing here is worth worrying about.

 

[Patman]

Silly me, I completely forgot that this is a rotary engine here, so the amount of wear metals we see cannot be directly compared to other engines. At the same time, chromium did make a huge leap up in this engine compared to the other oils run, and so did iron. So even with the chromium not being from the rings, it's still disturbing to see the number jump up. I'm still not a fan of RP oils at all. They seem to be all hype with no performance to back them up.

 

[SargeGTO]

Be careful PatMan...the RP lovers will accuse you of slandering them with no backup data....LOL....

 

[buster]

Quote:

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They seem to be all hype with no performance to back them up.

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