I agree that the spit-back portion is irrelevant but further in the document I think the carbonaceous deposits section is valuable just to ponder as a comparison between dyno and synth with ash% and deposits

 

Sorry, I'm late to this party.

Cleaning detergents in gasoline might be a double edged sword in a rotary, but detergents in the motor oils DO NOT STRIP AWAY LUBRICATING FILM in engines.

They keep particles suspended so the filter or oil drain can deal with them.

Non detergent or low detergent oils might foam less, but modern engines lasting more than a few races need some detergents. The refiners have had this down for more than 50 years.

 

Most modern fully synthetics engine oil oils are designed to be burned so I don't today it is an issue. Many modern piston engines burn oil by design.

Porsche's are one example. My bosses Panamera burns Mobil1 0W-40 at a rate of about a quart during each oil change interval. The car will tell you when the minimum oil level has been reached and you can just stop by the dealer and they will top it off and reset the indicator. This is common on modern Audi's, Mercedes, Fords, etc.

 

Again I am not asserting anything about 'burn-ability'

To revisit the article and its relevance:

1. An SAE paper by Idemitsu showing that tested dyno based oils left MORE carbon deposits/ash.
2. Insight into the development of a popular product, Idemitsu rotary racing oil, that has little to no information available online. I have yet to see a uoa/voa and understanding their logic for base selection and molybdenum is valuable

 

 

Again, test results from over 20 years ago on oil that almost no one uses. Until someone tests the oils in a controlled environment in a Renesis then these results mean nothing really.

 

just use whatever ...

 

Here is another bit of information I got from Redline oil which I have been using in my cars for the past 15 years.

My question which relates to new low ash oils that are appearing on the market and the Redline version if it.

Question:
I have 2010 Mazda RX-8 that I use mostly as my weekend/track toy. Car has straight trough exhaust so no catalytic converter.

Rotory engine(high rpm and high EGTs) injects motor oil into combustion chamber by design to lubricate the apex and side seals. So far I have been using 50/50 mix of your 5w-30 and 30wt race oil.

I was browsing your web site and ran onto few new oil products that advertise low ash formula(euro formula), which made me wonder if that would be more suited for my application?

Again my RX-8 burns oil by design and I would like to use oil that protects adequately while leaving the least amount of carbon deposits behind.

What are your thoughts and recommendations for my particular application?

Answer:
Thank you for contacting Red Line Oil, in your RX-8 for street/track use the 5W30 would be recommended, we have extensive history with this and the Race Oil in the rotary engine applications, they burn clean don’t cause seal sticking or leave deposits. The blend could be used though should be changed more frequently, say every 6 months.
The Euro Series products are fairly new and don’t have history with them in the rotary, though I wouldn’t expect an advantage or benefit.

Regards, Dave
Red Line Oil

 

Which makes sense for a high-end group V oil.

 

redline ftmfw

 

I found this article the other day and I'd never seen it posted on this site before. I figured this was the place to put it.

I've always been a big fan of RP and used it in my first engine until it was replaced. I've been running conventional in my new engine for the few months that I've had it but now that my SOHN adapter is nice and settled in I will be switching back to RP. Especially after reading this.

http://www.animegame.com/cars/Oil%20Tests.pdf

Enjoy!

 

When they do these tests, I always look for what is different, what they aren't testing.

In this case, the results are certainly interesting, but it also appears that the oils are tested at room temperature, not the ~200F that the oil in your engine is actually at.

So while I'm not discounting the test entirely, I stop short of drawing a conclusion to what it will do inside your engine, because that is simply a different environment.

 

At the end of the article they mention that they plan to do further in-engine testing.

I'll try to see if I can find anything to that degree.

 

You could always read through our used oil analysis thread. Oil testing of all sorts of brands, weights, and types, after sitting in the engine for 2,000-4,000 miles (depending on when the user did the test).

The oil is tested for wear metals, viscosity change, etc...

Royal Purple actually tests pretty poorly in those tests, Mobil 1 0w40 is consistently tested as one of the best, holds viscosity over the mileage the best with the one of the lowest wear metals. Also contrary to the test you linked.

I would expect that the difference between the used oil testing and the test you posted is simply that... one is used oil in the environment you care about, the other one isn't. To me, it's like testing the quality of your drinking water by seeing how well your house plants like it. It's kind of irrelevant.

 

Again, not saying this clearly demonstrates that RP is a good oil. It is just interesting to consider.

I have read through part of that thread and will continue to do so.

 

Fair enough



Just a bit different than your first comment

 

Oh sorry, I didn't mean to put it like that. I was just seriously considering going back, but for the time being I'm just trying to get the conventional oil out of the car and switch to a thicker viscosity now that I'm making use of a Sohn adapter.

I ended up just going with some Mobil1 0w-40 to see how the car likes it.

 

Not only that, but how do score tests and the like translate into real world performance? Do they even matter?

Here is one from Amsoil from 2012. Mobil 1 scores poorly in it too. (Royal Purple doesn't do so well either.)

AMSOIL Performance Testing Archives

Yet, millions of people have good experiences with Mobil 1 products the world over. Do these ASTM tests actually have relevance, or are they used to generate talking points only?

Color me skeptical.

 

Virtually all tests that don't actually simulate real world experience end up becoming just salesman PR points for whomever does well in the irrelevant test, which works, since there is always a slice of the population that never thinks the whole way through it.

 

My thinking is that high end manufacturers like Porsche and Mercedes that offer 100k factory warranties require certain oils (Mobil1 0W-40 in all of my bosses cars such as his Porsche Panamera, his CL65AMG, and his SLS AMG for example) so I would assume they have done sufficient testing if they trust it in their engines along very long recommended oil change intervals. Plus, Porsche's for example (and many other modern piston engines), consume oil by design and they will even top it off for free when the car tells you. That also tells me the stories and theories about Mobil1 not burning cleanly are just bullshit.

Now I am not just touting Mobil1 here, Castrol is also a great OEM recommended oil and many manufactures are using pure synthetics now (all 0W-20 and 0W-30 oils used by Honda, Mazda, etc.) Sure they have many reasons for choosing a certain oil but still.

 

, just came across this. Now don't get me wrong, I am sure these decisions are not made solely based on engineering and testing but I still don't think the bean counters would risk very very expensive engine replacement issue either by choosing the cheapest oil they could find.

 

Exxon-Mobil is a huge oil giant, and they are good at getting manufacturers to use their oils. It doesn't make Mobil-1 better than other synthetics just because Porsche and Mercedes use it. Does it make Bridgestone a better tire just because ,over the years, they have gotten Ferrari and Mazda to use it as original equipment ?

For many years in multiple IMSA-winning RX7s and in my own race RX7 we all used Amsoil synthetic and swore by it for rotary engines. Csstrol has been recommended for Mazdas by dealerships for decades. All this to say there is NO one synthetic or dino oil brand that is the best always and for all performance cars. The debate goes on .................

 

In my own alcohol-addled mind, I have reached the decision that modern synthetic oil is so good, it doesn't matter what you use. IIRC, Consumer Reports and some other groups have conducted long-term wear tests in taxis and police cars and concluded the same. CR, for their part, recommended buying the cheapest oil you can find, because it performed just as well as anything else in their real-world testing.

 

Funny, I was just thinking the exact same thing about the Sohn adapter after reading the latest S2 vs S1 thread fawning posts ....

 

All these years and people still haven't figured out that nearly all of the deposits in the combustion chamber come from gasoline and not oil metering.