No, we're not arguing semantics - these are simple facts.

So you claim to not need to prove the point, yet you continue to insist a point which is factually wrong? Are you that afraid of being wrong that you'd rather stick your head in the sand and chant "naah, naah, I can't hear you" when confronted with facts? It doesn't matter how you cut it - a hot straight 20 weight oil IS thinner than a cold straight 5 weight oil. That's a fact, despite your not conceding it. A hot 5W20 multigrade oil IS thinner than a cold 5W20 multigrade oil. You could do the extremely simple test on the exact 5W20 you use to prove it to yourself. Your refusal to try a simple test, and stubborn insistence that you're right, is pretty ignorant, wouldn't you say?

By the way, YOU made the reference to 20 weight vs. 50 weight oils - is straight from your post above.

Yes, "THICKER oils generally have a higher viscosity, and THINNER oils a lower viscosity" - at identical temperatures. The quote above makes absolutely NO reference to the relative viscosities of different weight oils at DIFFERENT temperatures.

Your pig-headed insistence that is simply wrong. NOT true in any way, shape, or form. Easily proved or disproved. I've done the lab tests, written up the University Mechanical Engineering lab reports that prove you wrong. You refuse to do the simple freezer/stove top boiling test to prove it to yourself. You're looking pretty stupid right now, unfortunately.

Regards,
Gordon

 

OK, you edited your post after I wrote my reply above. You're still wrong, and making a bad leap of logic. You also seem to be confusing nominal viscosity (especially with respect to multi-grades) with actual viscosity.

Let's consider - I said hot 20 would obviously be thinner than hot 50. You agree. BUT, there's NO way that statement has any bearing or could lead to the conclusion that "therefore, the oil gets thicker". Hot 50 has a lower viscosity than Cold 20. Hot 20 has a lower viscosity than Cold 5. Hot 5W20 has a lower viscosity than Cold 5W20. That's the statement that you seem to be having so much trouble with, and you could easily prove or disprove it to yourself. Why invest so much energy defending a position that you've never tested for yourself? I'm serious - you are misunderstanding viscosity vs. temperature with respect to multi-grade oils. The simple test I suggested waaay back would positively prove what I'm saying.

Don't be so scared to be wrong - be open to the possibility of learning something new.

Regards,
Gordon

 

From the site....

"The result is that at 100 degrees C the oil has thinned only as much as the higher viscosity number indicates. Another way of looking at multi-vis oils is to think of a 20W-50 as a 20 weight oil that will not thin more than a 50 weight would when hot."

If you want to clear it up for me, then tell me what this part of the above paragraph means....

"a 20 weight oil that will not thin more than a 50 weight would when hot."

If this means that for example...without knowing the detailed physics of viscosity.....

that 50 weight oil when heated to 100C will thin by only 10 weight units to 40 weight, then the 20 weight oil becomes 10 weight?

I am certainly not being pig headed, and certainly don't look stupid. I don't think that we need to reduce the topic at hand to who has the higher IQ...so perhaps after all of this back and forth....we can solidify what the point is for having a multi viscosity oil.

I am not scared to be wrong. I dont care about being wrong....if someone is going to tell me something different than what I believe then I want to understand what your point is. So far, you have not explained the point.

 

I'm not a tribologist. I'm not even really any kind of a professional... yet.

But is it possible that we are or at least should be talking about semantics here and get it over with? It seems that much of the discussion has been held up by arguments over what reduces to how you guys are talking about the ideas.

I havent had the chance to read RG's link, but secondhand it seems to say that multi-viscosity 5W-20 means that it will act like a SINGLE-viscosity 5 weight oil (non polymer) when cold, but when hot (100C) will act like a SINGLE-viscosity 20 weight.

so in a sense it's correct to say that multiviscosity 5W-20 IS more viscous than single viscosity 5W at high temperatures... but saying "it gets thicker at high temperatures" loses so much information as to make the statement inaccurate. This is simplifying it beyond recognition



In the same vein, yes viscosity does measure "flowability", but at the same time it really doesn't... it measures flowability only indirectly in that viscosity measures resistance to flow.... It is an inverse relationship to flow and so it isn't accurate to say "is a measure of flow" It's a key difference that holds up quick comprehension. Summarizing it like that confuses things, and seems to me to account for half an evening's worth of posts.



Although if I'm wrong about the 5W-20 then I guess this is all moot

 

No Zaku-8... you are right on the money. I sifted through all the posts and it IS just a semantics arguement born from overly generalized statements that have lost their intended meaning. Your explanation is exactly what I was getting ready to give.

5W-20 isn't getting thicker at higher temps as Gordon has said. Compare cold and hot 5W-20 and it's obvious. However, 5W-20 is not gettting as thin at temp as it would if it was plain 5W. This is what I suspect Maolin-34 is trynig to say. BUT... "not as thin" doesn't mean it gets thicker, it means the rate (is that the right term?) at which it becomes thinner under high temp has been reduced. How much? Like a 20W oil.

Have we gotten this cleared up?

 

It's 4a.m., maybe putting some numbers to this problem will 'put it to bed'.....

If we measure the viscosity of 5W20 at 40*C (quite warm) it could be 60 'centistokes'. This could qualify it for a '5W' rating at this temperature.

If we measure again at 100*C (boiling point) it might typically be only 6 centistokes, or if you like, ten times 'thinner'. So now it measures as a 20 weight, but is still much thinner than when it was 'cold'.

So thinner when hot, but not as thin as it would be without the viscosity index improver additives.

S

 

Never read such a load of cowpoe in my life.

The guy (certainly not an engine engineer) either :
- did not know what he was talking about and wanted to show off
- took the micky out of you (and that's not very nice).

Almost every single point is complete utter rubish and make NO SENSE at all. Not worth correcting or argueing - too far off...

 

nicely put...


and were people before seriously saying that gas does not get in our oil? Anyone smell there oil after a couple thousand miles??


Most things Maolin said were true. There was a hasty port campaign that screwed up the a/f ratios. They have been correcting that and for 05 there is a seperate flash for california. I'm not sure what to make of the synthetic argument, but the seals in the renesis are a different material then before and probably have lower friction.

 

Guys, as an automotive engineer, please let me add some perspective. I believe that Maolin is just relaying the information he gained while conversing with the Mazda engineer. Most of us agree that some of the things he mentioned were incorrect. This does not mean that he is lying about his conversation OR that the person he met could not have been a Mazda engineer.

Just because someone has the title of "engineer" on a vehicle program doesn't mean he/she posesses detailed knowledge about every subsystem in the car. There are hundreds, if not thousands, of engineers dedicated to working on any one vehicle program. Most of these engineers work in a very specialized area, thus they are certainly not experts when it comes to the entire vehicle. For instance, there is probably a small group of Mazda engineers dedicated to the design and release of the air induction system, another group of engineers who work solely on the exhaust system, etc. These engineers are experts in their particular systems, but may have very limited knowledge about the rest of the car.

The point I'm trying to make is that this Mazda engineer probably knows little more about the operation of the Renesis than any knowledgeable person on this forum. Much of his knowledge likely came by word of mouth from other Mazda engineers, and all of us know how tidbits of information can get distorted going from one person to another. Having worked a major new product launch, I know how this works. All of the engineers "gossip" about the decisions other engineering groups had to make, or why a certain component is failing. Much of the time, the only people who can truly be trusted to have the correct information are the engineers dedicated to working on those particular components or their management.

Also, don't read too much into titles. Anyone who graduates with a degree in engineering and goes to work for an automotive company is an "automotive engineer". Do you know what most mechanical engineers learn about internal combustion engines from college coursework? Nothing, at least from a practical standpoint. Most knowledge is gained on-the-job or while pursuing a hobby.

 

A lot of the used oil taken out of cars smells like gasoline. I think it has something to do with the breakdown of the oil over time. Gasoline does, afterall, come from refined oil.

 

Nice to wake up to something interesting to read Maolin.

My initial take on this thread is pretty bad... but not because of you Maolin34. Too sad that some posters apparently feel their technical authority challenged by someone else coming out of the woodwork with unconfirmed "heresay discussion" from within the Mazda community that may differ somewhat from their held knowledge.

Being way too eager to attack and apparently stiffle Maolin34's writings because he doesn't quite speak exactly as they would have spoken (reference the oil viscosity 'debate'), and who may have also typed something wrong (like that is something no one has ever done lol!) is rather childish IMO. How about a little tolerance before sending the attack dogs in folks?

I also notice how Maolin34 is not defensive but instead continues to tries to be civil even in the face of rather rude comments. Not the trait of someone w/mal intend IMO. Can't we all just get along? Shhhesh! :o

just my 2c - OK - so now you guys can pounce on me for being a 'defender' of this subversive Maolin34. Must be some kind of plot, right?

 

Gosh, what can I add to this? First am glad he started this post and shared. People are a little upset because they "if they think he is passing along false info" don't want him to confuse people or say things that are not true. I understand that but go easy on him...some people throwing around insults just show their lack of respect and maturity, frankly...lack of understanding also.

I think if we were all better writers we could express ourselves better when posting things but dont' take it to heart and give everyone the benifit of the doubt. I hope, and I think he did meet this guy/people at Ford and he is passing along information that was told to him, he is honest and is not trying to confuse us. Probably the engineer was being too general and not completely accurate but if I was at Ford and was told these guys are Mazda engineers I would have thought it was true too.

Not sure about some of the stuff but I hope some of it is true. I would be happy for all of you if there was a flash for more HP, better fuel economy, etc....I would be real happy also if I ever end up in a RX8....which I'm still in the hunt for.

Time will tell if some of that stuff was true but reading through this, after being confused by the back and forth of some of it, I'm gald it was brought up. I learned some more and that is what this is all about.

Play nice...fighting never brings much of any good!

 

then...


Not nit-picking...just found it funny. Good info, however, and you're exactly on-track.

 

Cool - cept nobody was fighting...just simple discussion/debate.

 

I don't agree with that, I think some people were insulting him, but look at us...we don't agree and I still love you man...like JESUS told me too...

LOL

 

Yeah, I thought about this before I posted. I'm perfectly willing to admit that just because I'm an engineer doesn't mean I have superior technical knowledge about all automotive systems :D. Fortunately, my post contained absolutely no technical content.

 

Me thinks some ppl may need thicker skin - But not the guy who started this thread, he's doing fine. He doesn't seem bothered by the replies; as he stated: They are simply relating what a 'Mazda Engineer' told them.

I've noticed a fear of conflict around these forums; it's as if when people has stuff out, others expect them to hate eachother....

It's just debate...even heated. Those things are healthy.

 

One thing I know for sure, I know more about the Renesis and the RX-8 than most of the service people at my local dealership, they are totally clueless. This is proven virtually every time I go to the dealership from some comment.

When I picked up the car yesterday it was late and the service person went to get it for me himself and when arriving with the car, I get the comment from him "I did not know these had those headlights". What headlights I said. "You know those bright ones." Oh, I said you mean xenon? Yeah, that's it.

FYI -- I am not engineer, automotive or otherwise. The things I have learned are from the people who share and post information on this site. This often helps me when I go to talk to the dealership about services issues. One of the many benefits I have gotten from this site.

Most of the people who post here are well intentioned. Many are quite knowledgeable about the RX-8 and rotary engines in general. I hate to see information supressed due to fear but it happens.

I think everyone can benefit from a chill pill, less grandstanding, name calling, and such. In order to have a free flowing discussion, you have to have a freedom to say something without fear of retribution or name calling simply because you have ideas -- even ideas that may differ from someone elses. Too many discussions get caught up in hair splitting semantics in order for one party or another to prove that somehow their knowledge is superior.

I have personally read a number of threads where rotarygod, clearly one of the most knowledgeable persons on this forum, has admitted he is in error. It takes a big man to admit the error of his ways, and an even bigger one to do it in front of other people.

 

I'll just say that I first applaude those that create forums like this for us to beat information to death. Bottom line, on a web-based forum like this, everything is heresay. I don't have to believe a thing that anyone says, and you would be a fool to simply do so all of the time. I think that without seeing someone from here offline, you can't even confirm that they own an RX-8. Is that really a picture of your car?!?! The thing is that we can say what we want, and we can express our opinions about everything. Like it or not, everyone is entitled to their own opinion.

I appreciate those that seem to stand up for me, and recognize that I am only the messenger. I think that it is interesting that with all of the "knowledge" that we have boucing around in this thread alone, I have not read one piece of imformation that has any formidable proof to stand behind it....and that goes for what I posted as well. The readiness of some to "dissect" the statements I made looking for lies or untrue statements have provided nothing to substantiate their claim that it's false. I certainly respect your rights to speak up, afterall, that's what this is forum is for.


Forgive me if being "pig-headed" is not accepting what someone says as being truth before "I" understand it myself, my way. The "discussion" about the oil viscosity I believe IS a difference in semantics. And it was very well put by Zaku-8, that is the issue exactly. Using the words from the provided website about oil, it generalizes alot, and uses words that it should not be using to describe very specific things. Viscosity is not something that should be described by words like thinner or thicker, but in that site it does. I pointed out that it in one of my posts, but the real question is thick or thin, what benefit is there from using a multi viscosity oil? My understanding simply put... For 5w-20, "flows" like 5 weight when cold (low viscosity) and "protects" like 20 weight when hot (high viscosity). What does "protect" mean, and why is it really important for an oil to have this flexibility? That is the question.


And lastly, for all those that know so much...which very specific parts of the Renesis engine (possibly for 05) were made by Volvo?

This is something that I will stand behind, as I have seen it with my own eyes.


Thanks guys.....amazing to see that this thread has been viewed almost 1700 times since last night. Is this like slowing down to gawk at an accident on the freeway causing a traffic jam? God knows "it's all BS"

 

On oil dilution by fuel -

It's actually pretty simple. The eccentric shaft has jets that spray oil into the rotor itself for cooling. This oil is also spread on the surface of the iron housings - that's the function of the oil control O-rings and casings. The O-rings keep the oil where it should be, and the casings "scrape" the oil film. This gives the rotors a film of oil to ride on.

Running an excessively rich mixture leads to "wetting" of the combustion chamber walls with fuel. Some of the fuel can actually get scraped back into the oiling system by the oil control o-rings/casings, causing dilution.

Dale

 

Haha see how easy it is to get your terms mixed up, if you read my post you see that I mean thinner at higher temps, and yes I think I knew it before I was in 7th grade.

 

Once again - you're confusing nominal viscosity with actual viscosity. The actual viscosity is measured in units of centistokes.

Look at what Zaku8 said:He's right - BUT the incredibly important point that you keep missing is that HOT 20 weight oil is THINNER than COLD 5 weight oil. A 5W20 behaves like a 5 weight oil when cold - check? It behaves like a 20 weight oil when hot - check? YOU assume that a 20 weight oil when hot is thicker (more viscous) than a 5 weight oil when cold. IT IS NOT.

Sorry, Japan8, you have the positions reversed. Maolin34 insists that 5W20 gets thicker, more viscous, at higher temperatures. I keep saying that it gets thinner, less viscous, but not as thin as if it were single grade. You are absolutely correct that comparing cold and hot 5W20 makes that point obvious - but Maolin34 refuses to try a very simple physics experiment to confirm this for himself.

Maolin34, that is why I have made the pig-headed references. You could easily asnd simply PROVE this to yourself, yet you refuse. Then you insist that nobody has offered any proof!!!! You ask for explanations, I keep trying to explain. Let's keep going.

Consider what our esteemed forum member StealthTL posted (by the way, Ray/StealthTL is an engineer who works in an oil refinery for one of the largest oil companies):Note that actual viscosity is measured in units of centistokes - the nominal viscosity is just a relative number that isn't a real unit. You suggested in an example that 5W20 thins by 10 'weights' - it doesn't work that way.

Let's carry Ray's example centistoke numbers further (numbers for illustrative purposes)...

Oil........................Viscosity at 0F...........................Viscosity at 200F
5.............................150 centistokes............................5 centistokes
20..............................250 centistokes............................20 centistokes
5W20...........................150 centistokes............................20 centistokes

So 5W20 has a viscosity when cold like a 5 weight oil, from our example numbers above, 150 centistokes. 5W20 has a viscosity when hot like a 20 weight oil, of 20 centistokes.
That means that the 5W20 is 7.5 times less viscous when hot than cold.
Straight 5 oil would be 30 times less viscous when hot than cold.
The 5W20 oil has thinned far less than straight 5 oil - but HOT 5W20 is much thinner, less viscous, than COLD 5W20 oil.
Your statement that 5W20 gets thicker, more viscous, is FALSE.

No, much is fact. The trick is sorting out facts from heresay.

Yes, you have read rebuttals with proof - you are choosing to ignore the proofs - perhaps because you don't understand them? Just because you don't understand something doesn't make it false.

You don't have to accept what I'm telling you about viscosity of cold vs. hot 5W20 - you can very easily and simply test it yourself to prove whether it gets thinner or thicker when heated. You dismiss the suggestion to perform the test - yet refuse to consider that you might be wrong. Doesn't that sound a bit pig-headed? Sorry if I keep using that word, but that does describe your insistence perfectly. You could prove yourself exactly what the oil does, you don't have to take someone's word for it - yet you refuse to prove to yourself one way or another. Then you insist you won't accept what someone says as truth before you understand it. Huh? The experiment would help you understand it. You refuse to do the experiment.

The engineer's contention that synthetic oil is too slippery is patently false. Many have offered points to illustrate, or prove this. Aside from the engineer's heresay, nobody else is supporting that contention that synthetic oil is too slippery. Who should have to prove the point? The contention that a more restrictive air filter improves mileage is completely false. The contention that the ECU does not actively measure fuel used in the engine is false (O2 sensor feedback to closed loop operation). We've given you the facts to prove those points wrong. How can you still insist that nobody has offered any facts to disprove the points in your initial post? They're here in this thread. If you continue to blindly insist that they don't exist, then that is of course your prerogative.

Regards,
Gordon

 

Thanks for that Dale. I thought I was being a bit **** when I detected a hint of gasoline smell in my engine oil. In my case, it doesn't take too many miles after an oil change for this "hint" to appear. At the risk of diverting the main focus of this thread (that might be a good thing anyway at this point), maybe you can offer up some comments on a couple of questions I have regarding this phenomena?

1. How detrimental is this diluted oil to the cooling and the longevity of the engine?

2. If in a later flash of the PCM the currently very rich A/F mixture is leaned out significantly, will that reduce the dilution a lot, somewhat, or not at all?

3. Accepting the "fact" of gasoline dilution of the oil, does it make sense to change the oil more frequently than the generally accepted, 3,000 mile interval?

Appreciate your (or other's) comments. Larry

 

This thread is badass!!

 

I read Maolin34's post and it doesn't seem like made up or totally misinformed information. Maolin34 listed the source, where and how he got the information. Seems reasonable enough to me.
Most of you know how much I like lies and bullshit and Maolin34's post has all the right things that don't raise flags.
I'm not convinced about the synthetic oil thing though.

Thanks Maolin34 for the post!

Vince