Went to Long Beach Mazda for an oil change yesterday. They use Motorcraft semi-synthetic 5w-20 & refused to put 5w-30 at my request. I should have had Rotoraygod get them on the phone and tell them a thing or 2 about oil :-(

 

My dealer told me Castrol Prospirit 5W-40, 0W-20, 0W-30, or 5W-20 (which is the factory fill) would be okay with the RX-8.

 

Canola FTW !

P.S. : I use Royal Purple 5w30 All year. but Im thinking about switching it to 5w40 next summer. 5w30 for winter.

For those *Anti-Synthetic* people just because it cost more than the others, Shell Full Synthetic Oil selling @ BJs for about 2.75 a quart, I'll try it after Im done with Royal Purple

 

Search requires more than three letters.......so I've heard.

 

I don't use vbulletin at all, but from what I understand, there are two options for search. One is an internal word list search, the other option is using mysql's fulltext search.

By default, mysql fulltext search has ft_min_word_len set to ignore words with 3 or fewer characters. So oil would be omitted. It's a one line change to my.cnf to change though.

I prefer google's site:rx8club.com searching, but there's limits to that for any new topics, and the fact that not all pages are indexed.

 

Having just purchased an RX8 the question of what type of oil was high on my list of questions at the dealership. I talked to their highest certified master mechanic who supposedly was an RX-8 expert (which I have no reason to disbelieve at this time), he stated that for the NE winters 5W20 was a must have (non synthetic of course) but during the hot summers I could use 5W30 if I so desired with no ill effects. If the viscosity of the oil is too high it might not get delivered to the engine in the right quantity. I was told the main reason you can't use synthetic is that the engine is meant to burn a small amount of oil (approx. 1/2 quart per 1K miles) and synthetic does not burn it actually will gum up and cause engine damage. Sure you guys know this already but thought i would share what I was told. Take care - Jeff

 

I've been using Royal Purple 5w20 as it meets the manufacturer's requirements as needed for my extended warranty (SL & 5w20).

 

5-20 if you have it rregularly available in your area. 5-30 if not and in some areas i think the 20-50 is a good idea. hotter areas like SOCAl the south west GA and Florida . especially if doing track time

 

Yeah same here. 5-20 in the winter and 5-30 in the summer

 

Stupid mazda dealers here in Jamaica have no recommendation for the oil and I keep telling em to check with headquarters to be certain thank god I found this thread.

Can someone point me to the actual bottle link of the RP 5w30 that I SHOULD be using ... I assumed since most ppl say 5w20 (winter) and 5w30 (summer) and where I live is pretty hot year round basically, I should jus use 5w30 and not go back and forth.

I await the hookup

 

5w20 before 5 K miles. After that I use 5w30, now Im @ 39K miles. Going to switch to 5w40 or 0w30

 

I'm so confused, didn't nevijeff say the guy say we can't use Synthetic oil?

nycgps: how comes you use it ?

 

Why cant *he* use Synthetic oil ? Because he listened to a moron.

I use it because I am pretty sure I know WAY BETTER than that *so called* master tech at a dealership who suppose to know Rx-8 ...

His error was, he actually believe *anybody* working @ a dealership. I cant say all but MOST dealerships has nothing but people who cant even get a GED.

5w20 is freaking thin, Mazda use it because its easier to get CAFE requirements, thats why everyone on earth did not get the last engine recall but USA. and with so many dead engines, it should tell you a thing or 2.

My ***, this dude have zero clue about how Rotary engine works. and ask him what kind of synthetic oil can withstand 1600f+ of temp ? When the best Synthetic oil's flash point is lower than 500F

People are getting screwed simply because there are too many morons giving out false information.

Gum up ? Go tell that moron tech who deserves a fired from the dealership to look at Expo's over 110 K Renesis motor.

 

How do you know this? You say it like it's fact. It's an interesting theory and it might be true, but it's by no means a proven fact.

It's hard to believe that, back in 2003, projected sales of a limited appeal rotary engine sports car would be high enough to affect CAFE requirements if it ran on 5W-30 rather than 5W-20.

It's also hard to believe that Mazda would recommend a grade of oil that would compromise the reliability of their prized rotary baby - an engine whose reliability would clearly be in the spotlight when the new model - the RX-8 - was introduced. And it's hard to believe that, if 5W-20 was, in fact, compromising reliability, that Mazda would then continue to recommend it five years later.

Oil technology marches on; another explanation for the 5W-20 reco is that 5W-20 - a relatively new oil - is a thinner oil fully capable of doing what you would need heavier oils to do before.

 

my mazda owners manual says 5-20 only.I use castrol gtx.Let me make it simple for you.mazda says to use 5-20 only, where is the part you dont understand, the engine injects some oil into the combustion chamber for extra lubrication. that injector is set for a 5w20 oil.

 

5w20 is capable of "to get better CAFE score", that is true.

but to lube parts? thats something really questionable.

Why is it hard to believe Mazda would recommend that would compromise the reliability ? They dont know, 5w20 was *new* to them back then. and sometimes even The experts will *assume* that something should be *ok*. They have to sell their cars, to make money. you know.

Look at the 16x engine design, and look at ours. they thought that they can live with just 1 injection point(to lube), but guess what happen ?

5w20 works for now, but who knows what will happen in the long run ? In the old days some older NA rotaries can go to the 250K mark, cuz there werent as much EPA Bullshit. Now, you'll be lucky to be able to find an engine that can go beyond even the 200K mark without errors. Even piston engines. and Im sure technology has improved *dynamically* since. so what happen ? Same kind of gas, still human beings driving the Rotaries, the only thing that has change is the *oil requirements* and some Fuel formula.

Dont forget Mazda is a business, just like any other business, in order to survive they have to follow certain rules. CAFE is one of the most important thing they have to follow in order to be able to survive in the America market. they need every tiny bit of *saving* they can squeeze outa the MPG.

Ever since they start using 5w20, people are getting more and more engine failures, and engine dies faster than the *old ones*. Some cant even make it to 150K mark. why ? and Mazda is not alone, go ahead and read some Honda forums, people are having the same problems. and wonder did Honda's quality gone down or something.

and dont forget, no other parts of the world got this engine recall thing, and so far we have the *highest* failure rate. and we're the only one who *suppose to use 5w20*, isnt that enough to tell you that something is going on ?

I read japanese rx8 forum as well, they never have any engine failures like the ones we get in USA, sure our market is bigger, but they laugh when I said we use 5w20 in USA. They said in Japan cars that use 5w20 dies much faster than the ones who dont.

Do you actually follow everything Mazda saids ? Like perform all service at a Mazda dealer, use only Mazda parts, etc.

I guess not, you're using Castrol GTX.

So , what makes you think you're really *following* mazda's words ?

 

There is much validity to what you say nycgps...

+ any person who stand behind wat they say and use it get my vote of confidence

i rollin wid u on the 5w30. :-)

I've seen too how often US suffers the fate of different standards for things we in other parts of the globe don't adhere to, so I'm running with your plan.

 

From the sounds of it, w30 is where it's at. Couldn't hurt, really.

 

To add my bitterness to the CAFE deal, FORD get's there CAFE requirements met when they spec 5w20 to average the 18/22 mpg right? Now add the expected 'Documented Owners Manual' of oil change every 6k miles? ... We all know regular oil doesn't have the viscosity, Flash point, or lower ash level that Synthetics (Ester Based) do. (Example Reference for 1999 searching Google)


But like any accident, you use regular oil, change every 6k miles, rev to 9k with regular oil that doesn't hold it's own with detergents losing it's performance to combat buildup (aiding flash point and prevent sheering). Failure is imminent. When the oil in the rotor chamber exceeds the flashpoint temperature, the oils molecular bonds change. Detergents are suppose to help isolate broken down molecules by preventing them from binding to the surface areas. With Royal Purple as example having a flash point around 450 degrees Fahrenheit, and comparing catalytic temps around 900 Fahrenheit, It's obvious the combustion temperature is exceeding the Flash Point rating for the oil to maintain it's stability, Why everyone likes to use Royal Purple as a synthetic to my guess is it's low ash rating, meaning less potential for carbon buildup. I guess having Royal Purple back the rotory use helps to huh?


Internet Search for Royal Purple Rating:


That said. who goes 6k miles before an oil change?

I'm still trying to figure out if the OMP manages the flow rate for a heavier oil... or if it's all controlled with the assumption of a 5w20 rating programmed into the PCM.

 

oil does not compress and it is a mechanical pump so it shouldn't matter what grade oil you use

 

wouldn't a heavier/thicker oil flow slower then a thinner oil? Less distribution in the higher rpm's?

Example:

2 buckets, 1 with 20w, other with 30w. Wouldn't the 20w bucket fill faster and finish first?

 

i just switched from castro gtx 5w20 to 5w30 like 2 oil changes ago... no difference

 

at what temp? 100F, 200F, 30F?

For example, at rated pour point, Castrol GTX 10W30 flows down to -33F, yet Castrol 5W30 flows down to -35F... very little difference. (and just for fire for the Synth vs conventional flames- RP and Mobil1 both pour down to -65F in their 5W based oils).

(FYI: Pour point is 5 degrees F above the point at which a chilled oil shows no movement at the surface for 5 seconds when inclined. This measurement is especially important for oils used in the winter. This is the temperature at which the oil will pump and maintain adequate oil pressure. The lower the pour point the better. Pour point is in degrees F.)

 

Both tests would be conducted at the same temps, so lets say 100 degrees & 200. The thinner/lighter oil would pour faster right? so how does delivery impact the rotor at the 6000-9000rpm range. If you used a hydrolic system pumped by hand as another anology, it would be harder to pump the thicker oil vs thinner, i perceive an end result of less oil that can be delivered at the higher rpm's, factored in with old oil that has lost it's detergent properties, would cause an engine failure scenario due to heat.

 

At above 100 I would not expect a noticeable difference between pumping 5W20 or 5W30 oil (that is the same brand and composition- ie/ both synth or both not synth).

I would be more looking at film strength at +180F being the difference between the two.

<edit. I guess you could do your own test, by buying two quarts of oil, heating them up in the oven until they are both 175F then pouring them out while counting how long it takes with a stop watch. Hardly scientific, but would probably give you a ball park difference in flow.<end edit>

Actually, I would be more concerned on older oil, or too thin oil, or oil mixed with Lucas, MMO, or similar snake oil additives foaming at high RPM.