5w20 OR 5W30?

[ZoomZoom2007]

I have heard a lot about Mazda USA requiring 5W20 for the RX8, but only because of the EPA standard on gas mileage. I have also heard this will lead to early engine failure because the 5W20 is too thin, breaks down, and doesn't provide adequate protection for my hot-running rotary engine. I drive my car like I stole it, (like you should!) so I don't want to mess it up over getting a few more miles to the gallon. Other places in the world, Mazda calls for 5W30. So help me out with this please? Don't want to tear up my baby.

 

[jazzman]

From what I have read, 5w20 can increase mpg slightly as well as reduce wear on the cat. However, it is not clear that 5w20 will continue to produce higher mpg #'s over the life of the engine - Especially if using 5w20 causes premature wear and tear on vital engine parts! The catch 22 here is that using something other than the factory recommended 5w20, while better for your engine especially if you drive hard, could possibly void the warranty. I am not entirely clear on this. Anyone?

 

[L3vzoomzooom]

I have a 2006 MZ3 hatch with a 2.3MZR I have found that 5w30 made my engine feel sluggish. Even my GF notices, and she isn't car person at all. I use Mobil1 or Syntec in 5W20 with a bottle of Zmax every other oil change

 

[SpooledupRacing]

ELF/Total 5w30 best stuff for rotaries...

The Renises engine is an emissions based rotary engine (side ports etc) the 5w20 was meant to be used to comply with keeping up less emissions and also for better mpg..

I just dont think that the 5w20 is a "durable enough" oil for a rotary...

If u have the omp on I would use something designed to be burned in the combustion chamber (elf/total 5w30 is)..

Otherwise if not I would use something thicker... I use 10w50 in my rotaries!!!

 

[lil_red_wagon]

thick weights for sure. i use 10w-40 bare minimum in my t2. it burns well and i can keep the oil pressure up marginally over normal.

 

[jmsj578]

I guess each of us has his/her own ideas about what's better for his/her car. I oftentimes read how many drive their cars and get a better understanding as to why some cars hold up and some don't. If one thrashes an engine long and hard enough, no matter what oil is used, it's going to last a shorter time than one that has been run more conservatively. With that, I use oil with the viscosity recommended by the manufacturer. I figure they have a little better idea what's good for their engine design than I do.

Of course, with our not running our RX-8's engine at top rpms on a regular basis, I suspect our engine will outlive its 96K warranty, just fine. If not, we do have the warranty to fall back on. Mazda's change to a 96K warranty tells me Mazda is pretty certain their engine can make it on their oil recommendation as long as it's not abused at length. I can ask no more than that.

 

[Riken]

5w30 ftw

 

[SpooledupRacing]

5w30 at the minimum... once it is boosted it would be 10w50 for me.

I still think it is engine oil QUALITY over weight and how often u change it etc..

 

[Riken]

Spoooool!!

 

[SpooledupRacing]

Sup RIKEN!!!!!

You know me I stand behind my oil lol... and I think 5w30 is just fine in an rx8.. my problem is I dont know of a quality oil in 5w20

 

[Riken]

Yep I wouldn't run 5w20, I think something thicker should be used like 5w30.

 

[lil_red_wagon]

we just about have the whole rotary crew from that other forum over here now, huh?

 

[Riken]

we just about have the whole rotary crew from that other forum over here now, huh?

lol I hatez posting by myself

 

[SpooledupRacing]

Thats good.. u keep posting here Riken... We will build the rotary forum!!!!!

 

[altspace]

Mmmmm...I love me some rotary oil.

 

[SpooledupRacing]

ELF/Total makes an oil specifically for ROTARIES!!!

Yes I sell it.. and I dont use it (only because I dont have an OMP and can use a thicker weight) If I had an OMP I would use the 5w30 they have for rotaries.. instead I use their 10w50 and LOVE IT!!!!

 

[Greenblurr93]

There is great debate over which oil is best for the rx8... but i saw a couple members tear down threads where the bearings shows signs premature wear and they were using 5-20/5-30.. the general consensus was that 10-30 would be best to help prevent this. (I personally dont use anything less that 10-30)

 

[Old Rotor]

I would not run 5w20w oil in a HOT climate. In my Mazda manual it says they recommend 5w20w but in Hot areas they say use a heavier oil. You might want 10w30w or even a 10w40w if you see 100F. Rotary engines run very HOT.

 

[Greenblurr93]

I've heard on more then one occasion that Mazda only recommends the 5w-XX oil to comply with emissions standards

 

[Riken]

^+1 Also everywhere else is 5w30