DA_PRINCE

Would anyone possibly know what the best non-synthetic oil for my '07 RX8 would be?? I'm already using Pennzoil 5w20. Anyone else using something different?

ken-x8

Pennzoil is fine, as is any other major brand that meets Mazda's specs - which are pretty generic. You can join the long running debate about what weight to use, but IMHO it's hard to argue with the weight the maker of the car recommends.

Every "What brand?" poll and thread points to Castrol GTX as being the favorite. That's what I use, and I've used that brand for over 40 years. Not sure why I picked it in the first place, but I keep using it because they sponsor John Force. I presume all the other users are also John Force fans.

Ken

wassup_nuthin

If this helps you any... I wouldnt put penz or quaker state in a bad lawn mower motor.... do yourself a favor and switch to mobil, valvoline, castrol something else besides that. penz top oil is like going to a cayses gas store and buying super unleaded gas which is 89 octain... its junk..

kevinD1226

as long as u change it every 3k miles theres no big differences using a good non synthetic and a good synthetic oil.. synthetic doesnt burn as easy as regular so that alone is my reason for not goin synthetic on a rotary, check out idemitsu oil specifically for rotarys

Silver_Surfer

Best dino oil? Penz oil? Better than shell of chevron motor oil for sure.







ken-x8, 40years ago? I lived in longbeach next to Lions Dragstrip. I would have to beg to differ and say Pennz was king back then. Heck even STP was bigger than Castrol. Psst. I heard John Force only gets paid from Castrol but uses Valoline oil

wassup_nuthin

statement corrected.. ^ i wouldnt use penz in a bad lawnmower motor***

DarkBrew

Castrol GTX-5W20

boanjangnararmine

Castrol GTX 5w30

chuck rx-8

i use valvoline.

nycgps

iTrader: (1)

Organic food vs Non-Organic food. Which one you go ?

I prefer the one with less chemicals any day, anytime. no matter how many *regular food* people telling me that Im wasting my money & its just food.

IT is almost impossible to tell if having just organic food can live longer, but Im sure the less chemicals Im taking, the less problems I will have. Even it cost almost 3 times as much.

For the record, Idemitsu *rotary* oil is Full Synthetic.

neXib

That must be the stupidest comparison I've ever heard :P

The engine isn't organic. The engine is "synthetic". At least use a real-world argument that concerns the engine if you are going to use non-synthetic, like "it's in the manual".

nycgps

iTrader: (1)

Since when did I say engine is Organic ? Re-read my stuff.

Organic food, which contains less chemicals, is better for humans to have it every day. but then group of *non-organic* food people comes out and say they eat regular stuff everyday & they're still alive with no issue.

U dont get it? damn u're mad slow.

Renesis07

iTrader: (1)

Same here, valvoline 5w20 for 46K miles now.

Average change-2000-2500

Longest- 4500

Everythings runnin good.

StealthTL

iTrader: (1)

The "non-synth/synth" argument was rendered moot long ago, when Mazda first spec'ed 5W20 oil - you can't make that grade, and pass the rigorous tests for 'staying in grade', without some superior basestock oils.

That means at least some of it isn't dinosaur juice, it's has synthetic added to help it meet the minimums.

Ergo, why settle for the minimum? Go big or stay home.

I'm amazed that some people will spend a thousand bucks on a bumper for purely cosmetic purposes, then fill the engine with oil that barely meets the legal standard to call itself a lubricant.

I compare it to making tools out of steel - yes, a perfectly acceptable metal which WILL do the job, for a short and pathetic time - but it's the vanadium, chromium and molybdenum that make a really good, long lived, shining work-instrument.......

04RX8man

Add another one to Castrol GTX 5w20

dag14qb

castrol is bean oil, it cooks, and can leave deposits and ruin bearings. IF you change every 2-2.5k shouldnt matter much...5w-30 all day

neXib

But for us people that are new, come here and even read most of the synth vs. non-synth thread and other threads it's hard to conclude anything. Where I'm coming from I know synthetic to be the best oil, my previous car I changed to fully synthetic on the first oil change and I could hear it sounded better immediately. Less of the slight tick of the (sorry can't remember English name of that part)

When I first came here I was also wondering about premix. Some stores seem to swear by it, and they should be experts, but all I've heard before is that premix is bullshit. This is another engine though, but at the same time you know the store want to sell products...

I wish someone would sticky a pretty basic summary that let you make your own conclusions. The way it is now you make a conclusion until some oldtimer like yourself comes in to say something you seem to KNOW is true. So may I ask what oil you use?

I don't have my car yet so I plenty time to get confused

GULAMAN

Surely you're kidding, right?
i'm sure you're refering to *castor oil*.

anyway, here's one vote for Havoline 5W20, with top-ups using 5W30.

nycgps

iTrader: (1)

if the bearing wear is not enough to convince you, look at the engine failure rate for cars that comes with & recommend 5w20 as their fill, they will be lucky to even make it pass 150K miles.

My new Honda FIT comes with 5w20 as factory fill, even the cap saids 5w20. Yesterday, at 514 miles, I flush the thing with 5w30 cuz I never believe in 5w20. I should've flush it at 15 miles. but I was really busy cant help it

neXib

Well the bearing wear is as far as I can see not consistent?

Is your opinion that 5w20 is too light? And that it's just recommended for emissions reasons etc. like many others seem to say?

Well, have to say that after reading a bit more I'm not sure that 5w20 is so good. Gonna ask my dealer here what they use when I get the car. I also need to have something that will tolerate down to 32F in winter if I don't use 5w20.

nycgps

iTrader: (1)

Im pretty sure if u open up any 50K motor u will see the kind of wear in the stationary bearings.

5w20 is too light(flame suit on) IMO, yes the motor still works, but down to copper and the scratch marks on the e-shaft? meh, thats not something I want in my motor.

In my opinion, 5w30 is the bare minimum for NOT ONLY this motor, it should be the bare minimum for ANY MODERN ENGINES. but too bad, CAFE are set by politicians does not know **** about science.

Haze

+1 Castrol 5/20.

Eight

iTrader: (2)

castrol 5-30

DGenR8

My vote! Castrol has been in my family cars since the first. Never had an engine problem.

Soapflake

Doesn't the car come from the factory with a synthetic/dino blend? Started putting roylal purple 5w30 in at 33k miles.