I'm getting so many mixed messages regarding which oil is best for my RX-8.. I just got it, so what in the world should I go with for best performance and feeling...

Some people say synthetic for the engine, others say sw20 non-synthetic.. wtf?

Can someone with experience give me a legit answer as to what I should be using?

Dude, first up, congratulations on getting your 8. Second, I recommend you do a search on this topic in here as it has been discussed to death in this forum, especially engine oils. I'm not an expert in rotary engines, but personally I'm using synthetic oil, and my 8 is doing great at 29k kms. You'll always get differences in opinion, but at the end of the day, it's up to you to choose. Knowledge is power. Hope that helps.

If you just bought it, the manual is your friend.....

S

I've read the manual in and out.. it says to use sw20 non-synthetic.

Yes it does. So, doesn't that answer your question. Brand is optional and subject to opinions. Your opinion is as good as the next persons.

I tried Redline oil for the transmission a little better than stock but emptied it and installed Amsoil Series 2000 75W90 gear lube, huge difference smooth as silk.

I recommend Amsoil for the transmission after it is broke in.

Also for the rear differential same 75W90 after it is broke in.

I switched to Amsoil 5W30 Series 2000 for the engine but I am still on my first change and have not driven enough to say yay or nay.

So you just got your car 4 years to Supercharge?

For motor oil I have been using castrol GTX 5w20 and Mazda 5w20. I change my oil every two months regardless of KMs and always make sure its topped up. The reason I use both oils as I have free service until 80k. So Mazda changes the oil for free every 4 months and I change it in-between.
From what I've read some syntic oils work good others don't mix well with the gas. I have decided to stay with the 5w20 and since rotary engines eat up the oil fast I will continue to use castrol 5w20 and change it every two months.
As for tranny/diff oil I have changed it twice since I got the car in August 2003. I tried syntic oil the first change and didn't like the way my tranny felt. So the second change I used Mazda recommended. So far I like the feeling. However in another year I may try something else.
You maybe thinking all my changes are overkill as they are not needed as per the manual. However I feel that a well maintained car will last a long time. I would like to keep this car as long as possible.
Since the rotary engine runs hot I would also think about flushing the rad fluid sooner then the manual recommends. For example the manual says change it at 96,000km. I just changed mine at 53,000km.

So you just got your car 4 years to Supercharge?

Nope, I have had it since October 9th, 2004.

13,000 miles is when I switched to Amsoil.

Sammyv2 which synthetic did you try for the tranny?

I change my oil often also. In Minnesota cold winters and hot summers are considered harsh driving conditions in my book.

Doesn't the manual say 7,500 miles in between oil changes?

I used Castrol syntic 75W90 for the tranny. I didn't like the feeling. It seemed to be a lot stuffer in the winter. I may try redline next time.

I beleive the manual for schedule 2 is an oil chnage every 4 months. Given the nature of the rotary I think that is way to long.

I've got Royal Purple in the tranny and differential. Changed it at 3500 miles. I think it is a bit smoother, possibly placebo, but I really was just after emptying out all the wear and tear shavings from the break-in.

Since the rotary engine runs hot I would also think about flushing the rad fluid sooner then the manual recommends. For example the manual says change it at 96,000km. I just changed mine at 53,000km.

Frequent coolant changes are a good idea. Keeping up the corrosion protection is important in a rotary. The engine is basically a sandwhich of Iron and Aluminum. A perfect recipe for corrosion.

Your engine oil choice is up to you, as long as it meets the SL spec, or better, but there is no ambiguity about tranny and diff oils, it's synthetic - hands down.

Redline/Amsoil/Royal Purple, any synthetic that meets the GL5 differential spec will outlast, outperform and out-shift any dinojuice based product.

"Hear me now, und believe me later!"
-Hans und Franz.

S

I've got Royal Purple in the tranny and differential. Changed it at 3500 miles. I think it is a bit smoother, possibly placebo, but I really was just after emptying out all the wear and tear shavings from the break-in.


I will say that when I changed it and Malamore was my witness there was a lot of silver in the transmission fluid. A few small pieces of metal too.

When he saw the amount of silver in the fluid he said he is definitely going to change his out soon.