Hey,
Just picked up a 2011 RX-8 GT with 63,000 km on it, only put on about 400 km so far but absolutely love it. It's cornering ability is crazy. Hard to complain about something that has a 9000 RPM red line...LOL

What is the preferred oil to use as well as the preferred octane level for fuel?

I was going to use 10w40 and 92-94 octane for fuel...

 

Welcome to the club

Oil depends a bit on your climate, if you're in the dead of Canadian winter, you may want 5w or 0w. But definitely a #w-30 or higher. There are MANY threads about oil choices, please read them and draw your own conclusions. It's a contentious topic.
Mazda recommends premium fuel, and it's wise to follow the that recommendation. 91-94 is fine.

There is a thread called 'New & Potential Owners' which goes through the common issues, maintenance points and general advice on owning an RX8. Suggest you read it.

 

Appreciate the advise, I am in the Calgary area so it tends to be between -10 and -30 Celcius and dry as we are a couple of hours from the mountains.

Cheers!!

 

I use the factory recommended 5w-20 conventional, never had a problem starting even when I parked outside.

Between 91 and 94 octane, I don't see any difference in power or fuel economy.

 

Elli,
Welcome
First of all, use the search function, oil has been discissed extensively. simply enter
oil site:www.rx8club.com or "Replace with whatever you want to search" site www.rx8club.com
in Google.
Here's some personal experience. No matter what season, I'd go for 0W for maximum cold start protection.
In summer I go for 0W40. People says that stationary gear, bearing failure is viscosity relaed, but I am not sure.
Use 20weight has its benefits, it flows better, better at heat transfer (oil is heavily used as coolant on RX8). At bypass pressure it flows more than 40 weight. It's your decision.
This is worth reading: https://www.ferrarichat.com/forum/th...e-this.136052/

During winter, I used to go for 0w20 since my oil temperature never exceeded 90, I assume it is about 10cst at 90.
These days I go for 0W40 all year. I don't know why the hell my oil temperature actually reached 101c (213.8f), at this temperature I belive that a 20 weight is too thin. Although there's no summer and winter oil anymore, select your oil base on the influence of season to your car's temperature is indeed important. And please note that although 0W40 and 0W20 are both 0W, at 40F, 40 weight is more vicious.

Mineral vs Syhthetic is another topic, I have a Sohn adapter so I don't have to worry about these. But at -30c, I would definitely use synthetic, mineral oil at that temperature is basically wax and there's insuffcient lubrication. Cold battrey+wax like oil+poor vaporiazed gas, your chance of flooding is relatively high. Flooding is hard on cats. You see the trend.

As for ortane, 91 (AKI method) is fine, I always mix 93 and 87 in for 91 octane (more 93 of course).
IMHO, when it is cold and your car never exceed 82c (thermostat opens), the use of 87 octane isn't gonna hurt, I am not sure, just guess, haven't have time to look for research paper yet.

 

Thanks, buying 91 is quite a bit cheaper than 94 and I appreciate the feedback on the 5w-20 oil as well...

ElliTech

 

I read a bit of the article https://www.ferrarichat.com/forum/th...e-this.136052/ and found ti to be quite interesting. I believe the RX-8 has 5w20 in it at time of purchase. After reading the article it would seem that 0w20 would be better for oil flow at startup and still have the same thickness at normal operating temperature as 5w20 does

Thoughts?

ElliTech

 

Outside north America Mazda recommends -30 oil for the 8, and I'd suggest using that instead of -20. Oil thins as it ages, so your -20 might be a -15 by the end of its run. -30 will stay above the Mazda recommended spec of -20. There is no downside to slightly heavier weight oil.

If you race, go -40 synthetic. You need the extra protection.

 

First off, congrats on the purchase. Prety hardcore to be running around in an Rx8 out there. Winter is brutal there!!!

Second, why is everyone always so against what the manual says? I don't get it. Recommends 5w-20. It's even written on the oil cap in the engine bay. So why do you need to deviate from it?
I've been running my 2010 R3 with the recommended for almost 2yrs now. No problems whatsoever with the oil or startups...
The only thing I do for piece of mind is change the oil out every 4500-5000km's. I stick to the original oil changing intervals. 8000km oil changes are simply too long. Goes for any vehicle regardless of what their manual or what the on board computer says...

 

our engine runs hot, my oil temp when stock often hits 110c, for 5w20, it’s gonna be too thin. (Note that oil will be thicker at lower temp and thinner and higher temp. ) Even a 30 weight isn’t sufficient. The main problem for 5w20 isn’t start up. Most manufacturers want the oil to be around 10cst at 100C, some 5w20 is pretty close to that at 100C, however when at 110C, 5w20 won’t be sufficient. However, if your oil temperature stays around 90C, 5w20 can be a very good choice.

 

You picked up the metropolitan grey GT from La Mazda didn’t you?

 

hohoho, of course nowadays it is cost prohibitive 🤥