So now I've read several posts about "premix". What is it and what does it mean. Do I need to do that b/c I'm picking up my '04 RX8 Monday morning(Feb 6, 2012). I know the car calls for high octane gas. Do I just put in some additive? Maybe some injector cleaner too?
Heavier oil or oil additive?
Since I'm new to the Mazda line and the RX8, I have to ask b/c I simply don't know.
Thanks.
In the test drives, the engine was smooth and the idle was good but not great. Just felt a bit of motor vibration I think.

 

premix is a term generally used for coolant. When you get coolant your supposed to mix half coolant and half water. Pre-mix coolant is just ready to go. If you have an rx-8 with a rough idle you should get some zoom-zoom cleaner (seriously!) I believe the part number 5555-10-025A. its somewhat like throttle plate cleaner, but made for rotary's. It works a lot of the time. Sadly, if that doesnt work, i would try new coils and plugs which is expensive or look for a busted motor mount. I am not sure about the high octane gas, I will try to find out about that, but i never heard that before. I know a lot of newer cars from 07? and up call for higher octane gas, but nothing more than premium.

 

Pre-mix is also a term for 2stroke fuel, here in Austria we have pumps (next to the normal gasoline, gotta be careful) that supply 2stroke premix as well as normal gas and diesel.

 

In modern cars, pre-mixed antifreeze is not always the best idea, in spite of what the label might say. Plus remember you are paying for half distilled water (pre-dilluted antifreeze) so its not the best bargain either.
All manufacturer's have a specific formula for their cooling systems. Some want a 40%/60% mix while others, may call for a 60%/40%, and yet others, 50/50.
Too much antfreeze can cause corrossion and early demise of aluminum parts. Not enough and rust can develop in the system.

Best practice is to check the owners manual of any car and follow the companies recommendations.