Does anyone know which type of octane of gas to be used. I went and looked at the car manual and it said prefer 91 but I can use 87 also. But then when you look at the back of the quickstart manual, it says 91 octany only. Thanks for the input

please search (button at the top of the page, under the rear right tyre of the blue RX-8 in the title graphic). thanks.

I did search, theres no thread that clearly states which octane is correct to use. I've seen many people in this board use 87 and 91 but why does it say 91 only in the quick tips manual

i noticed today it says Premium Gas Recommended inside the gas cover

For the gajillionth time. The owner's manual recommends higher octanes, but clearly states that octane as low as 87 can be used safely. They do warn that lower octanes such as 87 may results in decreased performance.

You're kidding! I can use 87 octane even though the fuel door says to use premium? Oh wait a minute...

THIS HAS BEEN DISCUSSED AS MANY TIMES AS THE HORSEPOWER ISSUE.

Jeez.

wow the sarcasm.. i just said i noticed the gas cap said that Today... i mean its only the 2nd time ive filled up teh tank since Aug 15th .. yes i barely drive the RX def not driving it to work...

Yes, I am aware that the owners manual says 87 is fine but what I'm trying to ask is that why on the back of the quick tips booklet which also comes with the RX, says 91 octane ONLY

pretty much its your choice
I will only use 91 because I'd rather be safe than sorry

I ALWAYS use 91% Super choice.

aussie77 wrote " They do warn that lower octanes such as 87 may results in decreased performance. "

This is OBVIOUS! Look you want to experience the car and performance, you can't go wrong with super 91%.

this isnt so simple, since the making more power with higher octane is for boinger engines to prevent detonation which allows the spark to be maximally advanced. in my old 6 port rx7, i understood to use the lowest octane fuel because it would burn the fastest.

the new sideport rotary i dont know yet, but you gotta go with mazda's recommendation, right?

how does the spark timing work in this motor? it still has four plugs right? leading and trailing?

james

hrm..this thread is more complicated than I wanted to know. I just wanted to know why on the back of the quick tips manual it says 91 octane only.

Your are right it says 91 octane only but then it goes into more detail in the manual. The lower octane made mine run better. Dunno why just did. I bought premium gas for the last 4 years and would still if I needed to. I just was looking for a solution to the soot on my back bumper and it was thought to be rich run residual. Faster burning gas (regular) was an alternative to try and it worked for me.