Just been reading the US RX-8 user manual. In there they state that we should use 96 RON or better unleaded fuel; anything lower and performance will be reduced.

I know most of us would be looking to use Optimax or the new BP equivalent anyway, but thought I would highlight it.

I was using supermarket special in my focus.

Just tried a tank of opti, going better, smoother, less pinking, cheaper per mile.

I'm convinced.

But you cant compare our octane rating to the US's, aparently its all measured differently.

UK cars minimum requirements are 95 RON

If you run it on super then the car will run better and faster and usually adds between 5 to 8bhp compared with normal.

On my TT I used to fill up with 95 during the week for motorway driving and then super for the weekend!

The manual says >91 octane rating (US I presume) or >96 RON recommended

91 to 95 RON for reduced performance

UK RX8s are 95ron.

Not sure the usual Optimax rules will apply for the rotary - certainly they used to only run on low-octane fuel because of the burn characteristics of the engine (long thin combustion chamber).
High octane fuel was not good for it....

Certainly it will be 95RON for me, if that is what the UK manual says.

Morgan.

Dont waste your money on Optimax and the like, the only way you'll get more performance is due to a lighter wallet. Standard 95RON unleaded is all it needs, and what the engine maps will be optimised for.

If anything is mentioned about 96RON or a above will be the direct result of a bung, sorry, co-sponsorhip deal, from the fuel companies. For example which fuel company's recent advert featured an RX8?

Cheers
---Dave

What about the (supposed) cleaning benefits of Optimax - do they apply to a Rotary?

RX-8's have dyno'd with higher HP if you feed them higher octane.

Engine has a knock sensor so will advance the timing if it can. Although i dont think optimax will give much better performance under all atmospheric conditions?

....so are you saying that the BP advert which shows an RX-8 advertising the better performance is a lie? Trades descriptions act - Advertising standards agency issue here!!!

I use 95 RON in my baby. Here its called "unleaded premium". The brand I use is guaranteed not to contain ethanol. I'm not about to risk it with anything less. I haven't tried Optimax yet.