Vitz RS 1.5 Japanese Import to New Zealand - What fuel octane 91 or 95?

[2005vitzRS]

I'm sure this has been covered extensively in the past.

Anyway, my car is an import from Japan and I have been told that in japan they don't use 91?

Until now I have been using 91 and the car has been driving really well. My last fill up however I tried 95 and I have noticed a slight improvement to performance (maybe im being biased).

Anyway, whats your thoughts? I'm asuming the car is still tuned for Japan and therefore a higher octane fuel is actually better and I should continue to use 95 in NZ?

I know that 95 is slightly higher in price but I don't really care about that. I just want to run whats best for the car.

The car is a 2005 Toyota Vitz 1.5 RS NCP91.

[IllusionX]

Research Octane Number (RON) 91 is regular unleaded fuel.. ie 87 in North America.

You probably get better mileage out of 95 because it is ethanol free? you can see it this way.. regular unleaded may contain up to 10% ethanol, which increases fuel consumption. So you do the math see if paying premium for ethanol free fuel is monetary more economical than using regular but getting worse mileage.

[juicyjosh]

http://www.yarisworld.com/forums/showthread.php?p=720355#post720355