'16/'17 0-60 Unleaded vs. Premium

I have, and can tell you that 91 octane makes a huge difference in drivability over 87.

My observations when using 91:
The engine is smoother
there is less turbo lag
the throttle response is faster
the turbo spools up faster and consistently
there torque down low is stronger
the engine hp is more in the high rpms (over 4000rpms)

What I find disappointing when using 87, is the turbo pressure was very inconsistent. There were times where I would accelerate and there was a depressing lack of torque. I also noticed engine ping a few times while using 87.

I now only use 91 exclusively
 
I have, and can tell you that 91 octane makes a huge difference in drivability over 87.

My observations when using 91:
The engine is smoother
there is less turbo lag
the throttle response is faster
the turbo spools up faster and consistently
there torque down low is stronger
the engine hp is more in the high rpms (over 4000rpms)

What I find disappointing when using 87, is the turbo pressure was very inconsistent. There were times where I would accelerate and there was a depressing lack of torque. I also noticed engine ping a few times while using 87.

I now only use 91 exclusively

Same here...for my low mileage use the extra cost on prem vs reg is only $20 a month!
 
What octane does Mazda recommend? Being that the engine is turbo charged, I would think it would be 91.
 
Mazda says 87 is fine. I didn't notice that much difference at first between 87 and 91 in performance, but over time noticed better mileage with 91, and it's feels smoother and powerful, so I switched to that.
 
I'll eat some crow here...I am into my 2nd tank of 91, after a long stint on 87, and its a noticeable difference. Torque off the line seems similar, but after the turbo spools, there is more power.
Highway passing power is much improved, as it pulls harder at higher revs. This must be the extra 25 peak hp.
I haven't calculated mileage yet, but will all the "experimenting" I have been doing, these 2 tanks might not show improvement!
 
All highway gasoline is unleaded...85 or 87 AKI up to the highest in your region...91 or 93 or whatever. Some is alcohol free---that's a different discussion.
 
Wow, our standard petrol in Aus is 91, with 95 and 98 ron being our Premium...
Different measurement system. Octane is measured using either a Research Octane Number (RON) or Motor Octane Number (MON). The tests are different, and the MON comes in about 8 to 12 points lower than the RON for the same gasoline.

The U.S. and Canada use an Anti Knock Index (AKI) which is the arithmetical average of RON & MON. Other parts of the world use just RON. The AKI will always be a lower number than RON for the same gasoline. Depending on the attributes of the particular batch of gasoline, the AKI will be about 4 to 6 points lower than the RON.
 
After putting nothing but 93 octane in my new CX-9, my last three tanks have been nothing but 87. Honestly, there is a difference but it is not nearly as dramatic as I had feared and is pretty much exactly as Mazda says and the dyno shows. Below 4000 RPM, there is zero difference.

Was a little surprised. So, when I can get cheap premium, I do that. When I can't and have to buy regular, I do that.

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