Lol "unverified" There is no question to me after owning both an NA and Turbo 2.5 CX-5.

 

Any MAZDA Skyactiv gas engine will produce better power output using higher octane fuels. And your power will also increase over a few days as the ECU adaptive change for the higher octane fuel usage. If you have someone with a DATA Logging Scan tool you can log some real time events to see why and which PIDs in the ECU are effect . In all it really is better for the engine to just run the higher octane fuels. BTW it als matters which brand you use. I recommend Chevron and then Shell in the order of choice and stay clear of 7/11 , short stop and even Costco fuels.
And no those number are so bad I am surprised that some still pass them around as "PROF" of anything except MAZDA does not post how they derived at the numbers. But then there is only one member of this forum and Mazda owner that seems to believ in them. I would love for him to take his MAZDA and get a DYNO test. LOL

 

Really? You think the NA 2.5 makes more power with 93 octane than 87? This make zero sense as if it was the case why wouldn't Mazda say so? They do for the 2.5T so if it helped the NA motor they would certainly advertise it.

I am sure you are referring to me with your last sentence. You seriously think I am the only one on the forum who thinks the 2.5T make more power than the NA? Hilarious. I have no need to dyno my car to know it's way quicker than my '19 2.5 NA ever was.

 

[QUOTE=chickdr19;215247]Really? You think the NA 2.5 makes more power with 93 octane than 87? This make zero sense as if it was the case why wouldn't Mazda say so? They do for the 2.5T so if it helped the NA motor they would certainly advertise it.

i think mazda doesn't want people thinking the NA needs premium fuel. They go to great lengths to play up it will run perfectly adequate on 87 octane. And it does run adequate on 87, you can get from point a to b just fine.

But i notice a nice bump in torque below 3k rpm, right in the daily driving zone when running high octane. I have run E33 mixtures at 95 octane, and the Gainz at low RPM are real.

25 years ago a 13 to 1 ratio engine would require race gas.

 

I see your point, but with the 2.5T Mazda lists both outputs for 87 and 93 so owners clearly know 87 is fine. I use 87 most of the time and mine runs well. I can't see a reason Mazda wouldn't want people to be able to take advantage of a power bump if it was easily obtained with 93 octane gas.

 

 

The 2.5 L naturally aspirated skyactiv engine will run completely adequate on 87 octane. And because the skyactiv engine is variable compression ratio, when you run 87 octane and your intake valve is allowing your compression to escape back out the intake system it'll actually make more noise and trick you into thinking you're making more power. When I run 95 octane the engine actually sounds slower, but actually pulls harder.

 

Mazda knows that Americans have a preference for running 87 octane, so they can save a few bucks and buy a Big Gulp at the gas station instead of running 93 octane.

 

Simple physics, higher octane will give most any engine higher compression and "better performance while decreasing knocking".
The question is does that performance increase HP (only dyno runs can determine that) and is it worth to spend the extra money (that depends on your bank account).
And yes, it's that simple.

 

Agreed. It could be the NA motor also makes more power with 93 octane gas, but considering Mazda lists two power levels for the turbo, if there was an appreciable boost from using 93 in the NA it would be in their best interest to let buyers know.