Mazda Skyactiv Fuel Type

[buster]

I know baldtc/Artem are using premium fuel in the Skyactiv engine, but is there any actual proof that run anything other than 87 in the lower US compression engines makes any difference? I have been running Shell 93 in both our Mazda 3’s (2.0 and 2.5) and have not noticed any difference at all. My wife is telling me her fuel economy went down, however, that could be a result of the much colder weather. She thinks it was the fuel.



If they lowered the compression of the US engines, what exactly does running super do and how? Fwiw, my car feels more sluggish on super, although that may be all in my head.

Some are saying it helps reduce fuel dilution. I guess I'm skeptical of the benefit. It's not a cost issue for me. I'm trying to understand how it's possible it could cause a performance difference.

 

[badtlc]

The compression is still very high. My used oil analysis prove it reduces fuel dilution but dilution hasn't been proven to be detrimental so don't worry about that if you dont want to.

The performance gains come from advanced timing (which you can prove yourself via OBDII port) and the leaner air:fuel ratio. Running 87 at such high pressures requires a very rich A:F to keep chamber temps down and prevent detonation.

There is no doubt the engines run better in premium. Whether or not that is worth it for you is purely up to you.

 

[buster]

Thank badtlc.

 

[wemay]

Different car, same results. I use premium in the Sonata which specifies 87 or higher. No MPG difference but the vehicle absolutely runs better.

 

[danthaman1980]

I run 93 octane premium in mine most of the time (89 octane mid-grade on occasion during long highway trips). I ran 87 octane a few times, and I did not like the way the car performed on the lower octane gas.

I can't speak to fuel dilution since I haven't done a used oil analysis - but I have noticed better fuel economy on premium vs mid-grade around town and at speeds under about 65 mph. Above 65 or so and the difference disappears.