2015 Mazda 6 Sport
Can anyone who uses both for their 6 tell me what significant differences they notice when using the different octane levels?
Some folks may like certain brands of 91 octane fuel which have no ethanol... Typically 87 octane has 10% ethanol. Ethanol can be corrosive but our cars appear to not have any corrosion of the fuel system prbs.Can anyone who uses both for their 6 tell me what significant differences they notice when using the different octane levels?
In fact if you are in Colorado or other higher-altitude and "regular" is 85 run it -- even with an 87 tune. I've made a few trips out there, have seen no misbehavior, but what I HAVE seen is a material difference (higher!) in mpg.Unless you're driving the turbo in a 2018+ model or have a tune specifically for that grade gas, the only difference you'll see is a lighter wallet with no perceptible performance change.
The 2.5L Skyactiv gas engine is designed for 87 grade. Going to a higher grade doesn't help (or hurt necessarily). Keep in mind there are no additional detergents or anything else that makes higher grade gas any better - unless your engine is designed to use it.
My first 2 cars were 78 & 79 Impalas (US Impala = CA Bel Air) and I can vouch that the 305 was finicky when it came to marginal fuels. Car #3 was a 70 Caprice (ooh... I got chrome this time) with the 350/4bbl which never had issues with bad gas.Many years ago I had a '78 Chev Belair - 305 2V if memory serves... and it would lightly ping on much of the Shell fuel... versus NOT on the same indicated AKI / Octane for other brands... like Chevron (which we get on the west coast). Shell, it seems to me, was always stingy when it came to octane.
I've been doing the same probably 90% of the time, unless the price difference for 89 feels too high.I have run 89 (mid grade) in my 2014 Mazda 6 since it was new. Works GREAT and the fuel mileage should be slightly better than with 87 octane fuel. Well worth the tiny difference in cost/mile.
The only thing that's gonna hurt is your pocketbook.I definitely will try 89 or 91 on my next fill up because it won't hurt to experiment and see the difference! Thanks for all the input guys
A few "partial truths" in there and possibly incorrect conclusions:The only thing that's gonna hurt is your pocketbook.