[Mazda3]

Ok, this is difficult, do not want to bore all with my life history. Briefly, I am a retired professional mechanic, competed with motorcycles in both MX and road racing, autocross, HPDE and time attack with cars. Private pilot and aircraft owner. I suspect that there are some, and there will never be any way to prove or count, engine failures due to misrepresented fuel. I am not looking for an endless argument here, and I have no way of knowing how widespread the scenarios are. This is purely to inform other performance enthusiasts of the reality of pump gas. I knew a very, even exceptionally honest gasoline retailer, problem was the distributer would only deliver a full tanker. This gentleman like most fuel retailers worked on a galleons per day schedule. However sometimes that average was slightly off. Distributer would send tank truck, tank truck could not return with any product. It should be intuitive that the largest seller was the cheapest lowest grade. Tanker showed up. dropped low octane, low octane tank filled with 200 gallons left in tanker, again no return, driver dropped remaining low octane in higher octane tank. Second scenario, as a private pilot it is very important to know the alcohol content in fuel, we test it at the pump. A long time and highly competent pilot who was also a long time machinist tested fuel at a local station and came up with 25 percent alcohol. My point is that if we tune to the limit of any octane level we have no guarantee regardless of the label on the pump that is the octane we are buying. I will always wonder how many engine failures are actually due to a lower than posted octane.

 

[2016rallylol]

Ok, this is difficult, do not want to bore all with my life history. Briefly, I am a retired professional mechanic, competed with motorcycles in both MX and road racing, autocross, HPDE and time attack with cars. Private pilot and aircraft owner. I suspect that there are some, and there will never be any way to prove or count, engine failures due to misrepresented fuel. I am not looking for an endless argument here, and I have no way of knowing how widespread the scenarios are. This is purely to inform other performance enthusiasts of the reality of pump gas. I knew a very, even exceptionally honest gasoline retailer, problem was the distributer would only deliver a full tanker. This gentleman like most fuel retailers worked on a galleons per day schedule. However sometimes that average was slightly off. Distributer would send tank truck, tank truck could not return with any product. It should be intuitive that the largest seller was the cheapest lowest grade. Tanker showed up. dropped low octane, low octane tank filled with 200 gallons left in tanker, again no return, driver dropped remaining low octane in higher octane tank. Second scenario, as a private pilot it is very important to know the alcohol content in fuel, we test it at the pump. A long time and highly competent pilot who was also a long time machinist tested fuel at a local station and came up with 25 percent alcohol. My point is that if we tune to the limit of any octane level we have no guarantee regardless of the label on the pump that is the octane we are buying. I will always wonder how many engine failures are actually due to a lower than posted octane.

I had my engine blow because someone put an orange slice in my fuel tank, don’t know if that answers your question

 

[trdtoy]

Good post Mazda3.

For many the fuel grade that they put into a car at the avg station will not matter. To someit will matter a lot. This is why I always suggest to anyone that requires a certain fuel to monitor and datalog their car and confirm with a familiar tuner for the platform what they should be seeing on a given setup. Doing this can help prevent disaster from striking. Can always use a car warranty to fix or make the station pay for damages but the best route is to prevent issues if at all possible.