Gentlemen, I happen to know quite a bit about fuels as I spent a few years as a test technician for Nissan's GTP program. My primary position was testing, flowing and matching fuel injectors for 900-1000 Horsepower IMSA GTP cars. I will share what I know with you. On the octane content of fuel, there are slight variations, but for the most part they are pretty accurate. Fuel fillers are a bigger problem, for example here in California they add additives to the fuel to make it run cleaner. Some states add ethanol, etc. But the bottom line is THAT SHOULD NOT MATTER. Your car is equipped with a knock sensor and if the engine is making strange sounds that is not good because the knock sensor should retard the ignition timing before you hear much. The knock sensor is like a stethoscope on the block and it can detect knock before you can. The only thing you should notice between fuel octane levels is a difference in performance. Next time your tank is close to empty put one gallon of 87 octane and drive it around for 5 minutes. If the engine is making some knocking, pinging noises, your knock sensor is not working correctly. Fill the tank up with 91 to bring the octane up and take it in to get checked out.
Now on to fuel brands. In real honest-to-god race cars all fuel injectors are tested for flow rates. Believe it or not, all injectors have slight variations in flow so you test flow hundreds and you match 4, 6, 8, 10 or 12 injectors. After each race the are tested again and re-matched because after being used in a 2 hour race the flow rates change again. I personally tested a thousands of injectors. What we found was that flow of used injectors decreased after every race when run on different race fuels. To solve this problem, we decided to test additives in the fuel to see if we could maintain high flow rates. We were concerned that we were getting a 5-10% reduction in fuel flow between the start of a race the last part of it. A 10% reduction in fuel flow could make the difference between first place and not even placing in the top 3. What we found was that Chevron Techron kept the injectors open longer. We ran tests with it in full blown race fuel and it didn't affect performance and it maintained the injectors clean. I do not work for Chevron if you are asking. Techron is the additive in Chevron fuels so I agree with the Chevron people. I have empirical data that Techron is the real deal and it works. Their formula is secret so I don't think other companies can get it, it's like the Coke formula. You can get other decent colas but only Coke, tastes like Coke. If you can't get Chevron in your town, try the additive. You can get it at Costco pretty cheap. Good luck.
Ignacio
