[drjer1]

JSC-Thanks for the link on "top tier gasoline". I always wondered if there was really a difference in additives and this answers my question. The current list adds some additional brands including Texaco and a couple I have never heard of. "The Fridge" (08 S5, Ibis White, loaded) just finished a 5800 mile road trip and I did notice some subtile (and not so subtile) differences in performance in different parts of the country.

 

[drjer1]

Along the lines of Top Tier Gasolines, why do the same brands have different formulations in different parts of the country? I'm not sure if this is the case elsewhere, but in the U.S., I noticed in the mid-west the highest octane level was 93 but in the far west (Calif. & Nevada), high test is 91 octane. This would be a hint to me that the formulation is different for different markets. Does this mean Shell (for example) is Top Tier certified in all markets or just some markets? How does the % ethanol content affect the certification?

 

[drjer1]

Thanks Doc--actually 2X1errors. Very subtle.