something clever,
i read a chemist said the refinery process for high octane reduces certain chemical compounds compare to lower grade gas.
since that was not a published source, i dunno the validity.
It was perhaps 10 years ago, I’m not sure exactly…of course, I can’t be sure that other additives weren’t added earlier, but as I said all of the local stations commonly got gas from the same source. Maybe some of the additives were added at the station for longevity reasons, I believe they were mostly detergents. I do remember that we added more to the higher-octane fuels.
AllShookDown,
i got more info on your specific question. thanks to chevron.
you want to mix your brand of fuel so that you will get different chemical additives.
you see chevron uses certain additives like techroline and these additives will clean your system, but they will become deposits in your engine. by switching brands, you are hoping that other additives will wash away the ones that chevron deposited. so by mixing, you are cleaning the cleaner, sort of to speak.
on another note,
california has same rule for all grades of gas. since california’s rule are so strict, there is very little difference between the grades. so you should only buy the octane that is recommended by your manufacture.
chevron disputes that their additives are similar to other brands. there is also the idea that higher grade of gas has more additives. i was not able to substantiate that.
according to california regulators, they claim california rule already requires the highest amount of additives that is necessary for clean burning engines. so no need for more additives.
so if you live in california, you get it easy and should shop for cheapest gas.
outside of california, you better check regulations.
Flying_Monk,
10 years ago, the regulation is different.
i believe current regulation on fuel additives are based on 1990 clean air act which had implementation date as of 1995, but additives are around since 50’s or earlier. i can be wrong about implementation date. don’t quote me on the implementation date.
also, most places share same refinery or at least same truck terminal, so gas trucks drive up and use same pipes to fill up gas. it may vary depending on places, but a lot of place just mix 87 and 92 octane to get mid grade. they also use the same pipe for 87 and 92, so there is some mixing when they do the switching which they do by timing. like they run 10 sec of 92 and then switch to 30 sec of 87. that is just an example and not exact time of switching. no idea what the switching times are. they don’t flush between grades, so there will be mixing.
many refineries share the same pipes to truck terminal, so they are mixed.
additives often include detergents, octane boosters, oxygenators, etc. they will add this additive package to the truck, but i guess in your case, they added it at the gas station. as i said, no where out of my readings have they say they don’t do that, so that means they can do that and actually do in your case.
i heard they put more for higher octane, but no research was done on that. it was all just hearsay or company claiming it with no proof. normally, companies will claim something and publish data to prove it like how good their additives are.
good to know you guys put more for higher grades. 