Top Tier gasoline

I have two vehicles that the owners manual recommends that I use top tier gasoline. The vehicles are a 2008 BMW 328I and a 2011 Buick Enclave. Top Tier gasoline is suppose to contain more detergent. I believe gasoline from any refinery can be delivered to any service station. I also heard that when gasoline is delivered to a Top Tier station the driver just pours in a can of detergent for every 10,000 gallons of gasoline. That suggest to me that I could toss in a thimble full of detergent from the local Autozone for every tank full of gasoline from a regular station. Does anyone have better insight as to how Top Tier gasoline is produced?

I don’t know the specifics of how top tier gas is made. Since the owner’s manual suggests it, I would just buy top tier gas and not worry about it. Top tier gas is usually priced the same as others anyway. Here’s a list of retailers:

The detergents are added to gasoline while the tanker truck is being filled. The same as they do when adding ethanol to the gasoline. The gas terminals hold their bulk gasoline in storage tanks. Then as the tanker is being filled they’re able to add whatever additives to that batch gasoline that’s required for that brand of gasoline. So while it’s true that all the gasolines come from the same terminal for the area gas stations, the difference in the brands of gasoline occur while filling the tanker truck.


The best I can tell is that it is the same old gas with some extra detergents.

Thanks for the information. I do use Top Tier stations. Based on your answer I assume that the Top Tier trucker only goes to a specific brand station or maybe other Top Tier stations? Any idea how much detergent is added? My Buick manual also says if you don’t use Top Tier gasoline then at each oil change put a can of detergent in the tank, but to use only GM brand. Do you think maybe that is just to sell their product?

A given truck will deliver to a given brand of gas station for a given load. They can then go back and fill up with a different ‘mix’ of bulk gas and detergent for a different chain. I wouldn’t worry about using GM’s brand, I’d actually use Techron if I needed to add extra detergent. But I also use a Top Tier gas, so I don’t worry about it.

Thanks everyone. I certainly know more now than when I asked the question.