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  • avatar texases 10/30/08 8:34 am PST

    Do I believe that Toptier refiners have agreed to a set of detergent specifications developed by several high-end car makers? Yes. Do I use TT gas? Yes. Is it worth driving way out of your way for, or paying a big amount extra? No. And I don't believe it's always true that higher octane gas has more detergents. You should test whether premium is worth it in your A5, as far as mileage goes. I would stick with premium in the A8.

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  • texases 10/30/08 8:34 am PST

    Do I believe that Toptier refiners have agreed to a set of detergent specifications developed by several high-end car makers? Yes. Do I use TT gas? Yes. Is it worth driving way out of your way for, or paying a big amount extra? No. And I don't believe it's always true that higher octane gas has more detergents. You should test whether premium is worth it in your A5, as far as mileage goes. I would stick with premium in the A8.

  • Stever@Edmunds 10/30/08 8:53 am PST

    I think it's mostly marketing hype, although some vehicles may run better on some brands of gas. The EPA requires that all gas sold in the US meet minimum detergent specs to keep injectors clean and keep carbon from forming deposits, thereby limiting emissions.

    "A twice-yearly gasoline-quality survey by the trade group Alliance of Automobile Manufacturers "hasn't identified any quality differences based on geography or brand," says Alliance spokesman Charles Territo. But, he adds, "That's not to say that certain vehicles won't perform better with certain fuels." (They say that because the car companies don't want the oil companies to dictate what kind of gas they should use).

    There's more in the USA Today article linked in the source below.

    Source: http://www.usatoday.com/money/industrie
    s...

  • karjunkie 10/30/08 9:03 am PST

    I do believe in the benefits of top tier gasoline when it is specifically recommended by the manufacturer. In my case, I do go out of my way to fuel up at either Chevron or Shell as these two are specifically mentioned by BMW. Chevron, in particular, uses Techron additive which I swear by and add to my other cars. The fact that I have never had injector problems on some of these with 200K miles has convinced me, although it is not a scientific conclusion. I had a weekend house in your neck of the woods, and if memory serves I think Turkey Hill buys its gas from Mobil or Chevron, so I am not surprised it is top tier rated.

  • tedebear 10/30/08 9:48 pm PST

    "I think Turkey Hill buys its gas from Mobil or Chevron, so I am not surprised it is top tier rated"

    Exxon Mobil is not Top Tier certified, or at least it was not when I last looked it up. My Chrysler vehicle owner's manual recommends Top Tier gas and I usually get it from QT. Many people wouldn't think one of the least expensive brands (in my area anyway) is Top Tier certified but it is.

  • dtownfb 10/31/08 1:02 pm PST

    I can't speak to whether the higher octane will make your Audi perform better. You'll have to do your own analysis.

    You have to read up on how this Top Tier gas got started. After 9/11 and subsequent hurricanes, refineries were cutting corners on gas production and some of the car manufacturers were seeing fuel related issues so they started this consortium of Top Tier gas manufacturers. the idea behind Top Tier gas is these gas providers have a certain level of cleaning detergents in ALL OCTANE LEVELS. This is why such brands as Amoco and Exxon are not part of this group. Over the past few years, refineries have tightened up which is probably a case of the "industry regulating itself".

    Top teir gas is a marketing tool for the gas manaufactures that use over and above the detergents required by the EPA. The fact that Mercedes, Ford, Volvo, Chrysler, etc are missing from this consortium tells yo tha not everyone is buying into this.

    The big question isn't do these gas manaufacturers have more detergents than regular gas stations, the questions are what level does your car need and does the EPA minimum meet that requirement? Does Shell/Texaco have more detergents in their gas than Rutters'? Yes. The big question is, "does it matter?" I think since this consortium was started by a handful of auto manuafcturers and has not been adopted across the industry speaks volumes. Also some very big gas producers are not on that list like BP and Exxon/Mobil.

    I live in York, PA and we have literally no Shell stations and maybe a handful of Top teir gas stations in my area (Snoco and a couple of Texaco stations). Our gas is dominated by Sheetz, Rutters, Tom's, etc. and we have BMW, Honda, Audi dealerships. So technically these companies should not sell cars in my area since we do not have the gas stations to support them.

    if you have a Shell station and want to use that gas, by all means do. But I wouldn't go out of my way or pay extra.

  • fezo 10/10/12 1:14 pm PST

    Since the last posts in here Exxon/Mobil has become Top Tier.

    Everything I've read says higher octane has nothing to do with detergent levels.

    I believe it's more than marketing but I could certainly be wrong.

  • benzgas 09/15/13 6:42 am PST

    Top Tier gasoline is recommended by most manufacturers. And yes there is a difference no matter what the octane level. Octane essentially has nothing to do with detergent level. Octane is a measurement of the BTU/burn time of the fuel. It is dertermined by testing the evaporation rate.
    Detergents are additives mixed in at the regional distributor prior to delivery to the retailer. Besides the detergent levels you need to look at the ethanol level. Ethanol does not have the BTU rating of gasoline hence the 10% or less requirement for Top Tier gasolines. Less ethanol means more MPG and more H.P. Hotter burn of gasoline over ethanol usually means cleaner burn and less deposits.
    Is it worth a couple of pennies to subject your vehicle to possible damage and lower MPG??
    I think not. Stay with the manufacturer's recommendations.
    Just compare the MPG of E85 vehicles. They have ratings for gasoline and E85. The E85 always has a lower MPG and HP rating.

    Oh! BTW. Exxon and Mobil merged in 1999 to answer the question about Exxon Top Tier rating.

    Source: https://www.google.com/search?q=btu+gas
    o...

  • Stever@Edmunds 09/15/13 12:26 pm PST

    If 10% ethanol gas was so damaging to passenger cars we should all be running ethanol free gas (you can find lists of stations that have it at pure-gas.org).

    I tried a tank last month on a road trip and it didn't affect my car at all. I was expecting a bit of a mpg boost, but nada.

    The local off-brand station is currently selling 10% ethanol regular for $3.79 right now, and offers ethanol free premium is $4.29. A regional brand down the street sells the "same" regular with the same 10% ethanol content for the same $3.79 and it's Top Tier gas.

    I use the Top Tier stuff since I have an affinity card that gets me cents off a gallon with that brand. Otherwise I buy the cheapest I can find.

    I don't think I could buy E15 around my town if I wanted to, much less the E85 stuff, which is 85% ethanol. You have to have a FlexFuel rig to run that stuff.

    There's a pretty good gas FAQ at eia.gov.

    Source: 

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5. morin2 140
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