Smith837

My pleasure. Welcome to the family!

And agreed, these recos seem to make sense, but need to verify before following them. I'll ask some engine pros I know and report back...

redrocker55

I can't believe some of the gas stations not on this list. One of my favorites is BP (old Amoco). They are supposed to have cutting edge additive packages/detergents in their fuels.

I typically run either BP or Shell in my vehicles and I've never had any problems. The top tier recommendation Audi provides, to me, is basically saying to not use the gas from the farmer down the road who is looking for someone to buy his last 10 gallons of fuel for his tractor that has been sitting in storage for 5 years.

My feeling is if you are using a fuel from a well known retailer and using their higher octane grades (these typically have a higher level of detergents compared to lower octanes) you shouldn't have any injector problems...the carbon buildup is probably a separate issue and one we don't have much real life info one yet in the 3.0 TFSI.

NWS4Guy

Well, we only have 92 octane here in the PNW, and 100% of all our gas has "up to 10% ethanol" in it, which hurts power, but we cannot change that. So what I mean is that I use the highest I can find, I also only use Shell, and this means 92 for me.

Top tier's are US gasolines which agree to follow a best practices guidelines voluntarily. This doesn't mean that BP isn't good fuel, or even better - just that they don't participate in this program, and therefore don't have this label.

Since most engines are not DI, there is reference to this, as a marketing ploy definitely (possibly it can have some effect on us, since the detergents in these fuels supposedly helps retard carbon deposit growth, which is independant of having the fuel spray wash the intake valves), since some fuels don't have this, and it costs to do this to the fuel, so they want to advertise the benefit of the extra cost and make money on this. All Audi's are now DI in all models - it seems to be the future of the modern engine, since it allows for much more efficient use of fuel and the ability to control things much more granularly.

Octane = controlled burning of the fuel to reduce knock potential (while not directly related to the power the fuel has, they are tied together until you start introducing things like Ethanol into the fuel)
Top Tier Detergent Gasoline = recommended fuels with engine cleaning additive

They are seperate things, but can both be in the same fuel you use, and are both recommended.

http://en.wikipedia.org/wiki/Octane_rating

http://en.wikipedia.org/wiki/Top_Tie...rgent_Gasoline

rktskicar

too bad we only have 92 oct with all the west coast eco-additives here.

m444

In California, 91 octane is premium.

The only top tier gas companies I see on the list around here are;
Union 76............$3.31/gal
Shell Oil...........$3.29/gal
Chevron.............$3.35/gal

Ones NOT on the top tier gas list, that are common here;
Valero............$3.23/gal (formerly BP)
Arco..............$3.18/gal
Costco............$3.15/gal

redrocker55

On the "bob is the oil guy" forum there is a pretty good thread on top tier fuels...

As with any forum you need to decide for yourself what you want to believe. But on here someone claims that top tier fuels must have at least 8% ethanol content all the time. There is also discussion here that BP chooses not to participate because #1 they believe their fuels exceed the top tier requirements and #2 this allows them the flexibility (you have to read into this a bit) to formulate fuels around the year differently for different markets. I'm sure the same thing applies to big oil companies like Exxon.

This thread is also 2 years old...but Shell is still selling V power and BP is still marketing Invigorate...so likely, not much has significantly changes since this thread started...it's worth a read for those of us interested in this topic.

(it's also great forum for oil)

http://www.bobistheoilguy.com/forums...Number=1098496

Hobbes

I use top tier. Shell is easy to find around here and we get 93 octane (although we also get stuck with ethanol), so Shell is the only gas my car has had.

qtroCUB

Cenex in Auburn has 94....

Right by Big-O Tires

220 8th Street Southeast
Auburn, WA 98002-6008

NWS4Guy

Complete garbage. The EPA setup this standard, and they mandate that the safe levels of negative environmental impact chmicals and protiens released in the exhaust and during burn is all. Now, understanding that one of the cheapest ways tp do this is introducing ethanol, which burns cleaner in many repects than gasoline (but it produces other things like formaldehyde and produces more than 2x the amount of ozone as gasoline for example), will produce the desired effect, so it's very commonly used as a result, but there is nothing requiring ethanol in US gasoline.

redrocker55

I hear ya...there is some gray area on this one...

Here's a few things I found on a gov't website...

http://www.eia.doe.gov/oiaf/aeo/othe...s/ethanol.html

EPACT2005 requires that the use of renewable motor fuels be increased from the 2004 level of just over 4 billion gallons to a minimum of 7.5 billion gallons in 2012, after which the requirement grows at a rate equal to the growth of the gasoline pool [19]. The law does not require that every gallon of gasoline or diesel fuel be blended with renewable fuels. Refiners are free to use renewable fuels, such as ethanol and biodiesel, in geographic regions and fuel formulations that make the most sense, as long as they meet the overall standard. Conventional gasoline and diesel can be blended with renewables without any change to the petroleum components, although fuels used in areas with air quality problems are likely to require adjustment to the base gasoline or diesel fuel if they are to be blended with renewables.

Several States have their own requirements for ethanol and biodiesel in their motor fuel supplies, which are reflected in AEO2007. Minnesota, a major producer of ethanol, has required all gasoline to contain at least 7.7 percent ethanol since 1997 [24]. Hawaii requires 85 percent of its gasoline to contain 10 percent ethanol, effective on April 2, 2006 [25].

I also found this on the top tier website...(this web address does a great job of breaking down the properties of top tier fuels).

http://www.toptiergas.com/deposit_control.html

1.3.1.2 Base Fuel. The base fuel shall conform to ASTM D 4814 and shall contain commercial fuel grade ethanol conforming to ASTM D 4806. All gasoline blend stocks used to formulate the base fuel shall be representative of normal U.S. refinery operations and shall be derived from conversion units downstream of distillation. Butanes and pentanes are allowed for vapor pressure adjustment. The use of chemical streams is prohibited. The base fuel shall have the following specific properties after the addition of ethanol:

Contain enough denatured ethanol such that the actual ethanol content is no less than 8.0 and no more than 10.0 volume percent.

Contain no less than 8 volume percent olefins. At least 75% of the olefins shall be derived from FCC gasoline as defined by CARB (advisory letter, April 19, 2001).

Contain no less than 28 volume percent aromatics.

Contain no less than 48 mg/kg sulfur. At least 60% of the sulfur shall be derived from FCC blend stock.

Produce a 90% evaporation distillation temperature no less than 290�F.

Produce IVD no less than 500 mg averaged over all intake valves.