No regular gas that is ethanol free is the ticket for mileage. 87 Octane gas has a higher btu value so more mileage.

Sorry I realized I put right in the first paragraph that 91 has a higher btu value where 87 has a higher btu value sorry. The lower the octane the higher the btu value. I edited it note, sorry about that. It was a typo

 

so if we want better mpg's we use lower octane/ethanol-free gas but if we want performace we should go for....high-octane ethanol-free??? lol

 

Yeah. Optimally 91 that is ethanol free is the best blend of Octane and mileage for any OEM setup. If you are chipped or bigger turbos then the highest octane is the best because you no longer care about MPG.

If you are going on a long drive and will just be sitting on the cruise control on a highway then put in regular you will get slightly better mileage and cost you less money for the fuel.

OEM cars like the Audi lineup are made to run on 91 that doesn't have ethanol for optimum performance. So that's the best gas. You can run 87 with no problems on just about every car in the line up. I'm not totally sure on the 2.7T to be honest maybe somebody could chime in, but the 1.8T is fine.

If you run 87 octane in a car ment for 91, expect to have a few less HP as during WOT as timing may be pulled slightly if some small amount of knock is heard by the sensor. 3-5 deg of timing at WOT will pull 5-8hp from the motor. It will allow the car to run on 87 but it won't meet the manufacturers specified HP ratings which on some models is won by one car vs. another by only a few HP. Most of that is all marketing.

 

oh i see!! that does makes sense now!!
so lets say i didnt care about mpg's or HP. does it make a difference what gas you buy when ur looking for max engine life??
cuz i've heard that "premium" burns cooler... would that even make a difference??
what im trying to say is whats the best fuel to keep ur engine running healthy (if it makes a difference?) and get longer engine life??

 

The fuel doesn't make a difference as long as it's quality fuel. There is some truth to those shell commercials where they are showing the difference between low quality fuel's and high quality fuels when they held up the valves showing the gunk buildup on them.

Really engine life is determined more by wear and tear. So a crappy filter that allows a lot of dirt through into the engine which contaminates the oil is what reduces engine life. I would just buy whatever fuel you are comportable with and have the oil changed when you should and not run a cheap air filter on the car. Thats your best bet.

 

oh alright! I'll stay with chevron then lol
btw does anyone know if shell owns chevron?? someone told me once that they did....

 

Thanks again all for replying... sounds like the jury is still out!

 

A thought: if you are not keeping the car for a period longer than 3 years (most leases) then use the regular. If you own the the car and want it to be free of problems for the longest period of time, try to obtain at least the 91 octane so the engine burns the way it was designed. Sunoco stations offer 91 octane. You can also (which not to many people know about) combine 89 and 93 to get the desired 91. I have read many articles that talk about this and how it's perfectly fine.

 

If you want to save a couple bucks and drive pretty conservatively, use regular but use brands that are specifically approved by Audi to be safe in terms of additives, etc. However, if you do quick accelerations where you kick in the turbo a lot or are in a very hilly terrain where going uphill kicks in pre-ignition knocking, then use premium (again, keep to Audi recommended brands).

 

what are the 'audi recommended brands'?