Audimacrebel

Picking up a 2006 A4 2.0T tomorrow. The dealer told me 93 octane only! IS that really needed? I'm a brand new Audi owner so I'm learning as I go here.

A4Audi4Fun

Look at the label by the fuel cap; 91 octane is the recommended minimum however lower could be used but you will have reduced power and may run the risk of engine detonation/pinging with lower octane. The cost difference between premium and lower grade fuel isn't likely to be more than $10 or so per week, so if $500 a year is what you are trying to save from an operating cost perspective, my statement would be "an Audi is probably not the vehicle you should be owning". The car is designed for 91 octane or higher - use that grade of gas and just enjoy it; one has to pay to play

My 2c worth.

Audimacrebel

Totally understand. I agree. Knew that going into this, I just wanted some validation. No worries on the extra cost, like you said, not as big and it looks at the pump.

MedicFox

i used 89 octane in Alaska when it started to spike between $5-$8/gal all summer and I drive an 03 A6, no problems at all, only slight notice in acceleration where it wasn't as quick. if you're in an area where it gets freakishly cold like -30, I suggest premium 91+ all the time or you will notice a few things lol

audijsh2413

I use 91 which is the highest octane offered at the pumps in the town i live in, and occasionally i will buy octane booster. Higher octane is not only better for your engine, its also more fuel efficiant (it burns slower) therfore less fuel used believe it or not

monkeytronic

Forced induction (e.g. turbocharged) and naturally aspirated high compression engines do tend to run most optimally with higher octane fuel.

BTW gains in fuel economy with higher octane gas are due in large part to the fact that engine management doesn't have to retard timing any where near as much as if it were running low octane gas where detonation (aka. pre-ignition or pinging) could prove destructive--especially so in FI and NA high compression engines operating under high load. Note this only applies with engines which have knock sensor feedback (as is the case with many modern Audi engines).

In the case of many older engines designed to run on low octane gas like, say, an older domestic large displacement, low compression NA V8, that does not have knock sensors will run less efficiently on high octane gas because engine management can not tailor operating characteristics appropriately where a slower burning, high octane fuel equates to partially unburned and therefore wasted fuel.

IOW the octane of gasoline by itself does not connote fuel efficiency.

jdwheel1

Monkeytronic has a great explanation of the octane issue and is right on the money (I am a mechanical engineer with gas engine training working for an oil company).

Some people that are trying to save $$ try to "blend" their own 91 octane fuel by refueling at 1/2 tank by alternating between mid-grade (89) and premium (93). That will work in theory, but if you got the bucks to buy a high performance car like an Audi, go for the high octane stuff... your car will love you for it. By the way, watch out for the "el cheapo" gas (including costco, bj's, etc). Often they do not have a good additive package and they scrimp on detergents leading to clogged fuel injectors over time. Stick to the name brands (they have reputations for quality and want to uphold them).

jeff968

I'm going to get flamed for this but I have run 87 regular many times without issue. My old A4 1.8T would ping like crazy on anything less then 93 but the newer 2.0Ts don't have any issue. Maybe performance is down??? Mileage is fine. On top of that, we buy our gas at BJs.

quattrovant

My friend, one day you will be on your way home with your wife, have to pull your car off the side of the road, probably raining or -30 below and 100 miles from anywhere Sunday at midnight. You are f***ed, and the wife will tell you about it for a very long time. You later find out you put a hole in your piston or a valve that got stuck from the crud buildup from the lack of using higher tier gasolines. Too lengthy to explain here but when you get a mechanics bill for about $3-$5k for being cheap the wife will NEVER ever let you forget or maybe girlfriend and your friends will laugh there buns off at your expen$e. It is not worth the risk in my opinion.
Please don't say it won't happen to me, because it does happen and it is just a matter of when.......

NateS5

This is the opposite of what I commonly hear, that gas is a commodity and there is very little difference between brands, it all comes from the same place, brand additives provide marginal benefit, etc.

Wow, no.