Fuel - Premium or Regular?

[raclro]

I have a V6 04, purchased new. For the first two years, I used premium nearly all the time. The last two years I use it only on about every fourth or fifth fillup. I find no difference I can detect in either performance of mileage. None whatsoever. Approximately 40 times per year I drive it at freeway speeds on a steep highway at over 11,000 feet elevation (I -70 through the tunnel). I have never heard it knock or noticed a lack of speed or pickup, and since I drive this same road many times it would seem obvious if it made a difference.
There is however a relationship between altitude and octane which I am not an expert on. Lower elevation requires greater octane from what little I know. My Touareg has never been below about 4500 feet so I have no idea how it would behave.

[imorgan]

Originally Posted by Vegas Matt

We used to have 100-octane (104 RON) at the pumps here in Vegas. When premium (91 octane (R+M)/2 (95 RON)) was at $2.40 a gallon, it was $4.25 a gallon! I'd hate to fill up a Touareg with that stuff! It did do well in my 2-stroke pre-mix for my old dirtbike, it seemed to burn cleaner and the engine ran more smoothly on the 100-octane gas.

Overall, though, I'd run what's recommended. 91 to 94 would all be good, 100 may be overkill, but it would be interesting to see what the 100-proof would do to fuel economy and performance.

Matt

You know what is sad - here I go dating myself - but I used to buy 100 - octane in the mid 70's to early 80's for less than $1.50 for my 74 Super Beetle!!

[zerokewl]

I put whatever is inbetween. Honestly a lot is dependant on your driving habits!

[prunotdi]

I have a 5000lbs tent trailer, premium is the way to go. I have a 2004 with the V6 and still plenty of power.

[californiacanadian]

I notice a little less power off the line but nothing drastic. I put premium when i go up in the mountains but otherwise its not like the v6 is a rocket anyway.