2009 A4 TSI

Nick Lawrence nick at beol.net
Thu Jun 5 06:50:12 PDT 2014

I also have trouble with this,   I would like to see a "real time" 
timing display.    Does using regular instead of premium automatically 
retard timing?  Or does the computer  have to sense knock then change 
timing?      I personally haven't seen increased mpg using premium on my 
cars. But I'm generally not on boost a lot.
Myth busters?

On 6/5/2014 8:37 AM, Paul Caouette wrote:
> OK!
> I can't help myself. Please look up the energy per unit volume of "premium" vs "regular" gas.
> I don't believe it is the fuel.  It is the way it is packed into the space where it is burned that increases the energy available. So, higher compression allows more fuel and oxygen to get pushed into the same volume awaiting that spark that lights it up. When a knock sensor detects a pre-ignituon. (Due to lower grade fuel) it regards the timing of the ignition. This will lead to less energy available in the flame front. But I don't think there is any more energy in premium gasoline. It is simply a better quality of the same stuff.
> Paul Caouette
> Sent from my iPhone

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