Subject: Re: 2009 A4 TSI
audi at humanspeakers.com
Thu Jun 5 12:30:22 PDT 2014
> The difference between regular and premium (high octane) gas is that
> high octane gas has additives which suppress pre-ignition. One of them
> is Tetra-Ethyl-Lead or TEL, a/k/a lead based chemical compounds.
Yes to sentence one. Not so much to sentence two for the last 40-odd years.
I think the major additive to increase octane is toluene/toluol.
> But I don't think there is any more energy in premium gasoline. It is simply a better quality of the same stuff.
Not "better", just "different".
And then again...
> Not sure if that was true, but they were very good and I never had any trouble again after I started using premium.
Some old wives (read automotive technicians with no training in
chemistry) aver that the additive package for "premium" contains more
than just knock-preventing compounds, but also better fuel conditioners,
for lack of a better phrase.
But I think it's just that running a high compression engine on lower
octane just mucks it up a bit. Premium lets it run cleaner.
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