[A4] Need for Premium Gas in 1.8T quattro?

Jake Spoon j8k3sp00n at gmail.com
Sun Sep 24 13:24:22 EDT 2006

Hi All,

Unless the Otto and Diesel cycles have been rewritten by revisionists,
turbos simply increase volumetric efficiency.  A 10:1 engine is the same
before and after aspiration;  however, the aspirated engine increases the
amount of fuel mixture entering the cylinder faster and accelerates
(supposed to) faster.

Your supposition that putting more fuel mixture into the cylinder seems
under CW to increase the compression;  however, it doesn't in ICE
engineering terms.  You are assuming that the intake time remains constant
and, if more fuel mixture is pumped into the cylinder, compression will be
higher because the stroke is a constant.  Intake time becomes shorter with
aspirated engines as they accelerate.

That ought to be clear as mud;  I can provide some really dry references for
nights when you can't get to sleep right away.


Jim Jordan

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