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Re: IA prices
Higher octane gas essentially has a higher anti-knock index (ability to
resist pinging or knocking/detonation). With higher boosts, knocking occurs
more easily. Prolonged knocking will destroy the engine. Normally, the engine
ECU detects knock and dials back (retards) the timing to avoid or reduce
knocking. According to Ned, the Audi ECU is capable of a max timing dial-back
of 7.8 degrees. So, if you are running high enough boosts or low enough octane
to exceed the 7.8 deg retard limit of the ECU, then you run the risk of
damaging the engine. The timing maps that Ned puts in the Stage I or II
are appropriately selected to give you safe operation at the max
allowable boost level.
Just as a point of reference, the early UrQs (MAC-02 ECU) have completely
static timing. Well, not completely static, since it varies by rpm, temp,
boost, etc. But they do NOT have knock-sensors and "dynamically-adjustable"
timing. The computer is helpless if you overboost/otherwise start knocking
the engine...caveat emptor fer shur!
There is one interesting aftermarket "high performance electronic ignition"
system advertised (J&S) that comes replete with knock sensor and automatic
"per-cylinder" retard (and a nifty -- optional -- LED bargraph display to
indicate amount of dynamic retard. I'm vacilating . . .)