Spark Plugs - pre ignition issue

[vwtype53 at yahoo.com (Benjamin Harder)]

I've been having an issue lately with pre-ignition (pinging) on my mk1's
2.0 16v engine.  Engine is freshly rebuilt with approximately 11:1 compression,
running CIS-E, stock ignition, always on 93 octane, etc.

If I set the ignition timing to stock settings (6-8 degrees) the engine
will ping (my knock sensor is obviously not functioning).  I will then retard
the timing to around 4-6 degrees and everything seems fine... just the fact
that I'm losing some performance.  :(

So, I checked my spark plugs to see that I was running the stock 3 electrode
Bosch plugs for the 2.0 16v, which have a heat rating of 6.
Due to my higher compression, I sourced a different Bosch plug with heat rating
of 5 (colder plug).  Thinking that this would dissipate heat faster
and help solve my pre ignition issue... nope.
The new plugs don't seem to have helped.

Anyone have experience in the high-compression world with this pinging
issue.  Sure I could run octance booster or race gas, but I know that
there must be a way to run 93 pump gas... right?  :/

If I go to a colder plug (like a 4 rating), would this possibly help?

TIA!


=====
Benjamin Harder
86 Scirocco 16v
80 Scirocco 16v
93 Passat GLX

http://www.geocities.com/vwtype53/

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