Quote:
Originally Posted by flightlead404
I was using Euro initially, but I think I'll switch to the non-Cali USA curves due to the slight octane difference between fuels in EU vs US.
This is a Cali car, but everything's been ripped out and its SC cams and bigger turbo so who cares, the basic US curves are similar.
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The problem is that the motor responds very well to advance and generally loves more timing. Another 6 degrees over stock makes a world of difference - especially with SC cams and a half-way decent turbo.
But, at least in my experience, even a stock US ignition curve with factory timing can/will cause knock at certain places in the map. For me it was 100% reproducible; 3000 RPM with light load/part throttle would do it every time. Even with race gas. The Euro curve was more aggressive.
Dynamic knock control works very well to solve this conundrum and tame these little dark corners of the map. The motor really loves the extra timing the other 99.9999% of the time. And you're protected against something untoward happening with an injector, filling up with junk fuel - or your dizzy plate sticking fully-advanced. For example.
And then once you're convinced that all this voodoo actually works, you can add extra advance and enjoy.
I was running the my Safeguard (dizzy/CDI unit) when I wrote this, which describes exactly the circumstances under which the Safeguard would detect knock for me:
My J&S Safeguard paid for itself last week... - and how it likely saved my a$$...
Replaced the Safeguard with John's Interceptor (for smart coilpacks) when went Motec/twin/plug/Cayenne COP (some might find this handout interesting
www.beru.com/download/produkte/fachaufsatz_zsp_e.pdf - Porsche spec'd these to make 25% more spark energy, and my tuner loves them).
John was, as usual, great to work with - even bench-testing a Beru to confirm wiring/that they worked with the Interceptor w/ no changes, and the correct settings. His units work perfectly - and he is, IMHO, another example of a small outfit providing top-shelf products/service/support.
Since motor was twin-plugged, I have seen no knock, BTW - just sayin'...