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, Mon, 25 Dec 2006 14:47:35
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I'm guessing where you are right now the temps are fairly cool or cold. That makes for ideal conditions for this engine to experience it's boost capacity. When it's summertime hot outside, that's when the limits of the stock intercooler reveals itself. Add to that the advanced timing and you may find that instead of the boost you now enjoy, all you get is ping and sluggish boost because of the knock sensor opening the wastegate. Also, if your engine is not in top tuned condition, you're not allowing for much leeway when things (ignition component wear issues) begin to effect the performance.
Ping doesn't occur under just boost. When cruising, both the centrifugal device inside the distributor, plus the vac line connected to the advance unit advances the timing to help with optimal gas saving. You add 4 more degrees of advance on that and you set up a perfect condition for a low level of pre-ignition at cruise. That's how hot spots develop and eventually burn up a valve or weaken it and eventually a crack and so on.
Then there's carbon build-up inside the combustion chamber. That makes for hot spots which leads to knock. A number of things contribute to carbon. I don't fully know the science of fuel combustion, but I can't imagine a too advanced timing is a good thing at cruise. Something about unburnt or improperly burnt fuel comes to mind. There's also the lowered temperture issue. Those are the things you need to look into.
Electronic mapped timing control really is the best way to extend the range of this engine. But, if you can find a way to address the top end over-advance on this distributor and vac advance unit while keeping the timing set advanced, then you may have yourself a really cool tweak. Just know that a smog test will almost always reveal a non-stock timing.
posted by 72.67....
, Sat, 23 Dec 2006 09:56:36, Mon, 25 Dec 2006 14:47:35, Sun, 24 Dec 2006 10:30:20
, Sat, 23 Dec 2006 21:15:46, Sat, 23 Dec 2006 21:42:30
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