Quote:
Originally Posted by Daox
You still have to deal with the knock sensor. And, you really don't want knock, so I'd recommend not doing this.
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AFAIK the knock sensor is only there to protect the engine, and will retard on a knock by knock basis (incipient knock), retarding a few programmed degrees when it gets a knock, then if it doesn't detect any further knock it advances back up slowly to the base map until it encounters knock again, then backs off again, then advances again.
The best systems have learning functions that populate steady state and transient knock limit correction maps. The normal way to get these maps to re-learn is to disconnect the ECU power supply so that it is starting again from zero.
Any engine modification to a vehicle that has a self learning function (even a fuel octane change) can benefit from a forced system reset.
Actually reaching the knock limit and staying there IS something we want for the engines to be as efficient as possible.
Quote:
Originally Posted by Daox
On another note about applying vacuum to the crankcase, I don't know what modern engine doesn't do this. Any modern engine is fitted with a PCV valve and anytime there is vacuum in the intake manifold theres vacuum in the crankcase.
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The vacuum in the engine is so small its virtually immesurable. To increase the vacuum in the crankcase to a level that will actually de-aerate the oil and reduce windage (the crank cutting through the oil mist in the crankcase and in effect a kind of aerodynamic drag) there needs to be a large vacuum source to the crankcase, such as multiple PCV valves in the rocker cover, exhaust extractors etc.