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With headphones, you can clearly hear knock at any RPM through the J&S.
You can easily add timing at 7000 RPM, and clearly hear knock over other noise. Knock has a distinct clack over the other buss sounds heard. With the J&S just set to monitor only, you can hear clear knock by forcing knock with extra timing, you can see the LEDs on the unit pick up the knock. You can then set the J&S to control knock, and the knock goes away.Optimum timing tables for power and spool, are not in any way balanced for the edge of knock. True optimum timing tables in lower RPM below 3500 will not cause knock on a Z32 with 8.5 to 1 C/R.
With optimum timing you typically do not have to start reducing timing from optimal due to knock from lack of octane on pump fuel, until about 4000 or higher RPM. The area that needs the most timing reduction, and is the most significant knock zone, is 4500 to 5500.
With higher than stock boost, your always going to knock MUCH easier at peak torque and full boost. Your only causing cyl pressure that requires more octane or lower timing with boost, because the compression is low enough not to cause knock before significant boost is added.
If you increase timing to the edge of knock below 3500 RPM your killing spool.
What people notice and comment on most after we dyno tune their cars, is how crisp the power is, and how much smoother the drive-ability is afterwards. To achieve the results we offer, the timing is anything but balanced to the edge of knock through the power band.
Because of the above stated reasons, IMO the factory knock system is useless, especially once a boost controller is installed. If you want knock protection where it will really be protection, you need to either add knock controller that handle the job in boost, or go to a stand alone system that has knock control.
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