Why are there so few choices for improving knock detection? I've seen the link Electro unit and it seems straight out of the early 80s.

I found some links to some kick *** OEM systems...

http://www.visteon.com/products/auto...on_control.pdf

http://www.delphi.com/manufacturers/...gnsys/ionized/

http://www.semiconductors.bosch.de/e...ine/engine.asp

I would think there is a way to harness the Delphi or Visteon system for the aftermarket....

 

The Bosch system is pretty much what everyone does: a band-pass filter around the expected knock frequency, amplifier, rectifier, and windowed integrator. Intersil had a nice chip out a few years ago (HIP9010/11) but I'm not sure if it's still in production.

Ion current measurement is relatively new and I think it was Saab that had a number of basic patents covering it. But if licensing is worked out you might see it more. It's certainly more complicated though, and if you already have a solution that works it may not be worth it.

Dave