Was scrounging around my favorite auto recycler/junkyard the other day and picked up a couple ESC modules with the calibration I was looking for (mid to late 80's 350 engines). Didn't have time to crawl under the vehicles to get a sensor or two, but will try to do that next time I'm there. I'm planning on wiring up a simple harness that will have battery and ground leads, along with a lead for the sensor output. This harness will then plug into a harness/box I already have that has the pulsewidth extender/driver to flash the BA LED that I usually mount on the rearview mirror so that it is easy to see in the car while at speed. This second harness/box also plugs into the factory ESC module so that the sensor signal is filtered and actual knock noise will trigger the output, causing the LED to flash each knock occurence.

I had planned to build this harness several years ago, and use it on my BB, but somebody at GM engine design decided that it was a good idea to put the coolant drain plug right under the motor mount, which didn't leave sufficient room to screw in a knock sensor. Some day when I get some spare time maybe I'll see if I can modify the motor mount a touch to get me the necessary clearance. Until then, there's lots of small block setups to play around with for amusement.

 

Just engineering curiosity here. Do you know how it's calibrated, or how many parameters it uses to filter out the mechanical noise from the actual knock noise?

 

I don't know about that one...

On my V12 - w/ a Megasquirt MS3 Pro it has Dual DSP inputs with bandpass filters- I'm running the stock Bosch ones that were on the motor originally- yet I have them turned off right now...more to learn.

I have seen others that tuned using the bore size...

Richard

 

Yeah, there's a decent correlation between bore diameter and knock wavelength. IIRC the Bosch knock sensors are a flat response design while the Delco sensors are tuned/resonant at the measured knock frequency of the engine it's installed on. (I don't know if GM presently uses the resonant sensors or has gone to the "one part number fits all" sensor.)

 

A knock sensor would be nice to have