Programmable digital knock filter?

[VX L67 Getrag]

Yeah it looks awesome, I guess it comes down to each sensor & what car there fitted to as to what frq's they work at & how close they are fitted to top of cylinder, but been told if it's anywhere near water jacket!

[festy]

I'm really impressed with it on the bench so far. There's something addictive to playing an audio loop over and over, adjusting the filter's settings each time round and seeing the filter respond differently. Next step is to fit it to an engine and see if it still produces decent results...

The "calculate" button in the Knock tool's screenshot will tell you the aproximate knock frequency based on your bore, i.e. 84mm bore is around 6.8kHz.
As long as you're using a proper flat response style sensor that number will be pretty close.
If you're using a "broadband" tuned sensor, just make sure the knock frequency is within the sensor's bandwidth.
My sensor is good for something like 1-18kHz, so is a turely generic sensor.

The simple way of tuning it is to plug a LED into the output, and induce some knock.
The LED will come on whenever knock is detected, so with a little bit of trial and error you can home in on the sweet spot settings.

My knock filter can run two sensors - so far I've only set it up to select from one, the other, or alternate between them (for a v engine, one on each bank).
It would be possible to have two completely different configurations for each sensor, but my program isn't clever enough to handle that yet
It's also got a tacho input with the idea of decreasing the filter's gain as revs increase, but I still have to get around to implementing that...

[VX L67 Getrag]

VERY IMPRESSIVE FESTY!

I've loved this thread & idea from the start & a nice LED sitting on top of DYNO would be easy to see, can even has an analogue input to be integrated into the logged dyno data with warning!

[Dazza92VP]

looking forward to getting one of these. definitely going to be a sought after item and is it going to be incorporated into 12p at all for knock logging?

[festy]

is it going to be incorporated into 12p at all for knock logging?

It should work just like a factory knock filter with 12P.
It's too big to mount on the memcal at the moment, but will connect to the 808's external knock filter pin like the '165s used.

[Dazza92VP]

awesome

[festy]

Next step is to fit it to an engine

Done

and see if it still produces decent results...

Yes it does

With high gain/low threshold filter settings I was able to get a LED on the knock output pin to flash by tapping on the engine with a spanner in the right spot - but in other spots it had no effect, regardless of the proximity to the sensor.

With the engine idling, I established the "noise floor" (i.e. I lowered the filter settings until the LED stayed off) then increased the timing by 10* and the LED started flashing a couple of times a second. I could barely hear the knock myself, but could just tell it was there.

The sensor is currently mounted right next to injector #4 - so about the worst place possible for background noise, but I'm pretty happy with it.

[Holden202T]

nice! interested to see how it goes

[VX L67 Getrag]

THIS LOOKS LIKE THE SHIZZLE!!
Can't wait to see 1 & get it in use!

Love your work Festy!

[vlad01]

so when do we get them?

awesome! taking the delco another step forward