dave-C2

I am thinking about installing a chip, but I want to avoid knock -which could be caused by various factors including inadvertent low octane gas.

I've done some searches and I think I am correct that the NA 1995 993 DME (with 55 pins) has a 0-5V output signal at pin #50 for knock. I don't know if the signal pulses for each knock or if the voltage varies with the intensity of the knock. I would guess that the signal would need some sort of processing based on frequency or voltage or both, with logic to identify potentially problematic conditions.

Since my car is driven primarily on the track my focus would be on WOT conditions.

Has anybody used this knock signal to drive a real time display or alarm?

Thanks in advance for any suggestions or comments.

maurice97C2S

Some guy(s) on the 944T side were using a counter available from a surplus shop to do just this .. I tried to buy one but they said 'US only', as I am a potential terrorist ..

Can't provide the details while away from home, but a well defined search might turn it up ...

cheers, Maurice

MPB993

I pulled together a binary counter on the knock signal with a reset after no knock for 5s. It is simple but does what I want it to do on my TPC 993. If the counter signals more than about 8 knocks in the 5s period I get an led on which could be attached to an alarm but I haven't got around to that part. The signal out from the ECU registers a knock event as opposed to intensity. Others on the 928 board have created a similar cct for their cars.
BR, Mark.

maurice97C2S

Whose counter did you use, Mark ?

cheers, Maurice

MPB993

Maurice, I built the circuit myself around a binary counter (ic 4040 or something similar cant remember as it was some time ago). BR, Mark.