Forum » General Tuning Discussion » Plex Tuning Knock Monitor

Plex Tuning Knock Monitor

General Tuning Discussion

Discuss all things tuning in this section. News, products, problems and results. 

Page 1

Hi Andre,

I saw ur plex tuning review and after that i purchase the knock monitor but one thing u mentioned was the 10khz highpass band filter

for detecting knock but that changes the cylinder bore size in the setting since u cant select 75mm bore with 10khz high pas filter when i change the filter the bore size changes also.

when i select the 10khz highpass the bore becomes 130mm.

and also the u cant set the threhold with out the rpm right because i dont see an option for it.

i hope u can help out on this one.

There are two aspects to the detection system in the Plex knock monitor. You need to set the bore diameter to suit your engine and this will set the correct frequency for the internal knock detection. The 10 kHz high pass filter I mentioned is part of the audio detection circuit and can be selected independent of the bore diameter.

After more time using the knock monitor, I will add (and this should probably go without saying), that 10 kHz high pass won't work for everything. When you set the bore diameter this will tell you what the knock frequency is likely to be. This can guide you as to what audio filter to apply. For example if your knock frequency is 6.9 kHz based on the bore diameter, I'd suggest starting with the 7 kHz band pass audio filter.

Ok thanks for the fast reply,

i will just have to see what settings works best for the engine im tuning.

i find when i use the highpass that im getting light det at part throttle aound 3000rpm with around 20 degree of timing afr 14.5

i pulled like 5 degree still was hearing some so im not sure what it was mayb the settings are to sensetive.

its at honda civic 75mm bore 12.5:1 CR and on 98 pumpgas.

so i'll just have to play around i think and see what settings works for this engine.