Harlan

iTrader: (3)

By popular demand, here is how to listen directly to your engine for detonation.

You will need:
Rx8 Knock sensor, bolt, and connector.
OR
100k resistor and a .01uf capacitor

And

Shielded Microphone cable (I cut apart an XLR cable)

Male RCA jack & a couple RCA cables

A 12volt equalizer with a frequency band centered near 2600hz
(Such as a 5band with a 2.5k)
Here is the one I used:
Soundxtreme Car Audio Passive Equalizer 7 Band 1 2 DIN Pre Amp EQ Sub Crossover | eBay

A 12volt mini amplifier.
12V Mini Hi Fi Amplifier MP3 Stereo Audio for Car Motorcycle Boat Home US Local | eBay


A small speaker or headphones.
I just used an old computer speaker I had in the closet.




First build your audio in cable.

Here is the recommended method:

Wire the knock sensor connector to the microphone cable. Connect the two wires of the knock sensor to the two wires of the cable, then connect a Male RCA end to the other end of the cable. Red to red, black to black. Connect the shield wire (the non insulated wire) to the outside (ground) of the male RCA connector with the black wire, connect the red wire to the center (signal) of the RCA connector.
Knock sensor (yellow/red wire) → red wire of cable→ RCA connector center
Knock sensor (black/white) → black wire of cable→ RCA connector ground
Unshielded wire → RCA connector ground

Remove the drivers side wheel and attach the extra knock sensor to the front housing. Connect the cable to the knock sensor then skip down to the section for both.


The not so good method:
Original reference
http://www.uprev.com/documentation/K...n%20Device.pdf

Use a cable splice or any other reasonable attachment method to connect the 100kohm resistor and .01uf capacitor to the yellow/red knock sensor wire then to the red wire of the microphone cable.

Knock sensor (yellow/red wire) → 100kohm resistor → .01uf → red wire of cable→ RCA connector center
Unshielded wire → RCA connector ground

This method may need a preamp depending on the EQ, also it will pick up the ECU's self checking signal and some other noise. Hence not recommended.

Both:
Run the completed cable through the rubber boot in the firewall where the wiring harness runs. If in doubt, refer to this thread
https://www.rx8club.com/series-i-do-...-trunk-173180/
Don't accidentally cut your harness!
Then connect to the line in on the equalizer. Go from the equalizer to the mini amp and the mini amp to either a speaker of a set of headphones. Power everything from the source of your choice, I tapped in by the cigarette lighter.

For operation, put the fader centered near 2.6khz to max and turn the others all the way down. When knock happens you will hear it, the rest of the time it's pretty quiet. Also most Eqs have front and rear out so you can take a RCA to 1/8th headphone adapter and use that to record engine noise while still being able to listen.

I don't have a good recommendation on where to mount the EQ and amp, mine is hanging out in the backseat right now. Eventually I'll find a place under the dash to mount it all and place the speaker so that it points directly at me.

If you're having trouble finding a connector for the knock sensor PM me, I'm currently looking at other knock sensors for frequency response/compatibility.

Harlan

iTrader: (3)

It's a denso but I haven't sourced any with the proper notches. Anyone know a good place to find desno connectors? I have a couple laying around that work but that's it.

dannobre

iTrader: (3)

If you only want a couple I think I would have them...PM me

logalinipoo

Did you ever try the standard DIY det can's found around the internet?

I've been looking around a lot lately, and am mainly wondering why you're focusing on isolating the frequency.

TeamRX8

iTrader: (25)

http://www.connectorexperts.com/inde...log%20High.pdf

Harlan

iTrader: (3)

Thanks for the link! It's nice to find a supplier of odball connectors. I'm currently using a bosch sensor on the front housing and I don't need to scavenge connectors anymore. The reason why I focused on isolating the frequency is because there is a lot other noise some from ignition coils and some from actual combustion. When you turn down all the other frequencies the knock becomes obvious especially at low rpm.

The DIY options available come down to either using a microphone or using an actual knock sensor. I referenced one in my first post. They work but could be better. Most aftermarket solutions use actual knock sensors and are either filtered(good) or non-filtered(poor) then use some sort of DSP to throw out false reading.

I currently have a ti tpic8101 chip that is working well on static tests. I haven't tried it on the car yet but it's promising.