Plex knock monitor V3 setup

Hi ,

this is my first post here , I have watch video on ytube, and read post here about the Plex V3 and this is far from user friendly.

We run a dyno shop with a hub dyno and water break engine dyno. We do most LS / small bloc chevy and some Ford modular and SBF . My goal is first to concentrate with LS and SBC .

Actually I m not even able to calibrate the monitor . The auto cal knock threshold calibration is far from close to fine tune.

I did a base run on pump gas , very concervative timing from 3000-5000, but between 3800-4000 I have added +10deg . The monitor show knock from 3500 and is flashing red up to the end of the run . I hear the engine in the earbuds but no knock.

Logging is not possible at this time because I have to configure everything .. could be ready to run from factory .

I have contacted info @ plex but no answers since 2 days . There help files is far from really help .

Thanks !

Hi Alex,

Ok. I have done a fair bit with the plex V3 and I am happy to help.

Assumptions:

You are mostly tuning v8's it would seem. So using 2 sensors - 1 per bank is how u are running the Plex.

Setup:

1. Download the plex device manager software and the plex data analysis basic software.

2. Connect your device to the laptop with USB or Ethernet depending on the model. If u have HD, both should work.

3. You need an Trigger Input for the knock config. I use RPM from CAN. This is in my opinion the best way to do it. Super simple - just fire the RPM CAN data at the plex from the ECU or data logger. I send it on CAN2 from my AIM logger. (see attachment 1)

4. Configure your CAN payload. (see attachment 2). Message can be LSB/MSB whatever is right for you.

5. Configure your engine and sensors. (see attachment 3). Set your bore size and this will set you 1st harmonic for knock frequency detection.

6. Set your sensor gain. Start with 4db. Then setup your audio output. 12db works quite well for me. With bandpass set around the knock frequency.

7. You threshold mode will be auto to start with. Leave it as this.

8. Transmit the config to the unit.

9. Fire up Plex data analysis basic. (see attachment 4). You will need to configure a tab layout or accept the default one.

10. Now you are ready to get a log. Plug in ethernet or USB. turn on car and hit stream in the top right. (see attachment 4). start stream/stop stream check you have a log after saving.

11. load car on the dyno. 2 options.

a. Pull 6 degrees out the map globally so you are a good amount away from knock. Do a run and capture the stream.

b. Lightly load engine on the dyno. Assuming you are turbo charged. 200-300mbar of boost. hold at 2-3k rpm and creep in IGN until you see knock. capture stream and review in plex data analysis.

12. Which ever option you choose. Review audio to ensure you can hear knock. Play on laptop with ear defenders to block out background noise.

13. Setup threshold mode as RPM table. You can do this as autocal (instructions in help software) if you prefer once you know you have zero knock or manually. (see attachment 5)

14. Tune car knowing the plex will pick up knock. :-)

If you need anything else. Just ask.

Thanks Richard for your detailed explanation !

I'm working on a engine dyno , LS CT525 crate engine to do our test and learning . To have the rpm I had to use the output from the msd6014ct

In the data analysis , when I stream I have a big lag from the actual data shown in the log , It s possible to reduce that delay ?

Thanks

Yes. Use Ethernet.

Hi Richard

I am using a crossover ETH cable but still cannot connect.

Have you experienced the same problem?

When I use the auto cal threshold instead the AUTO, the result is much lower and much more sensitive.

DynoDom,

I have the same issue with ethernet. My unit needs to go back to Plex. But I am working with USB for now. I sent u a FB message BTW. If you have a look. :-)

Alex,

I don't quite understand what u mean, please explain. Are you referring to it setting a lower threshold value?

Richard

Thanks for reaching out, but I am not using FB anymore. You can send FB Messenger messages.

Regards

D

Sent u a message on messenger mate. 👍🏻

Hi Richard

I used to have different accounts on FB, because I managed to not being able to log in. Perhaps you sent the message to one of the old ones, which I do not have access to.

A Message to info@SwissTechSupport.ch will work.

Apologies for the confusion.

Best regards

Dom