Link ECU (Aftermarket ECU) compatibility

Firstly, brilliant app and even better support from what I've read in the forums. Bravo!
I went to the track recently and used a trial of RC Pro and I was extremely impressed - safe to say I'll be purchasing this shortly. I performed a manual import of video (Captured on GoPro HERO) then export with overlay - loved it but did find the manual sync a little tricky on such a tiny screen on my phone.
My question is - I have an aftermarket ECU (Link G4) and I want to overlay some of the data captured by my ECU - these might be factory sensors like TPS for example, or an analog or digital input that's been wiring into the Link ECU expansion slots, e.g. an aftermarket oil pressure sensor. Is this possible and how?
My ECU supports serial protocol (and CAN shortly too) and I have some cabling allowing me to patch my phone (Samsung) directly to the ECU to read run-time data with the RealDash application for example. Would it be possible to have RC running and my phone connected to my ECU to read the data the data that way instead of using my OBDII port? I think my OBDII port is invalid now that I run an aftermarket ECU.
Thanks for an awesome app


  • edited May 2019
    If your ECU does not support OBD-II, then your only option is to build a DIY device to interface with the ECU and send the data to RaceChrono. Currently the only way has been using RC2/RC3 sentences over Bluetooth RFCOMM. Next version will have another way, and I will also release build instructions with source code for getting the data from CAN-Bus.
  • We use Linkecu Atom with RC via Bluetooth obd dongle, as you can wire an Obd2 port to the can-bus of linkecu.

    Not sure however if G4 Is supported, or was it from G4+ onwards.

  • This is my understanding too, and my next planned upgrade :)
    G4 can be sent away for a free hardware upgrade i.e. adding the CANBus port to the board - I'm looking forward to doing this and getting RC working wirelessly.
  • The Atom doesn't have the dedicated can-bus port on it either. It has the can-bus on the wiring loom connector, doesn't the G4 have it? We've just wired the other end of a obd2 extension cable to the wiring loom connector.

  • For model numbers less than 10000 the G4 doesn't have it, but they can be retrofitted by Link for free
  • edited March 2021
    Hi, bringing this one back from the dead.
    I have a Link G4+ that i can't get to communicate with Racechrono. I'll give some details below, but if anyone can give me some things to try, that would be greatly appreciated. I have a race event in 10 days, and i'd love to get this working.

    I'm using a generic ELM327 bluetooth dongle, which worked with Racechrono and my factory ECU no problems at all. I've recently upgraded to the Link ECU which sends OBD-II over CAN (On Board Diagnostics ISO 15764). I'm able to use my dongle and get data with other apps like Torque Pro and Realdash with no problem...only Racechrono will not show data.
    Oh, I've tried two different devices. 1, my Nexus 7 tablet. 2, My Samsung S7 with the latest version of Racechrono.

    What can I try or what info do you need to help me fault find the reason that Racechrono won't retrieve data?
  • @ROB-80E The generic "ELM 327" readers usually fake ELM 327 and have some small bugs. One of them is that they're not able to automatically detect the bus protocol. You can set it manually in RaceChrono > Settings > Vehicle profile > OBD-II Protocol. It should work then.
  • @aol , I've had this app for so long now and I didn't even know that those settings were there within the car profile. Thank you!

    However, still no go. I tried all four ISO 15764 protocols and it wouldn't transfer.

    Here's what I can tell you from the Link settings
    Bit rate = 500kbit/s
    OBD = ISO 15764-4

    Protocol Profiles 6 or 7 should work. I'll paste an output of the device output log of the two different profiles shortly.
  • edited March 2021
    Before I get those outputs, is it possible I need another initialization command?

    These are the commands that get's sent within my RealDash OBD communication file.

    Is it possible that one of these is the reason that it works with my ECU? If so, which commands should I add within RaceChrono?
  • Device output logs attached.

    a = profile set to automatic

    6 = profile 6 (500kbaud 11bit id)

    7 = profile 7 (500kbaud 29bit id)

  • edited March 2021
    I'm afraid RaceChrono's state machine gets confused by this reader. Looks like it outputs data from the previous session at the beginning, or something like that...

    Maybe consider one of the proper ones from my recommendations:
  • Ah bugger. Ok at least I know it's not a comms problem with the ECU.

    I have already ordered an OBDLink LX, I'm just concerned it won't arrive in time for race day.

    Thank you for all your help @aol .

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