Porsche 718 Cayman GTS model 982: choice of ODB2 and GEAR?

Hello I would like to use RACECHRONO on my Porsche 718 Cayman GTS model 982 year 2019, because the PORSCHE PRECISION TRACK app does not work, freezes and does not allow you to connect external GPS receivers.
I have already bought the PRO version of RACECHRONO, I think I will buy the RACEBOX MINI receiver (25 hz) and will synchronize the videos made with the action camera (insta 360) in post produtcion ...

... I only miss the OBD2 for which I ask you for advice: which one is compatible with my car? It is better one that is in the list of the Racechrono APP [ex PLX Kiwi, Carista, Tonwon ect] or are all good?
Finally, is it possible through OBD2 to have the GEAR engaged? I haven't seen it in any video on youtube (the PORCHE PRECISION TRACK app shows it)
Thanks Simone


  • edited April 2022
    You can find the list of OBD-II readers here: https://racechrono.com/article/faq/which-obd-ii-adapter-should-i-buy

    If you want to do raw CAN-Bus then you need OBDLink branded one, recommended ones are MX+/MX/LX, the CX is good but little bit slower.

    Certainly it's possible to get the gear using RaceChrono, but the question is if you can do this by plugging in to the OBD-II port, and if you can find the OBD-II custom PID for it. Or do you need to plugin to the car's harness elsewhere, create custom connector, and reverse engineer the CAN-Bus messages for the data you need ...

    The Porsche Track Precision app connects to the Wi-Fi on the car. I've taken a look at it on an older GT4, and it has a nonce authentication, which would needed to be cracked in order to get the data same way as the Porsche app. As RaceChrono is general purpose app for all vehicles, investing more time to do this was not justified, taking in account RaceChrono has other potential ways acquiring the data.
  • ok, i bought the OBDLink mx + the fastest
    - Connected as OBD2 I can see RPM and throttle (but the throttle is NOT accurate).
    Actually I have selected all possible data hoping to find gear by OBD2 (all slow and fast channels see attached) https://drive.google.com/file/d/1erEZxN-E5fLdvjzHTu9FLrkD6TVWBhJw/view?usp=sharing
    is it a mistake? maybe this slows down response? anyway i can't see the gear (my goal)

    - connected as CAN-BUS in other devices it works (is connected) but I don't see nothing, not even RPM.
    I have seen that it is not possible to connect it both OBD2 and CAN BUS simultaneously (one excludes the other) so if i have to connect as CAN-BUS I need the PIDS for my car and the difficult thing is that I also need PIDS for RPM because connecting it in as CAN I don't even see RPM anymore

    I know you can't give information about specific PIDS to all customers for all cars …would be impossible ... but i really don't know where to start to find it. I have searched the internet everywhere and also in other lap timer forums or specific Porsche forums, but I didn’t found.
    Are there some app which can reat them by OBD ?
    Do you think Porsche PIDS are the same for every Porsche (or every 718) or each model has its own? Can the official Porsche dealer help me to find them or they will not know what we're talking about?

    Finally as many of your customers I think have Porsche, could you please tell me if you know anyone who has PIDS for the 718 Cayman mod 982 or who can I ask?
    Having bought the OBD Link mx+ and using it only as standard OBD for only RPM is very sad.
  • edited April 2022
    You can select all the channels to be logged, but it will seriously slow down the update rate of all the channels.

    The throttle position / accelerator pedal position giving range of 10-90% is normal for OBD-II. If you want to adjust that, you can create a custom PID for it with equation to scale it to 0-100%, but honestly the data should be understandable even just as it comes.

    Gear is not a standard OBD-II PID. So custom PID needs to be found for it. From internet forums maybe? It's vehicle specific, just like all the other custom PIDs, hence the name. But it's possible different models use the same PIDs, at least the ones that are using the same ECU models etc. It's also possible to scan these with apps like Torque, in brute-force style, and then reverse engineer (figure out) what data is on each found PID. It's not very easy nor a quick process.

    We (RaceChrono) do not have any database of custom PIDs, so it's left to the users to figure it out. RaceChrono is a small company and we have to pick our fights in regard what we put our efforts into. That said I'm sure the standard OBD-II PIDs will give you accurate enough accelerator pedal position too.
  • OK

    too difficult to get all information, i think it's ok with RPM and Throttle. One question about it:

    • where have i to select RPM and Throttle, from fast channels or slow channels? They are in both

    If i select some of them it does not shows more the throttle in the video... selecting ALL (as now) it sohws throttle (but slowing down the update rate as you told me) and i can not understand which is the value of throttle and if it is from fast or slow channel

  • edited April 2022
    Slow channels are for slow changing channels like temperatures. Fast channels are anything that changes fast like throttle and RPM. Basically all channels share bandwidth, but slow channels are polled more infrequently, to have more bandwidth for fast channels.

    For throttle you can basically use what ever works for you. These are different sensors for it. Throttle position measures the position of the throttle body (engine part). Accelerator pedal position measures the actual pedal position instead.
  • "Gear is not a standard OBD-II PID."
    It now is, but most vehicles does not support it yet.
    0xA4 - Transmission Actual Gear

    I´ve used it to convert my DIY adapter values to OBD II
    -> https://racechrono.com/forum/discussion/2150/pid-a4-transmission-actual-gear

    @Tormento If you use f.e. 10 values, you want to have a fast update on RPM and Throttle. But engine coolant temperature, only once in a while. So you can use RPM and Throttle on the fast, Temp on the slow channel.
    So if you figured out the right throttle-channel, leave it on a fast one and throw out the other one, also on slow.
    Which is the "right" one, you need to findout yourself. The absolute throttle pos. is the valve itself, which is electronically controlled by your car. So if you kickdown the pedal to 100%, it might be limited gear dependend. Or is controlled by traction control as well.
  • @TriB Yes, I already forgot that one :) It was added for v7.5.0. Unfortunately it's new and most cars do not support the standard channel, and use a custom one instead.
  • @aol I remember you had some ideas about automatically detecting the gear based on speed and rpm? FWIW, I personally wouldn't wast the precious OBD bandwidth to query the gear number.
  • @timurrrr We have a working proof-of-concept, but it will need integration and a lot more testing. I'll get around to that once I clear some other stuff first.
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