Merging two OEM canbuses? or CANX2?

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Merging two OEM canbuses? or CANX2?

Post by TXBDan »

Hey all,

I have an LFX (GM V6) swapped RX8 and am running both the Mazda ECU (to run gauge cluster, EPS, fuel, etc) and the GM ECU (to run the engine). I have an Aim EVO4S logger which only has a single canbus interface which is connected to the GM canbus.

My goal is to collect the Mazda canbus' info as well. I'm interested in things like wheel speeds, steering angle, and fuel level. Both canbuses run at 500kbs. What would happen if I simply merged them together physically? I guess the gamble would be that there are no common PIDs/CAN IDs and they wouldn't step on each other?

Possibly the better choice to to make a can gateway using the new CAN X2. It could read selected PIDs from the Mazda and copy them over to the GM. What do you think?

Also, where can I find all CAN IDs/PIDs/scaling info etc to do this? I'd want to know what to read off the Mazda bus and know im not stepping on anything on the GM bus. I could potentially translate the values into GM PIDs so they pick up cleanly on the Aim logger using the GM canbus ECU config.


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Re: Merging two OEM canbuses? or CANX2?

Post by aUzer »

A RaceCapture Pro unit has 2x CAN bus connections plus and OBD port connection capability (along with other I/O connections, programmability, 10/25/50 Hz GPS, etc.). No affiliation other than a multi-year customer/user.

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Re: Merging two OEM canbuses? or CANX2?

Post by brentp »

You could use Lua scripting with RaceCapture to create a gateway, but since you already have a data system, you might consider the ESP32-CAN-X2 with some Arduino or circuit python to join them together.

The issue is, you might need a 3rd CAN bus to truly keep them isolated.

You might want to just identify all of the CAN IDs to see if there are any ID collisions, and then test it to see if there are any issues running the combined systems. Often devices simply ignore CAN IDs they are not aware of.
Brent Picasso
CEO and Founder, Autosport Labs
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