trash site

[Gabe]

Thanks so much for this @razorlab ! Do you happen to know if the tire pressure and temperatures are on the CAN as well? Would be a great addition to the already excellent list.

No. But there are other ways to get that info displayed along CAN data

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[Adonis]

No. But there are other ways to get that info displayed along CAN data

How? Do you have a way of reading the data straight from the tpms sensors broadcasting the data to the car?

 

[razorlab]

How? Do you have a way of reading the data straight from the tpms sensors broadcasting the data to the car?

He is using aftermarket TPMS system

 

[Yabai]

Edit: OBDLink CX doesn’t work. Tried it with MX+ and worked without any issues.

Says waiting for data and nothing shows up. Should I just try the mx+?

 

[Adonis]

Edit: OBDLink CX doesn’t work. Tried it with MX+ and worked without any issues.

Says waiting for data and nothing shows up. Should I just try the mx+?

It works on my BMW G42. Weird the CX is seemingly unreliable.

 

[AndyK5]

ObdLink CX works fine on my 2023. Might be an issue with this specific obdlink cx.

 

[richardracer]

I would like to offer a massive thanks to Razorlab for unlocking the puzzle of how to get advanced data out of my BMW 135i F20 and into RaceChrono Pro using fast CANBUS. I have been chasing this dream for track day usage for a couple of years and your article plus that of Porsche man PlanetKris plus the download config file finally made it happen. Good on you for sharing with a wider audience.

I used a set of plug & play components to avoid tapping into delicate canbus wires. Total cost around £300.

You may find a lot of visits to this site from BMW F series and G series owners looking for this solution!

Regards

richardracer

 

[richardracer]

Ps - this might help those with factory TPMS and getting that data in RCP. Courtesy of ChatGPT.

In 2012 BMW F20 models, monitoring real-time tire pressures is a game-changer for track days, as it helps you bleed off air to hit your target "hot" pressures.


On the F-series, the TPMS (RDC) data is broadcast on the CAN ID 0x365.


1. TPMS CAN Definitions (ID 0x365)


The pressures are usually sent in Bar or kPa. BMW's raw data for pressure typically uses a multiplier of 0.1 or 0.041 depending on the specific firmware version.

Tire	Offset (Byte)	Length	Equation	Unit
Front Left (FL)	0	1	A * 0.041	bar
Front Right (FR)	1	1	A * 0.041	bar
Rear Right (RR)	2	1	A * 0.041	bar
Rear Left (RL)	3	1	A * 0.041	bar

Note: If you prefer PSI, change the equation to (A * 0.041) * 14.5038.





2. Monitoring Tire Temperatures


The same CAN ID (365) often contains the Tire Temperature data as well. This is arguably more important on track than pressure, as it tells you if you are overdriving the tire.

Tire Temp	Offset (Byte)	Length	Equation	Unit
Front Left	4	1	A - 40	°C
Front Right	5	1	A - 40	°C
Rear Right	6	1	A - 40	°C
Rear Left	7	1	A - 40	°C

3. Implementation Step-by-Step


In RaceChrono Pro, these are coded exactly like your Wheel Speeds, but with a 1-byte length:

 

[razorlab]

Ps - this might help those with factory TPMS and getting that data in RCP. Courtesy of ChatGPT.

In 2012 BMW F20 models, monitoring real-time tire pressures is a game-changer for track days, as it helps you bleed off air to hit your target "hot" pressures.


On the F-series, the TPMS (RDC) data is broadcast on the CAN ID 0x365.


1. TPMS CAN Definitions (ID 0x365)


The pressures are usually sent in Bar or kPa. BMW's raw data for pressure typically uses a multiplier of 0.1 or 0.041 depending on the specific firmware version.

Tire	Offset (Byte)	Length	Equation	Unit
Front Left (FL)	0	1	A * 0.041	bar
Front Right (FR)	1	1	A * 0.041	bar
Rear Right (RR)	2	1	A * 0.041	bar
Rear Left (RL)	3	1	A * 0.041	bar

Note: If you prefer PSI, change the equation to (A * 0.041) * 14.5038.





2. Monitoring Tire Temperatures


The same CAN ID (365) often contains the Tire Temperature data as well. This is arguably more important on track than pressure, as it tells you if you are overdriving the tire.

Tire Temp	Offset (Byte)	Length	Equation	Unit
Front Left	4	1	A - 40	°C
Front Right	5	1	A - 40	°C
Rear Right	6	1	A - 40	°C
Rear Left	7	1	A - 40	°C

3. Implementation Step-by-Step


In RaceChrono Pro, these are coded exactly like your Wheel Speeds, but with a 1-byte length:

Thanks for this, glad the thread helped!

Looks like you didn't post the full Racechrono formulas above!

 

[Yabai]

Write up would be great. Trying to do this myself and it won't even show up on my Input channel

 

[razorlab]

Write up would be great. Trying to do this myself and it won't even show up on my Input channel

Seems the TPMS is wrong. Doesn't work. I wish people would test stuff before sharing.

 

[Yabai]

Going to try this on the car after work and report back but if anyone wants to try (or who are impatient) in the meantime feel free:

CAN ID: 368

Tire Pressure (PSI) - RaceChrono Equation

Front Left,"bytesToUint(raw, 0, 1) * 1.45038"
Front Right,"bytesToUint(raw, 2, 1) * 1.45038"
Rear Left,"bytesToUint(raw, 4, 1) * 1.45038"
Rear Right,"bytesToUint(raw, 6, 1) * 1.45038"

Tire Temp (C*) - RaceChrono Equation
Front Left,"bytesToUint(raw, 1, 1) - 40"
Front Right,"bytesToUint(raw, 3, 1) - 40"
Rear Left,"bytesToUint(raw, 5, 1) - 40"
Rear Right,"bytesToUint(raw, 7, 1) - 40"

Didn't work

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