BMW F80 M3 brake data?

HarryKim

Hello guys,

I just began to enjoy RC with Qstarz 818xt and ELM327 OBDII.

Just one thing... how can I extract brake pressure info from OBD II for BMW F80 M3?

Could someone throw some light here please... many thanks!

Cheers

Harry

HarryKim

... and can I also get hp and torque data (real-time) through OBDII? At least I can't see them in RC's list of fast or slow channels.

timurrrr

It's not a standard PID. You'll have to find a custom PID one way or another. If nobody posted that PID anywhere, it can be very hard to find.

If the brake data from car is supposed by e.g. AIM devices, I suggest you invest your time into finding the CAN ID for the brake pedal instead, and use the currently-experimental CAN mode with OBDLink devices. I believe there's a special model of OBDLink for BMW cars, @aol can confirm if it supports/will support the CAN mode.

aol_of_RaceChrono

AFAIK, all OBDLinks will work with BMWs, but don't hold me accountable if I'm incorrect They have a cheaper OBDLink CX specially made for some BMW specific app, but it should work on other CAN-Bus cars too, and other OBDLinks should work on BMWs.

HarryKim

Thank you all! Yes indeed I realised I need to find a custom PID yo get brake pressure data but I couldn't find any hint through googling unluckily.

Instead I found Bimmerlink can show the brake data and even allows me record the log. I surely tried to think about a good algorithm to merge this Bimmerlink's logo with RC's but it is just way too complicated to sync.

I think the last thing I can try is sending an inquiry directly to Bimmerlink team although I truly understand it will be a loooooong shot! :)

timurrrr

Another possible alternative is to make a "RaceChrono DIY" device and plug it into the CAN bus of the car.
You'll still need to figure out the CAN IDs for various data channels, but ultimately this will probably provide you with the best possible data quality.

aaronc7

What is bimmerlink exactly? An OBD dongle + phone app?

You just need an OBD splitter cable and another dongle that's capable of sniffing the obd frames. I just got one of these and it's pretty neat for the price: https://www.macchina.cc/catalog/a0-boards/a0-under-dash

Requires a little know-how, but not too complicated. You can pretty easily ID the OBD header and PID info that the bimmerlink (or whatever app) is using. Then you need to figure out the equation.

Like timurrrr said, tapping into the CANbus (vs OBD) is another option, but it also requires some know-how/experimentation/DIY. I haven't done this yet personally, but the downside of OBD is that it's a request/response model, so logging speed can become an issue when you start logging many things across multiple modules etc. CANbus is listen only to what's being broadcast across the bus.

HarryKim

Thank you all for additional comments. Well I am pretty much a novice for CANbus etc so I am afraid I cannot go further into such advanced works...! But now I am trying to merge the log created by Bimmerlink for brake pressure data into .csv file built by RC. The simplest way should be using a vlookup funtion with a TRUE flag... let's see what I would be able to figure out!

jgunny

HarryKim - I'm new to OBD/CAN as well and, like you, have been on a hunt to capture brake pressure (as well as steering angle) from my F82. I only recently discovered RaceChrono (have been using Harrys Laptimer) and I'm hopeful that the ability to enter custom PIDs from the UI will be another piece of the puzzle.

I found info on E46 custom PIDs (and a wealth of additional information that I'm still digesting) here: http://forums.bimmerforums.com/forum/showthread.php?1887229-E46-Can-bus-project. I have no idea if E46 PIDs will translate to the F8x platform, but fingers crossed.

Report back if you make any progress and I'll do the same. This is slow and steady project for me, so it may be a few weeks before I make any headway--though I do have a track weekend the first weekend in October and would love to crack the code by then.

Good luck!