JP66

So longer term I intend to use my trusty AIM Solo with a Smarty Cam attached, but for now I'm using the ever so simple Harry's Lap Timer on my iPhone. For simple lap times it's super easy especially since I bought the app years ago. I am learning that there are OBDII bluetooth connectors available that provide some data. My question is:

Is there a way to get brake psi using Harry's Lap Timer and one of these remote units? It seems it ought to be available since the Porsche Track app captures brake psi.

Thanks to any that can help

Too bad I didn't know about the Porsche Track app when I spec'd my car. It seems like a fun easy option. The video below was supposedly created combining video from an iPhone and the Porsche Track app on CarPlay. Not sure how that works, but it does look interesting.

ProCoach

No. The OBDII standard that generic readers (and even AiM's OBDII/CAN protocol) use does not include brake pressure.

PPTA is done through USB to a module in the car that supplies that. No OBDII required.

JP66

Sorry for being dense, and I know it's not truly relevant to my initial question, but what is PPTA and can I access that somehow without the Track App?

ProCoach

Sorry. PPTA=Porsche Precision Track App

Can't access it without access to the CAN of your car or with the PPTA.

krell

Bringing back an old thread . . . .

If brake pressure isn't available via OBDII then I presume throttle data isn't either. How are people using Harry's, Aim, or any other DAQ getting this data then?

edub

Brake pressure is on the canbus and any logger that can tap the canbus can get it if you have the PID.

Brake pressure is also in the EXLAP protocol, which can be accessed via an open source library (some assembly required) or https://www.petreldata.com/product/c...r-for-android/ which is quite decent.

My setup is in here, and I use circuitstorm on a spare android phone. https://rennlist.com/forums/data-acq...n-a-718-a.html

ProCoach

Since about 2006, there has been a generic OBDII CAN (as opposed to the previous, slower K-line) protocol for most cars. That is limited to a few basic channels primarily required for emissions based testing (RPM, ECT, MAT, MAP, TPS and some others). No brake info on that generic template.

Shortly thereafter, many (but not all) manufacturers started sending their own proprietary PT CAN info to pins 6 and 14 of the J1979 (OBDII) connector. GM Performance, the later Vipers, some Stellantis, Ferrari and some others provided massive information IF you had the messaging, scaling and offset to “read” the channel info. Some companies like AiM and Racelogic reverse engineered this info, some like Porsche and BMW made their apps the only easy way to read this info FROM THE OBDII PORT.

Now, it’s all over the map. Many companies, including Porsche, are installing gateways, or filtered, one way guardians of the vehicles CANbus. Enterprising hackers have worked out what messaging is there to add to the normally paltry number of channels usually made available.

Bottom line is OBDII is only an attachment point for many of these loggers, and what is available is governed by not only what the manufacturer deems necessary to send to pins 6 and 14, but also the time and effort to reverse engineer what may or may not be there.

malloc

Bringing back an old thread again! You can get throttle position and a bunch of vehicle parameters but not brake pressure unfortunately. I'm the creator of the app Track Attack (www.trackattack.app) and have worked on OBD a lot! Here’s a Track Attack video with data from a Bluetooth OBD adaptor showing throttle, rpm, etc recorded from my 981 Boxster GTS at the Virginia City Hillclimb (other data includes GPS and all phone sensors)

ProCoach

Throttle, engine speed and coolant temp, among a few other less useful measures, are always available through OBDII since 2006 or so, on some before that.

Just no brake info on the standard OBDII info in every car.

No brake info unless a proprietary CAN messaging template (sometimes available via the OBDII connection, sometimes via direct connection to the appropriate twisted pair) is used.

malloc

Yep that sums it up! Some of the other parameters I request for Track Attack are air intake temp, manifold absolute pressure, engine load. I'll be adding a boost gauge for turbo engines too.