ShakeNBake

I need to move mine, and hoping I can crib from someone's working scene. thx

katmeho

Working in the can connection but not for vbox. Have you done your tap yet?

ShakeNBake

I have not gone looking yet. I was not going to attempt until I confirm someone has it working.

LaSource

How are you guys tapping into the CAN bus?
I previously have used the clip on (non splicing) cable in a 996 GT3
...I read that the newer cars should be able to use the direct OBD port socket.
Any experience out there for the GT4?

Thanks.

katmeho

OBD2 is garbage in the GT4. There is very little that I can pull off that port. See my notes on my track day diary. It's a mess. CAN is going to be the fire hose of data. I am working on getting a 2 wire tap right next to the ECU which I'm told is at the rear of the car. Once I have that done I will document. Then it's just a matter of us hacking the stream to determine which PIDS that we want to watch. I'll have that eventually too. I won't do the AIM mapping but I will map the PIDS and put it into a Lula script to work with the autosport labs gear. Data for all!!!

katmeho

I'll be your Guinea pig. Hoping to have the tap done in the next 3 weeks.

ShakeNBake

You should be able to find a bus by the fuse box and center stack.

Mr. F1 Fan

WTF??? CAN...ECU...Fire hose....PIDS...Lula.... Hacking....

I want to understand. Help me pleaseeeeeeee............

katmeho

Ok. Here's my best Mr. Hand...

ECU is the cars computer. Ways to get into this computer are Porsche's proprietary track performance application (via Wifi - but it's a closed dat source, you get what you get and you don't get upset because papa Porsche says so) or either via standardized plug (OBD2) or to latch onto the cable that connects the car to the ECU (CAN). I call that latching on a tap. Real mechanics or race engineers probably have a proper name for it but I don't know what it is. Your tap has to physically connect to the wires in the car, just like the NSA connects to your home phone line. The data on the CAN wire/s has ALL (firehose) of data that the car needs to do its job. It's a lot of data and its crazy fast in its communications about adjustments that are taking place while driving. Think about how quick the car makes ABS decisions or when it chooses to use the traction control. The machine is much faster than the human brain and all of that data can be used to analyze your driving in real time and after the driving event. But the machine and ECU speak non human readable ones and zeros, like all computers. PIDS are the language (or more specifically the definition of variables and values) that allows humans to understand the car. Example...ECU says something like "142,82 176,18" (but it does it in a base language so it might look different) The PIDS are 142 and 176 and 82 and 18 are the values of those PIDS. What the hell does it mean? Well if 142=throttle position and 176=brake pressure, then this tells me that you are left foot braking into turn one. Add speed, GPS data, yaw angles and perhaps a ton of other data points and we can try to see a) how to go faster and b) what you need to do different to get the car consistently on the line you want or need to try for a different result. Cool huh? Data rules. I want more data and the CAN connection gives you access to the whole car. But here's the issue, what PIDS have Porsche defined in this ECU program and what are the values for each? That's the hacking part. Figuring out the PIDS to watch and why, along with sorting out the right value scale. Also, knowing what not to look at. Today I don't care about passenger rear wheel speed. Maybe if I have bad tire wear at Laguna I will need that to diagnosis an alignment (or more likely, driver) issue. Lula scripting is specific to my data hardware setup, it allows me to define the PIDS and map it to my analytics tools. It's an open source scripting language that allows flexibility rather than having to rely on a company to do that research, which is the value of buying an AIM or Motec product.... Those guys do all the work for you in their software. The cool thing is that once one of us cracks the PIDs code for the GT4 (and/or GT3) then we can all share that data and everyone's life can focus on seeing how poorly we are missing apexes and over braking. By now some of you are saying, damn it Mr. Hand, this is all Greek to my Spicolli self, why do I need to be in this class? Even the most basic and simple telemetry can make you a smoother, safer and quicker driver. If all you logged was speed, rpm and track position (GPS) you could determine things like your best corner entry speed ("whoa I can go through t2 15 mph faster than I thought") or proper gearing ("why is the car bogging down in t6? Oh it's because I'm way out of the powerband and should be down a gear")

Hope this helps. Also hope that some race engineer that reads this posts corrections, as this is only my understanding and experience with the topic. Not sure it's 100% correct.

Bill Lehman

I'm not a race engineer but I did race SCCA for 9 years and have tracked a Cayman for 8 years. I started running a data acquisition system 4 years ago (AiM Solo). This system is 100% GPS based and gives just about all of the data you need to find areas to improve your driving. This year I switched to an AiM Solo DL with a direct tap into the CAN using the cable coming out near the fuse box in the foot well. I stripped the wires and soldered. You also need to pick up 12v DC which I did in the fuse box. The CAN gives additional useful info but for my purposes its gives throttle position and a brake switch (987.1). The big plus for me is that the Solo DL ties directly into an AiM SmartyCam and adds data directly to my videos. For my purposes, I'm not sure a CAN connection is necessary. The GPS generated data used with the AiM Race Studio software is sufficient.

ShakeNBake

You need throttle, steering, RPM (for calculating gears) and brake pressure to complete what you are getting from GPS - all available on the CAN bus.

LaSource

Where exactly are you finding the CAN wires in a GT4?

ShakeNBake

I'm waiting to hear from Racelogic and my dealer. I assumed it is the same as a regular 981, makes no sense for the wiring harnesses to be different. AIM has an installation document - but I can't confirm this works in a GT4, nor do I have the scene file for a VBOX that listens to any data channels yet.

http://www.aim-sportline.com/downloa...11_104_eng.pdf

TRAKCAR

waiting for 2 camera HD version.

ShakeNBake

Yep, as am I. It's going to be awesome. Thought, I am concerned that the files will be 4x the size, so will not be as fast to xfer to laptop.