Purchased Data Acquisition System: AIM EVO 4 + Mychron3 Visor Dash + OBD2
03-08-2010, 02:06 AM
#16
Race Director
Hey guys,
These are great questions and I'm happy to share what I've gleamed so far. You may want to double-check with AIM though because my info is from several AIM sites across the world (the UK site has great Porsche related info).
It appears that there are two OBDII protocols that our cars use:
1. OBDII K Line (ISO9141/2) protocol (supports 997 MK1, 997 MK1 Turbo, 997 MK1 GT3, 987 MK1 Cayman, 987 MK1 Boxster and 996 MK2 models.
2. OBDII CAN which supports all 987/997 MK2 models (I think these use the Siemens ECU vs. the Bosch of the MK1's).
The ISO9141/2's minimum standard bit rate is 14.4kb, whereas the newer OBDII CAN minimum is 250-500kbs, so the data rate may not be quick enough on the MK1 cars to support good data acquisition. Having said that, each manufacturer has their own spec as to whether they provide the minimum speed or if they go higher, so I'll let you know how it goes when I plug the OBDII connector in and get a sense of the sample rate.
For your other question, the AIM seems to support several cars with the OBDII connector as long as they are a recent OBDII implementation, especially if the manufacturer uses CAN (high-speed). For example, the AIM website references the following makes as being compatible with their OBD2 CAN adapter: Mazda, Nissan, Audi, VW, Porsche, and BMW.
To give perspective of what's available from the two modes:
OBDII ISO:
Engine Speed
Speed Value
Engine Coolant Temperature
Throttle Position Sensor
Intake Air Temperature
Manifold Absolute Pressure
Mass Air Flow Fuel Level
Pedal Position Sensor
CAN via OBDII:
RPM
Throttle Position Sensor
Pedal position sensor
Front Left wheel speed
Front Right wheel speed
Rear Left wheel speed
Rear right wheel speed
Water temperature
Oil temperature
Oil pressure
Steering angle
Steering speed
Brake switch
Engaged gear
Fuel level
As you can see, the CAN protocol looks to be much more fun! I will likely go the CAN route at some point (comes standard with the EVO4) and leave the OBDII connector for when I share the unit with others. My challenge right now is to determine how to wire/mount the pieces in the car. One part of me wants to hardwire the EVO4 in with a switch somewhere and then attach the Mychron 3 Dash and GPS antenna before each event. Another part of me wants to make the whole thing plug+play.
Hope this helps!
These are great questions and I'm happy to share what I've gleamed so far. You may want to double-check with AIM though because my info is from several AIM sites across the world (the UK site has great Porsche related info).
It appears that there are two OBDII protocols that our cars use:
1. OBDII K Line (ISO9141/2) protocol (supports 997 MK1, 997 MK1 Turbo, 997 MK1 GT3, 987 MK1 Cayman, 987 MK1 Boxster and 996 MK2 models.
2. OBDII CAN which supports all 987/997 MK2 models (I think these use the Siemens ECU vs. the Bosch of the MK1's).
The ISO9141/2's minimum standard bit rate is 14.4kb, whereas the newer OBDII CAN minimum is 250-500kbs, so the data rate may not be quick enough on the MK1 cars to support good data acquisition. Having said that, each manufacturer has their own spec as to whether they provide the minimum speed or if they go higher, so I'll let you know how it goes when I plug the OBDII connector in and get a sense of the sample rate.
For your other question, the AIM seems to support several cars with the OBDII connector as long as they are a recent OBDII implementation, especially if the manufacturer uses CAN (high-speed). For example, the AIM website references the following makes as being compatible with their OBD2 CAN adapter: Mazda, Nissan, Audi, VW, Porsche, and BMW.
To give perspective of what's available from the two modes:
OBDII ISO:
Engine Speed
Speed Value
Engine Coolant Temperature
Throttle Position Sensor
Intake Air Temperature
Manifold Absolute Pressure
Mass Air Flow Fuel Level
Pedal Position Sensor
CAN via OBDII:
RPM
Throttle Position Sensor
Pedal position sensor
Front Left wheel speed
Front Right wheel speed
Rear Left wheel speed
Rear right wheel speed
Water temperature
Oil temperature
Oil pressure
Steering angle
Steering speed
Brake switch
Engaged gear
Fuel level
As you can see, the CAN protocol looks to be much more fun! I will likely go the CAN route at some point (comes standard with the EVO4) and leave the OBDII connector for when I share the unit with others. My challenge right now is to determine how to wire/mount the pieces in the car. One part of me wants to hardwire the EVO4 in with a switch somewhere and then attach the Mychron 3 Dash and GPS antenna before each event. Another part of me wants to make the whole thing plug+play.
Hope this helps!
Cars with CAN in USA required to use 500KBS speed. CAN bus can be either 11-bit ID or 29-bit ID. In Europe and other places 250KBS used.
Either protocol can support the parameters you list. It is a function of the Ecu and the firmware feature set that determines what parameters are actually supported and available for query.
Sincerely,
Macster.
03-08-2010, 04:49 PM
#17
Instructor
Join Date: Oct 2007
Posts: 201
Likes: 0
Received 0 Likes
on
0 Posts
Hi Gus, the car is in the shop getting a Guard LSD rebuild and the AIM install. I lucked out with the weather and was able to get a few clear days to get the car up there; no idea if it will last, and the car may end up snowed in at the shop. I'll provide an update when I get the car back.
Regarding buying a Data Logger this is a difficult decision to make, you know once you install and get used to one system I bet it is difficult to go back, AIM seens to be very good, I specially like the capability to connect to the Car ECU, and have a lot of info that can help you to really improve on the track, with out having to install sensors!! Locals here have mostly the traqmate, (traqmate seems a bit on the weak side on my opinion), so it can be an advantage to share data with others. Anyway I think I can always ask for the data and analyze it on my PC using their software, or I can have somebody's traqmate in my car for a session and compare the data.
Anyway I'll wait a little to see how your system work, also are you planning to synchronized video? what about HD video? I'm sorry for all the questions but I'm relative new to the sport, I still have to learn a lot, or at least that I wish...
regards,
03-08-2010, 07:40 PM
#18
Drifting
Thread Starter
Regarding buying a Data Logger this is a difficult decision to make, you know once you install and get used to one system I bet it is difficult to go back, AIM seens to be very good, I specially like the capability to connect to the Car ECU, and have a lot of info that can help you to really improve on the track, with out having to install sensors!! Locals here have mostly the traqmate, (traqmate seems a bit on the weak side on my opinion), so it can be an advantage to share data with others. Anyway I think I can always ask for the data and analyze it on my PC using their software, or I can have somebody's traqmate in my car for a session and compare the data.
Anyway I'll wait a little to see how your system work, also are you planning to synchronized video? what about HD video? I'm sorry for all the questions but I'm relative new to the sport, I still have to learn a lot, or at least that I wish...
regards,
Anyway I'll wait a little to see how your system work, also are you planning to synchronized video? what about HD video? I'm sorry for all the questions but I'm relative new to the sport, I still have to learn a lot, or at least that I wish...
regards,
I contacted Tony at Trakvision and they do in fact support the AIM output, so overlaying data on video should be no problem. In regards to HD, that really comes down to your camera. Right now I'm using an AIPTEK camera which records pretty well at 60fps and 720p widescreen.
Once I get it all setup and running, I'll try to make a video. My only real concern right now from the video aspect is the frequency of the datalogging being high enough for a nice video. I think we'd need at least 20Hz for RPM and SPEED to make the video smooth, but won't know until I try it. The default for the 997 GT3 CAN bus is 10Hz, but can be adjusted higher (at the expense of memory capacity for stored runs).
05-12-2010, 02:36 AM
#19
Instructor
Join Date: Apr 2006
Location: SF Bay Area / Switzerland
Posts: 126
Likes: 0
Received 0 Likes
on
0 Posts
Hi guys, need some help here.
I bought a video vbox for my 997 GT3 mkI thinking that all I would need is to connect the sold cable to the OBDII plug. Turns out it does not work.
Racelogic says it cannot work because the Porsche OBD2 plug does not have can signals routed to it, and you have to splice two wires to tap into the two CAN signals.
I seem to decipher from this thread that the AIM system can tap either ISO or CAN signals from the OBD2 plug, indicating that the signals are indeed available there ?
Can someone shed some light on this ?
I'd rather butcher the cable I got from racelogic than splicing cables on the car itself. Assuming I can find them.
Help appreciated.
I bought a video vbox for my 997 GT3 mkI thinking that all I would need is to connect the sold cable to the OBDII plug. Turns out it does not work.
Racelogic says it cannot work because the Porsche OBD2 plug does not have can signals routed to it, and you have to splice two wires to tap into the two CAN signals.
I seem to decipher from this thread that the AIM system can tap either ISO or CAN signals from the OBD2 plug, indicating that the signals are indeed available there ?
Can someone shed some light on this ?
I'd rather butcher the cable I got from racelogic than splicing cables on the car itself. Assuming I can find them.
Help appreciated.
05-12-2010, 04:44 PM
#20
Drifting
Thread Starter
Hi ze_shark,
The AIM system can indeed use either the CAN signal or the ISO protocol from the OBD2 connection. The distinction though is that the ISO protocol is not the same as the CAN signal, so Racelogic is correct that the OBD2 connector does not carry a CAN signal and won't work for your needs. If you had a mk2 997 GT3, the OBD2 connector does now carry the CAN signal.
Fortunately, tapping into the factory ECU is really easy and you get all sorts of data with only two wires. A good local shop can tap the wires in a matter of 30 mins. I'd recommend not using a cable splice, but instead to solder the wires either at the wire or at the ECU connector to ensure reliability.
The AIM system can indeed use either the CAN signal or the ISO protocol from the OBD2 connection. The distinction though is that the ISO protocol is not the same as the CAN signal, so Racelogic is correct that the OBD2 connector does not carry a CAN signal and won't work for your needs. If you had a mk2 997 GT3, the OBD2 connector does now carry the CAN signal.
Fortunately, tapping into the factory ECU is really easy and you get all sorts of data with only two wires. A good local shop can tap the wires in a matter of 30 mins. I'd recommend not using a cable splice, but instead to solder the wires either at the wire or at the ECU connector to ensure reliability.
05-13-2010, 01:41 PM
#22
Rennlist Member
This past weekend I hooked up the SmartyCam to the AIM system and was quite impressed with the ease of use. Auto on and the picture was quite nice. My USB port was not working on my PC so, did not get the right dash setup displayed. The tech people at AIM were outstanding. We worked an hour on Friday night, and when it appeared the problem was my PC, we set a time on Tuesday for another call. It was determined that one port would not work with the installation, but another would and everything now works fine!
05-27-2010, 05:51 PM
#23
Instructor
Join Date: Apr 2006
Location: SF Bay Area / Switzerland
Posts: 126
Likes: 0
Received 0 Likes
on
0 Posts
Hi ze_shark,
The AIM system can indeed use either the CAN signal or the ISO protocol from the OBD2 connection. The distinction though is that the ISO protocol is not the same as the CAN signal, so Racelogic is correct that the OBD2 connector does not carry a CAN signal and won't work for your needs. If you had a mk2 997 GT3, the OBD2 connector does now carry the CAN signal.
Fortunately, tapping into the factory ECU is really easy and you get all sorts of data with only two wires. A good local shop can tap the wires in a matter of 30 mins. I'd recommend not using a cable splice, but instead to solder the wires either at the wire or at the ECU connector to ensure reliability.
The AIM system can indeed use either the CAN signal or the ISO protocol from the OBD2 connection. The distinction though is that the ISO protocol is not the same as the CAN signal, so Racelogic is correct that the OBD2 connector does not carry a CAN signal and won't work for your needs. If you had a mk2 997 GT3, the OBD2 connector does now carry the CAN signal.
Fortunately, tapping into the factory ECU is really easy and you get all sorts of data with only two wires. A good local shop can tap the wires in a matter of 30 mins. I'd recommend not using a cable splice, but instead to solder the wires either at the wire or at the ECU connector to ensure reliability.
I've come to the understanding that I need to connect to the CAN_DRIVE_HI (BK/WH) and CAN_DRIVE_LOW (YE/WH) signals which are routed in multiple locations, among which the DME Control Unit on the rear shelf, and the Control Unit Gateway *somewhere* on the drive side, but I can't see it without tearing the car apart.
I have studied and followed Sharkwerks excellent DIY for ECU removal, but I still can't correlate with certainty which of the 5 connectors carries the D36/D37 pins which map to the two signals, neither where the TSX2_1 "passenger compartment rear" 30 pin connector is.
The wiring diagram says that there are 5 connectors (A through E) on the ECU, so am I simply looking for the fourth one on this picture ?
Isn't there a smarter, more easily accessible location that the ECU to tap CAN signals ?
05-28-2010, 11:33 AM
#24
Drifting
Thread Starter
The AIM website has a PDF file you can download with instructions and pics. Getting to the ECU is relatively easy, pull the carpet back and unscrew the metal plate. The ECU is under the metal plate. Here is the AIM document for a Mk1 997 GT3: http://www.aim-sportline.com/downloa....1_100_eng.pdf
05-28-2010, 02:25 PM
#25
Rennlist Member
I don't have pics of the install (my tech did it) but will try to post a PET diagram that will illustrate where the wires come and go.
As for the wire coding, the CAN Hi/Lo wires are colored the same as they are in the ECU harnesses.
05-29-2010, 02:46 PM
#26
Instructor
Join Date: Apr 2006
Location: SF Bay Area / Switzerland
Posts: 126
Likes: 0
Received 0 Likes
on
0 Posts
Thanks for the replies.
Would be interested to know where the pair is on the steering column.
I went for the ECU and it is relatively pain free, the twisted pair is reasonably accessible so hooking up there is not too difficult.
Can't say the same to get the Video VBox to work fully as expected ...
One odd thing is that the CAN data for steering angle seems unsigned on the Porsche. I get positive values whether I turn left or right. There's another data packet called steering direction, but haven't played with it.
The rear wheel speeds could provide interesting data to determine whether LSD wear stories are fact or legend.
Would be interested to know where the pair is on the steering column.
I went for the ECU and it is relatively pain free, the twisted pair is reasonably accessible so hooking up there is not too difficult.
Can't say the same to get the Video VBox to work fully as expected ...
One odd thing is that the CAN data for steering angle seems unsigned on the Porsche. I get positive values whether I turn left or right. There's another data packet called steering direction, but haven't played with it.
The rear wheel speeds could provide interesting data to determine whether LSD wear stories are fact or legend.
