I had our latest test session in Southern Spain, near Malaga. Objectives were to finalize the eTesta GPS6 and start tuning our test car after moving from US.
Current config of the vehicle
- ECU: MoTeC M130 with eTesta BMW S14 package. 1MBit/s CAN Bus.
- Power Management: MoTeC PDM30.
- Display: MoTeC C125 with Internal Logging
- Lambda: eTesta LAM3 Dual
- Injectors: Injector Dynamics ID725
- Engine: BMW S14, 2.3l. 300hp
- Sequential injection/ignition. 1 coil/cylinder
- Schrick valvetrain, Arrow Titanium connecting rods
- Clutch: Dual, 5.5" organic discs
- Water injection
Long GPS6 Run
This log was taken during a 4 lap run, all looks normal. Let's review the data starting from the bottom:
- There are no resets, see the eTesta GPS6 Startup count at the bottom. Number would increase if there would be a reset.
- Message OK/Fail is fine, 1 checksum error out of 90000. Data is not sent to the CAN bus if checksum check fails.
- Lat/Long is correct in all messages
- GPS Fix Quality is GPS all the time so fix was not lost during the run.
- Average HDOP is 1, between 0.9 to 1.1. (Lower the number, better)
- Speeds are correct vs wheel and reference GPS. No spikes or areas with difference to wheel speed.
- GPS and CAN Bus diagnostics are OK the whole time.
- GPS data is valid all the time and GPS Ticks is increasing correctly so MoTeC GPS Module is receiving the data correctly. Average GPS satelites is 9, so GPS is receiving the satelites as normal in this area.
- Lastly, GPS Altitude is correct, around 800m from sea level.
Low Speed GPS Performance
This graph shows an issue compared to GPS6. Reference GPS is reporting the speed as 0 kmh even when the car was moving judging from the GPS6 and wheel speed traces. We have observed this before and is made on purpose to eliminate the noise when the speed is very low. It is not really a problem in the reference GPS, it is a choice made during the design.
GPS Speed Delay Measurement
This log was take at the same time but logged with the MoTeC C125 Logging Display. It has 3 traces:
1. GPS Speed from 10Hz GPS
2. GPS6 Speed from 50Hz GPS6
3. Wheel Speed from wired ABS sensor.
As you can see, speed measurement from the 10Hz GPS can be almost 500ms delayed compared to wheel sensor. Situation will get even worse if there are less satellites available.
Please contact us if you have questions, comments about the data presented here or if you are interested trying out the eTesta GPS6.
Now that GPS6 is done, it is time to tune the car to 98 octane fuel. Also temperatures are much higher and the test track is 800m above sea level.
Before going into details, let's see the track and run a lap around it. Lap is 5.4km long with 6 sectors. Below is the track mapped with eTesta GPS6.