Test Session 08242017

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. 

Bemari and her younger brother, 320d. Yep, it's diesel but you can't beat 4.6l consumption (51.1mpg) and the torque.

 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 


First, let's tackle the GPS6 test. GPS6 is now available and released, see details here: GPS6. As with GPS1 all the way to GPS6, products are compatible with MoTeC M1 ecosystem.

Long GPS6 Run

This log was taken during a 4 lap run, all looks normal. Let's review the data starting from the bottom:

Download the full image here:GPS6 Long Run
  • 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

Download the full image here: 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

Download the full image here: Speed Delay

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.

Engine Tuning

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.

Test track layout

Lap Video

Below is one lap around the track, one of the laps used in the graphs below. Engine was limited to 6000rpm for now to keep it safe.

Ignition Timing

Download the full image here: Ignition

With the US tune, car was very lazy at the track and didn't respond.
Let's look at the ignition first as it was tuned for US, 91 octane pump gas which had to be very conservative to avoid the knocking.
In average, I was running 21 degrees of advance at WOT (Wide Open Throttle) with 91 oct gasoline. First, I added 2 degrees to the complete map and car started to respond. Then, to this last run shown here, I added another 2 degrees. So, Total of 4 degrees more compared to US ignition map.
Looking at the knock, it is still way below the threshold so it should be safe. I will leave the ignition as it is now, declare victory and move on.

Fuel Mixture

Download the full image here: Fuel Mixture

Next is the fuel mixture and there is not much needed to be done here. At WOT, mixtures are very close to Mixture Aim which is set to 0.88 Lambda.
Graph above shows the mixtures per cylinder (-4), all are within limits. I run set of excellent Injector Dynamics injectors which is a balanced set.
Fuel pressure is OK at 4Bar.

Closed loop fueling is used at partial throttle where Mixture Aim is Lambda 1.

S14 engine, especially with 50mm inlet manifold is an easy engine to map what comes to fueling. All you really need to map is 90-100kPa area.

Transients are another story though and that tune will be done later.

Other Engine Vitals

Download the full image here: Oil Pressure

Other engine vitals like oil pressure looks good, there are no drops at corners, at any rpm, load or temp.
All temps are also looking good except Inlet air temps tend to be high due to high ambient temperature, around 40 degrees. Water injection will fix that, we'll come to that later.
Look at the long_run_ignition graph to see details of the coolant, fuel, oil temperatures.

That's all for now, come and visit us again.