Category Archives: Tuning

Tuning Snafu

After loading a revised tune onto the car’s ECU I took a short drive and had a couple of alert lights come on the gauge cluster.  I plugged in the XTool to see what the problem was and the device could not connect with the ECU.

I decided I should return home, but now the car would not start.  I had to pull a MacGyver to get the bolts out of the ECU box, and then I disconnected the ECU, re-connected it, and then was able to start the engine to return home.  Upon arrival I hooked up VCDS and received the following alerts:


18010 – Power Supply Terminal 30
P1602 – 35-00 – Voltage too Low
16985 – Internal Control Module
P0601 – 35-00 – Memory Check Sum Error

The second one I had never seen before, but I immediately thought that maybe I hadn’t created a checksum on the latest bin that I had loaded on the ECU.  Looking in the folder with the development tunes I saw the latest file name lacked a CS at the end of the name, my indicator that the (C)heck (S)um had been set.  Doh!

It took unplugging the ECU for a while before I could get Nefmoto to connect to it, but finally it did and I was able to write a corrected file.

Lesson learned about staying vigilant when installing files on the ECU.

Still tuning the Turbo Concepts

I’m continuing to work on replicating the boost profile that the car operated at with the BorgWarner K04’s.  In this effort I am mainly concerned with the top end boost so that I can compare the pre-turbine backpressure produced by the Turbo Concepts Stage 1 turbochargers with that from the other logged turbo’s.  The current state of the boost profile is shown below:

Turbo Concepts Stage 1 Turbos Boost
Turbo Concepts Stage 1 Turbos Boost

This tune started from a FrankenTurbo F21 tune that I used with the same hardware, aside from the turbochargers.  The wastegates on the Turbo Concepts turbochargers are set about 1.5 psi less than what the FT’s had, so I was anticipating some adjustments needing to be made.  The first few revisions were not generating the results I was wanting, so I went back and logged the boost developed at a variety of fixed wastegate duty cycles.  A sample of some of these are shown below:

Turbo Concepts Fixed Wastegate Duty Cycle Boost Levels - 50, 60, 70
Turbo Concepts Fixed Wastegate Duty Cycle Boost Levels – 50, 60, 70.

I suspect one of the reasons this effort to modify the tune is proving a bit more of a challenge than I had anticipated is on account of the unsteady boost curve.  I’d have expected a fixed WGDC to produce a straighter line.   I was concerned with the wastegates when I was trying to set the pre-load and was having trouble, the variations shown above further my concern about the wastegates on these turbochargers.

WG Refinement

Matching 8 psi preload wastegates with the TTE550 sparked some discussion over the potential need to adjust the tune to accommodate this component pairing.

I’ve been satisfied with the responsiveness from the TTE550, but in the interest of finding out if “doing it the right way” would make any difference in the results I decided to undertake an effort to Calibrate the Tune’s KFLDRL table.  A detailed report on one persons attempt to do this is documented on the Nefmoto site and I’m using that as a starting point for my effort.

After setting CWMDAPP and KFLDRAPP appropriately I began by collecting 0% and 10% data.

 

0% N75DC
0% N75DC
10% N75DC
10% N75DC

 

An early observation is that I can likely refine where I am collecting data without adversely affecting the outcome.  Attempting to log boost data from 1000 to 6500 rpm in every gear is time consuming, risky, and not possible due to the speeds reached in 6th gear at 6500 rpm.  I’m not interested in conducting this work on a dyno so I am limited by conditions on public streets.

With the intent being to capture the maximum boost pressure achieved at a particular engine speed for each duty cycle setting, it looks as though I am able to use 6th gear to record from 1000-2500 rpm, 4th gear from 2750-4000, and 3rd gear from 4500-6500.  I believe this will produce ‘good enough’ results and reduce the amount of measurements I need to make.

Some additional measurements, 20% and 30%.  These were made at ambient temperatures about 20 degF greater than the other two, which raises the question, should the fixed wastegate duty cycle boost pressure be recorded at the same temperature?  I would think so, but then if it did matter what does that say for the KFLDRL results that are being tabulated and how they hold across different temperature ranges.

20% N75 DC
20% N75 DC
30% N75 DC
30% N75 DC

These latest results are prompting me to also drop taking measurements in 4th gear since I’m not seeing any value added from those readings.

I will be logging 3rd and 6th gears with only the <3000 rpm region of the 6th gear data being used.

Shown below are the composite 3rd gear results thus far.  Note: The 10% DC pull was very short.

0-30% Fixed WG Duty Cycle Boost Readings
0-30% Fixed WG Duty Cycle Boost Readings