Zahier contacted us after experiencing issues with his meticulously modified Mk5 GTI. He wanted an honest, custom ECU and TCU tune to suit the hardware on the car.

Specs as follows:

Model: VW Mk5 GTi DSG

Engine: 2.0 4-Cylinder TFSI (Turbo charged, direct injection)

Transmission: 6-Speed DQ250 DCT

ECU: Bosch MED9.1

Location: THANAS CPT

The car had the following modifications:

• Original K04-064 Turbocharger + Plumbing
• Audi S3 Injectors
• Autotech High Pressure Fuel Pump Internals
• Upgraded Intercooler
• Downpipe & Exhaust
• CTS Turbo Intake

As well as:

• Golf 7R brakes / EBC Disc and Pads
• Golf 7R Seats
• Golf 5 R32 Front and Rear bumper / Carbon Diffuser

He sent us some datalogs that he had taken. We reviewed the logs, and gave feedback on the potential areas of improvement and how we could assist in getting him closer to his power goal. He was still running the stock rail valve / rail pressure relief valve, which was limiting the maximum rail pressure and by extension boost that he could run.

We put together an ECU and TCU package and got the car booked into our Cape Town dealer, J2 Performance.

On arrival, the ECU and DSG(TCU) software versions were identified, and the car was strapped to the dyno for the baseline figures. J2 Performance fitted a new, genuine Audi RS4 rail valve and with the baseline done, we got to work crafting custom ECU and TCU tunes to suit the specific hardware and vehicle. If you're wondering what goes into tuning a K04-064 setup, the following is a basic list of adjustments needed:

1. Adjustment of the load/torque/boost targets;
2. Adjustment of the Boost control for the K04-064 turbo and actuator tension;
3. Adjustment of the HPFP scaling / rail pressure target and injection timing;
4. Setting a fuelling/AFR request suitable for higher power, to keep EGTs in check;
5. Adjustment of the ignition timing for higher boost, keeping in mind the larger exhaust housing;
6. Adjustment of the intake VVTI to allow maximum spool and cylinder filling across the rev range;
7. Rescaling of the torque model to communicate the correct torque level to the DSG/TCU;
8. Adjustment of various sensor limits to cater for the higher torque/boost/airflow;

There are many more subtle tricks and adjustments needed, but these are the basic changes made to the ECU, and as with every car we do, we DO NOT edit the knock sensor calibration, something that is all too common on the maps we see on cars arriving from many other 'tuners'. The TCU software it was running was 99% stock with only a few limiters raised. On our TCU map we adjusted the following, bringing it to Stage 2 level:

1. Torque limits;
2. Torque scaling ECU-TCU sync;
3. Quicker shift times;
4. Adjusted shift points;
5. Maximum engine speed;
6. Launch control setpoint;
7. Paddle shifter delay removed;
8. Launch control delay reduction;
9. Kickdown disabled;
10. Line and clutch pressure target adjustment

We went through a number of revisions to get the most out of the pure 95 octane pump fuel (no WMI or additives).

Before (exactly as it arrived, already tuned):

Power: 214 kW

Torque: 426 Nm

After:

Power: 246 kW (+32 kW)

Torque: 477 Nm (+ 51 Nm)

ow that's more in line with what you would expect for a K04-064 equipped car, keeping in mind that J2 Performance Dyno is a very torque-conservative dyno, especially in the mid-range, reading up to 60 Nm less than Dynotech on the same car/same tune arrangement (more to come on this in a future blog post).

The stock low-pressure fuel pump prevented us from holding the power all the way to redline, however upgrades to the fuelling system were planned by the owner in future, so our approach for the short term was to maximise the area under the curve, making the most of the available fuelling capacity in the mid-upper rpm range, and tapering the boost down at higher rpm.

Of course this is all on pure pump fuel, the power potential with fuelling mods and higher octane/WMI is substantially higher.

Here are some bonus pics of this awesome GTi-R32 ;)

Thanks for reading!