I’m getting started with removing the BW K04’s to replace them with FrankenTurbo’s F21 Mixed Flow turbine wheel turbochargers.
I’m knocking out a little bit on the car each evening. Putting up insulation in the garage is paying off big time now that bitter cold temperatures have arrived.
Here’s a surprising result, the chart shows the pressure in the signal line going to the N75 valve. The other end of this line is what taps into the turbocharger compressor housing.
The K04’s are operating at a higher Manifold pressure, but the reading from the compressor housing is less than what the K03 readings are for a K03 tune until about 5000 rpm, where the K03 tune drops manifold pressure significantly.
This morning the S4 went back onto the DynoJet dyno for a series of pulls with the BorgWarner K04’s and a moderate boost Daz tune.
The purpose of this session was to establish more baseline data for making comparisons to some aftermarket turbocharger options.
The ‘final’ results peak dyno numbers are of less interest to me than the shape of the torque curve. I am expecting a K04-hybrid turbocharger to be capable of more peak torque and power than the RS4 K04.
Here is the boost profile that this tune uses:
Boost and MAF
Boost and N75 Duty Cycle
Here’s a street pull:
Here is how the K04’s compare with K03 turbochargers on my car. K03’s are shown with two different tunes, one very aggressive and the other moderately aggressive.
What is notable about the chart above is how closely the torque curve of the K03 and K04 match one another.
Below are the EGT readings for each turbocharger/tune on the dyno.
