With a number of different turbocharger pairs sitting in boxes, and a good pair on the car, I’ve had trouble deciding what to do next with my S4.
![BorgWarner RS6 - FrankenTurbo F21 - TiAL 605](https://myaudis4.com/wp-content/uploads/turbo_collection_2018.jpg)
Then there is an incomplete engine sitting in the corner of my garage that will open some opportunities on account of the 2.8 heads and built bottom end.
![Istook Engine Clean Up](https://myaudis4.com/wp-content/uploads/istook_cleanup.jpg)
After several months of no progress on either I took some free time on New Years day to start preparing the car to pull out the engine.
![](https://myaudis4.com/wp-content/uploads/engine_pull_f21v3.jpg)
The built engine is not ready so that option is out for now. My goal with the TiAL turbochargers is to have them made over into 770’s, so that leaves me with a choice between the BW RS6 turbo’s:
![BorgWarner Audi RS6/K04 Turbocharger](https://myaudis4.com/wp-content/uploads/borgwarner_rs6_k04.jpg)
Or prototype FrankenTurbo F21 with ceramic coated turbine housings and Mamba wastegate actuators.
![Frankenturbo F21 with Mamba wastegate](https://myaudis4.com/wp-content/uploads/mamba-ft-1.jpg)
I’m leaning toward the F21s on account of them being an easy transition from the Turbo Concepts Stage 1 turbos that are presently on the car.
![Turbo Concepts DZX-271 Turbocharger Compressor Wheel](https://myaudis4.com/wp-content/uploads/turbo_concepts_compressor_wheel.jpg)
I’m curious how the ceramic f21’s perform
Between the Swaintech ceramic coating of the turbine housings, different compressor and turbine wheels, and Mamba wastegates, this setup will be quite different from the F21 that I drove with before.