TTE550 Turbochargers


The Turbo Engineers TTE550 turbocharger is another in a series of evaluations I am engaging in to determine what is the best stock motor turbocharger for my Audi B5 S4.

Picture of TTE 550 Compressor Housing and Wheel
TTE 550 Compressor Housing & Wheel


Picture of TTE 550 Turbine Wheel
TTE 550 Turbine Wheel


The TTE550 is a K04 hybrid turbo that is advertised to have K04-like spool but better top end.  This claim aligns well with my goals.  The TTE550 is one of the most expensive turbocharger options that I have encountered in the K04-hybrid category.  TTE advertises placing a strong emphasis on reliability through the use of quality parts.  I found their customer support prior to purchase to be excellent.

Options Available:

The TTE550 is essentially similar to placing an RS6 center into a RS4 housing.

  • BW RS6 in RS4 housing – should have similar performance characteristics to the TTE550.
  • FrankenTurbo F21 – A less costly K04-hybrid that utilizes a mixed flow turbine.  Already evaluated.
  • Silly Rabbit Motorsport RS4+ – A less costly K04-hybrid that utilizes a clipped K04 turbine wheel.


The TTE550 was promising enough to purchase for evaluation.

tte 500 turbocharger compressor housing


The TTE550 has performed well given the size of the compressor and turbine wheels.  While K04-like response has not been achieved, it has been a satisfactory performer.

Audi B5 S4 Information and Testing