Category Archives: Turbocharger

The Turbo Engineers, Turbo Selection, Turbocharger

TTE 550 Another Contender

The longer I wait the more interesting things become.

Another option that I’ve recently been made aware of is a product from The Turbo Engineers, an outfit in Germany.  While they have a large product line the turbocharger that caught my attention was the TTE 550 (image below).

The Turbo Engineers TTE 550 B5 S4/RS4 Turbocharger
TTE 550

This turbocharger pair is based off of the BorgWarner K04 with modified RS6 internals.  It’s a pairing of components that I have heard good things about and one that I think provides a great upgrade path to someone with K04’s that would like to max out their stock motor, or even push a little closer to the 500 whp range.

For less than the cost of new turbochargers TTE modifies the used BW K04’s, milling the compressor housing so that RS6 internals can fit into the K04 housings.  This means the turbo’s go right back where they came from in the engine compartment without need to purchase RS6 turbine housing compatible DP’s.

TTE offers a number of additional modifications for this turbo such as:

  • Ported exhaust entry
  • Gasket matched exhaust flange
  • Ported boost outlet
  • Ported compressor inlet
  • Compressor cover painted in black Hi-Temp coating
  • Actuator painted red in Hi-Temp coating
  • Lightened Turbine wheels

I’d like to find some additional performance results from users of this turbo, but the data supplied from the manufacturer looks promising.

My list of turbocharger candidates now looks like:

  • BorgWarner K04
  • FrankenTurbo F21
  • ProjectB5 RS6-X
  • SRM Billet K04
  • TTE 550

Next: FrankenTurbo F21 Mixed Flow

Turbo Selection, Turbocharger

New option from SRM

With the passage of a few months a new candidate has entered the scene.  I noticed that Silly Rabbit Motorsports has introduced a K04 hybrid variant to provide another option for me.

SRM K04 RS4+ (K04 Hybrid Turbo)
SRM K04 RS4+ (K04 Hybrid Turbo)

These SRM turbo’s bring a new twist to the candidate pool because they are similar in size to the FrankenTurbo F21 and ProjectB5 RS4-X on the compressor side, though the SRM uses a billet compressor wheel, but on the turbine side it is using a clipped wheel.

This is a very interesting development since I have theorized that one of the reasons my experience with the FrankenTurbo F4H-BT did not show much gain in the upper rpm’s, despite pushing 25psi out to redline, was that the airflow through the turbine side began to back up lowering the engines VE.  Perhaps a clipped turbine wheel would allow this size turbocharger to hold that 25+ psi and flow better, netting greater top end horsepower results.

Since the product is a recent introduction it remains to be see how they perform, but for now they will stay on the candidate list:

  • BorgWarner K04
  • FrankenTurbo F21
  • ProjectB5 RS6-X
  • SRM Billet K04

Note: As of July 2015 I have yet to see any results of how the SRM billet K04 turbocharger performs.

Next: TTE 550 Another Contender

Turbo Selection, Turbocharger

Turbocharger Selection Big Picture

This chart of torque from a number of dyno’s illustrates how different size turbochargers will delivery a different driving experience.

The car setups can differ greatly, having a significant affect on the outcome, but the general idea is to find a median value from a number of cars to help illustrate how a particular type of turbocharger might perform on a typical S4.

Turbocharger Torque Comparison
Torque Comparison

Next: New option from SRM