Finished reinstalling the engine today and started it up with the FrankenTurbo F21’s in the mix. I’m still on the legacy tune from the K04’s and larger injectors so I just did a leak check and let it idle for a couple of minutes.
[KGVID]https://myaudis4.com/wp-content/uploads/ft_startup.mov[/KGVID]Category Archives: Turbo Selection
Turbo Collection
On hand:
Bottom L-R: FT21 & BW K04
- The Turbo Engineers – TTE550
- Borg Warner K03
- FrankenTurbo – Mixed Flow F21
- Borg Warner K04
Today I finished removing the BW K04’s and installing the FrankenTurbo F21’s.
I had my first chance to op check the coolant catcher that I rigged up after the last engine pull. The point of the device is to keep the coolant inside the engine once I start hoisting the engine out of the car.
In the past I invariably have ended up with pools of coolant on the garage floor as the engine comes out, my hope was this little device would put an end to the messes. I was happy to see that it worked as intended and I didn’t have any major spillage on the floor.
The two coolant attachment points are joined together with the silicone hose.
K04 Dyno Baseline
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
Note: The PID was calibrated for loads experienced on the street since tuning was not done on a dyno. The load presented by the Dynojet differed from that on the street. The boost / torque oscillations seen on the dyno are not replicated on the street.
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.
