We asked one of our tuners to provide some feedback on his initial thoughts for the Focus ST turbo kit and here is what he said…
My observations with the turbo kit are as follows:
-The main item that I keep an eye out for with turbo kit design is waste gate priority and boost response. I am most concerned with the ability to hold a constant boost level with as little wastegate duty cycle feedback as possible. For instance, if a target of 20 psi is requested, and it requires a relatively constant duty cycle to maintain it, this makes the job of the engine calibrator much simpler as opposed to a situation where you need to vary the duty cycle 10-20% or more to prevent boost creep at higher RPM’s. This can often happen when the wastegate is placed in a less than ideal place or if the turbo charger is far too large. With cp-e’s Atmosphere kit for the Focus ST, this was of no issue. We were able to use a standard 3-port boost control solenoid and we found that it required very little feedback to hold boost within 1-2 psi of target from peak torque to redline.
-The boost response is pretty exceptional for the size of the turbo being used. It makes peak torque slightly later in the power band compared to the stock turbo, however the GTX2867R is able to maintain useful airflow until redline. This is very different from the stock turbo which is not able to do this.
I can extrapolate more on the engine tuning side of it, but as far as the turbo kit goes, the main thing I deal with is the boost response / control. As I stated there, it was quite good, and you guys should have some happy tuners working with it in the future.