Sauber have had a torrid 2016 campaign scoring no points and Kaltenborn puts the decision down to focusing on an aspect of the car they understand; the chassis.
"We certainly think it is the right [decision] and it has been driven by the technical decision makers in the team," she said.
"We know there is a big change coming up and with the size we have and the capacities we have, we needed to focus on that change.
"We didn't want to wait for that long, whatever changes might come on the engine side or not. It's clear that the engine supplier wants to develop as much as he can until the end of the possibilities, and we didn't want to wait that long.
"We decided to work around what we know; we have sufficient information on that environment around the engine. So we can now focus totally on the chassis side and on performance development."
Bahrain International Circuit - Winter testing
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