With new technical regulations being introduced next season which will lead to increased levels of downforce, Kaltenborn confirmed to F1i that Sauber took the decision earlier this year to use the current Ferrari power unit in order to be able to push ahead with its chassis development.
"I can confirm to you that we will be using the latest spec of the 2016 Ferrari engine in 2017," Kaltenborn said.
"The reasoning is actually that we took this decision a while ago - not just recently - at a time when actually the rules for next year were also not 100% clear. At that point of time we took a strategic decision to say that we want to focus the resources we have on chassis development, on performance development and in a way leave the engine side to the information and the areas which we know.
"So it was a pure strategic decision taken even before the rules for next year were actually finalised."
Confirming the decision came before Sauber was taken over by Longbow Finance, Kaltenborn says the team has the resources to compensate for any power unit deficit next season in its care development.
"Any statements being made that this was taken because we are apparently in delay with our developments are wrong. We are absolutely on plan, we have not suffered any delay there. Through the change in the ownership now of course we have the stability and the boost you need to step up the speed we're developing at.
"Obviously there's not going to be that development on the engine side but in our view it's the right step we've taken that whatever we might suffer on one side we are confident with the additions we have to the team to be focusing on compensating for that on the chassis side.
"It's a wilful step we have taken here. It did not have anything to do with any financial constraints, it was really that we want to focus on the chassis development. Our engineers are convinced that if there is any disadvantage you might have in terms of the power unit they want to compensate it through the chassis development."
Kaltenborn says the example of Toro Rosso also shows it is possible to negate a lack of power unit development over the season to a certain degree.
"Well we definitely looked at [Toro Rosso] but for us the decision was really taken a while ago because things were not 100% sure on the rules. We wanted to have the ability that if there is any change again we can react to that and the power unit side is then the known side for us."
Asked if Sauber is open to future options regarding its power unit supply - with Honda having recently ensured it is able to supply a second team in future - Kaltenborn replied: "We are always open-minded. You should always be open-minded."