Well i think Porsche remembers very well the 1990 disaster.

They came back to formula 1 with a brand new v12 designed for footwork/arrows, and this was a pluri annual partnership. The engine was about 190 kg when the ford was 136 kg.Despite being the heaviest engine of the year by far, the porsche engine was not reliable and not even powerfull.

Footwork asked Porsche to go F**k with their engine before the end of the first year...