Apparently BMW formula one teams used a similar trick to strengthen engine blocks in the early eighties.
Some of you might wonder how did the engine block resist to such immense detonation inside the combustion chamber. This may not be the answer you were looking for – and most of you might not believe it – but it seems BMW was in fact using seasoned inline 4 cylinder blocks – picked up from several junkyards – for their F1 operations. The interesting part about it was that the blocks were kept out in the cold and urinated upon in order to strengthen their composition.
While some may laugh at this strange solution by the German manufacturer, the urinating process is based on nitridization (a process which introduces nitrogen into the surface of a material and is widely used in automotive, mechanical and aeronautical engineering, having the property of a case hardening treatment of predominantly steel but also for titanium, aluminium and molybdenum). Why are we talking about nitridization? Because urine seems to contain numerous waste compounds, many rich in nitrogen. We can't yet figure out how the German engineers found this particular method to strengthen the cylinder blocks – and not use a more technological measure – but it makes for some interesting stories to tell out grandsons.
From here http://www.autoevolution.com/news/turbocharged-engines-in-formula-one-18108.html