It’s sort of common knowledge that replacing engine internals and especially adding some kind of forced induction comes with the need to upgrade the type of oil used. But how bad will it be if you just leave it as it is? In his 12-minute video, Motor Oil Geek very clearly explains what can (and will) go wrong.
The engine being experimented upon is an LS-series V8 by General Motors, which had received some drag-focused mods before the test. For starters, Motor Oil Geek puts it on the dyno in naturally aspirated form. He then drains the oil, puts some more in and installs turbos for a second test run.
A quick study shows that the oil from the turbocharged engine is significantly contaminated with fuel. It is inevitable in high-end tuning projects, but leads to a reduction in viscosity and lubricating capacity. As a result, the engine is running at an increased strain and accumulates wear. You may not notice it outright, but you will be reducing the life of your tuned setup if you continue using the same oil type as before.
But what oil type should you upgrade to? The advice is simple: listen to the professionals. There is no single recommendation, but if you had your turbos installed in a shop, asking there is a good way to start.