– Why are you supposed to put high octane gas in some (typically luxury brand) cars?

Question

– Why are you supposed to put high octane gas in some (typically luxury brand) cars?

In: 21

Answer 1

It is mostly for cars with turbos. The higher octane fuel burns more cleanly and there are less leftover bits of fuel in the exhaust. This is important because the manifold exhaust is what spins the turbo, which in turn pushes more air in to the engine making more power.

Anyways, turbos get really hot, and if there is unburned fuel vapor still in the exhaust, it can ignite and blow up the turbo. This is the main reason that I’m aware of.