2017–2021 Honda Civic FK8 Helix Air Oil SeparatorOverview Modern turbocharged engines recirculate crankcase blowby gases back into the intake tract through the factory PCV system. While effective for emissions control, these gases also carry oil vapor, fuel, and moisture that can accumulate in the intake manifold over time. These contaminants contribute to carbon buildup on intake valves, reduce effective fuel octane, and increase the likelihood of detonation. The PRL Helix Air Oil Separator is