Your engine is recycling its own oil vapor back into the intake and you're just… cool with that? Direct injection engines are especially brutal here. Without fuel washing over the intake valves, oil blow-by bakes into carbon deposits that choke airflow and kill performance over time. A catch can is one of those mods that doesn't make your car faster today — it keeps it from getting slower tomorrow. → Why your PCV system is working against you → The carbon buildup problem most people ignore until it's a $1,500 walnut blast → What separates a real catch can from a gas station air freshener with fittings → Why the first drain is always a wake-up call This is genuinely one of the best dollar-per-value mods you can do on any boosted or DI platform. We're talking under $200 to potentially save yourself from pulled intake manifolds and valve cleanings down the road. Save this for the next time someone tells you catch cans are snake oil — then show them what comes out at the first drain. ...