The Gen 4 Coyote Myth: Why Dual-Injection Engines Still Need an Oil Catch Can
If you spend any time scrolling through the forums or Facebook groups, you’ve undoubtedly seen the claim: “The S650 Mustang has dual injection now, so you don’t need an oil catch can anymore.”
It sounds logical on the surface. By pairing direct injection with traditional port injection, Ford engineered a system where fuel constantly washes over the back of the intake valves, seemingly putting an end to the notorious carbon buildup issues that plagued previous generations. But here is the hard truth that the forum experts are missing: clean intake valves are only half the battle.
While your valves might stay spotless, your PCV system is still actively dumping oil vapor, moisture, and unburnt fuel directly back into your intake tract. Left unchecked, this microscopic blow-by pools in your plenum, coats your intake tracks, and—worst of all—mixes with your incoming air/fuel charge to instantly degrade your effective fuel octane rating. In a high-compression, high-performance engine like the Gen 4 Coyote, that oil mist forces your ECU to aggressively pull timing to prevent knock, stealing horsepower you paid for.
Dual injection fixes a cosmetic maintenance issue; it does not protect your combustion purity. Let's dive into the fluid dynamics of why a premium oil catch can is still absolute insurance for your engine's performance.
Here is the full breakdown.
The Anatomy of Premium Separation: Multi-Level Mesh & Zig-Zag Channels
Not all oil separation systems are created equal. Walk into any local car meet, and you will see engine bays dressed up with cheap, empty aluminum cylinders masquerading as functional PCV filtration. If a catch can is nothing more than a hollow canister with an inlet and an outlet, it is doing little more than acting as an expensive visual accessory.
At high RPM, crankcase vapors travel through the PCV system at incredibly high velocities. Without mechanical intervention, suspended oil mist behaves like a gas, entering the container and flowing straight out of the exit fitting before it ever has a chance to drop out of suspension. Real, effective fluid separation requires a deliberate disruption of fluid dynamics: specifically, velocity drops, radical direction changes, and dense condensing surface area.
[Incoming High-Velocity Vapor]
│
▼
┌────────────────────────────────────┐
│ Stage 1: Horizontal Zig-Zag Baffles │ <-- Knocks out heavy droplets
└──────────┬───────────────────────┘
│
▼
┌────────────────────────────────────┐
│ Stage 2: Four-Level Stainless Mesh │ <-- Coalesces fine, microscopic mist
└──────────┬───────────────────────┘
│
▼
[Clean, Dry Air Exits]
To permanently trap blow-by before it can degrade your effective fuel octane, a premium system splits the filtration process into distinct structural stages.
1. Horizontal Zig-Zag Routing Channels
The first line of defense relies on simple physics: momentum. Oil droplets are significantly heavier than the air and fuel vapors carrying them. By forcing the incoming PCV charge through a series of precision-machined, horizontal zig-zag channels, the velocity of the air remains constant while the heavy oil molecules cannot negotiate the tight, rapid turns.
As the air snakes through the baffled channels, centrifugal force slams the heavy oil droplets directly against the solid aluminum walls. This mechanical impact instantly strips the bulk of the heavy liquid from the airstream, causing it to pool along the channel tracks and drain safely downward into the bottom of the reservoir, isolated from the active airflow.
2. Four-Level Dense Mesh Media
While the zig-zag channels eliminate the heavy, dense oil droplets, the microscopic oil mist—the fine, highly suspended vapor that looks almost like smoke—requires a molecular approach. This is where a highly structured, four-level internal mesh media becomes critical.
As the remaining air charge passes through these four distinct layers of dense, stainless steel mesh material, it is subjected to a massive increase in cooling surface area. This process triggers coalescence—the microscopic oil particles are forced to collide with the thousands of intricate wire surfaces. As they stick to the mesh, they clump together, forming larger, heavier droplets. Once the droplets grow too heavy to remain suspended on the media, gravity takes over, pulling the oil down past the final baffle layer into the containment well.
By the time the PCV air reaches the exit port, it has been almost completely stripped of liquid contaminants. The result? Only clean, dry air is reintroduced into your intake plenum, keeping your combustion chambers pure, your engine timing advanced exactly where it belongs, and your engine bay performing at its absolute limit.
🛒 Ready to protect your combustion purity? Shop the CCV Overflow Retention Block