Answering the search intent for OEM and performance-minded builders: a crankcase evacuation system with mufflers reduces crankcase pressure, lowers intake contamination, and can improve seal and combustion efficiency. These picks are suited for users seeking street reliability, track endurance, or street/strip setups. The top five products below were chosen for compatibility, parts availability, and practicality across common engines.
| Product | Brand | Key Benefit | Hose Size/Notes |
|---|---|---|---|
| Moroso 25901 Crankcase Evacuation System | Moroso | Reduces crankcase pressure across RPMs; track/dyno proven | 5/8″ hose; includes separators, caps, valve, weld-in nipple |
| Moroso 25900 Crankcase Evacuation System | Moroso | Vehicle-specific fit; comprehensive assembly | 5/8″ hose; includes separators, caps, valve, weld-in nipple |
| Moroso 68866 Crankcase Evacuation System | Moroso | Billet breathers; broad compatibility | 5/8″ hose; includes multiple grommets and check valve |
| Allstar Performance ALL34145 Evacuation System | Allstar Performance | Complete kit with breathers, valves, adapters | Includes hoses not included |
| Speedmaster PCE293.1001 Universal Evac System | Speedmaster | Universal design; track-proven concept | Images show components; fit varies by setup |
Note: For each option, verify hose diameter compatibility (commonly 5/8 inch) and fitment with your valve covers and headers. Some kits specify limitations or require additional hoses or adapters not included in the base package.
Moroso 25901 Crankcase Evacuation System
Best for: Performance-focused builds seeking strong seal across RPMs. Why selected: Includes two oil separators/breathers, a one-way valve, and a weld-in nipple; designed to reduce crankcase pressure and intake contamination. Suitable for engines using 5/8″ hose. Caution: Not all muffler configurations are compatible with all headers, and fitment may vary by engine bay.
Allstar Performance ALL34145 Crankcase Evacuation System
Best for: Builders wanting a complete, install-ready kit. Why selected: Includes two chrome breathers, check valves, weld-in adapters, grommets, and four hose clamps. Evacuation hoses are not included, so plan for compatible hose pairing. Choose this if you prefer a modular, widely available kit that can be customized.
Hot Rod Chrome Crankcase Evacuation Kit
Best for: Classic-looking, chrome-breather setups on universal bases. Why selected: Universal kit that installs in 1.25″ diameter holes. Limitations: May require additional piping or seals for specific valve covers or engines; verify compatibility with existing muffler systems.
Moroso 25900 Crankcase Evacuation System
Best for: Vehicle-specific installations that require a proven Moroso system. Why selected: Reduces crankcase pressure and has track/dyno-tested performance gains; includes separators, caps, and a weld-in nipple. Note: Use with 5/8″ hose; verify fitment for your header collection and valve covers.
Allstar Check Valve For Evacuation System
Best for: Systems needing reliable check valve components. Why selected: Sold in pairs and designed for 1.25″ valve cover holes; zinc finish provides durable corrosion resistance. Caution: Must be used with compatible 1.25″ breathers and hoses for proper sealing.
Moroso 68866 Crankcase Evacuation System
Best for: Systems requiring billet breathers and enhanced compatibility. Why selected: Includes two of each breather, billet adapter, grommets for different valve covers, and a check valve; designed for 5/8″ hoses. Limitation: Not recommended for vehicles with mufflers or downstream wide-band sensors.
Speedmaster Universal Evacuation System
Best for: Universal compatibility with track-ready performance. Why selected: Track-proven concept; components shown in product images; designed to align with Speedmaster’s DNA of blending classic and modern. Caution: Specific hose sizes and adapters may be required depending on your engine layout.
Buying Guide
What to consider when choosing a crankcase evacuation system with mufflers:
- Engine fit and valve cover compatibility: Some kits specify 1.25″ or 1.25″ dia holes, others use 5/8″ hose connections. Ensure the system matches your engine bay and valve covers.
- Hose diameter and length: Most kits use 5/8″ hose; verify that you have appropriate hose segments and clamps for a secure seal without restricting crankcase flow.
- Inclusion of components: Some kits include breathers, check valves, and weld-in nipples; others require additional adapters or hoses. Decide what you need to complete your setup.
- Header and muffler interaction: Some Moroso kits are not recommended with certain muffler configurations or downstream sensors. Check fitment with your exhaust and emissions sensors.
- Application type: Street, strip, or track-use may influence which kit provides the most reliable seal and minimal oil migration into the intake.
Frequently Asked Questions
- What is the main purpose of a crankcase evacuation system? It reduces crankcase pressure, improves piston ring seal, and minimizes intake charge contamination.
- Do these systems require mufflers? Some kits are designed to work with muffled exhaust setups, while others may have compatibility notes against certain muffler or sensor placements.
- Will I need additional hoses? Many kits include core components but may require extra hoses or clamps not included in the base package.
- Can I install these myself? Yes, installation is typically straightforward for those with basic mechanical skills, though some models require welding or precise fitment at the valve covers.
- Is a 5/8″ hose standard for these systems? Commonly yes, but always verify the specific kit’s hose size and compatible fittings.
- Are there performance gains to expect? Track and dyno testing often show improved seal and reduced oil intake, though gains vary by engine and setup.