The Husky 564XP deserves more than just a replacement filter

MaxFlow has developed a complete high-capacity filtration and intake system for the Husqvarna 564XP. This is not simply a foam element fitted into the space left beneath the stock shroud.

The complete MaxFlow Architecture™ combines:

• The Final Cut™ shroud modification
• A high-volume MaxFlow cover
• A substantially larger, high-capacity MaxFlow filter
• An exclusive internal airflow-modifying intake structure
• A purpose-built filter cage and mounting system
• The filtration efficiency, serviceability, and sustained-performance advantages expected from MaxFlow

The result is a fully developed filtration and intake architecture designed specifically around the needs of the Husqvarna 564XP.

• A chainsaw is a complete cutting system. Bar length, sprocket size, chain selection, sharpening, dogs and operator technique all affect performance.
• A filter does not create horsepower. The engine determines how much air it can use.
• Filter capacity matters because filters get dirty. Excess clean-filter flow is reserve capacity that helps maintain the airflow the engine requires as contamination accumulates.
• Centrifugal pre-cleaning does not replace final filtration. Fine particles still reach the final filter and still require dirt-holding capacity.
• Modern intake systems are more complex. EFI pressure sensing passages mean the filtration system may also need to preserve specific pressure and airflow relationships.
• Modified saws still depend on airflow. A performance modification cannot use air the filtration system cannot supply.
• The Final Cut™ creates space, not horsepower. More space allows a larger filter, greater capacity and sustained airflow.
• MaxFlow® does not claim boost or magic horsepower. Our goal is to make sure clean-air capacity does not become the weak link.
• Want the Full Technical Explanation? https://maxflowfilters.com/chainsaw-power-explained
  

Instead of reducing the filter system to fit beneath the original shroud, MaxFlow takes a different approach. The Final Cut is the deliberate modification of the stock shroud that makes room for MaxFlow’s high-volume filter cover.

That additional enclosure volume allows the use of a substantially larger filter, greater dirt-holding capacity, and the complete internal intake architecture developed for the MF564XP system.

The cut is not the performance advantage by itself. It is what removes the stock enclosure limitation and allows the complete MaxFlow system to be installed.

The Final Cut creates the space.
The high-volume cover preserves that space.
The MaxFlow filter and intake system put it to work.

We do not compromise the filter to preserve the shroud. We modify the shroud to preserve the filter.

The MaxFlow 564XP filter is not simply a glued up strip of foam attached over an intake.

It uses a proprietary MaxFlow foam formulation selected to provide the airflow, filtration efficiency, dirt-holding capacity, and durability required in professional chainsaw use.

Just as important, the filter is manufactured in the USA as a single, continuous foam element. It requires specialized manufacturing control to maintain the correct shape, wall thickness, density, and fit throughout the entire filter. There are no glued seams and no joined edges within the filter body. This matters because in a two-stroke engine environment of fuel vapor, oil mist, heat, vibration, and constant flexing, glued seams fail. MaxFlow eliminates that failure point by forming the filter as one piece. MaxFlow is the only manufacturer in this market producing this no compromise, seamless, one-piece foam filter element.

The foam element is supported by a rigid, purpose-built cage that maintains its intended shape and prevents the filter from collapsing or distorting under operating conditions. Sealed endwalls define the working filtration area and prevent incoming air from bypassing the foam at the ends. This ensures that air entering the clean-side filter volume must first pass through the filter media without the need for o-rings, grease or bushings. These features, along with a high-volume cover and internal intake components were developed to function together as complete MaxFlow Architecture™.

The filter does not simply surround the intake, the complete filter assembly becomes part of the intake.

The Husqvarna 564XP system is being developed according to the same principles that have defined MaxFlow professional filtration systems for decades:

A larger filter provides more usable surface area and greater dirt-holding capacity before restriction begins to affect engine performance.

Airflow alone is not enough. A professional filter must provide the required airflow while continuing to protect the engine in real cutting conditions.  With 98.0% efficiency, MaxFlow provides this.

The important question is not simply how much air a clean filter can flow.

The important question is how long that airflow can be maintained as the filter is exposed to chips, dust and fines throughout the working day.

The MaxFlow cage, filter, mounting structure and internal airflow system are developed together rather than assembled from unrelated universal components.

The system is designed for working saws that must be inspected, cleaned and returned to service quickly.

 Most aftermarket filter discussions begin and end with the filter material.

MaxFlow begins with the entire airflow path and MaxFlow Architecture.

For the 564XP, that means evaluating:

• The available enclosure volume
• Filter surface area and media capacity
• Airflow entering the filter
• Flow through the filter media
• Air movement inside the clean-side filter volume
• The transition from the filter into the engine intake
• Ease of inspection, cleaning and maintenance

Each part affects the others. That is why the MaxFlow 564XP is being developed as a complete system rather than as a bolt-on filter element.

 “Air Injection™” is a marketing name. Technically, Husqvarna describes it as centrifugal air cleaning that removes larger dust and debris before those particles reach the final filter.

The word “Injection” naturally suggests that air is being injected, forced, or pressurized into the intake. That is not what is happening.The flywheel fan moves cooling air and centrifugally separates debris. The engine still has to create the pressure differential that draws combustion air through the filter. Husqvarna Air Injection separates particles from incoming air, but it does not pressurize the engine intake or force air through the filter. It is physically impossible for this open flywheel cooling system to supply meaningful positive pressure to the final filter.

It is not sealed to the intake, and there is no compressor stage capable of creating a pressurized intake charge. Combustion air moves through the filter only when the engine creates a lower-pressure condition during the intake event. Atmospheric pressure then moves air through the filter toward the engine.In other words, the flywheel helps determine how clean the air is before it reaches the intake entrance, while the engine determines when and how much air is actually drawn through the filter.

Air Injection is an excellent centrifugal precleaner. Its purpose is to remove much of the larger contamination before the engine draws air through the final filter. The contamination that remains is disproportionately fine material — precisely the material the final filter must be capable of stopping.

With the 564XP consuming roughly 1,500 cubic feet of air per operating hour, even a small residual concentration of dirt can represent a meaningful cumulative contamination load over many tanks of fuel.

At wide-open throttle, the 564XP requires on the order of 20 CFM of actual intake airflow.

That airflow must enter the engine during extremely short intake events. The engine creates the low-pressure condition, and atmospheric pressure moves air through the filter to satisfy that demand.

That relatively small amount of air must enter the engine during extremely short intake events.

The engine creates a low-pressure condition, and atmospheric pressure attempts to refill that volume. Every restriction between atmosphere and the engine reduces the pressure available to satisfy that demand. This is why filter restriction matters. 

Air moving around the outside of a filter is not the same as pressurized air available to the engine. A simple comparison is a chainsaw operating with its intake area pointed into the wind. The moving air may slightly change the local pressure around the saw, but unless that airflow is captured in a sealed intake system and converted into pressure, it does not meaningfully increase the air available to the engine. Our Taylor anemometer testing* shows that while the intake consumes about 20 CFM of airflow, the Air Injection system provides an additional 8 CFM of airflow in that area, but with only negligible positive pressure.

The flywheel cooling system is similar to adding a light airflow around the intake area. It moves a large volume of air through an open shroud for cooling and particle separation, but it does not create a pressurized intake charge. Combustion air still crosses the filter only when the engine creates a lower-pressure condition and atmospheric pressure moves air toward the intake. The Air Injection system can reduce the amount of debris reaching the filter, but it does not force air through the filter or eliminate the pressure loss caused by filtration media.

No air filter is completely unrestricted. The objective is therefore to provide enough efficient filtration capacity that the engine can obtain the airflow it requires with as little pressure loss as possible.

That is why excess filter capacity matters. An engine requiring approximately 20 CFM should not be paired with a filter that is itself operating near a 20 CFM maximum. A filter operating near its flow limit requires a much greater pressure differential to produce that airflow. A filter with substantially greater capacity can provide the same engine airflow with much less restriction.

MaxFlow SuperFlow SF-600 flowbench testing at approximately 5 inches H₂O produced:

Husqvarna 548615502 — 50-micron nylon mesh — 79 CFM
Husqvarna 548615501 — 27-micron nylon mesh — 74 CFM
Husqvarna 548615503 — flocked/felt filter — 57 CFM
MaxFlow MF564XP — .500" oiled foam, 98.0% filtration efficiency — 95 CFM

These results demonstrate an important filtration tradeoff. The physically small OEM filter can obtain relatively high initial clean-filter airflow by using very open media. Unfortunately, an undersized element can lose available airflow very quickly as it loads — in some conditions after only a tank or two — while unusually porous media can allow fine contamination to reach the clean side. MaxFlow approaches the problem differently. Instead of relying on coarse media to obtain adequate flow through a small element, the MF564XP creates substantially greater filtration capacity through a much larger foam filter element. This allows approximately 95 CFM of filtering capacity, even with full depth foam and 24 grams of oil to maintain 98.0% filtration efficiency! The engine will never consume 95 CFM simply because that capacity exists. The purpose of that excess capacity is to allow the approximately 20 CFM the engine actually requires to cross the filter with very little pressure loss.  

An online dyno comparison has been shown in which a chainsaw produced less power with the air filter completely removed than it did with the stock filtration system installed. That result is entirely possible, but it does not demonstrate that additional filtration capacity reduces power. An open throttle-body entrance is not the same as a properly designed intake system. Removing the filter and surrounding intake structure changes airflow direction, turbulence, pressure pulsations and the pressure environment surrounding the intake and EFI sensing system.

The 564XP adds another important requirement: the EFI system depends on accurate information about conditions in the intake. Poorly organized airflow can disturb those pressure signals even when physical restriction has been reduced.

The MaxFlow® MF564XP system therefore does more than substitute a larger filter. MaxFlow Architecture™ includes the filter, high-volume cover, cage, mounting system, clean-side volume and internal airflow-management components designed to function together with the 564XP intake and its pressure-reference system. For that reason, comparing the stock intake with no filter or intake structure at all is not a test of the MaxFlow® system. It is a comparison between an engineered intake and an unmanaged open intake.

Muffler modifications can improve exhaust flow and, under some conditions, increase peak dyno horsepower. But exhaust modifications cannot create the air required to produce torque, The air must enter the engine first. Cylinder filling determines how much oxygen is available for combustion. If intake restriction reduces cylinder filling, torque declines. Since horsepower is calculated from torque and RPM, horsepower declines with it. You cannot exhaust air that never entered the engine. A highly modified exhaust may improve one part of the engine's pumping system, but it cannot compensate for an intake system that cannot continue supplying the airflow necessary to produce torque. For this reason, MaxFlow considers intake airflow and filtration capacity foundational to sustained engine performance.

MaxFlow® does not claim that installing an air filter, by itself, creates horsepower. The engine determines how much air it can use. A clean-filter dyno comparison may show relatively small differences between properly functioning intake systems, and those differences can be difficult to establish reliably when engine temperature, EFI adaptation, atmospheric conditions, test procedure, instrumentation and normal run-to-run variation are not tightly controlled. More importantly, that is not where the primary MaxFlow® advantage occurs. The meaningful comparison begins after the filters get dirty. A brand-new OEM filter may provide adequate airflow for the first few tanks of fuel. As its limited filtration area loads with contamination, restriction increases. The saw can then spend many additional tanks operating with progressively reduced airflow and a reduced ability to maintain torque. MaxFlow was designed to delay that restriction dramatically.

That is what we are about.

Field testing of the MF564XP has now demonstrated this capacity under actual cutting conditions.

A test MaxFlow element was inspected after approximately 50 tanks of fuel. The outside of the foam was visibly loaded with contamination. The clean side remained essentially spotless.

By comparison, an OEM-style 564XP filter shown after only about a day of use already exhibited visible fine contamination on its clean side. This is why capacity is so important. A small filter can begin with acceptable airflow and still become restrictive very quickly because it has very little area available to store contamination. A larger MaxFlow element distributes that contamination over substantially more media area, so restriction increases much more slowly. The result is not simply greater clean-filter airflow. It is the ability to maintain clean, low-restriction airflow for dozens of tanks of fuel.

A clean-filter dyno pull measures what a saw can produce for a few seconds. A working chainsaw needs to produce power all day. The meaningful comparison is therefore not simply: New OEM filter vs. new MaxFlow filter. The more important question is: How long can each intake system continue supplying the airflow necessary to maintain torque? An OEM filter may provide good initial performance, followed by a relatively short period of accumulating contamination and then many tanks of increasing restriction. MaxFlow is designed to remain much closer to its clean-filter airflow for dramatically longer periods. That is the difference between peak airflow and sustained airflow. And sustained airflow is what matters in the field.

It is unlikely that the MF564XP will produce less power than a clean OEM filter when the EFI system is operating correctly. If the OEM filter is already providing all the airflow the engine requires, a clean-filter dyno may show little difference. The advantage of the MF564XP is that it provides substantially more filtration capacity and airflow reserve, so the filter is less likely to become the restriction as contamination accumulates. Small differences on a clean-filter dyno are not applicable to why this system was developed. The greater advantage is maintaining the airflow required to produce torque after the work begins and the filter starts collecting dirt.

Air Injection separates debris.
Filter capacity determines restriction.
MaxFlow Architecture manages the airflow.
Airflow supports torque.
Sustained airflow supports sustained power.

The Final Cut creates the space.
The larger filter provides the capacity.
MaxFlow Architecture manages the air.

*The Taylor anemometer is used in a high-vibration, pulsating chainsaw environment, so we treat it as a comparative instrument and applied an empirical correction rather than relying on the raw reading alone.

The MaxFlow 564XP system has moved beyond the basic concept and prototype stage. The design now requires production tooling so the filter cage, intake components and associated parts can be manufactured consistently and accurately.

Tooling and pre-production validation take time, but they are necessary to produce the system correctly. We will release the kit when the production components meet the standards established by the developed system—not simply when a part can be placed on the market.

No deposit is required. We will contact you when production availability and final kit details are confirmed.

Yes. The complete MaxFlow system uses The Final Cut™, a defined shroud modification that creates the space needed for the larger filter system.

The production kit will include clear trimming instructions and guidance.

Because the stock shroud determines the maximum size and capacity of any filter placed beneath it.

A smaller under-shroud filter may be easier to install, but it would sacrifice the capacity that makes the complete MaxFlow system worthwhile.

No. The kit combines high-capacity filtration with a purpose-built cage, mounting system and internal airflow-modifying intake structure.

Not at this time. Production tooling and validation are still underway.

Join the availability list and we will notify you when release information is confirmed.

Yes. The production kit will include instructions explaining the required shroud trim and complete installation procedure.
 

No. Despite the name “Air Injection™,” the system does not inject or pressurize combustion air. Husqvarna Air Injection is a centrifugal pre-cleaning system. No Husqvarna literature or web information even suggests this idea. The flywheel moves cooling air through the shroud and around a scroll that separates much of the larger dust and debris before it reaches the intake entrance.

Air moves through the final filter only when the engine creates a lower-pressure condition during the intake event. Atmospheric pressure then drives air through the filter toward the engine. The flywheel helps clean the air available to the intake; it does not force air through the filter.

Husqvarna’s 98% figure refers to dust separation by the centrifugal pre-cleaning system. It does not mean that 98% of the flywheel airflow bypasses the intake or that the remaining air is injected under pressure through the filter. The filter is still required to capture the fine contamination that remains after centrifugal separation, and the engine must still draw all combustion air through that filter using the pressure differential created during the intake event.

The stock shroud limits filter size.
Filter size limits capacity.
Capacity determines how long airflow can be maintained.

The Final Cut is the point where the original enclosure stops determining what the filtration system is allowed to become.

MaxFlow® — Full power from the first cut to The Final Cut™.

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