Q - What size filter element (pore size) should I use?

A - A properly designed port manifold fuel filtration system is comprised of staged filters.  A 100 micron filter element should be installed between the tank and the pump and a 10 micron filter element should be installed between the pump and the injectors.

Q - What size canister should I use?

A - The DW in-line filters are available in 3 canister sizes.  Larger canister sizes provide less flow restriction and increased service intervals.  Small canister sizes provide a more compact installation.  Flow restriction data is available on the product tech pages (insert hyperlink)

Q - Which pore size is best: 5-micron, 10 micron, 40-micron, or 100 micron?

A - One pore size is not better than the other.  Different micron ratings are required to protect different fuel components.  As a rule of thumb: 100-micron for fuel pumps, 40-micron for carburetors, 10-micron for manifold injectors, and 5 micron for direct injectors. 

Q - Do I need a pre-filter if I have an in-tank pump?

A – If the in-tank pump is fitted with an adequate pre-filter (filter sock), then a single 10-micron filter installed before the fuel injectors is all that is needed.

Q - Can I use a filter element that is smaller than 10-micron?

A - Bosch recommends a filter element with a mean pore size of 10-microns for port manifold injection.  Using a smaller mean pore size will introduce an unnecessary restriction in to the fuel delivery system. 

Q - Some other filter manufactures offer and recommend a 5-micron filter element.  Why doesn’t DW?  Which is better?

A - Per the Bosch Automotive Handbook (9th edition 2014)…  “The required filter fineness is dependent on the fuel-injection system.  For systems with manifold injection, the filter element has a mean pore size of approximately 10-microns.  Finer filtering is required for gasoline-direct injection. The mean pore width here is in the range of 5-microns”.  The vast majority of high performance fuel systems utilize manifold injection and therefore, a 10-micron filter element is appropriate.

Q - Are the DW in-line filters ethanol or E85 compatible?

A - Yes, all DW in-line filters feature stainless and anodized aluminum internals and are e85 compatible.

Q - Are the DW in-line filters adequate a diesel fuel systems?

A – Diesel fuel systems have different filtration requirements than gasoline fuel systems.  The DW in-line filters were designed specifically for gasoline fuel injection systems.

Q - What size ports are on the DW filter canisters?

A - The filter canisters have female –8AN ORB ports.  Larger, -10AN ORB endcaps are available upon request.

Q - Do the DW in-line filters come with fittings?

A - To minimize cost and maximize flexibility, fittings are sold separately.  DW offers fittings to adapt the filter port to a male 3/8 barb, male 5/16 barb, male -6AN, male -8AN, or male -10AN.

Q - Can I replace my OEM fuel filter with a DW in-line filter?

A - Yes, DW in-line filters are superior to typical OE fuel filters.  Upgrading to a DW filter will usually result in decreased fuel flow restriction, increased service-interval, and longer fuel system component life.

Q - What is the service interval?

A - The required service interval will depend on filter volume and fuel contamination.  We recommend a service interval of 12-months or 12,000 miles.

Q - How do I clean the filter element?

A - A basic service would include removing the filter element from the canister and back-flushing with solvent.  Advanced filter services may additionally include Ultrasonic cleaning and post cleaning flow testing.