Oil Filters Revealed

HP1 Performance Filters

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This is a quick look at a few HP1 racing filters.  This filter is used in many racing applications where a filter compatible to the Chrysler/Ford reference would be used.  The mounting configuration is the same, but the main differences are: higher burst pressure (300-500psi), higher bypass pressure (20psi instead of 8psi), and a longer case and cartridge (hopefully).  The additional case length varies slightly, but only amounts to between 1/8"-1/4".  The higher bypass pressure is meant to prevent the filter from going into bypass as much during high RPM use.  The assumption is that a racing engine will use a high pressure oil pump, so the 20psi drop across the filter is less of a problem.

The other parts of this project:


The analysis is sorted by brand name in alphabetical order.  Only some brands and manufacturers actually sell a true HP1 filter.  Often it cross-references to it's more common Chrysler/Ford sibling filter (the reference filter), but they are not the same filter.  Detailed sections of some of the models follow.  Filters tested only in 1999 have the vintage specified as such.  If they have been verified as unchanged since then, they are labeled 1999-2008.  If this filter has never been acquired, the vintage is marked as N/A.  Note that even though the surface area is listed for comparison, the values don't correspond exactly to the filters' holding capacity.  This is a function of the media's composition as well as the surface area, which is not something I am equipped to compare.

Brand Model P/N Vintage Manufacturer Cost Element Surface Area
Baldwin Baldwin B253 N/A Baldwin/Hastings $12 ?
Champ Champ HP1 N/A Champion Labs ? ?
Fram Extra Guard HP1 1999 Honeywell (was Allied-Signal) $12 ?
Hastings Premium LF140 N/A Baldwin/Hastings $12 ?
Motorcraft Long Lasting FL-1HP N/A ? ? ?
Purolator Premium Plus HP1/39001 1999 Purolator $8 ?
WIX WIX 51515R N/A Dana/WIX $12 ?


These filters are manufactured by Honeywell (formerly Allied Signal).  See this 1999 email from an Allied Signal production engineer.  Also see episode 41 of the TV show "How It's Made" for a look at the production line for these filters.

Fram Extra Guard HP1

This filter cartridge has a small outside diameter with a rather low filter element surface area (193 sqin), and features cardboard end caps that are bonded in place using a thermal adhesive.  The rubber anti-drainback valve seals the rough metal backplate to the cardboard end cap and easily leaks, causing dirty oil to drain back into the pan.  If you have a noisy valve train at startup, this filter is likely the cause.  The bypass valves are plastic and are sometimes not molded correctly, which allows them to leak.  The backplate has smaller and fewer oil inlet holes, which may restrict flow.

The telltale signs for a Fram Extra Guard are:  It has 8 small holes for the oil inlet and a thin, cheap looking backplate, and is currently stamped with a "2Y".  There are 5 very small crimps holding the gasket in place.  If you look into the center hole all the way to the top of the filter, you will see a kind of "button" in the end cap of the cartridge (which looks like it's made of metal from there).  This is the plastic bypass valve.

Exploded view and backplate:

Average Retail Price $12
Cartridge Length 4.13 inches
Cartridge Outside Diameter 3.00 inches
Cartridge Inside Diameter 1.38 inches
Cartridge Pleats 34
Cartridge End Cap Type Cardboard
Anti-Drainback Valve Type Nitrile rubber diaphragm
Bypass Valve Type Spring-loaded plastic
Element Type Paper media, stamped metal seam
Element Length 47.5 inches
Element Width 4.06 inches
Element Surface Area 193 square inches
Shell Thickness 0.015 inches
Backplate Thickness 0.089 inches
Gasket Type Nitrile rubber


Premium Plus HP1/L30001

Exploded view and backplate:

Average Retail Price $3
Cartridge Length 4.13 inches
Cartridge Outside Diameter 3.25 inches
Cartridge Inside Diameter 1.63 inches
Cartridge Pleats 51
Cartridge End Cap Type Stamped-steel
Anti-Drainback Valve Type Nitrile rubber diaphragm
Bypass Valve Type Spring-loaded steel
Element Type Paper media, stamped metal seam
Element Length 79.0 inches
Element Width 4.00 inches
Element Surface Area 316 square inches
Shell Thickness 0.011 inches
Backplate Thickness 0.115 inches
Gasket Type Nitrile rubber


For modified engines running high oil pressures in race-only applications, the HP1 filter is worth considering.  It does provide some additional surface area relative to filters from the same manufacturer, but not any more than a few other alternative reference filters.  The additional bypass pressure may add some extra protection, but at the expense of some oil pressure when the filter element cannot flow all of the oil (high RPM, low temperature).  On the other hand, the 20psi drop could be used as an indication that the filter has become plugged and that the engine may be on the verge of failure due to a wear item.

If you want to hear my opinion take a look at the Oil Filters Revealed: Opinions and Recommendations page.  Which filter is the best?  There is no easy answer to that one.  It depends on what kind of oil you use and how much you are willing to spend.

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Updated 02/19/2008.

Copyright © 1996-2008 Russ W. Knize.