NTPOG Oil Filter Review

Author: Todd Marcucci
 


Background
The purpose of this review is to examine the different filters available for Hondas today, including Honda filters themselves. Most people probably don't realize it, but there are 3 different Honda filters (with different part numbers, made in 3 different countries! All happen to be very different, as well.

This "review" is intended to be as objective as possible. My opinions stated in the Comments of each filter summary and the Conclusions section are just that, opinions. You will need to review the data presented on each filter and draw your own conclusions as to what's right for you. NTPOG makes no claim as to the reliability or performance of any filter presented here, nor does NTPOG accept any responsibility for any damage caused by any filter. Please read the Conclusions below for more information as to what works, what doesn't, and what we recommend in terms of filters.

In response to several emails I have recieved: this is not a scientific test. I am not a Petroleum, Chemical, or Mechanical engineer (though I am Electrical with quite a mechanical background). I make no claims as to any filter material shown here with respect to flow or filtration. As you will see, though, it does not take a rocket scientist to understand that a filter with 200 square inches of material will flow better than one with 100 square inches, or that a filter made of cardboard will hold up to less pressure than one made of steel. This review is not intended to find the "best" filter, but rather, inform the "curious" or technical buyer as to what they are getting for their money. Why pay more for one brand of filter identical to another when one is half the price?

I would like to thank Russell Knize for his Mini-Mopar site and his Oil Filter Study page for "Mini Mopars." It was the motivation and source of methodology for my own interest in Honda filters.

Choices
There are a lot of filters out there, varying in price, marketing, and availability. You might not be surprised to find that several filters may share design, materials, and construction while wildly varying in price.

Here are the ones we've tested in no particular order:

Filter Mfr. Part Number MSRP Retail
Bosch Premium 3312 N/A $4.99
Fram Extra Guard PH3593A $5.07 $2.99
Fram Tough Guard TG3593A $10.15 $5.99
Honda (Canada) 15400-PT7-005 $5.99 $4.40
Honda (Japan) 15400-PR3-014 N/A $6.15
Honda (USA) 15400-P0H-305 $5.99 $4.40
Mobil 1 M1-104 N/A $9.99
STP 2808 N/A $2.86
HAMP (Japan) H1540-PR3-408 N/A $13.00
Vic (Japan) C-805 N/A $6.00
Amsoil Super Duty SDF20 $11.40 $7.50
Napa Silver 21334 $4.29 $3.39
Napa Gold 1334 $10.24 $6.99
Mobil 1 M1-105 N/A $9.99

Oversized Filters
One of the things people are interested in is going to a larger filter. Why? With a larger filter you can increase your oil capacity (volume) as well as the surface area and cooling of the filter. Both will help your engine's lubrication system to run a little more efficiently. When it comes to racing, this is important, every little last bit helps. "Why would [insert manufacturer name here] *not* use a larger filter if it needed it?" There are many reasons for a manufacturer to pick a supplier or design- application, cost, availability, trade restrictions, and so on. Most manufacturers pick a filter design and stick with it as long as they can and across as many models as they can.

The last two filters listed, the Mobil 1 M1-105 and M1-208 are both "oversized" filters. These filters are from different applications but will work on Hondas as they share the same outlet thread (20mm x 1.5) as well as the gasket diameter and inlet shapes (though inlet area does vary). Please read the reviews as area may be a limiting factor on your model- these filters do require more room!

Explanation of Analysis
The procedure followed for each filter in this analysis is as follows:
- Photo and record purchase data for each filter
- Note outside appearance
- Measure and note inlet hole size(s)
- Cut filter casing around circumference of filter, just behind mounting plate
- Photo and catalog filter components
- Note component construction such as bypass valve and cartridge end caps
- Measure and note cartridge-to-cap and cartridge-to-can distances
- Record filter cartridge size and number of pleats
- Note and photo filter media and oustanding features
- Dissasemble, measure, and record filter media size
- Measure and note can (casing) wall thickness

This analysis is not the most technical, no flow data has been taken, but should be representative of quality of construction and capacity. Filters with a small amount of media will likely have poor flow and filtering capacity, while a filter with a large media will likely flow better and filter better. This can be mitigated by small inlet holes or poor clearance between the cartridge and the casing of the filter. Inlet area is given by the sum of the areas of the inlet "ports" or holes, and the outlet area given by the 20mm hole in the center that is the fitting the filter screws on to. I have not measured this but would expect it to in actuality be around 10-15mm to account for wall thickness.

Finally, in the following analysis the following items were all in common:
- Stamped steel backing plate (cap) with nitrile rubber gasket
- All filters have anti-drainback "diaphragm" valve
- Approx. .032" thick casing (can)
- Glued filter media/end cap construction


Individual Filter Analyses

Bosch Premium

Retail Price $4.99
Physical Appearance Same as Mobil 1 and STP, different labeling
Inlet Hole Pattern 4 x .250" + 1 x .313"
Inlet Area .273"
Filter Cartridge Length 1.875"
Filter Cartridge Outside Diameter 2.875"
Filter Cartridge Inside Diameter 1.125"
Number of Pleats 44
Filter Element Length 57.50"
Filter Element Width 1.875"
Filter Element Surface Area 107.8"
Filter Element Thickness .032"
Cartridge-to-Can Distance .250"
Cartridge-to-Cap Distance .375"
Bypass Valve Type Stamped steel with neoprene gasket/seal


Comments:
The Bosch appears to be of excellent quality. The Bosch, Mobil 1, and STP appear to all use identical materials and construction, with only the Mobil 1 having a different filter media (appears to be coated). The pleat seperation/uniformity does not appear as good as the Mobil 1 or STP filters, though this may be a manufacturing issue (I may have gotten an odd one). The Bosch, Mobil 1, and STP bypass valve utilizes a stiffer spring than any of the others and a rubber seat/seal which should help prevent leakage. This filter is well made and looks to be an identical (though more expensive) alternative to the STP.



Fram Extra Guard

Retail Price $2.99
Physical Appearance Same as Fram Tough Guard, different labeling
Inlet Hole Pattern 12 x .125"
Inlet Area .147"
Filter Cartridge Length 2.250"
Filter Cartridge Outside Diameter 2.875"
Filter Cartridge Inside Diameter 1.375"
Number of Pleats 40
Filter Element Length 45.00"
Filter Element Width 2.250"
Filter Element Surface Area 101.3"
Filter Element Thickness .032"
Cartridge-to-Can Distance .375"
Cartridge-to-Cap Distance .188"
Bypass Valve Type Molded plastic, no seal


Comments:
The Fram filter appears well-made in terms of actual build quality (uniform pleat seperation, consistent glue, etc.). Contrary to The Mini-Mopar site evaluation, neither of the two Fram filters tested here had the "assembly" strings around the filter element, possibly a recent improvement made by Fram. There is a clear indentation where this string was (I presume it was removed prior to final assembly). The filter element is somewhat "fuzzier" than any of the Bosch, STP, or M1 units, though not as much as the Honda (US-made) media. I'm not sure how much this might deteriorate over time. The poor sealing of the plastic bypass would likely result in some continual bypass, and after only a few minutes of playing with the valve I was able to get it to stick open. This bypass design would appear to be very poor. My primary concern with this filter are the cardboard end caps- I would be suspicious that the cardboard would deteriorate over time and may come loose, especially considering that the cardboard is in the way (partially) of the oil flow. I would be particularly concerned about this in a racing environment where higher pressures are common.



Fram Tough Guard

Retail Price $5.99
Physical Appearance Same as Fram Extra Guard, different labeling
Inlet Hole Pattern 12 x .125"
Inlet Area .147"
Filter Cartridge Length 2.250"
Filter Cartridge Outside Diameter 2.750"
Filter Cartridge Inside Diameter 1.375"
Number of Pleats 46
Filter Element Length 52.00"
Filter Element Width 2.250"
Filter Element Surface Area 117.0"
Filter Element Thickness .064"
Cartridge-to-Can Distance .375"
Cartridge-to-Cap Distance .188"
Bypass Valve Type Molded plastic w/screen, no seal


Comments:
This filter looks identical in construction to it's cheaper brother. The only apparent differences are the filter media (different color, twice as thick, and more densely packeed) and a "screen" over the bypass valve. The intention (according to Fram) of the screen is that if the filter becomes clogged the screen will help keep out debris. My only comments on this are 1) if you have debris big enough for the screen to catch, it's probably pieces of the filter coming apart or you have much bigger problems(!), and 2) if the screen becomes clogged (see #1) then you're going to lose flow and probably damage the engine *because* of the filter. Also, this valve is of the same design as the "Extra Gaurd" above, with the same flaws. This filter would logically provide better filtering due to increased thickness and surface area, though the thicker material may only result in more leakage through the poor sealing of the bypass valve.



Honda (Made in Canada)

Retail Price $4.40
Physical Appearance Same case as other Hondas, unique plate
Inlet Hole Pattern 8 x .250"
Inlet Area .393"
Filter Cartridge Length 2.125"
Filter Cartridge Outside Diameter 2.875"
Filter Cartridge Inside Diameter 1.125"
Number of Pleats 47
Filter Element Length 71.00"
Filter Element Width 2.125"
Filter Element Surface Area 150.9"
Filter Element Thickness .032"
Cartridge-to-Can Distance .375"
Cartridge-to-Cap Distance .250"
Bypass Valve Type Molded plastic, no seal


Comments:
Externally, this filter looks like the other 2 Honda filters (except for the "Made in Canada" stamped on the end). All 3 Honda filters have unique part numbers (see the summary tables). This filter, though, when opened, is identical in construction to a Fram. Same "fuzzy" media, dent from string in media, glued cardboard end caps, bypass valve... the build quality looks fine but again, those cardboard pieces don't leave me with a very warm feeling. With increased surface area and increased inlet area, though, this filter should flow more than either of the FRAM units.

Dissasembly of a used filter shows that some of the fibers do part from the filter. While the detail can't be seen in the photo above, there were fibers that were "hung up" in the perforated center portion. The material did not look quite as "fuzzy" as it did new, which I presume is from some fibers having left the filter. This filter had 1000 hard miles over the course of one month on it. The cardboard was perfectly intact, though I suspect this would deteriorate over time.



Honda (Made in Japan)

Retail Price $6.15
Physical Appearance Same case as other Hondas, unique plate
Inlet Hole Pattern 8 x .250"
Inlet Area .393"
Filter Cartridge Length 2.375"
Filter Cartridge Outside Diameter 2.875"
Filter Cartridge Inside Diameter 1.125"
Number of Pleats 54
Filter Element Length 71.00"
Filter Element Width 2.375"
Filter Element Surface Area 168.6"
Filter Element Thickness .032"
Cartridge-to-Can Distance .188"
Cartridge-to-Cap Distance .125"
Bypass Valve Type Stamped steel, no seal


Comments:
As is the case with Hondas in North America, Japan has at least two suppliers of filters: Toyo Roki and Tennex. The Toyo Roki filter is the new filter shown above (and described below). This filter was obtained as a "replacement" part. The used filter that is shown dissasembled (over the oil pan) is made by Tennex. This filter is what came on my new S2000; I would assume that it is the filter used on new Hondas made in Japan. This filter is almost identical to the Vic filter tested below, except for the smaller size and 51 pleats (instead of 54). Though I have not dissasembled the Tennex JDM filter and measured it, I would expect to see only slightly less surface area due to the smaller size of the Toyo Roki (see below).

Anyone familiar with Hondas knows that the Japanese keep the best for themselves. This aparently applies to oil filters as well. The Toyo Roki uses steel end caps, a steel bypass valve (with very stiff spring), and a media that looks similar in thickness and quality to the STP and Bosch filters. This unit uses the same end caps and bypass valve that the US-made Honda filter uses. Something interesting, though, that's unique to the Toyo Roki filter is the unequal-length pleats (see above). I'm not sure why they are like this, but none of the other filters (including the JDM Tennex, Vic, and HAMP) that were tested had this.

It should be noted that these filters are NOT available in the North America at all- they are only available in Japan, the orient, and more than likely the UK and Australia. The only way to get one from Honda in the US is to purchase a new Honda made in Japan- this is the filter that they put on the car in their factories (the Tennex). Here, you will likely get either the US-made or Canadian made filters. In the US, if you order the JDM part number, you will be subbed a US or Canadian filter instead. So far there is no one known to be importing these filters, you will have to find one and have it shipped yourself. The filter tested here was purchased over-the-counter in Hong Kong (the price listed has been converted from HK$).



Honda (Made in USA)

Retail Price $4.40
Physical Appearance Same case as other Hondas, unique plate
Inlet Hole Pattern 6 x .250"
Inlet Area .295"
Filter Cartridge Length 2.250"
Filter Cartridge Outside Diameter 2.875"
Filter Cartridge Inside Diameter 1.125"
Number of Pleats 47
Filter Element Length 66.00"
Filter Element Width 2.250"
Filter Element Surface Area 148.5"
Filter Element Thickness .032"
Cartridge-to-Can Distance .188"
Cartridge-to-Cap Distance .188"
Bypass Valve Type Stamped steel, no seal



Comments:
This filter looks identical to the Toyo Roki-made JDM filter at first glance- externally the same construction, the only indicator is the "FILTECH" stamped on the outside (a large US manufacturer of filters under various brand names). Internally it's *almost* identical to the JDM filter- steel end caps, steel bypass valve. What makes it stand out as different is the radically different filter media. The material on the Japanese filter looked like the STP or Bosch units. The US media looks much, much worse than the Fram. The media is noticeably "fuzzy" with small fibers protruding out from every angle. While the filter itself is constructed very well (like the Japanese one), the furry nature of the media makes me question how long it lasts and what it will release into the oil system. It also has the least surface area of all the Honda filters (though only a few inches less than the Canadian one).


Mobil 1

Retail Price $9.99
Physical Appearance Same as Bosch and STP, different labeling
Inlet Hole Pattern 4 x .250" + 1 x .313"
Inlet Area .273"
Filter Cartridge Length 1.875"
Filter Cartridge Outside Diameter 2.875"
Filter Cartridge Inside Diameter 1.125"
Number of Pleats 40
Filter Element Length 57.50"
Filter Element Width 1.875"
Filter Element Surface Area 107.8"
Filter Element Thickness .032"
Cartridge-to-Can Distance .250"
Cartridge-to-Cap Distance .375"
Bypass Valve Type Stamped steel with neoprene gasket/seal


Comments:
The Mobil 1 appears to be of excellent quality. The Bosch, Mobil 1, and STP appear to all use identical materials and construction, with only the Mobil 1 having a different filter media (appears to be coated- darker color). I can't comment on the effectiveness or any additional filtering or benefit to the Mobil 1 filter, though Mobil 1 claims it's more effective. The pleat seperation/uniformity appears better than the or Bosch filter. The Bosch, Mobil 1, and STP bypass valve utilizes a stiffer spring than any of the others and a rubber seat/seal which should help prevent leakage. Check out the last pic for a shot of a used Mobil 1- this is a 1 month old filter with 1000 hard miles and conventional (non synthetic) oil. Let this be a reminder to you to change your filter regularly!



STP

Retail Price $2.86
Physical Appearance Same as Bosch and Mobil 1, different labeling
Inlet Hole Pattern 4 x .250" + 1 x .313"
Inlet Area .273"
Filter Cartridge Length 1.875"
Filter Cartridge Outside Diameter 2.875"
Filter Cartridge Inside Diameter 1.125"
Number of Pleats 46
Filter Element Length 57.50"
Filter Element Width 1.875"
Filter Element Surface Area 107.8"
Filter Element Thickness .032"
Cartridge-to-Can Distance .250"
Cartridge-to-Cap Distance .375"
Bypass Valve Type Stamped steel with neoprene gasket/seal


Comments:
The STP appears to be of excellent quality. The Bosch, Mobil 1, and STP appear to all use identical materials and construction, with only the Mobil 1 having a different filter media (appears to be coated). The pleat seperation/uniformity appears better than the Bosch filter. The Bosch, Mobil 1, and STP bypass valve utilizes a stiffer spring than any of the others and a rubber seat/seal which should help prevent leakage.



HAMP

Retail Price $13.00
Physical Appearance Looks identical to JDM Honda filter in construction, materials
Inlet Hole Pattern 8 x .250"
Inlet Area .393"
Filter Cartridge Length 2.375"
Filter Cartridge Outside Diameter 2.875"
Filter Cartridge Inside Diameter 1.125"
Number of Pleats 40
Filter Element Length 62.50"
Filter Element Width 2.375"
Filter Element Surface Area 148.4"
Filter Element Thickness .032"
Cartridge-to-Can Distance .188"
Cartridge-to-Cap Distance .125"
Bypass Valve Type Stamped steel, no seal


Comments:
This filter is nearly identical to the JDM filter. The only apparent difference is less filter material- about 12%. The inlet hole pattern, case, filter cartridge, bypass, and drainback valves are all identical. This would be an excellent alternative to the JDM filter as it's more available in the states.



Vic (Japanese)

Retail Price $6.00
Physical Appearance MUCH bigger than any other tested
Inlet Hole Pattern 5 x .25"
Inlet Area .245"
Filter Cartridge Length 2.875"
Filter Cartridge Outside Diameter 2.875"
Filter Cartridge Inside Diameter 1.500"
Number of Pleats 54
Filter Element Length 62.50"
Filter Element Width 2.75"
Filter Element Surface Area 171.9"
Filter Element Thickness .032"
Cartridge-to-Can Distance .250"
Cartridge-to-Cap Distance .250"
Bypass Valve Type 5/16" stamped steel, no seal


Comments:
First impression is size- it's substantially bigger than the stock Honda units. Note in the picture above that the Vic is about an inch taller than the Honda. From the inside, though, the filter shows only slightly more (less than 2%) filter material. The bypass valve is troubling (see above). It is held in place with two rivets which would be under stress (the same stress as the spring). While I do not think it is likely, a poorly installed or weakened rivet could easily cause the bypass valve assembly to come loose and cause serious damage. Fortunate for the rivets (but not for you), the spring is much easier to compress than on the other units I opened. I do not have a tension gauge or any method to quantify this, but I would suspect this valve to bypass under high pressure (say, high RPMs). The hole is quite small, too, less than half the size of the other filters. In the event you really did need it to bypass, I'm not sure you would get proper flow through the valve. Overall, build quality is excellent and the filter material is very uniform (as in the Toyo Roki JDM Honda filter).



Amsoil Super Duty

Retail Price $11.40
Physical Appearance Unique design, cartridge similar to Bosch/STP
Inlet Hole Pattern 7 x .219"
Inlet Area .263"
Filter Cartridge Length 2.250"
Filter Cartridge Outside Diameter 2.625"
Filter Cartridge Inside Diameter 1.500"
Number of Pleats 44
Filter Element Length 52.50"
Filter Element Width 2.25"
Filter Element Surface Area 118.1"
Filter Element Thickness .032"
Cartridge-to-Can Distance .500"
Cartridge-to-Cap Distance .375"
Bypass Valve Type Stamped steel, no seal (similar to JDM Honda)


Comments:
This filter is well constructed and has a little more surface are than the Mobil 1 unit. Cost reflects it, though, based on the suggested price (on their web site). Being or purchasing through a distributor will get you the retail price shown here. There was nothing in this filter that stood out as a possible quality or filtration issue. If you are looking for maximum filtration/flow and quality in the stock size, this is probably your best choice (for oversized, see below).



Napa Silver (Made in the UK)

Retail Price $3.39
Physical Appearance Unique design, small hole pattern
Inlet Hole Pattern 6 x .250"
Inlet Area .295"
Filter Cartridge Length 2.625"
Filter Cartridge Outside Diameter 2.750"
Filter Cartridge Inside Diameter 1.375"
Number of Pleats 54
Filter Element Length 76.00"
Filter Element Width 2.50"
Filter Element Surface Area 190.0"
Filter Element Thickness .016"
Cartridge-to-Can Distance N/A
Cartridge-to-Cap Distance N/A
Bypass Valve Type One piece stamped steel (see below)


Comments:
This filter's only claim to fame lies in it's surface area- 190 square inches. Other than that, it's by far the most poorly designed and constructed. The large surface area comes in part from the fact that there is no filter "cartridge," the casing of the filter itself is used as a cartridge. It is also due to the fact that the filter material was half the thickness of the others tested- only .016" thick! While this design saves money, the lack of a proper cartridge and small end plate holes look like it would seriously impede flow. The stamped-steel spring bypass valve looks like it would not only seal poorly, but also flow poorly when open, and be likely to stick open if it ever did. In all, the design of this filter is so questionable that I would recommend against it's use, certainly in racing.



Napa Gold (Made in US by Wix)

Retail Price $6.99
Physical Appearance Much larger than others
Inlet Hole Pattern 8 x .250"
Inlet Area .393"
Filter Cartridge Length 1.750"
Filter Cartridge Outside Diameter 2.750"
Filter Cartridge Inside Diameter 1.250"
Number of Pleats 51
Filter Element Length 72.00"
Filter Element Width 1.75"
Filter Element Surface Area 126.0"
Filter Element Thickness .032"
Cartridge-to-Can Distance .750"
Cartridge-to-Cap Distance .625"
Bypass Valve Type Unique cartridge-type (see below)


Comments:
This filter is greatly improved over the Napa silver. While the can is one of the largest tested, the filter cartridge is deceptively small. This still results in additional oil capacity and cooling, though would not improve flow. The filter area is still respectable, though (more than the Mobil 1), as well as overall build quality. The bypass valve is very unique, integrated into a "cartridge" that installs on the outlet. While it would require less distance for the oil to travel should the valve open, it does not appear that it would flow very well in reverse. Based on construction and placement, though it would appear unlikley for it to leak, however. All things considered, for the price this is a good filter.



Oversized Filters
I had found these oversized filters while searching for compatible outlet thread sizes on different manufacturers' web sites. I turned this one up after finding that the 1988 4WD Mitsubishi Montero used the same size thread as Honda filters. While we have only tested the M1-105 here, the STP 3950 shares a similar construction and size (and also fits). Coming soon, we will open and measure the STP and Bosch versions of this oversized filter, as well as others.

Mobil 1 M1-105

Retail Price $9.99
Physical Appearance Noticeably larger, about 30% externally
Inlet Hole Pattern 5 x .250" + .313"
Inlet Area .322"
Filter Cartridge Length 1.813"
Filter Cartridge Outside Diameter 3.250"
Filter Cartridge Inside Diameter 1.000" opening, 1.750" internally
Number of Pleats 60
Filter Element Length 90.00"
Filter Element Width 1.50"
Filter Element Surface Area 135.0"
Filter Element Thickness .032"
Cartridge-to-Can Distance .000" (not needed, front bypass)
Cartridge-to-Cap Distance .313"
Bypass Valve Type Integrated into outlet (see below)


Comments:
This filter shares the same quality of construction of the other Mobil 1, Bosch, and STP units. This one, however, has a unique bypass valve integrated into the outlet. When pressure is high enough, the oil forces the valve open and should travel right from the inlet, through the valve, and out the outlet (very short path). As for size, this filter is about 30% larger than the M1-104 overall. The filter has about 30% more filter material as well, so should flow better. Externally it measures 3.75" in diameter and 3.00" long- be sure to check for fit before you try one! I can verify that it works fine on the base 5th gen Prelude (not sure about the SH), the S2000, and 4 cylinder Isuzu Troopers. This filter does share the same gasket diameter and inlet shape (though it has more holes and subsequently more area) as the M1-104 and should work fine on M1-104 applications (assuming you have the clearance for the larger case).

Conclusions
Essentially you will have to decide for yourself. How often do you change filters? If you answer is 3k miles or less, some of the cheaper filters are likely more cost effective and probably safe to use (like the Fram or domestic Honda). If the answer is 5k miles or more (say you use synthetic oil), I'd suggest a high-quality filter that should last longer like the Mobil 1, STP/Bosch, or Japanese Honda filter.

If you race, flow is as important (if not more) than filtering. The filters shown here with higher total inlet areas, largest cartridge clearances and largest surface area are probably better bets. I would still recommend staying away from filters that use cardboard, simply from the consistently higher pressures in racing. I'd be concerned about the longetivity of the filter (cardboard) under those conditions. Then again, if you race, a higher capacity replaceable-media filter might be a better bet altogether!

A serious word of caution to experimenters: if you are thinking of trying out different filters, or ones we haven't listed here, be careful! In the course of testing, I tried a Purolator PureOne oversized filter (PL10193); it leaked pretty bad. Upon inspection, I found the gasket to be MUCH too large, large enough that the oversized M1-105 filter (and M1-104, OEM size) gasket actually fit inside it. If you experiment, be very careful, and look over the filter before testing it. Check the filter immediately upon starting the motor and look for leaks. Be sure to keep a watchful eye on it, and monitor oil pressure if possible.

Check back, there are more filters on the way. For comments, questions, or to submit a different filter for analysis, please e-mail the author.



This page last updated 12/19/01.