Okay, I know this is really technical, but the SDF13 - what is the diameter?

 

2.56 inches which is 6.5024cm.

 

Thanks man!!!!

 

The SDF 20 is a better choice than the thimble sized SDF 13.

 

are you refering to the 3.0L or the 3.5L???

 

This filter will work on both the 3.5L and 3.0L It is the same length as the SDF13 (short/thin), has the same gasket diameter, but is wider.

The SDF 36 is the longer version of the SDF20 (short/wide).

 

So any of those three will work?

SDF13 or
SDF20 or
SDF36

???

 

Yes, but the SDF-20 is the best fit for Maximas.

 

if the SDF20 is the best, then why do they reccomend the SDF13 on their site? Im not saying anyone is lying to me, but why would they put the "wrong" one on their homepage?

 

It is because the SDF13 is the closest sized filter to the OEM. The SDF13 is the same size as the Mobil 1 M1 208. The M110/Bosch 3323/NAPA Gold 1356 are the same width but are an inch longer.

A reputable Amsoil Dealer from BITOG recommends the SDF 20 as a better alternative to the incredibly tiny SDF13. Here is a tidbit that I found.

"Amsoil Filter Substitutions - in most cases, the substitute is simply a longer version of the same filter. Make sure there is enough clearance to use it and remember that the engine can rock back and forth on its' mounts!"

Stock Filter/Substitute Oversized Filters

SDF-57/SDF-34/SDF-96 (toyota/Saturn)
SDF-34/SDF-96/SDF-15 (many early VW/Audi engines)
SDF-29/SDF-23 (many GM V-6 engines)
SDF-20/SDF-36 (many Honda/Isuzu engines)
SDF-96/SDF-15 (early model Toyota/Datsun engines)
SDF-15/SDF-26 (many Ford V-6/V-8 engines)
SDF-25/SDF-24 (many GM V-8's)
SDF-41/SDF-99 (early Ford Powerstroke diesels)
SDF-13/SDF-20 (many Nissan/Mitsu/Mazda engines)

 

here is the reply Amsoil sent me reguarding this....

From: AMSOIL Technical Services



Thank you for contacting AMSOIL with your concerns.



In response to your inquiry, the information you received about using all these filters is incorrect. The SDF13 is the only AMSOIL filter authorized for the ’02 Maxima. You cannot safely make filter substitutions by measuring them. The SDF13 is a stand alone filter and we should probably ask you who gave you this interchange information.



Thank you again for the opportunity to respond to your concerns. As always, please feel free to contact us again if we can be of further assistance.



Sincerely,



Jim Van

 

Amsoil Tech is practicing CYA. The SDF 13 is not a bad filter; there are better options.

If you check the oil analysis spreadsheet, many people have used the SDF20 successfully without a hitch.

I am not obsessed with using extremely oversized filters but the SDF 13 belongs on a go kart not a performance sedan.

 

AMSOIL SDF filters have tremendous capacity as they contain a very generous amount of premium filtering medium. You can not necessarily judge the capacity of the filter by the size of the case...I have cut several filters open and you would be surprised at the difference in quality. Yet with all things being equal, the SDF-20 should have a higher capacity than the SDF-13 since the 20 is larger and they are both from the same manufacturer. But the real question(s) should be how much capacity do you need considering the length of time you intend to keep the filter in service; the mileage/condition of your engine; the overall superior efficiency of the SDF-13; and does it meet the requirements of the OEM?

The by-pass relief valve on the SDF-20 is calibrated to open at a higher psi differential (18-20 psid) than what it is on the SDF-13 (12-16 psid)...although I'm just speculating, the calibration of the SDF-13 is probably more closely matched with OEM specs. If Nissan has spec'ed 12-16 psid as the magic number, using a filter with a higher setting could limit oil flow in cold-start environments or if the filter were to become clogged...and that's not healthy for your engine.

As Johnny points out, many people are successfully using the SDF-20 without any problems. However, I know of no-one who has had problems with the SDF-13 and I sell/install a lot of them to/for Nissan owners. I have used the SDF-13 exclusively on my car since '98 and have several customers who have been successfully using the SDF-13 for years...one customer has a '96 max...he puts over 25K per year on the car and has put in excess of 130 K on the car since changing to AMSOIL, using the SDF-13 and changing it at 10K intervals. His car uses absolutely no oil between changes.

I agree that AMSOIL might be doing some CYA with regard to their recommendation; however, that probably goes back to the calibration of the pressure relief valve and Nissan's recommendation in that regard. They would not want to recommend something to the contrary for the obvious libility that would go with it. Just because a filter will screw on to the threads does not make it a good match for the engine.

Size can matter, but in this case good things come in small packages :-) ed

 

Thanks Ed! Thats got to be the most informative post ive read here in months!!!