Bypass Valve setting varies with Manufacturer?

[HondaRD]

I just noticed that bypass settings for Purolator is 12-15psi, whereas it is at 8-11psi for Wix as it applies to all honda cars (except for newer models excluding the S2000). I wish I new what the bypass setting was for the OEM honda filter. This makes me wonder then, if the bypass setting is not such a big deal especially for those who decide to use an oversized filter where the only difference besides the larger size is the bypass valve setting. The bypass valve setting has been the primary reason why I would not consider going to a oversized filter, but it would appear from this data that it may not be such a big deal afterall if it can vary from 8-15psi.

[ February 19, 2004, 09:56 PM: Message edited by: HondaRD ]

 

[TC]

The "stock" replacement filters for my 2002 Mopar have the following bypass psi's:

-Baldwin: 8 psi
-Purolator: 12-15 psi
-Wix/Napa: 16 psi
-Hastings: 22 psi

(I'm going by memory -- I may have swapped the Baldwin and Hasting numbers, but you get the idea.) This 8-22 psi spread manages to encompass the broad spectrum of street filter bypass settings -- the only numbers I recall seeing outside this range are the higher pressure race filters, occasionally with 30 psi settings. I suspect three things:

1. Forget the factory bypass setting. It has little relevance to another filter manufacturer's base plate, internal flow channels, media flow resistance, bypass valve construction, etc.

2. Go by the aftermarket manufacturer. If Wix suggests a 16 psi setting for your "stock" Wix replacement filter, strive for that number if you opt an oversized Wix. Same for Purolator, AC Delco, etc.

3. The larger the total media area, the less significant the bypass setting since it is less likely to go into bypass anyway. (Whether during clogging, pressure spikes, or high RPM/high flow, the larger cartridge is more able to flow oil through the media, rather than having to bypass it. A typical filter might have 100-200 sq in of media, with "oversize" versions maybe having 25-100% more, but if one had 10 times that amount, the significance of the bypass valve would approach nil, excepting for extreme conditions.)

[ February 19, 2004, 10:04 PM: Message edited by: TC ]