The purpose of an oil filter is simply to filter out foreign particles from the oil that will damage the engine. The primary factors for a filter are the size of particles it will capture and the flow rate it will sustain.

Obviously you want a filter that can maintain acceptable flow, while removing the most amounts of particles. Oil flow is critical for lubricating a performance engine, while particle removing is important for engine longevity.

If you had a pure racecar you would want a filter with the best flow, since you would be replacing the oil every race and engine life is not relevant. For a streetcar engine life is very relevant.

The UPF44 filter is a Gen-3 Synthetic non-woven laminate filter that is actually made by Champion Labs for AC Delco.

The Mobile-1 filter is a Gen-5 Synthetic non-woven laminate filter that is actually made by Champion Labs for Mobile-1.

The AMSOIL SDF filter is a Gen-12 Pressed Cellulose filter that is actually made by Baldwin for AMSOIL.

There is no correlation to generations between Synthetic and Pressed Cellulose filters, only between themselves.

The real comparison of these filters can be easily expressed by their Pore Sizes and Flow Rates. The key is to balance flow vs. filtration. Remember that flow is also relative to overall particle removal. If a filter flows twice as fast, then the oil will travel though the filter twice as often and remove more particles.

Fram TG8= Lg Pore>40 / Smallest Pore>15 / Average Pore>41
Fram TG8= Flow@ 20psi = 4.3 gpm Raw Media / fl-oz/in³/min>2.02
Purolator = Lg Pore>43 / Smallest Pore>10 / Average Pore>42
Purolator = Flow@20psi = 3.8 gpm Raw / fl-oz/in³/min>1.49
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UPF44 = Largest Pore>45 / Smallest Pore>17 / Average Pore>43
UPF44 = Flow@ 20psi = 3.0 gpm Raw Media / fl-oz/in³/min->1.97
Mobile-1 = Largest Pore>56 / Smallest Pore>16 / Average Pore>52
Mobile-1 = Flow@ 20psi = 5.3 gpm Raw Media / fl-oz/in³/min>2.27
AMSOIL = Largest Pore>52 / Smallest Pore>17 / Average Pore>50
AMSOIL = Flow@ 20psi = 9.5 gpm Raw Media / fl-oz/in³/min->3.58
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WIX = Largest Pore>65 / Smallest Pore>19 / Average Pore>58
WIX = Flow@ 20psi = 5.9 gpm Raw Media / fl-oz/in³/min->2.50
Fram X2= Largest Pore>61 / Smallest Pore>23 / Average Pore>57
Fram X2= Flow@ 20psi = 8.5 gpm Raw Media / fl-oz/in³/min->4.49

From the above list you can see that the UPF22/Mobile-1/AMSOIL filters are all high-flow “small particle” filters. The WIX/FRAM X2 filters are “large particle” filters. They will leave more particles in our oil, but generally flow faster. Fram TG8/Purolator are low-flow “small particle” filters that will clean the oil well, but restrict oil flow though the engine greatly.

I personally would not put a large particle filter on a modern performance engine like our Z06’s. They do not meet the standards specified by GM. I would also not use a very restrictive filter like the Purolator. For the oil filters that flow well with good filtration, the results are obvious.

The Mobile-1 filter flows at almost twice the rate as the UPF44, while filtering out the same particle sizes. The AMSOIL flows at 3 times the rate, while filtering out the same particle sizes.

This is the difference between OLDER generation filter technology and newer generation filter technology. All the good filters (UPF44/Mobile-1/AMSOIL) will also last significantly longer then the junk filters. In case you don’t change your oil as often as you should.

The UPF44 is a very good filter overall. It is however not the best by any means.