What's beta ratio mean in a practical way

[westwind999]

I was comparing filters, looking for one with a little more size and I compared two Wix filters. The beta rating is different 21/37 for the 51348 vs 14/31 for the 51516, not sure what that means. Everything else pretty much lines up.

I generally gather that beta rating is a comparison of dirt entering the filter vs dirt leaving the filter. So how would these two beta ratings affect my engine? (99 Saturn SW1 SOHC 1.9) Hand waving logic says just go with the bigger one but what about the specs?

 

[glenncof]

www.filtercouncil.org/techdata/tsbs/89-5R3.html
www.filtercouncil.org/techdata/tsbs/04-2R1.pdf

The above are references on the testing/calculation of beta.

You can contact wix and verify but I believe 2/20=14/31 means B(14um) = 2 which is 50% efficient and B(31um) = 20 (~95% efficient). These look like derived values.

If this is correct the 14/31 is slightly better but almost identical. I don't know Wix defintion for nominal but the 51346 is almost the same/slightly better.

The consideration for you is more likely capacity. The 51516 could have 50-100% more media; with higher capacity based on can size. This might be important if you had a dirty engine or wanted to run longer intervals.

So it depends on your needs and the price.

 

[westwind999]

Thanks for the info. Since I haven't got a lot of feedback I just emailed Wix to see if the can explain the numbers.
Here's what it says exactly on the website 51348 (3.404 high) Beta Ratio: 2/20=21/37 micro rating 19 and 51516 (4.828 high) Beta Ratio:2/20=14/31 micro rating 20

When I searched about beta ratio there's a target particle size and an ability to remove it. So the small filter gets half of the 21um particles and the bigger one gets half of the 14um particles. (advantage bigger one) Similarly the small filter get 95% of the 37um particles and the larger one get 95% of the 31um particles. (advantage bigger one again) Micron rating 19 vs 20, (advantage small one) but maybe not as important as the beta rating?

Let me know if that makes sense. I'll post back what Wix says.

Thanks

 

[westwind999]

Still no reply from Wix. I was also looking at the 51515 which is like the L30001 purolator from my old f150. It's beta ratio looks even better at 13/23 (from the Wix site) and is ~.75" bigger around. I'll have to check to see if I have clearance for it to fit.

Seems like the bigger is better logic applys.

 

[Gary Allan]

It's been assumed that all three filters have the same media. The reduction is present in each velocity lowering evolution to a larger can volume. You get to a diminishing rate of return as the velocity changes less. The single pass test (allegedly the lower one, not the 2/20 xx/xx numbers) is mostly uneffected.