Filters provide another level of protection for modern fuel injection systems which are very easily clogged, it is important that these contaminants are removed before they reach the injectors and cause damage. The fuel filter’s job is to filter these particles out along with any water that may be in the fuel.
Filter Micron Ratings Explained (by Donaldson) – The published micron rating (or particle size that a filter captures), does not fully convey an understanding of the performance of the filter – unless you also know the efficiency at which it is measured. The efficiency of a liquid filter on a given particle size is frequently described as either a Beta ratio (ß), or as a percentage (%). (Make sure that a manufacturer is testing to the industry accepted
standards – allowing for true apples-to-apples comparisons.)
In other words, two filters that both claim to capture the same size particles or have the same micron rating may provide vastly different performance results.
For example, when comparing two filters that are both rated at 5 microns, if filter A has an efficiency of 99% it will remove 99% of contaminant 5 microns
and larger from the fuel. If filter B has an efficiency of 50% it will only remove 50%, or roughly half, of the same contaminant from your fuel. Filter B may allow up to 50 times more contamination to pass than filter A, a very different level of performance!
