[GMCDURAMAX]

I've never seen this topic covered very well.


How much does a secondary filter need to flow? I know that the bigger the filter the longer it will last, but what flow rate is needed.


Specifically:Will a racor 645 flow enough for a stock duramax and will it last as long as the stock primary filter?

 

[OC_DMAX]

The maximum flow rate for the stock OEM Racor filter is 48 gph, this per the Racor rep. The Racor 645 (R45S element) is rated at 45 gph (I believe). So it should work.


Having said that, the Racor 600 series fuel filter elements are almost identical in cost and use the same filter head. So I would use at least the R60S filter. This filter flows 60 gph and is about 2 inches longer.


Will the R45S element last as long as the OEM? If you mount it Pre-OEM, I would say no. The "S" element has a 2 micron rating, while the OEM is supposed to have a 4 micron rating. If you mounted the R45S element in a Post-OEM position, it would probably be pretty well matched to the OEM. Just my guess.Edited by: OC_DMAX

 

[GMCDURAMAX]

Thanks, you answered another question before i asked it.Does the racor 690 also use the same head? I found a good price on the 645 so I'll probably order it and use r60s replacement filters.

 

[LanduytG]

I have had a couple of customers open their 60 series filters after 15K and they felt that it was good to go at least another 5K. These were pre OEM as well. So with that said I beleive the 45 will go as long as the OEM. But like stated above why not use the 60.

Greg