Fuel filter question

[DDahl]

I have a question for the experts. It appears that we all would benefit from a 2 micron fuel filter. However, the stock lift pump is not strong enough (hence the new 7 micron wonder filter -- cheaply made I might add -- I was shocked that Fleetguard would make such a cheap looking filter). It is my understanding that the CP-3 has an internal low pressure gear pump. Would it be possible to split the line between this low pressure pump (80 psi as I understand it) and the main high pressure pump and plumb in a high quality 2 micron filter there. This would avoid the current lift pump issues. It is my impression that the Dmax uses something like this for its fuel filter (I know that they do not use a lift pump). Thus on our Dodges the lift pump would push fuel through the stock filter into the CP-3 low pressure gear pump which would raise the pressure and pump the fuel through a good 2 micron filter which would then feed the high pressure section of the CP-3, rail, and injectors.

 

[HeberRam]

DDahl, I not being an expert on the CP3 pump, find your logic doable, however, I don't think you will find a filtering system to handle 80 psi fuel pressure going through a 2 micron filter and maintain little or no line loss in the process? You are correct in the assumption, dodge went to a 7 micron filter for the stock filter, because anything less ie. , 5-2 micron filter the in tank lift pump could not push enough fuel. You have a couple of different options. Go with an aftermarket fuel pump like fass which can include a fuel water/separator and a 2 micron filter and bypass the stock filter system, or go with a fast pump or walburton or whatever pump, pump to the stock 7 micron fuel/water seperator and then to a 2 micron filter before the CP3 pump. I choose the latter, with a 150 GPH fass pump through the stock 7 micron fuel filter/water separator to a GDS 100 GPH 2 micron filter to the CPE pump. Max fuel pressure to the filters is approx. 18 psi, a range the filter media's can handle. I like this system, as the 7 micron filter takes the "hit" and 2 micron does the "polishing" of the fuel. The location of the 2 micron filter is neatly tucked in the engine compartment, keeping it dry from road debri, salt and warm from the engine heat during the winter.

 

[rbattelle]

It's not possible to plumb anything between the low pressure pump and the high pressure pump within the CP-3 because the passageways between the two are internal to the pump.



Easiest thing to do is plumb in a 2-micron filter between the stock filter and the CP-3.



-Ryan

 

[C Rigsby]

I'm a little confused, which isn't hard to do on some issues. It appears the new Fleetguard 7 micron filters may restrict the flow. I just purchased 6 to have a spare or two but if it might cause a problem I'll take them back. I have a 2003, HO, 6-spd.

 

[DDahl]

Thanks for the input. Too bad we can't plumb a 2 micron filter between the CP3 low pressure and high pressure pump sections. Oh well!

 

[HeberRam]

C Rigsby, I don't know what mods if any, you have on your 03', on a stock truck pressure is around 8-10 psi at idle. If you have a fuel pressure gauge, you would probably see a drop of 1-2 psi with the 7 micron filter. Under heavy load, maybe another 3-4 psi. That still keeps you in the positive pressure zone. heavily modified trucks, will be in the " suck it dry mode". :--) Again, that's why I believe Dodge opted for the 7 micron filter, and not the 5 micron filter that Bosch recommended. The new 7 micron is much better than the old 10 micron, which was stock, and of course 2 micron is the best.