I bought an airdog 150 at the TS event on saturday, and was talking to an airdog rep..He said to delete the oem fuel filter after installling the airdog because having another filter would slow the supply of fuel to the engine..Is this what everyone else is doing???seems like to me that having the other filter would just be a backup on making sure the fuel is clean...

I wouldnt do it especially if it is under warranty. Most people don't delete there factory fuel filters and have not had a problem. I also dont think the Airdog filters good enough to get rid of the factory filter

Did you talk to them about their incorrect fittings and what they are doing to fix the problem?

Did you talk to them about their incorrect fittings and what they are doing to fix the problem?
Good point X2

i know a guy that did that with his fass. he has not had any problems so far

Leave it. I have been running a pre OEM filter followed by a lift pump and then up to the OEM filter and this setup has worked great on high horsepower tunes as a daily driver. it cant hurt to filter diesel, it is horrible filthy stuff.

leave it, mine is that way and unless i run a huge tune i don't have any problems.

ive never had a problem even with running huge tunes.

Whats the story with the incorrect fittings..I didnt know anything about it.
Also the guy said it was ok to have it running all the time, didnt know if it was better to wire it to a switch that i could turn off and on when i need it???

Whats the story with the incorrect fittings..I didnt know anything about it.
Also the guy said it was ok to have it running all the time, didnt know if it was better to wire it to a switch that i could turn off and on when i need it???

I would let it run all the time.

The fittings

Well the Dorman fitting doesn't fit the stock pickup unless you cut it and a lot of people including me have gotten wrong ot had missing fittings.

this is kinda of a silly question and off topic, but i have a fass 150 and it runs ALL the time the ignition is in the first position and i was wondering if the pump was always running the exact same speed (150gph) or does it slow down when there is resistance (no fuel being consumed)? thanks

From my limited understanding the Fass/Airdog etc, are low pressure high volume pump which means a Fass 150 CAN flow as much as 150 gallons per hour. A lift pump doesn't flow this much fuel all of the time it just makes sure that the CP3 (which is a lower volume high pressure pump) has a good supply of fuel to keep the fuel rail pressurized.

so when it's idleing for example, it is not pushing 150 gph correct? i guess i could see a benefit from this being that the fuel would be filtered many times before being burned

A FASS might do 150 GPH stand alone with no restrictions. In other words just sucking fuel and pumping it out the outlet into the free atmosphere.

But hooked up on the truck...there are restrictions which will create pressure in the lines. So at idle the restriction might be high and the FASS will build up say 15 psi or whatever with little flow going into the engine system. The FASS has an internal bypass I think...so it holds its 15psi pressure max with little flow.

As you stomp the throttle...fuel starts flowing again and the pressure will drop and flow rate will increase.

So at idle...little fuel being consumed...high pressure in delivery lines. Full power...much fuel being consumed...less restriction to flowing fuel...GPH's increase...pressure in delivery lines is lower than at idle.

Now the FASS with its high delivery rate may well supply way more fuel than can be consumed at full power. So it might hold pressure at the internal bypass setting most all of the time.

Just because the FASS can pump 150 GPH free flow doesnt mean your Duramax fuel system can accept 150 GPH and flow it all back to the tank while burning what it needs.

I have no idea what the stock engine and fuel lines can handle as far as GPH. But I do not believe that your circulating 150 GPH all the time through your entire fuel system.

yea i wouldnt expect it to be pumping 150gph all the time! lol i figured those number to be a little "beefed" anyways. my wallet would be hurtin big if i could actuallt burn 150gph haha

If you remove the stock filter assy don't run out of fuel. The air dog and fass don't self prime well.

I just put the PPE pump on yesterday, and used to have an edlebrock 1792 and they both self primed pretty well.

If you remove the stock filter assy don't run out of fuel. The air dog and fass don't self prime well.
why wouldnt they?

I dunno. Mine self prime fine. Honestly you should carry a quart of ATF or two stroke with you anyway. It primes filters really well, and dont everyone get into a discussion about additives, this is what a GM tech in town told me, and he does injectors on LB7s in 4.5 hours if that gives you an idea of his capability haha.

so just dump the quart of 2 stroke oil into the filter and that helps prime it??

This will supply all the fuel to run the 425 tune right...It seems right now it runs better on the 350 tune.

so just dump the quart of 2 stroke oil into the filter and that helps prime it??
yeah. the oils thicker viscosity helps keep bubbles out and saturates the filter really well. i never even have to prime mine i can just crank it over with the pump off and it immediately fires up. try it next time youll enjoy it!

This will supply all the fuel to run the 425 tune right...It seems right now it runs better on the 350 tune.
sometimes that is true. some trucks dont hold rail pressure like others do, so the larger tune could be completely draining your rail, making it not run as well as the 350 tune.