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+--- Thread: Air Dog or FASS (/showthread.php?tid=935)
Air Dog or FASS - 386lover - 09-25-2016
Has anyone used Airdog or FASS fuel filter systems? I know they're fairly popular among the diesel pickup crowd.
RE: Air Dog or FASS - gearhead - 09-25-2016
Yes they do work well for keeping air out of the fuel. They may give you a couple of tenths of mpg gain. The main thing is that preserves your injectors. It keeps them full of fuel with no cavitation from air. Air in a injector is like a plasma cutter to steel. The air can cut away at parts and the tip. Also air effects injection timing because air compresses and diesel doesn't. So it will retard timing slightly from air. The more air the worse it will get. Plus air messes up the atomization of the fuel being sprayed. The best thing to do is take off your lift pump and remove primary fuel filter. Then put the fass or airdog in the primary fuel filters place. Put the fuel line from output of primary right to input of fuel module. But for a application where power doesn't matter as much leave lift pump in place and just put the fass or airdog in place of primary. Make sure to put toggle switch on the fass so if you have to have the key on for some reason it is not just running for no reason. The new systems have the bypass line which really helps get the air out.I am believer in it i have used sight glasses in the fuel lines and seen before and after.
RE: Air Dog or FASS - preacherboy24 - 09-25-2016
I have it on my truck. Gearhead has seen it. When I had my N14 it helped but the thing I really liked about it outside of what Gearhead posted is the fact it helps diagnose fuel system problems. If you have a system problem you can bet its not after the Air Dog because it will take the air out of the fuel and push the fuel to the pump as opposed to the pump sucking the fuel. If there is a leak after the Air Dog you will see since it kicks on with the ignition switch.
My N14 had an issue with the fuel pump. I didnt know it until one day I forgot to turn the ignition off. I had the engine set for a 3 min shutdown for cooling the turbo. The engine shut off and the Air Dog kept running. I noticed some fuel on the ground below my fuel pump. Later that day I did the same thing but no fuel. Next day I did it again and fuel on the ground. Took the fuel pump in and sure enough it was sucking air through a crack in the housing. Somehow the shaft in the pump had to be indexed just right and fuel had to be pushing the pump for there to be a leak...
Its also been said the filtration is really good on these. For an N14 that is a must since the injectors are the achilles heel on these things. I figure it will keep my ISX injectors happy.
You also have to remember the lift pump on the ISX only works until the engine is running. The Air Dog keeps pushing fuel to the pump keeping it happy. Rawze flamed me for having one saying if you have an air leak in your fuel system....fix it. I have big fuel tanks on my truck and when get into stop and go traffic with half or less in the tank the fuel sloshes around enough to get airated. Diesel is oil and will not give up that air as fast as water does so you know its getting to the fuel pump. Air Dog keeps that air out of the fuel before it hits the pump.
As far as fuel mileage is concerned I really couldnt tell you. It will not go down and I'm sure it will go up. That being said even if it didnt go up its still a good idea because of what it has to offer outside of fuel mileage.
RE: Air Dog or FASS - Unilevers - 09-25-2016
(09-25-2016 )gearhead Wrote: Yes they do work well for keeping air out of the fuel. They may give you a couple of tenths of mpg gain. The main thing is that preserves your injectors. It keeps them full of fuel with no cavitation from air. Air in a injector is like a plasma cutter to steel. The air can cut away at parts and the tip. Also air effects injection timing because air compresses and diesel doesn't. So it will retard timing slightly from air. The more air the worse it will get. Plus air messes up the atomization of the fuel being sprayed. The best thing to do is take off your lift pump and remove primary fuel filter. Then put the fass or airdog in the primary fuel filters place. Put the fuel line from output of primary right to input of fuel module. But for a application where power doesn't matter as much leave lift pump in place and just put the fass or airdog in place of primary. Make sure to put toggle switch on the fass so if you have to have the key on for some reason it is not just running for no reason. The new systems have the bypass line which really helps get the air out.I am believer in it i have used sight glasses in the fuel lines and seen before and after.
i second this and have seen it firsthand.
another added benefit is you can crank up the outlet pressure to flood the IFSM to support higher power levels.
RE: Air Dog or FASS - Brock - 09-26-2016
I remember reading somewhere that someone was claiming fass to be useless on the isx because it has such a high fuel real pressure before injection and that very high psi actually separates the air from the diesel before injection.
Any truth to this?
RE: Air Dog or FASS - Rawze - 09-27-2016
(09-26-2016 )Brock Wrote: I remember reading somewhere that someone was claiming fass to be useless on the isx because it has such a high fuel real pressure before injection and that very high psi actually separates the air from the diesel before injection.
Any truth to this?
I have never seen an ISX gain anything from those systems that was any power level of 600 HP or less. The only thing it serves to do is cost you money and mask fuel system problems that you may be having.
I have tested them with it installed and without, and the MG/stroke into the cylinders does not change a bit.
For competition, perhaps they are great to add that bit of front-end flow to your truck if your stomping the fuel pedal but a truck driver that hauls freight does not do this unless your a moron with an ego trip.
That is my opinion and i'm sticking to it, no one has to agree.
RE: Air Dog or FASS - in2trux - 09-27-2016
(09-25-2016 )gearhead Wrote: The main thing is that preserves your injectors. It keeps them full of fuel with no cavitation from air. Air in a injector is like a plasma cutter to steel. The air can cut away at parts and the tip.
Like our #3 injector? That piston looked like it was hit with a plasma cutter.
Probably not a bad investment to add some longevity to parts, forget perceived fuel savings,
that's KR mumbo jumbo.
RE: Air Dog or FASS - kryten - 09-27-2016
I had a FASS installed last October and sometime between then and the first time I changed filters the fuse blew. Driving up and down the road I could not tell but, and it's a fairly big but, when I have the RPM displayed on my scan gauge at idle with the FASS not working the RPM swing was 595 to about 610. After I replaced the fuse the swing was 599 to about 604, so it is doing something to smooth things out.
RE: Air Dog or FASS - Pd6cas2 - 09-29-2016
I have the Fass on my Cm570 isx , it's great for diagnosing problems. First week I had it on ,found my prime problem, lift pump was leaking .
Here's the downfall I've had with Fass , it's left me stranded on the side of the road ,
Issue was it suck my passenger tank dry . Shop that installed it put valves on the return lines so I can regulate the return flow to each tank.
Cost me $386.00 for roadside to bring 10 gallons of fuel and help me spray either to get started .
Only happen once ,learned my lesson and I've been a happy customer.
I also have the optional heater installed .I put a switch on it don't need heat in summer ,I live in Minnesota and heater works great for me.