I guess i put my 2 cents into this topic. At work we run Internationals, they run a 2 filter setup, water seperator first and then the primary filter. I can tell you just form changing them all the time that they both remove air. There isnt anything special to either filter. I say this because you can fill a filter full to top, put it back on the truck and drive it around for a week. Take the filter back off and its half full of air. So where did this air come from, out of the fuel I suppose. So my guess, and granted it is only a guess, probably the only things that makes a fass or airdog better than regular filters is they designed the housing to bleed that air off the top of the filter back to the tank. Dont they have a straw on them that goes to the bottom of the center of the water seperator?

 

i change filters on trucks to. usually if filter is half full of air its because theres a microscopic hole on the suction side of pump/fuel filter assembly that is allowing fuel to drain back. the size of this hole is determined by how much air is in lines and filter.

but you are right does it pay to have a fasss? im not knocking them but doesnt all pumps remove air?

 

I've had this discussion with FASS people before. The main question I had was if all the diesel engine manufacturers know about this "problem" then why haven't they done anything about it???
I was told that FASS held a patent on it's air removal system.... Hmmm. So Cummins, CAT, International or any of the Big 3 wouldn't be interested in buying this wonderful innovation for their vehicles? To make better efficiency? To make combustion more efficient and save wear and tear on expensive fuel system parts that may fail under warranty? To alleviate some EPA mandates? If this technology was worth a grain of salt, someone would have bought the rights to FASS or others a long time ago and made the inventor an extremely wealthy man.
I can go on and on...

 

You might want to be a little more careful in you're phraseology there, Airdog:
Unless you would care to quote the passage and cite the reference directly. Your demo is nothing more than a circus sideshow trick. What those manufacturers say is that air in the fuel "can" be an issue under certain circumstances in malfunctioning systems with leaks and in conditions where entrained air is generated in unusual circumstances. This is nothing new. What is new is the relatively recent appearance of vendors hawking ridiculously expensive pump/filter setups basically representing a solution in search of a problem.

 

too funny...

 

no_6,

(quote)

As for sloshing fuel and sucking air, it just doesn't happen unless there are broken parts or jury rigged fuel pickup system. All the newer trucks have fuel cannisters that eliminate the sloshing problem and have the fuel returns plumbed into them to help.

Hmmm, lets return warm aerated fuel directly into the fuel pickup so we can keep pumping this fuel to the fuel system with no removal of any entrained air. This is really a zero sum game. You don't get gains by adding to the problem. There is always a cost somewhere. [/QUOTE]





I don't know what "system" you are refering to, but in my setup the fuel return goes to the tank fill pipe, not the fuel pickup. The dip tube pickup is down at the deepest point, far away from the returned "hot" fuel. The hot fuel you refer to will have less effect on the tank temperature than the weather, as the tank is right out in the breeze all the time and has a large surface area. I even installed an immersion type heat exchanger in a fuel tank on a boat to absorb heat from another system. This tank saw no wind on it's surface and was partially insulated. It definately saw a temperature increase and was never a problem.

And yes, you and all of us can and do get air in the fuel pickup whenever we run very low or out of fuel. Is this a mystery? It's called running out of fuel. As the level becomes very low sloshing begins to admit air into the system. As this process becomes worse with even less fuel, the engine sucks more and more air and begins to run rough and loose power, but will soldier on if the air is being pushed on through and enough fuel is still present to allow injection pressures. Finally there is too much air in the mix and the engine stops. This problem is especially pronounced on sailing yachts where the tank can be held over at 30 degrees or more and bounced around for hours or even days. Sloshing is an issue that must be dealt with in trucks too as they start and stop, corner and hit bumps.

You are right that I have not spent time with Dodge engineers discussing fuel system design. And, apparatly they have not seen the need to incorporate a magic invisible entrained air remover either. I've looked and I can't find one, so I must conclude it's not needed. I have designed a number of diesel engine fuel delivery systems and they have all worked well with designs that managed visible air. Air that inevitably gets into the suction side of the transfer pump, or into the filter housing, and must be dealt with before the injection pump.

Maybe you should talk to Cummins and do us all a huge favor. Sounds like we all will get better performance, cleaner burning, and engines that last longer. Or just show us some kind of data or proof that invisible air is directly linked to damage of some kind. Or better yet, remind me once again that "no" air can get into the suction line unless it's "jury rigged" or "broken".

Sorry for the earlier sarcasm, but it sounds like you're trying to invent a problem.

 

Sounds like you have a unique and effective set up.
FWIW - No serious bearing on this discussion but your comment reminded me of a study done by 'Scotty' on TDR, and varified by me. After 1/2 hr driving, tank temperatures average 15* F warmer than OAT.... across a range of summer time temps.

RJ

 

Interesting. I did not have a specific value for it.

 

Now why would you go away from the OEM design that was implemented to stop the very thing you are talking about then site it as a problem??

The stock tank has baffles to minimize sloshing until very low fuel levels, it has a fuel cannister that is mixing returned fuel with tank fuel in an attempt to stop everything you site as being the main culprit for air in the fuel. Minimal abstract reasoning would suggest that OEM has in fact designed in some things to minimize fuel aeration without adding a lot of complexity and cost.

Your missing my point on hot fuel. Hot fuel is much easier to entrain air into. The effect of heat on the fuel combustibility is a net positive up to about 110 degrees farenheit IF it doesn't contain excessive amounts of air. The more you return thru the tank fill tube and the warmer it gets just adds to the problem. Once again, sloshing is no where near as large a problem as constantly returning large amounts of warm agitated fuel.


Inventing a problem??? I wish I was smart enough to identify a problem and a solution like that.


The crass comments about vendor hawking and such are about what is expected from a lack of experience or knowledge. For those interested in the background of the AirDog they can check out Pittsburgh Diesel web site and see if Brue Mallisons blogs are still available along with some of the testemonials and user testing of the product. There is more than a little scientific basis and testing data available to make an informed decision rather than relying on baseless opinions for content.

 

Yep, definitely won't be getting any experience with Airdog anytime soon.
Pittsburgh Diesel blog about OTR trucking = Cummins diesel pickups. Riiiiight. Same logic applies to apples and oranges.

Buyer beware applies to magic product = reader beware applies to Internet forums. Educate yourself from numerous sources and remember everyone out there is trying to get your money and get you to believe they know it all.

 

It seems like a fairly simple idea, pump fuel air mixture in the top third of a coke can sized container, the air rises to the top, the fuel is sucked out the bottom, and a return for the now disentrained (is that a word) air can go back to the tank.

I think the original idea for a "FASS" was a similiar item.

It would seem that Airdog or FASS ought to sell a stand alone Air Seperator. Just a device that you pump fuel into and out of that removes the air. They would have a whole other avenue to market, cost to produce should be extremely cheap, sell them for a hundred bucks a pop, and could sell one to every tom dick and harry with a diesel that wanted to try it.

There is my 2 cents...got change???

 

Here is a simple test to see about air and water in diesel fuel. Get a clear jar fill it about 2/3rds full put the lid on it and swirl it around, watch how many bubbles there are in the fuel. Now remove the lid and fill the jar all the way Put the lid back on it then swirl it again. What do you have now?

It is a known fact that air and water are present in diesel fuel. It is also known that water can removed by a filter and little less known air can removed by a filter.

What I would like to see is a comparsion with the AIRDOG/FASS and the clear hose test and then a duel filter setup with same filters and a different style pump. See how much air is found.

If you notice, diesel fuel mixes with air readly when it is sloshed around, and there is air availible to mix with it such as with the return line to your fuel tank.

When you deal with a factory fuel system that is putting out 10 psi or less the air is not compressed as much as it would be if that same fuel was compressed at 20 psi.
Although I am not an expert on entrapped air in fuel I do know that by compressing fuel then running it through a filter system will remove and or compress that air so the it is smaller in area.