The FASS and airDog are a simple air trap configuration that uses the fact that air and air entrained fuel are lighter than the other fuel around them. Pumped thru a series of chambers, the lighter portion ends up at the tops and is drawn off by the relief valve while the heavier fuel is drawn from the bottom of the chambers.

The difference is on the injection side when the air is removed. Entrained air in compressed fuel virtually disappers because it is compressible and will eventually collect into larger and larger pockets that will compress. The impact thru most of the system is really neglible on lubrication.

Where it all becomes apparent is at the injection event. The fuel goes from 18-23k psi into the cylinder which is around 700 psi at TDC, since the air is compressed when you release into a lower pressure area all the air bubbles expand. Since these are buried in the fuel stream the more air you have the more rapidly expanding null combustion pockets there are. Everyhwere there is air there are cool spots killing the heat generation that eventually translates to power and efficiency is affected. Not to mention the expansion tends deflect the fuel stream out of the configuration that was designed for it.

Testing of the HPCR systems was done with much cleaner fuel that you end up with by sloshing thru a tank, pump, etc. What the design parameters are seldom met in many OE implementations.

The big thing with the AD and FASS is their water seperation capabilites are lacking, the OE filter is better at that and so far I don't believe there are any filters for them that meet OE standards for weater seperation. IIRC, even the micron rating on the filters is not down to the 2 micron needed to make sure the HPCR system doesn't fail.

The benefits are pretty well documneted in the big rig industry where they came from. Whether or not there is a justification in a pickup is unclear. They are a good high pressure pump with other side benefits, if you have to replace it with something might as well be these that are specific for the application.

 

Any chance you could point the direction to find this evidence? If there is proof that this makes a tangible benefit I would like to know. Mostly I hear a bunch of "This is how it works" and It gives you "more hp and fuel economy". Which, don't get me wrong, I don't doubt. Its the "how much more" I want to know. If all it gives you is 1-2HP is it really worth it? Maybe on a dyno queen or the guys involved in levels of competition far above what most of us can attain it is a big deal. For most of us? Pure hype. Might as well buy a Fitch catalyst and those cool little magnets while your at it.

 

Bruce Mallison at Pittsburgh Power had some pretty good articles\testimonilas on the benfits and results they had installing the original Fuel Preperator in the big rigs. Whether that has survied some 12-15 years of changes is a good question. If you want more in depth info might give them a call or Pure Flow Technologies and see what they have to say. Naturally you will get the marketing hype but they will probbaly have some in depth info that may help make up your mind.

I have see 15-20 HP gains on VP trucks with just a FASS install, less on others. The big gains are obviously not only air removal but quite likely fixing supply pressure.

A hard and fast number for benefit is hard to quantify because there a lot of things that go into the equation, fuel quality, treatment, miles, etc. Where is the break even on say a 5% gain in efficiency? That is subject to individual usage, so you can't just blanket statement it. Obviously if you drove 8k per year and I drove 108k per year there is going to be an actual and perceived difference in the benefits.

Its like anything else on these trucks, does it help us gain or end goal and do we like it. Sometimes actual worth is only in the eye of the beholder so make your decision and be happy with it.

 

I'd say 5%, even 2% is very optimistic. Doubt it could be measured under other than laboratory conditions. Otherwise the manufacturers would be doing it OEM if the benefit was that great.

 

Your just kidding yourself thinking that.

The manufacturer has ZERO incentive to add complexity and cost to these vehicles OTHER than to meet safety and emissions. Neither of these initiatives will be met by adding a FASS or other fuel treatment system.

The justifucation is not there, like the transmissions, like gauges, etc, etc, etc.

It doesn't take laboratory conditions to measure and quantify the benefits, thats done in every day use. Even a 2% increase is quantifiable in certain cases. The question is and always will be; does it help me achieve my goal at an acceptable cost.

 

Well I beg to disagree. If the efficiency increase is anywhere near 5% then that would certainly boost emssions performance in meeting CARB requirements. It would also provide a nice competitive advantage in the MPG area as well. How much do you think those air seperators cost to mass-produce integrated into a puel pump assembly anyway?

It ain't that much, and I doubt FASS or AirDog will ever tell.

 

Agreed the cost to mass produce would not be a significant road block.

However, its the process to get to that point that is costly. Any components that deal with the fuel system, air system, exhaust, and\or exhaust aftertreatment are subject to CARB standards. This includes hearings, tests, documentation, etc, etc, etc. In order for it to be practical and feasible the ROI is going to have to be much more than 2-5%. It is simply too costly to try to push this thur an EPA hearing when everybody and their dog gets to throw roadblocks in the way.

Need I point out that the oil industry in this country has THE biggest group of lobbyist in action and can pay for ANY study to refute anything that may be proposed? Just imagine the flurry of maneuvering that takes place when ANY potential loss of revenue is proposed.

Lets be clear what we are talking about here, CARB is concerned ONLY with emissions and the impact on air quality. EACH AND EVERY vehicle line\configuration sold has to meet or exceed emissions requiremnts AS DESIGNED. CARB cares not one whit for mileage, longevity, or any other criteria. It literally does not matter if efficiency is reduced 10% to meet standards, thats the consumers problem.

CAFE ratings is where efficiency and mpg's count, but, its an AVERAGE and is not applicable to each and every configuration. If a manufacturer's average is where it needs to be duet sales of small efficient cars it doesn't matter if emissions on the bigger heavier ones drives actual mileage into the toilet. As long as the vehicle meets emissions and the CAFE ratings average up it is rubber stamped and we pay for it.

Sorry, but until the roadblocks to innovation are removed we will NEVER see the results in an OE vehicle. It simply is not feasible and fiscally possible to fight these things into production given the current laws and controls.

 

It certainly took many orders of magnitude more time, work, red tape and money to get diesels to the 2010 emissions standards, what with DPF's, EGR, urea systems, etc. than would adding a simple fuel processing device that promised to provide significant improvements in that and other areas. NOX levels go down with improved combustion efficiency.

No, the reason it's not done is simple: it's not all it's made out to be, which is in all reality just another marketing ploy to sell $500+ fuel-systems-in-a-box.

 

Would it were that was true!

Unfortunately its not and the EXACT reason why a lot of these mods are not EVER making it to production. As I said before efficiency and emissions are two opposed ideals. You can't positively affect one without negatively affecting the other.

NOX emissions increase dramtically with increased combustion temps and pressures, so does efficiency. Kinda ends up being a Catch-22 situation.

Emissions diesels run stoichiometrically lean for a reason, they cannot be allowed to reach maximum burn efficiency or emissions rise. This is achieved by retarded timing, multiple events, and several different versions of EGR. Just exactly how the newer engines are designed with the resulting loss in efficiency.

There are actually few changes to the 6.7 to meet 2010 emissions standards, notably the diesel particulate filter and cooled EGR. The filter takes care of the soot created from the incomplete combustion that is used to lower the NOX emissions. The cooled EGR was needed to better control and limit NOX. Other than those 2, a lot of the design changes from the 5.9 carried over. Since the fuel and air systems were already CARB approved there were minimal changes to additional systems that had to be approved.

You really need to think from the other side of the sales desk for a while. Its all about the bottom line and maximizing shareholder returns. In other words, do it cheaply and keep the EPA at bay.

 

Is this the cerberus from cumminsforums?