fuel system upgrades

[KSears]

I need some imput, been reading these threads and hearing all kind of good advice and trying to benefit from as much as possible. I am interested in the fuel supply side of things. What is the general opinion of the FASS setup compared with alternatives and where is the best place to look to compare results and best pricing? Does it or similiar systems make a big difference in performance or economy? How hard is the install and what kind of time involved and problems should one expect? Thanks in advance for all your help.

 

[rbattelle]

You'll get a wide range of opinions on this, most in favor of FASS. Personally, I think people can do much better than FASS by designing their own custom system. But it all depends on your mechanical aptitude (I assume yours is high considering your list of mods). FASS is an easy installation (very easy) right out of the box. It's like buying a prebuilt computer.



As for performance or economy gains, again you'll get differing opinions. My personal opinion is that if your existing stock system is functioning normally, and the engine is stock, a change to a FASS (or anything else) will have no effect on either fuel economy or performance. If your existing stock system is malfunctioning, or you have a performance box (as you do) then you may notice a change in performance and possibly economy by installing an upgraded LP fuel system.



Of course, your truck has an in-tank pump from the factory, so that automatically complicates your installation. I'm not familiar with FASS's current offering to replace the in-tank pump.



-Ryan

 

[JRG]

I too am interasted in this subject. It seems that it has not yet been determined what the best thing to do is. There are many varibles & ideas ie: modded cp3, high flow w/regulated return, cooled return, sound control, longevity, these are all issues I am watching to see what others are finding out.



JRG

 

[BradyWilliams]

You do have a few choices out there but Brad has made a very good product and it has been a great product for us as well. Thanks

 

[Diesel Nut]

FASS has a few advantages, one is its simplisity. Its popular and fairly cost effiecent. Also, this means that parts availability is better dueto the popularity. Just be aware of the fact that you DO NOT contact the manufacturer for issues. I don't agree with this style of business but it is what it is. They pawn off all the problems to the distibutors, so just be aware. I just ordered my FASS 150, so you can see how worried I am.

 

[KSears]

"Of course, your truck has an in-tank pump from the factory, so that automatically complicates your installation. I'm not familiar with FASS's current offering to replace the in-tank pump. "



ok, how does one deal with this part of the equation, I am sure someone must have encountered this ,please help, I am mechanically inclined but always looking to save time and aggravation if possible. .

 

[steved]

As for performance or economy gains, again you'll get differing opinions. My personal opinion is that if your existing stock system is functioning normally, and the engine is stock, a change to a FASS (or anything else) will have no effect on either fuel economy or performance.

I am one that saw a pretty good mileage increase with the FASS as well as a smoother running truck. It also helped in top end... the truck simply keeps pulling hard till redline... and this is an almost completely stock truck...



I got the FASS because of the simplicity... an all-in-one kit, done.





steved

 

[Gypsyman]

Check out our site for an alternative. I'm working on the in-tank trucks as we speak and your current pump will stay in place as a backup. Peace of mind is always a good thing.



Richard

 

[rbattelle]

I am one that saw a pretty good mileage increase with the FASS

Got data?



-Ryan

 

[steved]

Got data?



-Ryan

Yes.



Have written every mile down since I bought the truck... the FASS gave me about one MPG... mileage fluctuates, but on the average, it is up.



steved

 

[Bekim]

Are their any pics of your FASS install/system. I'm sure we'd all like to see 'em?

Thanks steved
Bekim

Yes.

Have written every mile down since I bought the truck... the FASS gave me about one MPG... mileage fluctuates, but on the average, it is up.

steved

 

[steved]

Are their any pics of your FASS install/system. I'm sure we'd all like to see 'em?



Thanks steved

Bekim

I'll try to get some, but it is installed according to their instructions.



steved

 

[rbattelle]

Yes.



Have written every mile down since I bought the truck... the FASS gave me about one MPG... mileage fluctuates, but on the average, it is up.



steved

In that case I'm impressed. A 1 mpg improvement to your lifetime average is huge. That's gotta be around 5%. What are the averages before and since FASS?



It's not immediately clear to me why an LP fuel system would result in better economy versus a normally-functioning stock truck. And I don't buy that it's some magic "air filtration" offered by FASS, because I know my custom system with Stanadyne filter has no air in it. But the slope of my average economy curve didn't change with the addition of my system, as evidenced below.



Obviously the curve is asymptotically approaching 18. 8 or 18. 9 MPG. The fuel system went on at exactly 46k (by coincidence, not design), when the average was 18. 7. Just before 47k it jumped to 18. 8. Given the global trend in the curve, that cannot be attributed to the new fuel system.



The second plot shows the per-tank fuel economy. Clearly there was no measurable jump in economy directly associated with the new fuel system at 46k.



Apparently, FASS provides at least 5% improved economy, which is unbelievable. It's got me scratching my head.



-Ryan

 

[steved]

In that case I'm impressed. A 1 mpg improvement to your lifetime average is huge. That's gotta be around 5%. What are the averages before and since FASS?



It's not immediately clear to me why an LP fuel system would result in better economy versus a normally-functioning stock truck. And I don't buy that it's some magic "air filtration" offered by FASS, because I know my custom system with Stanadyne filter has no air in it. But the slope of my average economy curve didn't change with the addition of my system, as evidenced below.



Obviously the curve is asymptotically approaching 18. 8 or 18. 9 MPG. The fuel system went on at exactly 46k (by coincidence, not design), when the average was 18. 7. Just before 47k it jumped to 18. 8. Given the global trend in the curve, that cannot be attributed to the new fuel system.



The second plot shows the per-tank fuel economy. Clearly there was no measurable jump in economy directly associated with the new fuel system at 46k.



Apparently, FASS provides at least 5% improved economy, which is unbelievable. It's got me scratching my head.



-Ryan

Whatever... it made a difference for my truck... sorry if THAT is too much for you to grasp. Just reporting what I have experienced since installing the FASS... sorry that it might actually work as advertised and that you don't believe that. I won't ever bring this up again... it was one of the best single mods I have done for this truck...



The end.



steved

 

[rbattelle]

Whatever... it made a difference for my truck... sorry if THAT is too much for you to grasp.

It is. But I guess I'm something of a dimwit.



I'm genuinely curious what the physics behind the 5% jump are. What does the FASS do, specifically, that results in such an improvement with just a pump, a water separator, and a hydraulic filter?



You say you've collected data like I have. Data doesn't lie, so I believe you when you say you've got 1mpg from the FASS. But everything has an explanation, and my feeble intellect is having trouble with reasoning out that improvement.



-Ryan

 

[Bekim]

The Spring 2006 Edition of Diesel World Magazine has a two page feature on the FASS system. Pages 36-37. The article talks about an 8% mileage boost (that's about 2 mpg for most of us), and better performance. They say only that you get a better burn since aerated fuel isn't constantly being recirculated.
The mileage claim is made by Diesel Performance Products in the article.
Cheers
Mike
###

It is. But I guess I'm something of a dimwit.

I'm genuinely curious what the physics behind the 5% jump are. What does the FASS do, specifically, that results in such an improvement with just a pump, a water separator, and a hydraulic filter?

You say you've collected data like I have. Data doesn't lie, so I believe you when you say you've got 1mpg from the FASS. But everything has an explanation, and my feeble intellect is having trouble with reasoning out that improvement.

-Ryan #ad

 

[cerberusiam]

What does the FASS do, specifically, that results in such an improvement with just a pump, a water separator, and a hydraulic filter?

Maybe the FASS, or for that matter the Airdog, is not just a pump, seperator, and filter? Maybe there is actually something to the air seperation process that benefits economy.



Along with removing the entrained air, supplying the CP3 with enough fuel to generate the injection pressures called for by the ECU would seem to benefit the injection event by making it more exact and not allowing the ECU to compensate by other means. The HPCR system is pretty reliant on sufficient pressure to provide accuate fuel injection events to meet the demands of power and emissions. Add to that 3 injection events, fuel minus as much air as possible it should naturally create a more even atomized spray that promotes a more even release of energy.



Ryan I don't believe for a second your a dimwit , but, I am curious why you reject the possibility of entrained air reducing economy? I am not so naive I believe it is a cure all for fuel delivery problems but there seems to be some pretty good evidence the FASS/Airdog contributes beyond just fuel delivery.

 

[rbattelle]

Maybe the FASS, or for that matter the Airdog, is not just a pump, seperator, and filter? Maybe there is actually something to the air seperation process that benefits economy.



but, I am curious why you reject the possibility of entrained air reducing economy?

Oh, I don't reject that entrained air would reduce economy. But I don't see anything special about FASS (or airdog) that removes entrained air any better than my Stanadyne filter does. And I didn't see any mileage improvement.



And certainly feeding the CP-3 with the proper volume of fuel will provide maximum economy. That's why I'm only comparing fully-functional stock fuel systems with no fuel boxes to fully-functional aftermarket fuel systems. Users with dead or dying stock fuel systems will almost invariably see a big economy improvement from either replacing the OEM system with another OEM unit that's functioning properly, or with an aftermarket unit. That's why some people report phenomenal mileage gains when the dealer installs an in-tank pump - their original system was malfunctioning, and the performance gain is not so much a gain as a "return to specification".



So if, perhaps, FASS is more than just a hydraulic filter, separator, and pump, what is it? I mean, I thought the aluminum block simply contained passages for fluid pumping between the filters. Does it have something else in it? It must, because you've got Steve with data showing a conclusive 5% boost in fuel economy attributable entirely to the FASS, and you've got DPP claiming an 8% boost in economy.



What is that "something"? Everything has a reason. And please - I'm not bashing FASS or Airdog here. I'm just trying to understand what the fundamental difference between a well-designed Racor or Stanadyne or Davco pump and filter arrangement and the FASS/Airdog offering. From where I'm sitting, the device characteristics don't directly support the data or the manufacturer claims.



To put it another way, what are Racor, Stanadyne, and Davco NOT doing that FASS is?



-Ryan

 

[OHale]

Check out our site for an alternative. I'm working on the in-tank trucks as we speak and your current pump will stay in place as a backup. Peace of mind is always a good thing.



Richard

Richard, I checked out your site and your system look pretty interesting. My truck is stock, I'm primarily interested if your system would keep the truck running if my stock LP failed. My guess (and it's only a guess) is that when the stock LP fails it provides a restriction to fuel flow to some or all extent. (?)



Thanks,

Olin

 

[cerberusiam]

Well, since every link I have for the operation of the Airdog/FASS is now broke, no pictures.



My recollection and understanding is such; the design in the block incorporates air traps that pull off and hold the air that results from running the fuel thru a gear pump. The fuel exit ports are lower than the air trap and keep the churned air and diesel higher than the heavier air free fuel so what is going out is more pure fuel without air in it. According to the diagrams there is a series of passages and bleed off points that act as seperators so what is pressurized out is diesel with as much entrained air removed as possible.



My description is rather poor and a diagram would clarify a lot of what the FASS is aimed at doing, in addition to providing a constant high flow fuel delivery. I don't think the filter systems mentioned do any of the air removal but if I am mistaken educate me.



Is the FASS snakeoil? That pretty much is a personal decision as to whether you believe the design will work as described and give a benefit. The cost benefit analysis is another whole story and is really a peronal decision.



FWIW, my impression of the FASS is the design is solid, it does what is advertised, and there are benefits to using it. Quantifying the benefits is a lot harder and I neither want or care to convert anybody with my opinions. I choose to use it because I believe it solves several problems and will provide a benefit in the long run. Cheers.