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Hey guys
Just thought i would show off my truck in here. She's nothing too special but she's paid off and makes me a living. Mainly came to the forum to get some info from the experts. Its coming time for an overhaul for the old 400 big cam and i wanna get some more power outta the old girl. Not sure which cpl it is I'll have to check it out tonight






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Add a dual fuel line to the front head for 25 hp a fass gives another 25. Make sure you change your vibration damper when you do an overhaul. Could add a crank balancer too.
 

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Loooking good, it's nice to see older trucks still on the job.

Getting a little more power out of her is relatively simple, you can do the dual fuel lines, but I would save the $700 dollars on the FASS and buy a decent set of injectors, that will net you more than 25hp for less money. Let me know if you want to go that route.

I had good luck and was pleased with the results when I did injectors, and that was with a pump with stock settings, I feel it is safer to leave the pump set at stock and get more fuel into the cylinder instead.
 

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Is that because you don't think the FASS works? I was always under the impression those units(and others like them)were originally designed to work on PT pump motors.
 

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Is that because you don't think the FASS works? I was always under the impression those units(and others like them)were originally designed to work on PT pump motors.
The way I look at it is that if you are starving a PT gear pump for fuel you have other problems, the way the gear pump is setup it will only pump and pull what it needs, there is no reason to force feed it.

An engine that relies on a supply pump likes say a B/C cat responses well to a well pressurized flow and actually need it. I see a point and time that it may be needed, but no one outside the electronic cat crowd will ever trash the HP level that it would require a feed pump to maintain power.
 

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I see,i always thought they were supposed to take air out of fuel. I guess i'm thinking of the fuel preporator. Do they even make them anymore?
 

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Yeah, they are even more expesnsive. The gear pump in a way does the same thing as either pump. I seriously doubt anyone has proven the claim of 25hp on the dyno, and it they did it was done along with a pump tweak as well, because all the fuel to the injectors is still limited by the pt system.
 
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You can go from 20 mic filter to 10 or 3 mic with fass. You get a fuel/water separator as well. 1/4 mpg increase in economy. Fass adds more fuel as it now is supplied to pt at 15 psi so when the gear pump pressurizes it is at a higher pressure to your injectors. Think of it as a fresh fuel filter as compared to a dirty one. Which would you rather drive?
 

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You think the PT compounds the pressure from the FASS? That's why there is a bypass back into the gear pump from the main housing because it only uses the fuel in needs, it will not change the output pressure.

I'm trying to get the guy to invest some money in something that will make a noticeable difference in the way his truck performs, and if tuned properly excellent fuel mileage can be had due to the way his driving style will change with more power. I just don't see spending $700 on something that might get you 20hp, when you can spend $450 and gain close to 100hp with just a simple parts change. Guess that dosent make sense.
 

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Sorry I wasn't trying to spend his $$$. Just providing info. It must raise rail pressure. I was told not to turn up pump much and add fass or you would bend the injector push rods. Increasing injectors would be best but anyone can install a fass or dual line. A well set pump makes driving much more enjoyable.
 

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In the interest of full disclosure, I sell Airdog fuel pump-air separators. I will not be quoting prices or making model recommendations.

In my own experience they do work. On my own truck I only use an electric pump to send fuel to a weak kneed Cat transfer pump. Someone once told me that Cat pumps are good pumpers but terrible suckers. When I replaced my mechanical pump I could not get over 30psi at the filter head. That was with a NEW pump. My mileage suffers greatly when pressure falls below 40 and that is where I change filters. My local cat house said it was pumping fuel so they would not exchange it. The new pump was barely better than the old one. I installed the electric transfer pump and now enjoy around 50psi. It did wonders for my mileage and changing filters is now a breeze.

Before deciding to hook up with the good folks at Pure Flow, I did quite a bit of defensive research. Ive heard plenty of snake oil sales pitches and I was not about to damage my rep by selling said oil. I found an SAE paper that explained that diesel fuel has air in it all the time. Its not from sloshing or filling the tank, its just there in tiny microscopic bubbles. Those are small enough to not do any harm. If the fuel is used in a gravity fed system thats what youll end up with in the injector pump. The paper also discussed the fact that as soon as you put the fuel under a vacuum (pulling fuel up to the engine from the bottom of the tank) those microscopic bubbles come out of suspension and join to become larger more visible air pockets. No amount of pressure or mixing will return the air to its previous state.

We have been dealing with air bubbles like these ever since we put the fuel tanks below the level of the injector pump. The engine will run and run well. Products like FASS and Pureflow Airdog pump and filter setups are designed to remove that air from the fuel as it heads to the injector pump. It is returned to the tank along with excess fuel returned from the injector pump itself. Will they remove ALL the air? Ive not tested that. But given enough time in the second filter most should be gone. If you visit the companies websites you will note in the illustrations that the so called "clean" fuel is drawn from the bottom portion of the filter can and since air rises naturally it can escape the top of the filter mount to be returned to the tank.

Nowhere in any sales literature (either company) does it say the fuel gets to spinning or aligns its molecules. The ones that do, in my opinion, are selling snake oil.

Now being the cheapazz that I am, I thought about making my own air separator until a kind soul brought up the idea that if the electric pump failed in my home made machinery, my mechanical injector pump would immediately attempt to pull fuel BACK through the return lines, quickly filling my injectors with air. Now then, that being something I didnt want to fix on the side of some dark highway and lacking the expertise to reliably prevent such an occurrence, I opted to use the same parts I sell. I just wanted to bring that up in case anyone else is so motivated to save a buck. Both the FASS and the Airdog are plumbed to prevent back feeding.
 
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