Fuel System Design Ideas

FaSSt9602

FaSSt9602

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I have been trying to gather some information on a good, solid, not over the top fuel system for my truck, and I have been reading post after post and picking many people brains for ideas and thoughts on a fuel system. If you want to figure fuel line size into it, lets say -8 main feed to -6 splits...

I am for sure going with either a FASS, or more than likely, the new AirDog2 stand-alone system, and I think that would be the starting point for 95% of people here unless you are going for an over=the-top build, so lets leave that as equal on all systems.

I have seen three major systems show up on here and I think all are good ideas, but there has to be pros/cons to each so I would like to see what people have to say about them. What would be the capabilities/limits of each set-up?

1) FASS run to the stock housing, and into the heads (with or without larger upgraded lines to the front of the heads) and only a cross-over line on the back of the head. Fuel is regulated at the FASS and the cross-over simply equalized pressure to try and keep the rear injectors from starving for fuel.
Pro: Somewhat easy to install and the least expensive
Con: Fuel still more or less "deadheading" in the system. Fuel sits in the line or head until injected. Any air still trapped in the system until injected.

2) FASS run to the engine with some sort of bought/homemade regulated return system.
Pro: 100% of the fuel running through the head and back to the tank at all times. Fuel always there at selected pressure and not stuck getting hot.
Con: FASS is regulated...redundancy with the regulated return?

3) FASS to distribute to all 4 corners of the heads. -8 to -6 hanging over the engine like a spider. One of the newer versions that a few people have run.
Pro: Rear injectors fed fuel.
Con: Still "deadheading"?

1A) A twist on 1. FASS to a Y-block on the front side of engine. New larger lines to front of heads. New "corss-over" lines on the back of the heads that meet at another Y-block which has a "regulated" orifice with a line going back to the tank. There is no regulator on this only the small orifice to allow fuel to move through the system
Pro: Heads tied together with equal pressure. Orifice allows for some fuel to continually be sent through the complete system in order to prevent "deadheading" and heating up of the fuel.
Con: ???

These are the 3 most popular methods (and 1 that I recently spoke to a vendor about) that I have seen. Again, these would fit what most people would be doing here and I think there could be some useful information shared on the different systems. What is everyone's opinions? For my personal use it will be with 190cc injectors max (most likely), so any of these should be up to the task, but I would like to put something together that works and will continue to work just in that off chance I go bigger.

Troy
 
FASS 150/180....-6 line to the motor. Cut out the secondary fuel filter housing and Y it with -4 lines to the heads.
Come out the back of the heads with -4 into another Y then straight back to the tank.

The FASS regulates the pressure...no real need for an adjustable regulator or any kind of "orifice" with that pump.

Simple, inexpensive and will provide enough fuel for just about anything you want to do.

PS...all these -8 to -6 lines are drastic overkill on 99.9% of trucks out there.
Save your money.
 
Unless I misunderstood what Dan at FASS was telling me, yes.
Doug would be able to answer that for sure....I have been known to hear things wrong before.
 
UNBROKEN said:
FASS 150/180....-6 line to the motor. Cut out the secondary fuel filter housing and Y it with -4 lines to the heads.
Come out the back of the heads with -4 into another Y then straight back to the tank.

The FASS regulates the pressure...no real need for an adjustable regulator or any kind of "orifice" with that pump.

Simple, inexpensive and will provide enough fuel for just about anything you want to do.

PS...all these -8 to -6 lines are drastic overkill on 99.9% of trucks out there.
Save your money.
Click to expand...

What if you have the itp rr like I do? Then what do you recommend, Rich? Thanks.
 
I had a Aeromotive regulator foul in the same set up Rich described and I could not keep the pressure above 25psi. with it open in the return off the heads. I was running the 660 pph. aeromotive marine pump. It would pin a 100lb. gauge when working properly with the boost reference. FASS may be completely different but I would think you needed something to restrict the fuel out of those heads. Open 6an lines are gonna take ALOT of flow to build any pressure I would think.
 
I talked with Dan at FASS several times. Since we have swapped out and replaced all but one of the 150/180 pumps I have sent out. They had found a fixed orrifice return to the tank was the optimal solution. Rich's setup worked well for the first system they designed for us using his truck. The problem was after a longer term durability of the big pump dead heading. 180 gallons per hour will drain my 38 gallon fuel tank in a little over 12 minutes.

Thats more fuel delivery than what a buggati veyron goes through at 252 miles per hour. Since it drains its tank in like 10 minutes. Dan at FASS says to use a fixed oriffice. How is that different from a spring type regulator? Well the regulator has to be cracked open. Orifice doesn't. If the pump bangs off the regulator it can lose prime and the fuel drops out of the pickup tube. Then it sucks air. Then you here it go nuts purging it off back into the filler neck. You could put a simple ball valve or whatever fitting in the return.

Ok so since the cylinder head has a .355 inch hole in it. And 6an is .375 thats the largest line you could ever need. So a kit with a 4an line and fitting is technically about 35% of the size of the port in the head. So why spend the money on 4an kits? I have no idea. A supply to the motor that would maintain constant volume across each 6an to the head would be theoretically the largest ever needed. So don't worry about 20an fittings.

If you are hell bent on changing it our buddy Earl at Earl's fittings makes a 6an to 12mm x 1.5 90 degree swivel. Then do whatever your heart tells you. Go into one head and out the other like a big circle. Fill from the front. Fill from the back. Who cares.

Last but not least. If you feel as though you might just be lighting money on fire with this. Don't do it. Send it over to me and I'll let you know how many BTUs can be generated by burning up the cash.
 
Does anyone have the size of the fitting needed for the front/rear of the head? If it can fit, which it should on the front, is there an advantage to using a full flow fitting going into the head as apposed to a banjo bolt?
 
FaSSt9602 said:
Does anyone have the size of the fitting needed for the front/rear of the head? If it can fit, which it should on the front, is there an advantage to using a full flow fitting going into the head as apposed to a banjo bolt?
Click to expand...

I don't know if you read my post above. 12mm x 1.5 is the threads in the head.
 
Understood, but without getting under my truck and looking at the clearance between the back of the head and the up-pipes, is this fitting low-profile enough to fit? I figured that is why most kits came with Banjo fittings, but I would rather not use them...
 
may I recomend somethin here for this??? visit www.trustedperformance.com

As far as running a line from the back of the head, they are extremely close to the up-pipes and no flexible line is rated for the much heat. That's why you want a Stainless Steel tubing back there with a banjo. this is the fuel system that will be one my truck once we get her back on the road for 2.6 class sledpulling!! their kit wont be overkill but still be enough to supply the fuel if going with a bigger injector later on down the road.......
 
That is where I am planning to do some shopping as well, but am 90% sure I am going with either the FASS or AirDog2, and since they are self-regulating, I don't want, or need to spend the extra money on a regulated return set-up...

For those out there that have a FASS and a regulated return (Blk350on20s for one), how are you running it? Is the regulator more or less turned up so high that is does nothing, or is your FASS set-up so high that the regulator is doing the work?
 
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