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Fuel return line

Cali6.5

Cali6.5

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I notice when researching LPs that some of them advertise a regulator so no need for return fuel line. I thought that the return line was the IP and injectors back to the fuel tank and that the LP only has a line in from the tank and the line out to the FFM. I noticed the ADII flow diagram shows flow going back to the tank with removed air in it. Can someone shed a little light on the aftermarket pumps and have or not have additional return lines to the fuel tank?
Thanks
 
Airdog pumps remove air from the fuel and will need to tap the return line for this purpose. Otherwise most lift pumps don't address air and thus don't need a return line.
 
So with an AD system there will have to be a return line fabricated to go back to the tank? If there was an aftermarket sump installed then the return could go back to the original fule lift line correct?
 
So if I go with something like the AD (that doesnt have a 6.5 style harness, I think) could I just snip and couple wires to AD? Is there more than a hot and nuetral in the harness? How about cutting the harness off of the stock LP that I have now and the connecting it to the AD and then wuick connect to factory harness?
 
If you going to all the trouble go ahead a build a harness with a relay to take the load side. You can use the stock LP connector, but use it as a trigger to relay only and run some heavy gauge wire to power AD.
BTW: The walbro will supply enough fuel for any 6.5 I know of.
http://leroydiesel.com/Fuel_Delivery.html <Also scroll down to 4th item Raptor-100
 
You know I was oringinally going to do that, it seems real simple. Is the AD air separation thing a big deal? is it snake oil so to speak? It sounds to me like in your opinion that one wouldnt need more than walbro? Walbro is just the line and out correct? I think I read that it uses the factory harness?
 
I just installed the AirDogII DF-165 (joy starts on post 156).
Return Line is included in the kit along with an adaptor at fuel filler neck (Some assembly required).
An electrical harness is also included in the kit so no need to DIY that one. You could splice in to the OPS circuit at the LP but another member here, Jrocket01, is seeing electrical issues (lights flickering etc) when high demands are placed on his AirDog 100gph unit.
Fuel Line lengths will have to be adjusted according to your mounting location. But, there is plenty of material to work with so one can mount it just about anywhere except a trailer and make the runs work.
D-Max installation manual available on the AirDog web site for download so you can see what's included and get an idea of what you're up against.

IMHO, Unless you plan on some very hard driving and feel you need the increased fuel demands, pickup the Walbro and save the difference over the $670 for the AD-165. If you're in a good place and are one who enjoys discovery, then by all means, go for it.

With my Walbro, I also purchased the Wix Pre-LP filter set up too. For power, one just nips the connector off the old LP and splices it on to the Walbro. Same thing could be done with the AirDog except for the issue mentioned already.
 
THanks Pave. I get it the AD has a harness that goes to the fuse box or somewhere up there and just disregards the harness that is there for the stock pump.As seen on my avatar pic, I have a 9600 lbs horse trailer and when it is loaded with horses and what not it should be 14K-16K. There is a 2 mile long 6% grade that I will have to travel over at times, does that sound like the walbro could handle that? I want to do the fuel system first in preparation for ATT, FFM mods and maybe IC. I would love to not spend $600+ on a LP but was kind of sucked in with the whole air separation thing of the AD. I didnt see info like that on the walbro.
 
What exactly is in the tank? I figured just the straw with sock and then the level indicator but then saw the upgrade component on the AD site and thought maybe there is more there. If the Walbro is enough then I was thinking of a sump and run a custom bent hard line (I bend SS tubing at work) to the filter then to pump then to FFM. It would very clean with hard lines, no rubber hoses. I think the Walbro just has NPT threads that I could attache fittings to?
 
I don't know much about the AD system, so only will reffer to the Walbro.
As I said 99% of 6.5's will benefit alot from it. I noticed an imediate improvement on my Suburban. I get reports back all the time from customers that love it.
That combined with FTB and I don't think you will run out of fuel even towing.
Im going to get with my machinist and see if we can come up with a fitting to draw fuel from the bottom of the tank (like a sump). My target price will be $35 for it.
And yes Walbro uses stock Harness, I inlude a connector to make it plug and play or you can cut the one from the stock pump.
 
I can't comment as to the Walbro's ability to seperate air from fuel. I just don't have the knowledge base. The new Walbro's are supposed to be quite capable in meeting demands but if you've got concerns...You may want to take a look at the towing resource forum too. Fuel and exhaust specific discussions there.
The AirDogs can be purchased in several capabilities and the DF-165 (Probably others too) is supposed to be self regulating, able to adjust to the demands the motor places on the fuel system. The max output is adjustable with the turn of a screwdriver. Again, bang for the buck.
If you're near West Covina, you could PM jrocket01 and link up with him for some hands/eyes on time.

On Edit: The previous owner of my DF-165 had this thing set at the mid-point, with the filter removed from the FFM, he said he keyed on to fill the bowl a bit and fuel shot straight up against the hood and deflected about 30' to the front of the truck. I wasn't there but that's the story...just saying.
 
Burning oil said:
I don't know much about the AD system, so only will reffer to the Walbro.
As I said 99% of 6.5's will benefit alot from it. I noticed an imediate improvement on my Suburban. I get reports back all the time from customers that love it.
That combined with FTB and I don't think you will run out of fuel even towing.
Im going to get with my machinist and see if we can come up with a fitting to draw fuel from the bottom of the tank (like a sump). My target price will be $35 for it.
And yes Walbro uses stock Harness, I inlude a connector to make it plug and play or you can cut the one from the stock pump.
Click to expand...

Leroy, what's the difference between the FRB-5 and 10 you're marketing now...output wise. That may help him decide.

Cali6.5, with your fab skills, and availability of line, you'll have an easier time installing the new pump. I'm looking forward to the pictures. Hope I haven't embarrased myself with my set ups.
 
Thanks Pave. You know I started really intimidated by a lot of this but assuming that there arent exotic threads to get in the way everything can just be fitted up really clean. Even if there are exoctic threads...just get a machine shop to make a fitting. Maybe easier said then done. I have to do all my gauges first including LP pressure so I can compare before and afters. Then I am going after the fuel supply, then the ATT. I just cant get the money fast enough. Man since I started this stuff about 2 months ago I am just addicted, cant stop looking at what to do and have spent so much $$ getting reliability taken care of that I have to slow my role cause I just want to swipe the card and get it all done now. Thanks to everyone for their input.
 
Looking at the link that Leroy put up. The small Walbro puts out 45GPH. I have a 30+/- gallon tank and it takes hours of the engine giving everything to burn that much fuel. Why would someone need more pump than that, yet Walbro alone has one or two bigger pumps. Who's truck can burn 45GPH? Is there something that I am missing?
 
manf #s are usually best case scenarios. ie no input restrictions and no output restrictions. if you factor in tank sock bends in the line etc on the input side and the more line and a filter on the output side the actual gpm might be much lower.
 
ak diesel driver said:
manf #s are usually best case scenarios. ie no input restrictions and no output restrictions. if you factor in tank sock bends in the line etc on the input side and the more line and a filter on the output side the actual gpm might be much lower.
Click to expand...

Thats right, and with a FRC10 you'll probably see 9-10 PSI at the IP/idle and 3-4 at IP/wot.
 
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