Big line question

[Lone Watie]

Well, I'm on my way now, got the bug. Couldn't wait any longer and installed my 3/8 vulcan line from FF to VP this afternoon. Moved my FP gauge down to the tapped fitting for the VP inlet. Re-primed the entire system (running isolator with little to no loss tested against a test gauge). Still running around 14-14.5 at idle, so thinking that lift pump not quite where it should be, but primes (key-bump) at a higher PSI than before I changed out the line, so thinking that opening that line up a bit helped out (positive thinking). Stuck now on next move, been reading past couple hours on airdog v. fass, etc (again, don't want to stir up a debate, as I understand it all will boil down to personal preference), or raptor v. fass hpfp, we'll see. Stuck my head up under the truck today and got a decent look at the fuel tank top, and think I can do this no problem without dropping or moving anything once I decide on which system to go with. I appreciate all the insight and suggestions here, and look forward to keeping you all posted on my next move. I did drop another 150 or so today with Geno's on some nice to have things like drain plugs, etc. Question, can I expect a bigger PSI difference if I just moved the OEM pump back to the frame rail, or will it just be a matter of it being easier on the pump because it's pushing not sucking? Also, I was reading elsewhere here of running air dog with factory filter still in place for fuel heating, will that head loss of fuel moving through 3 filters v. the airdog's 2 before the VP affect the overall pressure too much, or is the regulated pressure of the air dog sufficient to overcome this head loss? The good thing with all this is I'm no longer a virgin in the ways of messing with my fuel system and getting air out of it. I remember when truck was new, and original VP went out due to incorrect fuel gauge and fuel starvation, that first time I changed out the filter how long it took to get started again made me really worry that I was hurting something. Now I can get it back up and running with a few bumps and turns of the wrench in no time. By the way, pulled 23.4 out of last tank of fuel, hand calculated compared against the SGII, and includes 2500 feet of elevation drop/gain for my round trip to work. Been really grandmothering the thing though to achieve that, i.e. 55-65 depending on the gradient. I calculated last night a savings of around 150 bucks a month v. 15-16 mpg at 82 mph which is where I was 6 weeks ago which equals more goodies for the truck.

[guesswho512]

I was reading elsewhere here of running air dog with factory filter still in place for fuel heating, will that head loss of fuel moving through 3 filters v. the airdog's 2 before the VP affect the overall pressure too much, or is the regulated pressure of the air dog sufficient to overcome this head loss?

that is how i have mine plumbed. i believe mopar1973man's fuel system is that way also. remember that the VP44 has a fuel temp sensor, and it uses it to adjust timing.

The good thing with all this is I'm no longer a virgin in the ways of messing with my fuel system and getting air out of it. I remember when truck was new, and original VP went out due to incorrect fuel gauge and fuel starvation, that first time I changed out the filter how long it took to get started again made me really worry that I was hurting something. Now I can get it back up and running with a few bumps and turns of the wrench in no time.

perfect practice makes everything goes smooth/fast:cool:

By the way, pulled 23.4 out of last tank of fuel, hand calculated compared against the SGII, and includes 2500 feet of elevation drop/gain for my round trip to work. Been really grandmothering the thing though to achieve that, i.e. 55-65 depending on the gradient. I calculated last night a savings of around 150 bucks a month v. 15-16 mpg at 82 mph which is where I was 6 weeks ago which equals more goodies for the truck.

i am so jealous! my personal best is 18.0MPG! thats with 2stroke and 90% highway @55-65mph empty. i typically get 14-16.:banghead:

[Mopar1973Man]

Well, I'm on my way now, got the bug. Couldn't wait any longer and installed my 3/8 vulcan line from FF to VP this afternoon. Moved my FP gauge down to the tapped fitting for the VP inlet. Re-primed the entire system (running isolator with little to no loss tested against a test gauge). Still running around 14-14.5 at idle, so thinking that lift pump not quite where it should be, but primes (key-bump) at a higher PSI than before I changed out the line, so thinking that opening that line up a bit helped out (positive thinking). Stuck now on next move, been reading past couple hours on airdog v. fass, etc (again, don't want to stir up a debate, as I understand it all will boil down to personal preference), or raptor v. fass hpfp, we'll see. Stuck my head up under the truck today and got a decent look at the fuel tank top, and think I can do this no problem without dropping or moving anything once I decide on which system to go with. I appreciate all the insight and suggestions here, and look forward to keeping you all posted on my next move. I did drop another 150 or so today with Geno's on some nice to have things like drain plugs, etc.

Something to think about more that name is the GPH rating of the pump. You should at least get a 100 GPH pump.

Question, can I expect a bigger PSI difference if I just moved the OEM pump back to the frame rail, or will it just be a matter of it being easier on the pump because it's pushing not sucking?

There is little gain for moving the stock pump. But you got to remember the stock pump is about 25-30 GPH max.

Also, I was reading elsewhere here of running air dog with factory filter still in place for fuel heating, will that head loss of fuel moving through 3 filters v. the airdog's 2 before the VP affect the overall pressure too much, or is the regulated pressure of the air dog sufficient to overcome this head loss?

No... That's a internet myth... I'm hooked up with the stock filter and only have a 1-2 PSI drop. 17 @ Idle and 15 at WOT.

The good thing with all this is I'm no longer a virgin in the ways of messing with my fuel system and getting air out of it. I remember when truck was new, and original VP went out due to incorrect fuel gauge and fuel starvation, that first time I changed out the filter how long it took to get started again made me really worry that I was hurting something. Now I can get it back up and running with a few bumps and turns of the wrench in no time.

I was the same way years ago. But now it doesn't bother me to completely blow the system out and reprime the whole thing.

By the way, pulled 23.4 out of last tank of fuel, hand calculated compared against the SGII, and includes 2500 feet of elevation drop/gain for my round trip to work. Been really grandmothering the thing though to achieve that, i.e. 55-65 depending on the gradient. I calculated last night a savings of around 150 bucks a month v. 15-16 mpg at 82 mph which is where I was 6 weeks ago which equals more goodies for the truck.

My comments in blue...

Really good to 23 MPG isn't it... Now catch my high mark at 25.3 MPG... Typically on the open highway I'm pulling 21-22... Around here at home it can vary widely from 18-22 MPG depending on which road I have to travel up.

[Lone Watie]

My next goal is 25, but at what expense? 50 on the interstate? I'm already probably not making too many friends here in N. AZ with the truckers on I-40 bearing down on me before they realize there's an old lady driving a cummins. Probably will have to let the bug fester in me and start doing other things to achieve 25. I don't mind 55-65, it actually makes my drive to work more pleasant as I don't have to worry about constantly switching lanes to pass people like me, and the fact I'm saving significant bucks is icing on the cake. Question, without doing anything else other than what I've already done, and without stomping on it, will I gain much with BHAF with mpg, or is my stock set up sufficient flow for my OL style of driving? Thanks, I know this subject been discussed elsewhere, but forgot the answers.

[Mopar1973Man]

Basically you need a box that taps the VP44 and give considerable timing. some say Smarty is good for the 3rd Gens and for the 2nd Gen I'm in favor of the Edge Products. Like myself I'm running a Edge Comp on 5x5 and typically set my cruise at 55-60 MPH.

[Lone Watie]

Any possible way you could sketch up a quick flow diagram of how you have your air dog plumbed with the stock filter including the return line? Thanks, I can't seem to find the answer, but is the air dog output pressure internally regulated, or can you adjust it like the raptor pump?

[Lone Watie]

Also, I think you answered already, but when running through stock filter housing, are you using a stock filter there, or just the canister alone for fuel heating?What are advantages between air dog and air dog II?

[Mopar1973Man]

Any possible way you could sketch up a quick flow diagram of how you have your air dog plumbed with the stock filter including the return line? Thanks, I can't seem to find the answer, but is the air dog output pressure internally regulated, or can you adjust it like the raptor pump?

It is adjustable about the spring is internal and you need to pull the reurn fitting to access it. Pressure supply heads to the inlet of the stock filter. return head to the filler neck hose on the fuel tank. And suction is from my draw straw or (stock sender AD 100).

Also, I think you answered already, but when running through stock filter housing, are you using a stock filter there, or just the canister alone for fuel heating? What are advantages between air dog and air dog II?

Yes there is a filter in the stock canister too... You'll find you only need to change that about every 50-60K miles. But as for fuel warming and WIF light its nice... It cold winters it does help to getting the fuel warmed up a biut and remember the VP44 does monitor fuel temps and adjust flow and timing rates from this information. AirDog 100 - Uses stock pickup in tank (100 GPH) AirDog 150 - Uses a drawstraw add-on (150 GPH) AirDog II - Suppose to use the stock pickup in the tank but not sure... (165 GPH)

[Lone Watie]

In an air dog install, does the factory return line from the VP stay in place, if so, how does the return line for the air dog from the pump affect the factory return line at the tank? Thanks.

[Mopar1973Man]

In an air dog install, does the factory return line from the VP stay in place

Yes. it stays in place.

if so, how does the return line for the air dog from the pump affect the factory return line at the tank? Thanks.

Doesn't... The AD doesn't use that line...

[Lone Watie]

Will this work to take the fuel line off the top of the tank?

http://www.jcwhitney.com/jcwhitney/sku/images/large/I_362315_CL_1.jpg

[Mopar1973Man]

Not needed... Just squeeze the 2 blue tabs inward and lightly pull the line... My trick is un-screw the sender nut and then drop the tank down easy allowing the sender to hang. Then you can get right up there and squeeze the tab and pull ti loose...

[1danny70]

hey mopar man, danny here, question on one of these threads i read last nite and i can't find it now, but you and other people were talking about a 1/2 " line from lift pump to the vp44, i just changed mine in nov. 09(vp44) and i checked the pressure, and my numbers were 14 when i bumped it, then when i started it , it fell to about 12, and when i revved it up to 2krpm it fell to 10psi, my question is would running this bigger line help my fuel pressure and save my fuel pump as well, i also put the wally world 2-cycle oil in every fill up, and if you could tell me where the line runs, was it from the lift pump to the fuel pump, i looked on the vulcan web site and saw they had a universal kit for my truck, which is an 02 3/4 ton 5-speed with 117k on it and mine is all factory i don't have anything fancy on it, please help thx danny

[Mopar1973Man]

Yes... The increased line size does improve fuel volume and keep pressure higher... But also the stock fuel system isn't strong enough... The stock lift pump is like 25-30 GPH...(UGH!) I suggest a minimum of a 95-100 GPH pump.

[1danny70]

what type of lift pump are we talking about and is this an easy thing to do my self, putting the 1/2'' line kit and lift pump in.

[Mopar1973Man]

Here is what is all about... http://mopar.mopar1973man.com/personal/2002/airdog-150/airdog-150.htm

[1danny70]

moparman is there any other options for me on the big line question i had last nite, thx danny

[Mopar1973Man]

moparman is there any other options for me on the big line question i had last nite, thx danny

Ok you could do a big line kit and a Holley 150... http://forum.mopar1973man.com/showthread.php/1312-Holley-HP150-Installation-PICS?highlight=holley