got a new blue chip vp44, then got a raptor rp 150 installed and realized i actually have an in tank pump and didn't know it. i bought this truck used and never had to deal with the fuel system. i replaced the vp and installed the raptor in place of a stanadyne pump on the frame that just wasnt high enough on the fuel pressure so the raptor plumbed right into the spot where the stanadyne was. i suffered a little brain damage until i discovered the in tank pump as i had no fuel up front at all when bleeding the system. i had accidently unhooked the power for the in tank pump, whoops.... didnt know it was there so i unplugged a harness and plugged in the raptor, i ended up slicing both sets of wires into one for the Ecm plug
so both pumps are working together now and my current fuel pressure is 14 idle. 12-13 wot, hardly any drop at all( stanadyne was 10psi idle, 6-7 wot)
i will address the in tank set up later when i change out out the lines to the bigger stuff do the draw straw or sender if need be. if anything blows out i can still hook up my stanadyne with a little time and effort as my back up set up. i spend alot of time in the boonies so i need a second system. all this will go if anything bad happens and get the full mechanical fp.
so i am feeling much better now about my new vp and having good psi etc... now to try and get big line stuff everywhere and get the banjo bolts off everything that are still on the stock filter housing.
this game never ends....... but my truck runs after sitting for 4 months saving up for the parts

 

are you guys liking my set up? fp good etc... is the raptor set too high?

 

I have my raptor set at 18 idle, can go as low as 14 WOT with 15k lbs behind me.

The same question comes to mind for me....Do i have it set too high?

I would think that any fuel line could handle 30 psi fairly easy, but I really dont know. lots of air pressure hoses hold 100 psi with ease.

If it gives you peace of mind, I have been running this setup for about 30k miles with no issues.

I may actually even be higher than 18, it max's my guage out at 18.

anybody out there think we are gonna bust something at these pressures?

 

I think you're both good on fuel pressure. MeanGrn, the only thing that worries me about your set up is that your running two pumps inline. I believe you would be better off removing the in-tank pump from the system.

 

i will at some point, but my *** got kicked on this and i dont have a shop or anything to work in and it's full on winter up here where i live
what problems could that expedite? most i have talked with dont like the draw straw as you have to keep tank at 1/4 all the time and i know some still use the sender set up as well and i might do that if i can find one, otherwise gonna do big lines, draw straw if i have too etc... and be done
and as far as i know most guy were running dual systems like this for years with no problems, i already had another pump where i put the raptor and i have owned this rig for 4 years with no problems

 

I'm not saying your set up is wrong. It has obviously been working for some time now. I just feel that it is not the best option.

In the fire service, when we are performing a relay operation (pumping water from a source to the actual attack truck) we always try to use the bigger pump at the source. This insures the source pumper can supply more water than the attack truck can use. If the trucks are revesed it's possible to not have enough water for the larger pump, which could lead to damage or poor performance.

In your situation, I'm sure we could agree that you have the lesser pump at the source. The trick is for the intank pump to always supply enough fuel for the Raptor.

If its working then you should be alright. If one pump has problems then the other pump has to work that much harder to overcome the failed or failing pump. Since you are monitoring fuel pressure you should be able catch any problems early. Then you would only need to figure out which pump is the problem. You seem ready to address any issues as they arise.

 

I think you guys are right on target with fuel pressure. When I first installed my Airdog I was at 24psi at idle. It caused me hard starting when the truck was warm. I dropped the pressure down to 15 at idle and I am good to go now.
The draw straw is not an issue anymore if you do the install correctly. When your fuel tank is installed it has straps at each end which allows the middle (where the drawstraw resides to droop. Now when some folks were doing their installs they would set the tank on the flat ground which removes the sag. This is primarily where the 1/4 tank issues comes in to play from what I understand. When installing a drawstraw, prop the tank up on a couple 4X4's at each end. This will give you the droop you are looking for and then you can measure your straw appropriately. I can get mine down to 1/8 a tank or more (I don't like to get lower then that and even that is too low sometimes, the dollar rules my fill schedule though).
Just some things to think about.

swordfish

 

I like to fill up at 1/2 tank. Keeps me from knocking the bottom out of a Ben Franklin.