Drawstraw Users - How low can you go?

[MikeH]

The older I get the more stops I need to make. Good excuse to pull over and fill up. I won't let my tank go under 1/2 and always add a injector cleaner/lubricant to the fuel. My VP44 is coming up on 130K since being replaced back in '07. A full tank will provide cooler fuel to the VP and the lubricant  (Opti-Lube Summer) handles any wear issues. Also, keeping your tank full prevents moisture from building up. It cost exactly the same to run on the top half of the tank as it does the bottom half...but it's your choice.

[Mopar1973Man]

Just did another trip where I ran right down to EMPTY mark no issues with 1/4 tank slosh or anything she kept on pumping and going. 

[Red Rambler]

Just so I am following correctly, @Mopar1973Manyou have your sending unit and float still installed in your tank, and your draw straw is in the middle of it? Or do you have a remote hole for your draw straw that doesnt pass through your sending unit basket? Just trying to look at my options as I might need to get a draw straw in the future. 

[Mopar1973Man]

The hole drilled for the draw straw. Not inside the sender bracket.

 

 

 

This is the thickness of a standard quarter (coin) between the tip and the tank bottom. Straight cut and then lightly notched with the edge of a grinder. to prevent sucking tight to the bottom. Never had 1/4 tank slosh issues or losing prime on steep grades. 

Edited January 25, 2021 by Mopar1973Man

[Red Rambler]

Thanks sir, is this the same as what you have? 

 

http://www.vulcanperformance.com/Draw-Straw-3-p/ds3.htm

 

 

Edited January 25, 2021 by Red Rambler

[Mopar1973Man]

Most part yes. Mine was the supplied draw draw with my AirDog but I know the truth that Eric and Vulcan Performance produce it. So yeah that is like it but mine was a bit different fitting wise as you seen my photos. 

 

The big things...

• Cut the straw STRAIGHT. No angles!
• The straw must be with in the thickness of a single quarter coin (my design) or 2 quarter coins (FASS Design) between the straw and the bottom of a empty tank.
• You may notch the end of the straw but no more than like a 1/8 of a inch and no more.
• Make sure to measure with the tank EMPTY. A full tank will deflect the bottom by nearly 1/4" from full to empty.

The trick is do this all on the empty tank so as the fuel runs out the bottom of the tank will rise back up to the straw allowing everything to be draw up and used. Where cutting to much gap now create the 1/4 tank slosh problem.

[crf450ish]

I don't have any pictures of my draw straw in the tank, but it's been working flawlessly since the day I installed my fass pump, draw straw and new VP nearly 8 years ago. I used the 2 nickels stacked on each other method when I installed my draw straw. Somewhere on another forum buried deep in the comments I read that's how you measure the proper length so as to account for the "sag" the fuel tank will have when full of fuel. 

 

Like a couple others have said, I too use the 1/4 tank mark as empty, therefore I like to fill up before it gets to 1/4. However, there's been a handfull of times I just simply could not get to a fuel station before that 1/4 mark...

 

I've been down to a 1/4 tank numerous times due to the fact I had no choice but to keep driving, many times in Montana when there wasn't a fuel stop anywhere for miles and miles. Each time this happened, when I did finally find a fuel station, I made sure not to decelerate or accelerate harshly as what little fuel there was left in the tank was sloshing around and air was being fed into the lines. A few times I heard the lift pump motor speeding up at the same time I watched my fuel pressure dip below 10 psi. I would always immediately throw the truck into neutral so as to let the engine run without a load. In my mind this was just a shot in the dark way of preventing any further wear on the VP because I knew there was air being sucked into the line.  

 

Always a rear end puckering situation to be in. Nevertheless, it's still going strong. 

On 1/26/2021 at 5:26 AM, Mopar1973Man said:

Most part yes. Mine was the supplied draw draw with my AirDog but I know the truth that Eric and Vulcan Performance produce it. So yeah that is like it but mine was a bit different fitting wise as you seen my photos. 

 

The big things...

• Cut the straw STRAIGHT. No angles!
• The straw must be with in the thickness of a single quarter coin (my design) or 2 quarter coins (FASS Design) between the straw and the bottom of a empty tank.
• You may notch the end of the straw but no more than like a 1/8 of a inch and no more.
• Make sure to measure with the tank EMPTY. A full tank will deflect the bottom by nearly 1/4" from full to empty.

The trick is do this all on the empty tank so as the fuel runs out the bottom of the tank will rise back up to the straw allowing everything to be draw up and used. Where cutting to much gap now create the 1/4 tank slosh problem.

I might install a new draw straw and use your method of measurement when I replace lift pump. My current lift pump is about on its last leg. Wish I would've known about your method 8 years ago 

[dieseldon]

Don't know if anyone remembers any of my posts from last summer when I was installing my air dog, but instruction sheet and my stock in tank sender/basket didn't make sense to me, I ended up taking it (fuel basket) to a local Cummins sled pulling guru mechanic and he told me ,  NOT TO USE THEIR DRAW STRAW! Just connect to stock setup, other than top hose connector, he said I was lucky that I hadn't ruined it yet drilling holes, ruining screen and what not, because people were running out of fuel too soon, especially on a hill, sloshing around or??

 Well, I took his advice and haven't had any issues, sender, basket, straw, fuel delivery seem to work just fine.

Maybe if I decide to exceed 500hp I'll need to re evaluate?

[Mopar1973Man]

Might check fuel temp in the summer below a 1/2 tank. Being you be re-pumping that hot return fuel from the head return.

[Threadzy]

I’m running my fuel supply through the stock basket. My return line is run to the filler neck. I still have 1/4 tank issues. Before the filler neck return I would see fuel temps as high as 165. Looking forward to seeing what it does now come summer time. This spring I may drop the tank again and install a draw straw. Like Mike has his. I usually fill up between 1/2 and 1/4 tank but if for what ever reason I need that last 1/4 tank I want it available. My Raptor 4G 150 pump I just put in came with a draw straw to put in the fuel bucket but if it’s having issues now I don’t see how that would help with the 1/4 tank issue. 

[dieseldon]

16 hours ago, Mopar1973Man said:

Might check fuel temp in the summer below a 1/2 tank. Being you be re-pumping that hot return fuel from the head return.

What is the critical temp to watch out for? And what exactly is the issue? How exactly does a slightly larger drawstraw cool down fuel?

I was under the impression that the vp needed good fuel pressure to thrive, (above 5psi) now I need to worry about temperature?

I can't help wondering why that mechanic, who works on and installs these systems on a daily basis would have me run it like that?

[Mopar1973Man]

 

55 minutes ago, dieseldon said:

What is the critical temp to watch out for? And what exactly is the issue?

Fuel start to create asphaltenes when you start getting upwards in temperature. I'm not sure what temperature but I know my setup never gets over 140*F much. This starts to plug up fuel filters. I monitor fuel temp right out the VP44 with the Quadzilla tuner. Even my last trip in 2020 to Arizona with temperatures over 115*F I never broke over 145*F fuel temp. Even after 600 miles of driving. My fuel temp and IAT temp follow within +/- 5*F.

 

55 minutes ago, dieseldon said:

How exactly does a slightly larger drawstraw cool down fuel?

It doesn't. The fact my straw is NOT in the fuel sender basket. This make my fuel cooler because the return from the rear of the head is the hottest fuel returned to the fuel basket. That fuel is heated to the same temperature of the head metal.

 

55 minutes ago, dieseldon said:

I was under the impression that the vp needed good fuel pressure to thrive, (above 5psi)

No. This is incorrect. Optimal is 14 to 20 PSI this keeps the return valve on the VP44 open and cooler fuel moving always. Below 14 PSI to 10 PSI that overflow valve start to close and completely closed by 10 PSI. So the 5 PSI number is rather damaging being the overflow valve is completely close no return fuel at all. This will continue to build heat in the pump. 

 

55 minutes ago, dieseldon said:

I need to worry about temperature?

I can say safely the fuel temp of 140*F and below is no cause for alarm at all. I think the P0168 code for VP44 fuel temp is set at 195*F IIRC. I've only seen 1 member with a over temp code. I've extended my filter changes to 60k miles being the filter stay much cleaner and at 15k miles my filters still looked new. I've seen members here reporting 150 to 160*F temps with returns in the fuel basket. 

 

AirDog 150 filter after 15k miles.

 

54k miles on this AirDog 150 and barely colored... Stock filter is the same time.

Edited February 3, 2021 by Mopar1973Man

[Dieselfuture]

29 minutes ago, Mopar1973Man said:

've seen members here reporting 150 to 160*F temps with returns in the fuel basket. 

I'm one of them, I think I seen mine at 170 before

[dripley]

Well I am the crazy one. Both return lines to the basket along with the pick up. I dont know the fuel temp. My last VP went 270k+ and about 245k of that was on that set up. I also like to run my tank low between fill ups running the interstates. I am not trying to cast doubt on whats being said, its just how I roll. also never had a over temp code from the fuel. I dont know how hot it gets.

[LorenS]

As much as we all like to tinker, maybe the next big thing is putting in a 3-way valve so we get benefits of warm fuel in the winter and cooler fuel in the summer. Or, install a radiator-style thermostat so we don't even have to think about it! Mine goes to the basket and I went over 150 this summer. Just a DRP, so no fancy return.

 

Has anyone run separate returns from the VP44 and head? One to basket, one elsewhere?

[Royal Squire]

Perhaps if you’re having 1/4 tank issues it’s because your fuel gauge is inaccurate 

[LorenS]

2 hours ago, Royal Squire said:

Perhaps if you’re having 1/4 tank issues it’s because your fuel gauge is inaccurate 

Nope. I "run out" with 7 gallons in the tank after I drive down an off ramp.

[Threadzy]

Mine started doing it after my Raptor 100 was installed with the big line kit. I’m sure it will be the same with the 4G 150. I’m thinking it’s sucking the bucket dry or a crack in the plastic tube in the bucket. I put a new fuel sending unit in it a few years ago.   Haven’t felt like dropping the tank again. 

[Mopar1973Man]

13 hours ago, LorenS said:

As much as we all like to tinker, maybe the next big thing is putting in a 3-way valve so we get benefits of warm fuel in the winter and cooler fuel in the summer. Or, install a radiator-style thermostat so we don't even have to think about it! Mine goes to the basket and I went over 150 this summer. Just a DRP, so no fancy return.

 

Has anyone run separate returns from the VP44 and head? One to basket, one elsewhere?

 

This though I would bother doing either. Cooler fuel is welcomed for the PSG. This keeps the the electronics and the mechanical parts cool. Most of my 5 years of driving in subzero weather taking @MoparMomto dialysis I never got much below +20*F at -30*F outside temperatures. Do remember that my truck still has the factory fuel filter and fuel heater and the leeched heat from the heat taking care of fuel warm in the winter time. Like right now I'm 50 to 70*F fuel temp for a +20*F to +30*F day. Also my IAT and Fuel Temp are running side by side most times. (+/- 5*F) between IAT and fuel temp.

[Dieselfuture]

28 minutes ago, Mopar1973Man said:

Do remember that my truck still has the factory fuel filter and fuel heater and the leeched heat from the heat taking care of fuel warm in the winter time.

How is that heater controlled, is it always on or iat does it?