Engine/Transmission (1998.5 - 2002) Vulcan Draw Straw

[AFoulk]

I had someone tell me today that if I were to install one of these, I wouldn't be able to run my fuel lower than half a tank or something like. I guess the reasoning is that you install the Draw Straw outside of the factory sending unit/pickup which means the Draw Straw would be outside of the baffles and once the fuel gets low enough and starts sloshing around, you'd have fuel pick up problems. Is this true?

 

[jkalchik]

I put one in last October, in my 99 SB QC. I regularly run down under a quarter tank. I've never had an issue, and I've had the DTE in the overhead console go under 50 miles a couple of times.

Caveat. I *DID* install the pickup way down near the bottom of the tank. If you install it higher, YMMV.

 

[Cummins724]

I have been running one in my truck for over a year... . no problems. I have run the tank down below "E" many of times with no problem. You adjust the pickup depth of the straw yourself by cutting the tube near the bottom of the tank..... unless you cut the straw really short... . I don't understand why they said you would have a problem.

 

[Huff N Puff]

I had someone tell me today that if I were to install one of these, I wouldn't be able to run my fuel lower than half a tank or something like. I guess the reasoning is that you install the Draw Straw outside of the factory sending unit/pickup which means the Draw Straw would be outside of the baffles and once the fuel gets low enough and starts sloshing around, you'd have fuel pick up problems. Is this true?

He's right,You take a big chance when you pull erated fuel into your injection pump it may miss and stumble, you may not feel any issues,but small amounts of areated fuel will reak havok on your injection pump. To take advantage of the draw straws flow capability you need to open up the fuel module, when you open up the module sloshing fuel will let air in. If you dont open it up the draw straw will suck it dry.

 

[jeepit]

He's right,You take a big chance when you pull erated fuel into your injection pump it may miss and stumble, you may not feel any issues,but small amounts of areated fuel will reak havok on your injection pump. To take advantage of the draw straws flow capability you need to open up the fuel module, when you open up the module sloshing fuel will let air in. If you dont open it up the draw straw will suck it dry.

I am going to go with the Draw Straw in the stock canister. I am not so sure of the areation problem this may cause. I could see this more likely to occur when the straw is placed outside the fuel module as in the case of a Draw Straw II.

 

[NoSeeUm]

I have had no problems, but I do worry about air like you do.



It sounds corny, but this is advice from my Dad who was a mechanic for many years.

It has been my experience that an automobile runs just as well on the fuel in the top half of the tank as it does on the fuel in the bottom half of the tank

Jim

 

[Cummins724]

I'm lost on this subject. How would the Straw suck air? It is touching the bottom of my tank & sticking out of the bottom of the module just like the stocker. You could run my truck down to the last drop & never know that the pickup tube has been modified. It works just like the stock unit.

 

[AFoulk]

HuffnPuff, in other words the draw straw would be a wast of money then? If I interpreted what you said right, with the drawstraw installed in the stock module, it will actually suck the module dry if your drawing enough fuel? Is there anyway to put a bigger draw tube in the tank and not have to worry about fuel sloshing away from it when the level gets low? I plan on installing an AirDog or FASS system so I figured that should take care of any ariation problems.

 

[Cummins724]

HuffnPuff, in other words the draw straw would be a wast of money then? If I interpreted what you said right, with the drawstraw installed in the stock module, it will actually suck the module dry if your drawing enough fuel? Is there anyway to put a bigger draw tube in the tank and not have to worry about fuel sloshing away from it when the level gets low? I plan on installing an AirDog or FASS system so I figured that should take care of any ariation problems.

The draw straw requires you to drill a 5/8" hole in the bottom of the module & 3 more holes around it..... no chance of sucking it dry. All the stock screens are eliminated except for the bottom cap screen where the draw tube suction tube ends. Everthing in the stock module is eliminated except the fuel level float/assembly. I have the instructions here if anyone would like me to fax them to you.

 

[blacksheepdiesel]

AFoulk,

With an AirDog your aeration problems are solved as that is what it is designed to do - remove the air from the fuel before passing it on to the injection pump. Does not matter whether or not you have the factory suction tube or the Vulcan (installed correctly, not cut off too short). If you have the factory suction tube and install an AirDog you are wasting time and money on the Vulcan draw straw - simply not needed. Trust me, I've driven my truck for 140,000 miles with the AirDog putting out 19psi at idle and WOT and it is drawing the fuel through the factory suction tube.

Godspeed,
Trent

 

[Cummins724]

AFoulk,



If you have the factory suction tube and install an AirDog you are wasting time and money on the Vulcan draw straw - simply not needed. Trust me,

I had a rusted, leaking fuel pickup assembly that was just on its way to busting off completely. I was lucky for getting the straw when I did. They are aluminum & no way of rusting.

 

[blacksheepdiesel]

Cummins724,

Agreed, if there is an issue with the module like yours, absolutely go with the Vulcan. If there is nothing wrong with it, no need to spend time & $ unless a guy just wants to.

Godspeed,
Trent

 

[NoSeeUm]

I'm lost on this subject. How would the Straw suck air? It is touching the bottom of my tank & sticking out of the bottom of the module just like the stocker. You could run my truck down to the last drop & never know that the pickup tube has been modified. It works just like the stock unit.

Some where I have read on TDR where some one had a problem. I am not sure how they went about installing the Draw Straw.



Doesn't the OEM draw tube have a foot valve of some sort?



Jim

 

[Fishin Guide]

The whole aeration of diesel is rediculous.



We are pulling fuel from the lowest point, not at the top of the formation of foam. I have run a Draw Straw for over 40K miles with NO issues. We have done the clear hose test and there is absolutely no air in the sytem.



In my opinion, the entire "air filtration" is nothing more than a marketing gimmik. For every claim one way, you can find one just the opposite. BTW, I have some Tornados for sale that will increase your milage and power. If you use two in opposing directions, it straightens the airflow and raises the pressure density of the charge!



See what I mean, I can claim anything! :-laf



I can tell you this. With the addition of the Draw Straw, my system went from sucking some air to sucking nothing but fuel! This was due to the funky stock leaking module fittings. Why were they doing that? Because I was pulling enough volume to warrant an increase from . 24" ID.



Dave

 

[NoSeeUm]

Yeah, what Dave said... .



But my interest is sparked up on that Tornado. I am thinking it is one of the few these I have not put on my truck and for some reason that makes me think I need one.



Got a Link?



Jim

 

[Fishin Guide]

I'll senf ya a PM Jim! :right:



Dave

 

[rweis]

Just a FYI:



There is another thread about installing the DrawStraw and trying to figure how deep the fuel is when the "low fuel" MIL comes on.



We figured that there is aobut 3. 5 gallons / inch in the bottom 3 inches of the tank. If you go to "low fuel" (10 gallons remaining) and the tank is level there is about 3 " of fuel.



In the flat land where I drive 3" is plenty. Mtns you might want to consider more depending on where you drive (grade).



One person on that thread was thinking about installing a sump to insure the DS had fuel. There were thoughts of baffels (tank does not have baffels) to keep fuel around the DS. One idea was for those that bypass fuel BEFORE it is heated by the VP44, dump it in a sump for the DS. Add a aux tank to keep the OEM fuller.



Some thoughts,



Bob Weis

 

[Huff N Puff]

HuffnPuff, in other words the draw straw would be a wast of money then? If I interpreted what you said right, with the drawstraw installed in the stock module, it will actually suck the module dry if your drawing enough fuel? Is there anyway to put a bigger draw tube in the tank and not have to worry about fuel sloshing away from it when the level gets low? I plan on installing an AirDog or FASS system so I figured that should take care of any ariation problems.

Below 1/3 tank of fuel under heavy braking or acceleration you will pull air I have experianced this first hand I have a Preporator,I would hear the air pass thru it, the hum would change to a sporatic buzz. If your truck is stock, the intank pump is adequate. If your fueling pretty heavy, gang it up with a pump outside the tank. To you guys out there who say areation is not a problem,Have you ever filled your tank and watched it froth out the filler neck. Diesel fuel froths and erates really easily. The Airdog and the Preporator will get rid of little amounts of air big gulps might be another issue. What do you guys have against the fuel pumps in the tank, engineers have been doing this for decades,in cars and aircraft, Ive been doing this for a living for 30YEARS. I trust the engineers in this case cause it makes sense. I guess you guys know better.

 

[Fishin Guide]

I don't mind an in tank pump. Now, find one that will last and support my horsepower.



I am curious wher all that air goes the filter takes out though? I mean, is it a vacuum? Or is it pumped back into the tank? Cause if it is, and that fuel is falling from the top of the module or say, the filler neck, it is being aerated even further?



Dave

 

[AFoulk]

I wasn't so much worried about the ariation as I was not being able to draw enough fuel. I'm not planning on getting real "gonzo" with the truck, but we all know how those plans change I just wanted to go with with a FASS or an AirDog for the added press. incase I do decide to get crazy with it and I liked the idea of having the extra filtration of the filters that come on them. As for the engineers, if they new what they were doing, they wouldn't have mounted the lift pumps on the engines to begin with. Its not always about what "works" with them, its about cost most of the time. Trust me, we've dealt with engineers a lot at the Mack dealer I work at. Just for example, we had a new truck with an engine vibration and we tried everything, couldnt' get rid of it. So finally they suggest ripping the front of the engine apart, pull the auxillary shaft, put it back together and run it. Their theory was that maybe the shaft was bent slightly from the factory and that was causing the vibration... this was all just to test that theory. Now, keep in mind that on a mack, the aux. shaft drives the air comp. and the oil pump. Now I'm guessing they thought long and hard about this one before suggesting it. So our service manager said "ok, how long do you want us to run this thing without oil press. ?" Their response... " oh *@!t, maybe we don't wanna do that. " I've found engineers aren't always as smart as everyone makes them out to be