Idea on using both tanks with big fuel

Magnum PD · Feb 5, 2014

I was bound and determined to use the stock valve tank selector so I could use both tanks. I knew the drawbacks. But after reading the article in DP magazine when they went from 238/100's to 300/200's along with the S467 and gained minimal HP because of the stock fuel tank system, I knew I had to get a 5/8" pickup tube.

Still not wanting to give up the rear tank, (front one is already off) I wanted to see if there was SOME way to use the rear tank.

Got to thinking and I could use the stock lines from rear tank to plumb it into a small electric pump and to pump fuel into the stock 3/8" supply line.

Wiring is something I could use some help on. Since the harness for the selector valve would not be used, could I use a hot wire from that harness to run the pump when I switch to the rear tank or is there no hot wire on that harness?

Nodge · Feb 5, 2014

I've been tossing this idea around lately, I've considered using a separate pump for each tank, and using the selector for the return only, with a check calve ahead of each pump.

Magnum PD · Feb 5, 2014

When my front tank gets low, I just flip to rear tank, pump fuel to front tank, 1/2, 3/4, or more by flipping back and forth looking at the gauge.

Good thing is, is that I don't have to modify the rear tank.

mustube · Feb 6, 2014

I read somewhere on here that someone put a sump on each tank and one sump had a T that connected to the other tank so you have one sump feeding the other tank and the other sump leveling the fuel level and feeding your fuel pump. Didn't read much into it since I have a SD but it's something to look into.

Bair · Feb 6, 2014

mustube said:
I read somewhere on here that someone put a sump on each tank and one sump had a T that connected to the other tank so you have one sump feeding the other tank and the other sump leveling the fuel level and feeding your fuel pump. Didn't read much into it since I have a SD but it's something to look into.

That's sounds like my setup. Works good. Had it like that for 3 years and no problem. Mine sends all the return to the back tank so on long runs the front tank gets empty first. I'm thinking of splitting the return an sending some to the front tank and see if it'll even out.

96 CCLB
08 RCLB 2wd 6sp for sale
08 ECLB 2wd sold

backwoodsboy · Feb 6, 2014

I've been giving this a lot of though recently as well.
I'll post up the schematic I have drawn tomorrow if I can find it.

Wayne · Feb 6, 2014

There's gotta be some servo operated ball valves or an equivalent. have the tank selector switch operate the servos to open the ones for the tank you're on, and close the ones you aren't using aught to do it. If something like hat doesn't already exist, you just need to find somebody with the enthusiasim for it.

backwoodsboy · Feb 6, 2014

Wayne said:
There's gotta be some servo operated ball valves or an equivalent. have the tank selector switch operate the servos to open the ones for the tank you're on, and close the ones you aren't using aught to do it. If something like hat doesn't already exist, you just need to find somebody with the enthusiasim for it.

It isn't as easy as you'd think to find a 12v, diesel rated, normally open ball valves that have an adequate cross section.
Last I checked Parker had some, for $118 bucks a piece. Multiply that by 4 (one for each supply and return line) and things get expensive in a hurry.

The system I've come up with is much simpler, and has some added benefits. If it will work in the real world...not sure, but I'm fairly confident.

bluedge8 · Feb 6, 2014

Magnum, you lost me with your first post, so right now you still have a stock system? and have both tanks? As I look to put injectors in my truck in the future I have thought a lot about this, and have come to the conclusion that a large rear tank is the way to go. Same capacity, all in one spot, and if you guys are anything like me, will be able to use more fuel because you are not leaving 3-5 gal's of fuel in each tank. I see the "want" of keeping both tanks, but at stock capacity it just doesn't seem worth the cost and effort.

m j · Feb 6, 2014

Nodge said:
I've been tossing this idea around lately, I've considered using a separate pump for each tank, and using the selector for the return only, with a check calve ahead of each pump.

I think this is the way to go. -06 check valves are availble

Biggreen96 · Feb 6, 2014

Subd. I have an idea of how to do this with valves but would need to know if there is a hot in the harness for the selector. I'll get back later today and explain my idea I looked into.

Magnum PD · Feb 6, 2014

To say it simple, I want to pump fuel from back tank to front tank with small electric pump and power it with a hot wire from selector valve harness.

backwoodsboy · Feb 6, 2014

I couldn't find my original schematic, but here is one I put together in paint real quick between classes.

My theory is, there is a very limited amount of time where you are going to be WOT in a high pulse-width tune. After 20 seconds or so you're either at the end of the track, the sled isn't moving, you're going 120+ and there is a curve up ahead, or the dyno pull is over. Towing heavy where you are deep in the throttle for extended periods of time hopefully your p.w. is pulled back enough that the injectors aren't using anywhere near their capacity.
All of the lines between the 'reserve' tank and engine (both supply and return) are 5/8".
When you are light in the throttle, the HVLP lift pump is able to fill the 'reserve' tank. At the point where this tank is full, from a combination of the HVLP and engine return line, it is then returned back to the same tank it is being drawn from via the stock selector valve.
Times when you are using all the fuel your injectors will supply, you have the stock line coming from the selector valve feeding fuel to the 'reserve' tank via a lift pump, the 5/8" return line from the engine is dumping into the reserve tank, and you have an additional 2L of fuel already in the reserve tank.
An additional benefit of the 'reserve' tank is that by feeding into the top and drawing from the bottom deairation should be occurring.
I've also though about submersing the Bosch 044 pumps in the tank to reduce inlet restriction, minimize the number of items hanging off of the frame, and use fuel to cool the pumps.

A lot of these ideas I borrowed from Tarm's fuel system thread and adapted for use with dual tanks, so credit where credit is due.

Swaan · Feb 6, 2014

Why do you want to keep your stock tanks. Just get a 38 gal rear, re plumb all your lines to bigger and be done. More cap then your two stock tanks and way simpler.
Sometimes I think you guys over analyze things.
The stock lines and valves are just too small for big injectors or pumps that pump a lot of fuel.

bluedge8 · Feb 6, 2014

Swaan said:
Why do you want to keep your stock tanks. Just get a 38 gal rear, re plumb all your lines to bigger and be done. More cap then your two stock tanks and way simpler.
Sometimes I think you guys over analyze things.
The stock lines and valves are just too small for big injectors or pumps that pump a lot of fuel.

I think that is what I said,,,,,:ford:

Magnum PD · Feb 6, 2014

Swaan said:
Why do you want to keep your stock tanks. Just get a 38 gal rear, re plumb all your lines to bigger and be done. More cap then your two stock tanks and way simpler.
Sometimes I think you guys over analyze things.
The stock lines and valves are just too small for big injectors or pumps that pump a lot of fuel.

Reasons for me

-You have to buy tank, straps, sending unit and lines $200 bucks?
-Cant use spear tire holder any more
-time to change everything over
-already have close to 40 gallons now

All I need is a small cheap pump, filter, and a few wires