The quest for more fuel... TESSEN's Auxillary tank design!

[sck_nogas]

Okay, as I've shared a few times, I'm on the quest for the ability to carry more diesel fuel, and since I've moved my spare tire I can finally look into doing this.
The design I've been messing around with has a current volume is 3.7698 ft³ which could in THEORY hold another 28 gallons of fuel. (more likely to hold a mere 24-25 gallons)

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But how should i connect things? I've got a few ideas. I want to avoid having a second fill connection, since I'm weird that way. Plus, I like the idea of being able to run most of the time with the aux tank completely empty for MOST of my driving, but when it's time to go into the wilderness, I then store more fuel (like a camel).

• Since I'm an automatic, I have a dual tank config.
  
  
• GrowlerBear has done a few modifications to his mid tank to connect another 3rd tank
  
  
• So, if I didn't do any internal modifications to the Mid tank, like GrowlerBear. I'd have this...
  
  
• But, my current thinking is to have a simpler transfer option using electric facet fuel pumps to move fuel back and forth only needing to add two T connections to the stock hoses. Plus with a faster marine fuel transfer pump, I can move fuel incredibly quickly!
  

So, I purchased the pump and components, then started mocking up the design using foam core board to do a few test fits... (this version of the foam core model needs to be slimmed down more to add more clearance for the shocks and leaf springs.

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Next up is to look at finding someone in Southern California to weld up the auxiliary tank! Plus add a SOLID bash guard to protect it.

Update #1: Pictures of the install are available further on in this thread.
Update #2: Parts list and design files are also available further on in this thread.

 

[Pdxdeli]

Looks pretty good. What are you hoping to have the tank made out of? I know a few aluminum fabricators that do fuel cells and aluminum work from my racing days in San Diego.

 

[sck_nogas]

Looks pretty good. What are you hoping to have the tank made out of? I know a few aluminum fabricators that do fuel cells and aluminum work from my racing days in San Diego.

Aluminum is my first choice But will require a thick bash plate to protect it. PM, me the details of your fabricators!

 

[sk66]

I would add a secondary manual bypass for the pump to allow gravity feed. Nothing would be worse than pushing out too far knowing you have plenty of fuel and then having the pump fail. With the bypass you could still use the fuel; and drain the tank to replace the pump. And are you sure the stock vent will allow you to transfer fuel at that rate w/o creating a vacuum?

 

[Kellyn]

I just became a Long Range America distributor and we're working to get a fully functional L300 kit to the market. I love your progress on the tank!

 

[sck_nogas]

I would add a secondary manual bypass for the pump to allow gravity feed. ... And are you sure the stock vent will allow you to transfer fuel at that rate w/o creating a vacuum?

Agreed. Nice modification. The actual fuel pickup for the tank would mount from the top, like the fuel sender would be. So I'd likely need to add a manual fuel siphon to the bypass. As for the stock vents allowing enough air volume to move the fuel that quickly, will have to see.

I just became a Long Range America distributor and we're working to get a fully functional L300 kit to the market. I love your progress on the tank!

Thanks, I've tried to make it as simple as possible to install and remove. The fewest modifications as possible to allow fully independent control.

That is why I liked the Peel Electronics Pump controller and gauge, so I can see and control the auxiliary fuel level separate from the main fuel tanks, and then used a simple DPDT (On-Off-On) wired to do a reversing polarity connection to the Johnson F4B-19 12v fuel transfer pump. That way I can shut off or switch the pump from suck to blow.

But, I'd love to be a beta tester for Long Range America!

 

[sk66]

Agreed. Nice modification. The actual fuel pickup for the tank would mount from the top, like the fuel sender would be. So I'd likely need to add a manual fuel siphon to the bypass.

Those manual siphons normally incorporate a oneway check valve, so you could probably just replace the ball valve with one. Personally, I think the tank is hanging a bit too low; especially after you install a heavy skid plate to protect it. If it were me, I would sacrifice 3-8 gal of capacity to get it up out of the way more.

 

[Growlerbearnz]

Now I've seen the photos the rear edge of the tank is a bit concerning. My Pajero tank angles up at the back, so if I pop a wheelie (blue line) the first thing to hit the ground will be the tow bar.

What happens if you just slice a wedge off the back, raise that vulnerable rear corner up so it's tucked behind the tow bar?

 

[natematos]

I just became a Long Range America distributor and we're working to get a fully functional L300 kit to the market. I love your progress on the tank!

Been waiting for one of these for a while as a 5spd owner, just wish they weren't so expensive but what can you do haha.

 

[sck_nogas]

Now I've seen the photos the rear edge of the tank is a bit concerning. My Pajero tank angles up at the back, so if I pop a wheelie (blue line) the first thing to hit the ground will be the tow bar.

What happens if you just slice a wedge off the back, raise that vulnerable rear corner up so it's tucked behind the tow bar?

View attachment 8167

That's why I made the foam board model. Will be refining and modifying the design for a few iterations before I'm 100% satisfied.

 

[InstrumentOfPeace]

Would carbon fiber be an option? (May be rhetorical question as I know nil about fuel tanks.) just figuring as you have a foam mockup for one.

 

[sck_nogas]

Would carbon fiber be an option? (May be rhetorical question as I know nil about fuel tanks.) just figuring as you have a foam mockup for one.

Carbon Fiber might be an option, but WAY too expensive and would require a fuel bladder to be legal. Aluminum is easier...

 

[sck_nogas]

Now I've seen the photos the rear edge of the tank is a bit concerning. My Pajero tank angles up at the back, so if I pop a wheelie (blue line) the first thing to hit the ground will be the tow bar.

What happens if you just slice a wedge off the back, raise that vulnerable rear corner up so it's tucked behind the tow bar?

View attachment 8167

Well, After actually getting my 3rd revision of the tank model to fit better.

1. Narrow the front of the tank by 2 inches to allow the shocks to clear easily.
2. Shorten the front of the tank by 3 inches to make sure the rear differential clear easily.
3. Notch the two protrusions under the rear bumper to allow the tank to fit up where I originally intended.... (think I can cut them out when we make the tank)

This is what I've got (so far)


And this is where it fits...




So now the volume is 3.4183 ft³ (theoretical 25½ US Gallon capacity ) and thus it should safely hold between 20-22 gallons.

 

[InstrumentOfPeace]

iView attachment 8295

And this is where it fits...

Irrespective of what’s being put there, the angle of departure would be cutting it a bit close. Jmho

 

[Megerald]

Would you consider a larger tank from abroad? I remember Brown Davis used to make them and a few other companies here?

 

[sck_nogas]

Would you consider a larger tank from abroad? I remember Brown Davis used to make them and a few other companies here?

I would! Do you have links to them?

I have found links to a 105L (27 gallon) replacement tank for the pre-1989 Mitsubishi Express 4WD (MPZR1) as well as the 1989- Mitsubishi Express 2WD (MEX2R2) but I highly doubt either of them will fit a 1991 Automatic Transmission JDM 4WD Delica. (frame vs. unibody)

I have also found options for some spare tire tanks, but they don't have a Delica version either.

 

[sck_nogas]

Well, since it's uncomfortably hot in San Diego right now, I decided to cobble together a quick pump and controller test.

I added a 12v relay for the pump power, since the pump will draw about 12-15 amps when pumping.

Then I shoved the switches into some left over foam board so I could easily control the pump.

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I repurposed some garden hose and a 5 gallon Home Depot bucket for a test, and...

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60 seconds of pump moved 5 gallons from my pool into the bucket, aka 5 GPM! But, I noticed that the pump was causing the hoses to collapse under the vacuum!

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Left side is coming from the pool, right side goes to the bucket. When I manually tried to un-collapse the hoses to put the water back, I was getting about 7-8 GPM.

Interesting detail, the pump controller switch is currently configured to run for 1 minute and then auto shutoff. Or maybe it's because I don't actually have a sender, that the pump controller is thinking the tank is full and thus stops after 60 seconds? (Asking the vendor already)

 

[Megerald]

I would! Do you have links to them?

I have found links to a 105L (27 gallon) replacement tank for the pre-1989 Mitsubishi Express 4WD (MPZR1) as well as the 1989- Mitsubishi Express 2WD (MEX2R2) but I highly doubt either of them will fit a 1991 Automatic Transmission JDM 4WD Delica. (frame vs. unibody)

I have also found options for some spare tire tanks, but they don't have a Delica version either.

What I've found is a lot of Australian manufacturers have stuff but it's never listed. I've found a variety of things from towbars to bullbars which haven't been listed. I'll make a few calls for you

The only reason I came across it was because I saw a towbar for a Mazda MX-5/Eunos Roadster (I think you call them Miata) for sale. I thought it was a fake where someone had just plated it at their shed. Turns out it was real and they did in fact, legally make (and certify) them. The guy I spoke to said only the "newer" catalogue was online.

 

[sck_nogas]

What I've found is a lot of Australian manufacturers have stuff but it's never listed. I've found a variety of things from towbars to bullbars which haven't been listed. I'll make a few calls for you

Thanks! I appreciate the effort.

So far, the fabricator has quoted me approximately $100 in materials, and reasonable ($40) labor rate with no idea how many hours/days he thinks it'll take. I've already asked him to provide a rough guesstimate and will see.

 

[bikerjosh]

Thanks! I appreciate the effort.

So far, the fabricator has quoted me approximately $100 in materials, and reasonable ($40) labor rate with no idea how many hours/days he thinks it'll take. I've already asked him to provide a rough guesstimate and will see.

Nice work. $40/hour sounds great, but 20-30 hours sounds like where a lot of my projects have gone over the years.